JP7398969B2 - Substrate processing method, substrate processing apparatus and storage medium - Google Patents

Description

The present disclosure relates to a substrate processing method, a substrate processing apparatus, and a storage medium.

2. Description of the Related Art Conventionally, an etching process for etching a film formed on a substrate such as a semiconductor wafer has been known as one of the semiconductor manufacturing processes.

Patent No. 5448521 specification

The present disclosure provides a technique that can efficiently etch a substrate having multiple types of films.

A substrate processing method according to one aspect of the present disclosure includes a first etching step, a changing step, and a second etching step. In the first etching step, the substrate having the first film and the second film is etched at a first etching rate. In the changing step, the etching rate is changed from the first etching rate to the second etching rate. In the second etching step, the substrate is etched at a second etching rate.

According to the present disclosure, a substrate having multiple types of films can be efficiently etched.

FIG. 1 is an explanatory diagram of substrate processing according to the first embodiment. FIG. 2 is a diagram showing the configuration of the substrate processing apparatus according to the first embodiment. FIG. 3 is a flowchart showing the procedure of processing executed by the substrate processing apparatus according to the first embodiment. FIG. 4 is an explanatory diagram of the change processing according to the first embodiment. FIG. 5 is an explanatory diagram of substrate processing according to the second embodiment. FIG. 6 is an explanatory diagram of substrate processing according to the third embodiment. FIG. 7 is a diagram showing the configuration of a substrate processing apparatus according to the fourth embodiment. FIG. 8 is a diagram showing the configuration of the first processing tank according to the fourth embodiment. FIG. 9 is a diagram showing the configuration of the second processing tank according to the fourth embodiment.

DESCRIPTION OF EMBODIMENTS Below, embodiments (hereinafter referred to as "embodiments") for implementing a substrate processing method, a substrate processing apparatus, and a storage medium according to the present disclosure will be described in detail with reference to the drawings. Note that this embodiment does not limit the substrate processing method, substrate processing apparatus, and storage medium according to the present disclosure. Moreover, each embodiment can be combined as appropriate within the range that does not conflict with the processing contents. Further, in each of the embodiments below, the same parts are given the same reference numerals, and redundant explanations will be omitted.

In addition, in order to make the explanation easier to understand, each of the drawings referred to below shows an orthogonal coordinate system in which the X-axis direction, Y-axis direction, and Z-axis direction that are orthogonal to each other are defined, and the positive Z-axis direction is the vertically upward direction. There are cases.

(First embodiment)
<About substrate processing according to the first embodiment>
First, the details of substrate processing according to the first embodiment will be explained with reference to FIG. FIG. 1 is an explanatory diagram of substrate processing according to the first embodiment.

As shown in FIG. 1, in the substrate processing according to the first embodiment, for example, a wafer W having a tungsten film 101, a titanium nitride film 102, and a silicon oxide film 103 formed on a polysilicon film 100 is etched. Specifically, the silicon oxide film 103 is formed in multiple layers on the polysilicon film 100 at intervals, and the titanium nitride film 102 is formed around each silicon oxide film 103 so as to cover the silicon oxide film 103. be done. Further, the tungsten film 101 is formed to cover the titanium nitride film 102 and the silicon oxide film 103. Therefore, before the etching process, the titanium nitride film 102 and the silicon oxide film 103 are covered with the tungsten film 101.

In the substrate processing according to the first embodiment, recesses are formed on the wafer W by etching back the tungsten film 101 and the titanium nitride film 102. In the substrate processing according to the first embodiment, a chemical solution containing phosphoric acid (H3PO4), acetic acid (CH3COOH), nitric acid (HNO3), and water (H2O) as components is used as a chemical solution for etching the tungsten film 101 and the titanium nitride film 102. is used.

Specifically, in the substrate processing according to the first embodiment, first, only the tungsten film 101 is etched to expose the titanium nitride film 102 (first etching process). After that, in the substrate processing according to the first embodiment, the tungsten film 101 and the titanium nitride film 102 are simultaneously etched (second etching processing).

In the second etching process in which the tungsten film 101 and the titanium nitride film 102 are etched simultaneously, the selection ratio between the tungsten film 101 and the titanium nitride film 102 is preferably 1:1. However, if a series of treatments is performed using a chemical solution containing the plurality of components described above at a selection ratio of 1:1, the time required to etch the tungsten film 101 in the first etching process may become longer. , and it is not efficient.

Therefore, in the substrate processing according to the first embodiment, the first etching process is performed using a chemical solution in which each component is mixed at a mixing ratio such that the selection ratio of the tungsten film 101 to the titanium nitride film 102 is greater than 1. And so. Thereby, the etching rate of the tungsten film 101 in the first etching process can be made higher than the etching rate of the tungsten film 101 when the first etching process is performed using a chemical solution with a selectivity of 1:1. . Therefore, the tungsten film 101 can be etched in a short time in the first etching process. In other words, the processing time of the first etching process can be shortened.

Subsequently, in the substrate processing according to the first embodiment, a changing process for changing the etching rate of the tungsten film 101 is performed. Specifically, in the substrate processing according to the first embodiment, the etching rate of the tungsten film 101 is lowered by changing the blending ratio of each component in the chemical solution, and the selection between the tungsten film 101 and the titanium nitride film 102 is improved. Make the ratio 1:1.

Here, the inventor of the present application has found that the etching rate of the tungsten film 101 and the titanium nitride film 102, especially the etching rate of the tungsten film 101, increases as the proportion of water in the chemical solution increases compared to other components of the chemical solution. This was discovered through experiments. Therefore, in the substrate processing according to the first embodiment, the tungsten film 101 is The etching rate was lowered. Details of this point will be described later.

In the substrate processing according to the first embodiment, the modification processing may be completed before the first etching processing is completed, that is, before the titanium nitride film 102 is exposed from the tungsten film 101.

Thereafter, in the substrate processing according to the first embodiment, a second etching process is performed in which the tungsten film 101 and the titanium nitride film 102 are etched simultaneously. The selection ratio between the tungsten film 101 and the titanium nitride film 102 is changed to 1:1 by a changing process before the start of the second etching process. Therefore, in the substrate processing according to the first embodiment, the tungsten film 101 and the titanium nitride film 102 can be etched at the same etching rate in the second etching processing. Therefore, recesses can be formed on the wafer W with high precision.

In this manner, in the substrate processing according to the first embodiment, the tungsten film 101 is etched at the first etching rate in the first etching process. Further, in the substrate processing according to the first embodiment, the etching rate of the tungsten film 101 is lowered from the first etching rate to the second etching rate, so that the selection ratio of the tungsten film 101 and the titanium nitride film 102 is set to 1:1. change. Then, in the substrate processing according to the first embodiment, a second etching process is performed in which the tungsten film 101 and the titanium nitride film 102 are etched at a selection ratio of 1:1.

Therefore, according to the substrate processing according to the first embodiment, the wafer W having multiple types of films can be efficiently etched.

<Configuration of substrate processing equipment>
Next, the configuration of a substrate processing apparatus that performs the above-described substrate processing will be described with reference to FIG. 2. FIG. 2 is a diagram showing the configuration of the substrate processing apparatus according to the first embodiment.

In the substrate processing apparatus 1 shown in FIG. 2, etching processing is performed on a plurality of wafers W at once by immersing the plurality of wafers W held in a vertical posture in a chemical solution. As described above, a chemical solution containing phosphoric acid, acetic acid, nitric acid, and water is used for the etching process, and the tungsten film 101 and the titanium nitride film 102 are etched by this etching process.

As shown in FIG. 2, the substrate processing apparatus 1 according to the first embodiment includes a processing tank 10, a substrate holding section 20, a chemical supply section 30, a circulation section 40, an individual supply section 50, and a control device 60. Equipped with.

(processing tank)
The processing tank 10 includes an inner tank 11 and an outer tank 12. The inner tank 11 is a box-shaped tank with an open top, and stores a chemical solution therein. A lot formed by a plurality of wafers W is immersed in the inner tank 11. The outer tank 12 is open at the top and is arranged around the upper part of the inner tank 11. The chemical solution overflowing from the inner tank 11 flows into the outer tank 12 .

(Substrate holding part 20)
The substrate holding unit 20 holds a plurality of wafers W in a vertical position (vertical state). Further, the substrate holding unit 20 holds a plurality of wafers W in a state where they are arranged at regular intervals in the horizontal direction (here, the Y-axis direction). The substrate holder 20 is connected to a lifting mechanism (not shown), and can move the plurality of wafers W between a processing position inside the processing tank 10 and a standby position above the processing tank 10.

(Medical solution supply section 30)
The chemical liquid supply unit 30 includes a chemical liquid supply source 31 , a chemical liquid supply line 32 , and a first valve 33 . The chemical solution supply source 31 supplies a chemical solution containing phosphoric acid, acetic acid, nitric acid, and water as components. Specifically, the chemical liquid supply source 31 supplies a chemical liquid in which each component is mixed at a mixing ratio such that the selectivity of the tungsten film 101 to the titanium nitride film 102 is greater than 1. In other words, the chemical liquid supply source 31 supplies a chemical liquid in which each component is mixed at a mixing ratio that etches the tungsten film 101 at the first etching rate (>second etching rate).

The chemical liquid supply line 32 is connected to the chemical liquid supply source 31 and supplies the chemical liquid from the chemical liquid supply source 31 to the outer tank 12 of the processing tank 10 . The first valve 33 is provided in the chemical liquid supply line 32 and opens and closes the chemical liquid supply line 32 . The first valve 33 is electrically connected to a control section 61, which will be described later, and is controlled to open and close by the control section 61.

(circulation section 40)
The circulation unit 40 circulates the chemical solution between the inner tank 11 and the outer tank 12. The circulation unit 40 includes a circulation line 41 , a plurality of chemical solution supply nozzles 42 , a pump 43 , a heater 44 , a concentration meter 45 , and a filter 46 . Further, the circulation section 40 includes a drain line 47 and a second valve 48 .

The circulation line 41 connects the outer tank 12 and the inner tank 11. One end of the circulation line 41 is connected to the outer tank 12 , and the other end of the circulation line 41 is connected to a plurality of chemical solution supply nozzles 42 arranged inside the inner tank 11 .

A pump 43, a heater 44, a concentration meter 45, and a filter 46 are provided in the circulation line 41. Pump 43 sends out the chemical solution in outer tank 12 to circulation line 41 . The heater 44 heats the chemical liquid flowing through the circulation line 41 to a temperature suitable for etching processing. The concentration meter 45 measures the concentration of the chemical solution flowing through the circulation line 41. Specifically, the concentration meter 45 measures the concentration of each component of the chemical solution, that is, phosphoric acid, acetic acid, nitric acid, and water. Note that the circulation unit 40 includes a plurality of densitometers, specifically, a densitometer that measures the concentration of phosphoric acid, a densitometer that measures the concentration of acetic acid, a densitometer that measures the concentration of nitric acid, and a densitometer that measures the concentration of water. It may also be equipped with a densitometer. The filter 46 removes impurities from the chemical liquid flowing through the circulation line 41.

The drain line 47 is a flow path branching from the circulation line 41 between the concentration meter 45 and the filter 46, and discharges the chemical liquid flowing through the circulation line 41 to the outside of the substrate processing apparatus 1. Note that the discharged chemical solution is heated by a heater 44. For this reason, the drain line 47 may be provided with a cooling section that cools the heated chemical solution. The second valve 48 is provided in the drain line 47 and opens and closes the drain line 47 .

The chemical liquid stored in the outer tank 12 is supplied to the inner tank 11 from a plurality of chemical liquid supply nozzles 42 through a circulation line 41 . The chemical solution supplied to the inner tank 11 overflows from the inner tank 11 and flows out into the outer tank 12 again. In this way, the chemical solution circulates between the inner tank 11 and the outer tank 12.

The pump 43, the heater 44, and the second valve 48 are electrically connected to and controlled by the control section 61. Further, the concentration meter 45 is electrically connected to the control section 61 and outputs the concentration measurement result to the control section 61.

(Individual supply section 50)
The individual supply unit 50 includes a water supply source 51a, a phosphoric acid supply source 51b, an acetic acid supply source 51c, a nitric acid supply source 51d, a water supply line 52a, a phosphoric acid supply line 52b, an acetic acid supply line 52c, It includes a nitric acid supply line 52d and third to sixth valves 53a to 53d.

The water supply source 51a supplies water. The water supplied from the water supply source 51a is, for example, deionized water. The water supply line 52a is connected to the water supply source 51a, and supplies water from the water supply source 51a to the outer tank 12 of the processing tank 10. The third valve 53a is provided in the water supply line 52a, and opens and closes the water supply line 52a. The third valve 53a is electrically connected to the control section 61, and is controlled to open and close by the control section 61.

The phosphoric acid supply source 51b supplies phosphoric acid. The phosphoric acid supply line 52b is connected to the phosphoric acid supply source 51b, and supplies phosphoric acid from the phosphoric acid supply source 51b to the outer tank 12. The fourth valve 53b is provided in the phosphoric acid supply line 52b, and opens and closes the phosphoric acid supply line 52b. The fourth valve 53b is electrically connected to the control section 61, and is controlled to open and close by the control section 61.

The acetic acid supply source 51c supplies acetic acid. The acetic acid supply line 52c is connected to the acetic acid supply source 51c, and supplies acetic acid from the acetic acid supply source 51c to the outer tank 12. The fifth valve 53c is provided in the acetic acid supply line 52c, and opens and closes the acetic acid supply line 52c. The fifth valve 53c is electrically connected to the control section 61, and is controlled to open and close by the control section 61.

The nitric acid supply source 51d supplies nitric acid. The nitric acid supply line 52d is connected to the nitric acid supply source 51d, and supplies nitric acid from the nitric acid supply source 51d to the outer tank 12. The sixth valve 53d is provided on the nitric acid supply line 52d, and opens and closes the nitric acid supply line 52d. The sixth valve 53d is electrically connected to the control section 61, and is controlled to open and close by the control section 61.

The third valve 53a to the sixth valve 53d are electrically connected to the control section 61, and are controlled to open and close by the control section 61.

(Control device 60)
The control device 60 is, for example, a computer, and includes a control section 61 and a storage section 62. The storage unit 62 is realized by, for example, a semiconductor memory element such as a RAM or a flash memory, or a storage device such as a hard disk or an optical disk, and stores programs that control various processes executed in the substrate processing apparatus 1. Remember. The control unit 61 includes a microcomputer and various circuits having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), input/output ports, etc., and executes programs stored in the storage unit 62. The operation of the substrate processing apparatus 1 is controlled by reading and executing the command.

Note that this program may be one that has been recorded on a computer-readable storage medium, and may be one that is installed into the storage unit 62 of the control device 60 from the storage medium. Examples of computer-readable storage media include hard disks (HD), flexible disks (FD), compact disks (CD), magnetic optical disks (MO), and memory cards.

(Specific operation of substrate processing apparatus 1)
Next, specific operations of the substrate processing apparatus 1 according to the first embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a flowchart showing the procedure of processing executed by the substrate processing apparatus 1 according to the first embodiment. FIG. 4 is an explanatory diagram of the change processing according to the first embodiment.

As shown in FIG. 3, a first etching process is performed in the substrate processing apparatus 1 (step S101). In the first etching process, the control unit 61 controls a substrate transport device (not shown) that transports the plurality of wafers W, and transfers the plurality of wafers W to the substrate holding unit 20. Thereafter, the control unit 61 controls an unillustrated lifting mechanism to lower the substrate holding unit 20, thereby immersing the plurality of wafers W in the chemical solution stored in the processing tank 10.

In the first etching process, the chemical liquid supplied from the chemical liquid supply unit 30, that is, each component is mixed in the processing tank 10 at a mixing ratio such that the selectivity of the tungsten film 101 to the titanium nitride film 102 is greater than 1. The chemical solution is stored. As a result, the tungsten film 101 formed on the plurality of wafers W is etched in a short time at the first etching rate which is higher than the second etching rate which is the etching rate of the tungsten film 101 in the second etching process to be described later. Ru.

As shown in FIG. 4, in the first etching process, the control unit 61 controls the third valve 53a of the water supply line 52a, the fifth valve 53c of the acetic acid supply line 52c, and the nitric acid supply based on the measurement results of the concentration meter 45, for example. Opening/closing control of the sixth valve 53d of the line 52d is performed. As a result, the treatment tank 10 is replenished with water, acetic acid, and nitric acid, so that the concentration of the chemical solution in the treatment tank 10 is kept constant.

Subsequently, the control unit 61 determines, for example, whether a preset time has elapsed since the first etching process was started (step S102). The above-mentioned "preset time" is, for example, longer than the time required for the first etching process minus the time required to change the etching rate of the tungsten film 101 from the first etching rate to the second etching rate. set for a short time. The control unit 61 repeats the determination process in step S102 until the set time has elapsed (step S102, No).

On the other hand, if it is determined in step S102 that the set time has elapsed (step S102, Yes), the control unit 61 starts the change process (step S103).

In the change process, the control unit 61 opens the second valve 48 to discharge the chemical liquid flowing through the circulation line 41 from the drain line 47 to the outside of the substrate processing apparatus 1 . Further, the control unit 61 closes the third valve 53a and the fifth valve 53c to stop the supply of water and acetic acid to the processing tank 10, and opens the fourth valve 53b and the sixth valve 53d to stop the supply of water and acetic acid to the processing tank 10. Phosphoric acid and nitric acid are supplied to tank 10.

By stopping the supply of water to the processing tank 10, the water concentration of the chemical solution stored in the processing tank 10 decreases. As a result, the etching rate of the tungsten film 101 decreases from the first etching rate to the second etching rate, and the selection ratio between the tungsten film 101 and the titanium nitride film 102 is changed to 1:1.

In this manner, in the substrate processing apparatus 1, the etching rate of the tungsten film 101 is lowered from the first etching rate to the second etching rate by changing the compounding ratio of the plurality of components contained in the chemical solution. As a result, in the first etching process, the tungsten film 101 is etched at the first etching rate in a short time, and in the second etching process, the tungsten film 101 and the titanium nitride film 102 are etched at a selection ratio of 1:1. I can do it.

Furthermore, in the substrate processing apparatus 1, the etching rate of the tungsten film 101 is lowered from the first etching rate to the second etching rate by reducing the mixing ratio of water among the plurality of components contained in the chemical solution. As described above, the etching rate of the tungsten film 101 tends to increase as the proportion of water increases compared to other components of the chemical solution. Therefore, by reducing the mixing ratio of water, the etching rate of the tungsten film 101 can be reduced in a shorter time than when changing the mixing ratio of other components.

Furthermore, in the substrate processing apparatus 1, a part of the chemical solution is discharged from the processing tank 10, and a new solution (here, a chemical solution containing phosphoric acid and nitric acid) containing less water than the discharged chemical solution is added to the processing tank 10. The etching rate of the tungsten film 101 was lowered by supplying the tungsten film 101 to the tungsten film 101. In this way, by discharging the chemical solution with a high water concentration from the processing tank 10, the mixing ratio of water can be reduced in a shorter time. That is, the etching rate of the tungsten film 101 can be reduced in a shorter time.

Subsequently, a second etching process is performed in the substrate processing apparatus 1 (step S104). In the second etching process, a chemical solution that etches the tungsten film 101 and the titanium nitride film 102 at a selection ratio of 1:1 is supplied to the wafer W in which the tungsten film 101 and the titanium nitride film 102 are exposed. As a result, the tungsten film 101 and the titanium nitride film 102 are etched at the same etching rate (second etching rate). After finishing the second etching process, the control unit 61 ends the series of substrate processes.

As shown in FIG. 4, in the second etching process, the control unit 61 controls the opening and closing of the third valve 53a, the fifth valve 53c, and the sixth valve 53d, as in the first etching process. , the concentration of the chemical solution in the processing tank 10 is kept constant.

(Second embodiment)
Next, substrate processing according to the second embodiment will be described with reference to FIG. 5. FIG. 5 is an explanatory diagram of substrate processing according to the second embodiment. As shown in FIG. 5, in the substrate processing according to the second embodiment, the temperature of the chemical solution is lowered in the change processing. This reduces the etching rate of the tungsten film 101 and the titanium nitride film 102 from the first etching rate R1 in the first etching process to the second etching rate R2 in the second etching process.

The chemical solution has temperature dependence, and as the temperature of the chemical solution increases, the etching rate of the tungsten film 101 and the titanium nitride film 102 tends to increase. Therefore, in the first etching process before the change process, the tungsten film 101 is etched at the relatively high first etching rate R1 by supplying the chemical solution at the first temperature T1, which is relatively high, to the wafer W. I can do it. That is, in the first etching process, the tungsten film 101 can be etched in a relatively short time.

Further, in the second etching process after the change process, a chemical solution having a second temperature T2 lower than the first temperature T1 is supplied to the wafer W. Therefore, the tungsten film 101 and the titanium nitride film 102 are etched at a second etching rate R2 lower than the first etching rate R1. This prevents, for example, the tungsten film 101 and the titanium nitride film 102 from being excessively etched in the second etching process. Moreover, surface roughness of the tungsten film 101 and the titanium nitride film 102 after the second etching process can be suppressed.

In this manner, the substrate processing according to the second embodiment changes the etching rate to the first etching rate by changing the temperature of the chemical solution from the first temperature T1 to the second temperature T2 lower than the first temperature T1 in the changing process. The etching rate is lowered from the rate R1 to the second etching rate R2. Therefore, according to the substrate processing according to the second embodiment, the processing time of the first etching process can be shortened, and the processing accuracy of the second etching process can be improved. Note that the temperature difference between the first temperature T1 and the second temperature T2 is, for example, about 5° C. or less. The substrate processing apparatus 1 may include a temperature measuring section that measures the temperature of the chemical solution in the processing tank 10 or the circulation section 40, and the control section 61 controls the temperature of the chemical solution based on the measurement result of the temperature measuring section. It's okay.

In addition, the inventor of the present application found that the change in the selectivity between the tungsten film 101 and the titanium nitride film 102 is small with respect to changes in the chemical temperature. In this way, even if the temperature of the chemical solution is changed, the selectivity between the tungsten film 101 and the titanium nitride film 102 hardly changes. Therefore, for example, in order to maintain the selectivity ratio of 1:1, the mixing ratio of the chemical solution is changed. The selection ratio can be easily controlled without requiring such effort.

In the second embodiment, the chemical liquid supply source 31 of the chemical liquid supply unit 30 supplies a chemical liquid in which each component is blended so that the selection ratio between the tungsten film 101 and the titanium nitride film 102 is 1:1. As a result, in the second embodiment, a chemical solution with a selectivity ratio of 1:1 between the tungsten film 101 and the titanium nitride film 102 is stored in the processing tank 10.

Further, the control unit 61 according to the second embodiment can reduce the temperature of the chemical solution stored in the processing tank 10 by, for example, stopping the heater 44 in the change processing. However, the present invention is not limited to this, and the substrate processing apparatus 1 according to the second embodiment may include a cooling section (not shown) in the circulation line 41. In this case, in the change process, the control unit 61 may reduce the temperature of the chemical solution stored in the processing tank 10 by stopping the heater 44 and operating a cooling unit (not shown). By actively cooling the chemical solution using the cooling unit, the time required for the change process can be shortened. As the cooling section, for example, a cooling coil, a cooling jacket, etc. can be used.

In addition, in the changing process according to the first embodiment, the control unit 61 may change the temperature of the chemical liquid as in the changing process according to the second embodiment by controlling the heater 44 and a cooling unit (not shown). Thereby, for example, the time required for the first etching process can be further shortened. Moreover, the processing accuracy in the second etching process can be further improved.

(Third embodiment)
Next, substrate processing according to the third embodiment will be described with reference to FIG. 6. FIG. 6 is an explanatory diagram of substrate processing according to the third embodiment.

When the first etching process and the second etching process are performed, metals such as tungsten contained in the tungsten film 101 and titanium contained in the titanium nitride film 102 dissolve into the chemical solution, so that the metal concentration of the chemical solution gradually decreases. Rise. When etching is performed using a chemical solution with a high metal concentration, for example, there is a risk that the etching rate may fluctuate or the electrical characteristics of the product wafer may be affected. Therefore, it is preferable to suppress the increase in the metal concentration of the chemical solution.

Here, it is possible to suppress the increase in metal concentration by draining all the chemical solution in the processing tank 10 and replacing it with a new chemical solution that does not contain metals every time a series of substrate processing is completed. be. However, such a method is not preferable from the viewpoint of reducing the amount of chemical liquid used or the time required for exchanging the chemical liquid.

Therefore, as shown in FIG. 6, the control unit 61 performs a metal concentration suppression process to suppress an increase in the metal concentration of the chemical solution so that the metal concentration of the chemical solution does not exceed the threshold value TH during a series of substrate processing. good.

Specifically, during a series of substrate processing, the control unit 61 discharges a portion of the chemical solution in the processing tank 10 from the drain line 47, and supplies a new chemical solution containing no metal to the chemical solution supply unit 30. from there to the processing tank 10. In this way, during a series of substrate processing, by replacing part of the chemical solution that contains metal with a new chemical solution that does not contain metal, it is possible to suppress the increase in the metal concentration of the chemical solution. . Since such metal concentration suppression processing is performed during a series of substrate processing, the time required for chemical solution exchange can be shortened. Furthermore, by replacing some, but not all, of the chemical solution with a new solution, the amount of chemical solution used can be suppressed.

For example, the control unit 61 may start the metal suppression process when a preset time has elapsed since the first etching process was started. Here, the "preset time" is, for example, the time until the metal concentration of the chemical solution in the processing tank 10 reaches the threshold value TH from 0 ppm, and is calculated in advance through experiments or the like. Note that a series of substrate treatments may be started from a state in which a chemical solution containing a metal (a chemical solution whose metal concentration is the threshold value TH) is stored in the processing tank 10. In this case, the control unit 61 may start the metal suppression process simultaneously with the first etching process.

Furthermore, the rate of change in metal concentration over time can be determined by the above-mentioned experiments and the like. Based on this information, the control unit 61 controls the second valve 48 and the first valve 33 to appropriately replace the chemical solution so that the metal concentration of the chemical solution falls within a threshold range centered on the threshold value TH. It can be done in the right amount and at the right time.

(Fourth embodiment)
In the embodiment described above, the first etching treatment and the second etching treatment are performed in one treatment tank 10, but the first etching treatment and the second etching treatment may be performed in different treatment tanks. good. FIG. 7 is a diagram showing the configuration of a substrate processing apparatus according to the fourth embodiment.

As shown in FIG. 7, a substrate processing apparatus 1A according to the fourth embodiment includes a first etching processing apparatus 70, a second etching processing apparatus 80, and a transport apparatus 90.

The first etching processing apparatus 70 includes a processing tank 71 for first etching processing (hereinafter referred to as "first processing tank 71") and a substrate lifting mechanism 72. Further, the second etching processing apparatus 80 includes a processing tank 81 for second etching processing (hereinafter referred to as "second processing tank 81") and a substrate lifting mechanism 82.

The processing tanks 71 and 81 can accommodate one lot of wafers W. The first treatment tank 71 stores a chemical liquid whose etching rate is a first etching rate (hereinafter referred to as "first chemical liquid"). Further, a chemical solution having a second etching rate (hereinafter referred to as "second chemical solution") is stored in the second processing tank 81.

The substrate lifting and lowering mechanisms 72 and 82 transfer lots to and from a transport device 90, which will be described later. Further, the substrate lifting mechanisms 72 and 82 lower the lot to immerse the lot in the processing tanks 71 and 81. Further, the substrate lifting mechanisms 72 and 82 lift the lots from the processing tanks 71 and 81 by raising the lots.

The first etching processing apparatus 70 performs a first etching process by immersing the lot in a first chemical solution stored in a first processing tank 71 . Further, the second etching processing apparatus 80 performs the second etching processing by immersing the lot in the second chemical solution stored in the second processing tank 81 .

The transport device 90 transports the lot between the first etching processing device 70 and the second etching processing device 80. The transport device 90 includes a rail 91, a moving body 92, and a substrate holder 93. The rail 91 extends along the direction in which the first etching processing device 70 and the second etching processing device 80 are arranged. The moving body 92 is configured to be movable along the rails 91 while holding a plurality of wafers W. The substrate holder 93 is provided on the movable body 92 and holds a plurality of wafers W lined up one after the other in an upright position.

Next, the configurations of the first processing tank 71 and the second processing tank 81 will be explained with reference to FIGS. 8 and 9. FIG. 8 is a diagram showing the configuration of the first processing tank 71 according to the fourth embodiment. Moreover, FIG. 9 is a diagram showing the configuration of the second processing tank 81 according to the fourth embodiment.

As shown in FIG. 8, the first processing tank 71 includes an inner tank 11 and an outer tank 12, like the processing tank 10 described above (see FIG. 2).

The first processing tank 71 includes a circulation section 40A. The circulation unit 40A circulates the processing liquid between the inner tank 11 and the outer tank 12. The circulation section 40A includes a circulation path 41, a nozzle 42, a pump 43, a filter 46, and a temperature adjustment section 49.

The circulation path 41 connects the inner tank 11 and the outer tank 12. One end of the circulation path 41 is connected to the outer tank 12 , and the other end of the circulation path 41 is connected to a nozzle 42 arranged inside the inner tank 11 .

Pump 43, filter 46, and temperature adjustment section 49 are provided in circulation path 41. Pump 43 sends out the first chemical solution in outer tank 12 to circulation path 41 . The filter 46 removes impurities from the first chemical solution flowing through the circulation path 41 .

The temperature adjustment unit 49 is, for example, a heater or an electronic thermostat, and adjusts the temperature of the first chemical solution flowing through the circulation path 41 to a set temperature. Pump 43 and temperature adjustment section 49 are controlled by control section 61.

Further, the first processing tank 71 includes a first chemical supply section 30A. The first chemical liquid supply section 30A includes a first chemical liquid supply source 31A, a first chemical liquid supply line 32A, a first valve 33A, and a first switching section 34A.

The first chemical liquid supply source 31A supplies the first chemical liquid. The first chemical solution is a chemical solution containing phosphoric acid, acetic acid, nitric acid, and water as components, and has a mixing ratio that etches the tungsten film 101 (see FIG. 1) at the first etching rate (>second etching rate). It is a medicinal solution containing various ingredients.

The first chemical supply line 32A is connected to the first chemical supply source 31A, and supplies the first chemical supplied from the first chemical supply source 31A to the inner tank 11 or outer tank 12 of the first processing tank 71. The first valve 33A is provided in the first chemical liquid supply line 32A, and opens and closes the first chemical liquid supply line 32A. The first switching unit 34A is provided in the first chemical supply line 32A, and switches the destination of the first chemical flowing through the first chemical supply line 32A between the inner tank 11 and the outer tank 12.

The first valve 33A and the first switching section 34A are electrically connected to and controlled by the control section 61. For example, when storing the first chemical solution in the empty first processing tank 71, the control unit 61 controls the first valve 33A and the first switching unit 34A to supply the first chemical solution supply source 31A to the inner tank. 11, a new first chemical solution is supplied. Further, when replenishing the first chemical solution to the first processing tank 71, the control unit 61 controls the first valve 33A and the first switching unit 34A to supply the first chemical solution supply source 31A to the outer tank. 12, a new first chemical solution is supplied.

Further, the first processing tank 71 includes an individual supply section 50A. In addition to the configuration of the individual supply section 50 described above, the individual supply section 50A further includes a third switching section 54a to a sixth switching section 54d. The third switching unit 54a is provided in the water supply line 52a and switches the destination of the water flowing through the water supply line 52a between the inner tank 11 and the outer tank 12. The fourth switching unit 54b is provided in the phosphoric acid supply line 52b, and switches the destination of the phosphoric acid flowing through the phosphoric acid supply line 52b between the inner tank 11 and the outer tank 12.

The fifth switching unit 54c is provided in the acetic acid supply line 52c, and switches the destination of acetic acid flowing through the acetic acid supply line 52c between the inner tank 11 and the outer tank 12. The sixth switching unit 54d is provided in the nitric acid supply line 52d, and switches the destination of the nitric acid flowing through the nitric acid supply line 52d between the inner tank 11 and the outer tank 12.

In addition to the configuration of the individual supply section 50 described above, the individual supply section 50A further includes a third flow rate adjustment section 55a to a sixth flow rate adjustment section 55d. The third flow rate adjustment section 55a to the sixth flow rate adjustment section 55d are configured to include a flow rate adjustment valve, a flow meter, and the like.

The third flow rate adjustment section 55a is provided in the water supply line 52a and adjusts the flow rate of water supplied to the inner tank 11 or the outer tank 12. The fourth flow rate adjustment section 55b is provided in the phosphoric acid supply line 52b, and adjusts the flow rate of phosphoric acid supplied to the inner tank 11 or the outer tank 12. The fifth flow rate adjustment section 55c is provided in the acetic acid supply line 52c, and adjusts the flow rate of acetic acid supplied to the inner tank 11 or the outer tank 12. The sixth flow rate adjustment section 55d is provided in the nitric acid supply line 52d, and adjusts the flow rate of nitric acid supplied to the inner tank 11 or the outer tank 12.

The third valve 53a to the sixth valve 53d, the third switching section 54a to the sixth switching section 54d, and the third flow rate adjustment section 55a to the sixth flow rate adjustment section 55d are electrically connected to the control section 61 and are controlled. Opening/closing is controlled by section 61.

For example, when storing a new first chemical solution in the empty first processing tank 71, the control unit 61 controls the third valve 53a to the sixth valve 53d and the third switching unit 54a to the sixth switching unit 54d. Then, water, phosphoric acid, acetic acid and nitric acid are supplied to the inner tank 11. Further, when replenishing the first chemical solution to the first processing tank 71, the control unit 61 controls the third valve 53a to the sixth valve 53d, the third switching unit 54a to the sixth switching unit 54d, Water, phosphoric acid, acetic acid and nitric acid are supplied to the outer tank 12.

Next, the configuration of the second processing tank 81 will be explained. As shown in FIG. 9, the second processing tank 81 includes the same inner tank 11, outer tank 12, and circulation section 40A as the first processing tank 81 described above.

Further, the second processing tank 81 includes a second chemical supply section 30B. The second chemical liquid supply section 30B includes a second chemical liquid supply source 31B, a second chemical liquid supply line 32B, and a first valve 33B.

The second chemical liquid supply source 31B supplies the second chemical liquid. The second chemical solution is a chemical solution containing phosphoric acid, acetic acid, nitric acid, and water as components, and each component is mixed at a mixing ratio that etches the tungsten film 101 at a second etching rate (<first etching rate). It is a chemical solution.

The second chemical supply line 32B is connected to the second chemical supply source 31B, and supplies the second chemical from the second chemical supply source 31B to the inner tank 11 or outer tank 12 of the second processing tank 81. The first valve 33B is provided in the second chemical liquid supply line 32B, and opens and closes the second chemical liquid supply line 32B. The first switching unit 34B is provided in the second chemical supply line 32B, and switches the destination of the second chemical flowing through the second chemical supply line 32B between the inner tank 11 and the outer tank 12. The first valve 33B and the first switching section 34B are electrically connected to and controlled by the control section 61.

Further, the second processing tank 81 includes an individual supply section 50B. Since the individual supply section 50B has the same configuration as the above-mentioned individual supply section 50A, a description thereof will be omitted here.

In the substrate processing apparatus 1A according to the fourth embodiment, first, a first etching process is performed in the first processing tank 71. In the first etching process, the plurality of wafers W are lowered using the substrate lifting mechanism 72 to immerse the plurality of wafers W in the first chemical solution stored in the inner tank 11 of the first processing tank 71 .

Subsequently, in the substrate processing apparatus 1A, a transport process is performed to transport the plurality of wafers W that have undergone the first etching process to the second processing tank 81. In the transport process, first, the plurality of wafers W are pulled up from the first processing tank 71 by raising the substrate lifting mechanism 72 . Thereafter, a plurality of wafers W are transferred from the substrate lifting mechanism 72 to the transport device 90. Subsequently, the transport device 90 moves from the first processing device 71 to the second processing device 81 and transfers the held plurality of wafers W to the substrate lifting mechanism 82.

Subsequently, in the substrate processing apparatus 1A, a second etching process is performed in the second processing tank 81. In the second etching process, the plurality of wafers W are lowered by the substrate lifting mechanism 82 and immersed in the second chemical solution stored in the inner tank 11 of the second processing tank 81 .

In this way, the first etching process and the second etching process may be performed in different processing tanks (the first processing tank 71 and the second processing tank 81).

(Other embodiments)
In the embodiment described above, an example has been described in which the first film is the tungsten film 101, but the first film does not necessarily need to be the tungsten film 101. For example, the first film may be a molybdenum film, an osmium film, an iridium film, a ruthenium film, a rhodium film, a copper film, or a nickel film. In this way, according to the substrate processing according to the embodiment, a substrate having a first film and a second film other than the tungsten film 101, such as a molybdenum film, can be efficiently etched.

When the first film is a molybdenum film, the temperature of the chemical solution (the first chemical solution and the second chemical solution) is preferably at room temperature (for example, 20° C.±10° C.) or lower. Molybdenum falls under the category of base metals, has a high tendency to ionize, and is relatively easily oxidized. Therefore, by using a chemical solution at room temperature or lower, it is possible to prevent the molybdenum film from being excessively etched due to the etching rate of the molybdenum film becoming too high.

When the first film is a molybdenum film and the etching rate of the chemical is changed by lowering the temperature of the chemical as in the second embodiment, the control unit 61 changes the temperature of the chemical from, for example, 25°C to 20°C. It may be lowered to Further, the control unit 61 may lower the temperature of the chemical solution from room temperature (for example, 25°C) to a temperature below room temperature (for example, 5°C). In this way, by lowering the temperature of the chemical solution to a temperature below room temperature, the etching rate of the molybdenum film can be further slowed down.

When the first film is a molybdenum film, the treatment tank 10 does not necessarily need to include a water supply system (water supply source 51a, water supply line 52a, and third valve 53a). The same applies to the first processing tank 71 and the second processing tank 81.

Further, in the above-described embodiment, an example in which the second film is the titanium nitride film 102 has been described, but the second film is not limited to the titanium nitride film 102. For example, the second film may be a tantalum nitride film. According to the substrate processing according to the embodiment, a substrate having a second film and a first film that are either a titanium nitride film or a tantalum nitride film can be efficiently etched.

The type of film formed on the wafer W is not limited to the example of the embodiment described above. For example, in the first and second embodiments, a case has been described in which a chemical liquid containing a plurality of components is used, but the chemical liquid may be a chemical liquid containing only a single component such as hydrofluoric acid. Further, in the first and second embodiments described above, an example was given in which one film is covered with the other film, but a plurality of films may be exposed.

In the embodiment described above, an example was described in which the etching rate in the second etching process (second etching rate) is lower than the etching rate in the first etching process (first etching rate). However, the present invention is not limited to this, and the etching rate in the second etching process (second etching rate) may be higher than the etching rate in the first etching process (first etching rate). For example, after etching an unnecessary step in a certain film among a plurality of films with high accuracy in a first etching process, it may be desired to etch a plurality of films in a short time in a second etching process. In such a case, it is preferable that the etching rate in the second etching process (second etching rate) is higher than the etching rate in the first etching process (first etching rate).

Furthermore, in the embodiment described above, an example has been described in which a plurality of wafers W are etched at once by immersing the plurality of wafers W in a chemical solution stored in the processing tank 10. For example, the wafer W may be held by a holding part that rotatably holds one wafer W, and a chemical solution may be supplied to the rotating wafer W from a nozzle arranged above the holding part. The wafer W may be etched by etching.

Further, in the above-described embodiment, an example was described in which so-called wet etching is performed in which the wafer W is etched using a chemical solution, but the method of etching the wafer W is not limited to wet etching, and may be dry etching. Good too.

As described above, the substrate processing method according to the embodiment includes a first etching process (for example, first etching process), a changing process (for example, changing process), and a second etching process (for example, first etching process). 2 etching treatment). In the first etching step, a substrate (eg, a wafer W) having a first film (eg, tungsten film 101) and a second film (eg, titanium nitride film 102) is etched at a first etching rate. In the changing step, the etching rate is changed from the first etching rate to the second etching rate. In the second etching step, the substrate is etched at a second etching rate.

Thereby, for example, by making the second etching rate lower than the first etching rate, it is possible to shorten the processing time in the first etching process and improve the processing accuracy of the second etching process. Therefore, according to the substrate processing method according to the embodiment, a substrate having multiple types of films can be efficiently etched.

The second etching rate may be lower than the first etching rate. Thereby, it is possible to shorten the processing time in the first etching process and improve the processing accuracy of the second etching process.

In the first etching step and the second etching step, the substrate may be etched by supplying a chemical solution containing a plurality of components (for example, phosphoric acid, acetic acid, nitric acid, and water) to the substrate. In this case, the changing step may reduce the etching rate from the first etching rate to the second etching rate by changing the blending ratio of a plurality of components. In this way, the etching rate can be changed by changing the blending ratio of multiple components in the chemical solution.

The first film may be any one of a tungsten film (for example, the tungsten film 101), a molybdenum film, an osmium film, an iridium film, a ruthenium film, a rhodium film, a copper film, and a nickel film; may be either a titanium nitride film (for example, the titanium nitride film 102) or a tantalum nitride film. Moreover, the chemical solution may contain phosphoric acid, acetic acid, nitric acid, and water. In this case, the changing step may reduce the etching rate of the tungsten film from the first etching rate to the second etching rate by reducing the mixing ratio of water in the chemical solution.

In this manner, by lowering the blending ratio of water in the chemical solution, the etching rate of the first film can be reduced in a shorter time than when changing the blending ratio of other components.

In the first etching step and the second etching step, the substrate may be etched by immersing the substrate in a chemical solution stored in a processing tank (for example, the processing tank 10). In this case, the changing step is to change the etching rate from the first etching rate to the first etching rate by discharging a part of the chemical from the processing tank and supplying a new chemical with a lower water mixing ratio than this chemical to the processing tank. The etching rate may be lowered to 2.

In this way, by discharging a chemical solution with a high water concentration from the processing tank, the water blending ratio can be reduced in a shorter time. That is, the etching rate of the tungsten film can be reduced in a shorter time.

In the first etching step and the second etching step, the substrate may be etched by supplying a chemical solution to the substrate. In this case, the changing step may reduce the etching rate from the first etching rate to the second etching rate by changing the temperature of the chemical solution from the first temperature to a second temperature lower than the first temperature. In this way, by changing the temperature of the chemical solution, it is possible to change the etching rate.

The second film (for example, the titanium nitride film 102) may be covered by the first film (for example, the tungsten film 101). In this case, the first etching step is to etch the first film at the first etching rate, and the changing step is to change the etching rate of the first film from the first etching rate before the second film is exposed from the first film. The etching rate may be lowered to the second etching rate.

As a result, for example, the first film can be etched at a higher etching rate in a short time without worrying about the selectivity between the first film and the second film until the second film is exposed. . Further, after the second film is exposed, for example, the first film and the second film can be etched simultaneously at a desired selection ratio (for example, 1:1).

In the first etching step, the substrate may be immersed in a first processing tank that stores a first chemical solution having a first etching rate. Further, in the second etching step, the substrate may be immersed in a second processing tank that stores a second chemical solution having a second etching rate. Further, in the changing step, the etching rate may be lowered from the first etching rate to the second etching rate by moving the substrate from the first processing tank to the second processing tank. Thereby, for example, the first etching process and the second etching process can be performed on the substrate without performing liquid exchange.

Further, the substrate processing apparatus according to the embodiment (as an example, the substrate processing apparatus 1) includes a supply section (as an example, a chemical solution supply section 30 and an individual supply section 50), a changing section (as an example, a second valve 48, an individual It includes a supply section 50, a heater 44, a cooling section (not shown), and a control section (as an example, a control section 61). The supply unit supplies a chemical solution to a substrate (eg, wafer W) having a first film (eg, tungsten film 101) and a second film (eg, titanium nitride film 102). The changing unit changes conditions for supplying the chemical liquid by the supply unit (for example, the blending ratio of each component in the chemical liquid, the temperature of the chemical liquid). The control unit performs a first etching process in which the substrate is etched at a first etching rate using a chemical solution, and a changing process in which the etching rate is changed to a second etching rate different from the first etching rate by controlling the changing unit. , and a second etching process of etching the substrate at a second etching rate using a chemical solution. Thereby, a substrate having multiple types of films can be efficiently etched.

The chemical solution may contain multiple components (for example, phosphoric acid, acetic acid, nitric acid, and water). In this case, the changing unit (for example, the second valve 48 and the individual supply unit 50) may be able to change the blending ratio of multiple components in the drug solution. Further, the control unit may reduce the etching rate from the first etching rate to the second etching rate by controlling the changing unit and changing the blending ratio of the plurality of components. In this way, the etching rate can be changed by changing the blending ratio of multiple components in the chemical solution.

The changing unit (for example, the heater 44 and a cooling unit, not shown) may be able to change the temperature of the chemical solution. In this case, the control unit controls the changing unit to change the temperature of the chemical solution from the first temperature to a second temperature lower than the first temperature, thereby changing the etching rate from the first etching rate to the second etching rate. It may be lowered. In this way, by changing the temperature of the chemical solution, it is possible to change the etching rate.

The substrate processing apparatus according to the embodiment (for example, the substrate processing apparatus 1A) includes a first processing tank (for example, the first processing tank 71) and a second processing tank (for example, the second processing tank 81). You may be prepared. The first treatment tank stores a first chemical liquid whose etching rate is a first etching rate. The second treatment tank stores a second chemical liquid whose etching rate is a second etching rate. Further, the supply section may include a first chemical solution supply section and a second chemical solution supply section. The first chemical supply unit supplies the first chemical to the first processing tank. The second chemical supply unit supplies a second chemical to the second processing tank. In this case, the changing unit may be a moving mechanism (for example, the transport device 90) that moves the substrate from the first processing tank to the second processing tank. Thereby, for example, the first etching process and the second etching process can be performed on the substrate without performing liquid exchange.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. Indeed, the embodiments described above may be implemented in various forms. Moreover, the above-described embodiments may be omitted, replaced, or modified in various forms without departing from the scope and spirit of the appended claims.

W Wafer 1 Substrate processing apparatus 10 Processing tank 11 Inner tank 12 Outer tank 20 Substrate holding section 30 Chemical supply section 31 Chemical supply source 40 Circulation section 50 Individual supply section 51a Water supply source 51b Phosphoric acid supply source 51c Acetic acid supply source 51d Nitric acid supply Source 60 Control device 61 Control section 62 Storage section 100 Polysilicon film 101 Tungsten film 102 Titanium nitride film 103 Silicon oxide film

Claims (13)

A first film that is one of a tungsten film, a molybdenum film, an osmium film, an iridium film, a ruthenium film, a rhodium film, and a nickel film, and a second film that is one of a titanium nitride film and a tantalum nitride film . a first etching step of etching the substrate having the substrate at a first etching rate;
changing the etching rate from the first etching rate to a second etching rate lower than the first etching rate;
a second etching step of etching the substrate at the second etching rate ,
In the first etching step and the second etching step, the substrate is etched by supplying a chemical solution containing phosphoric acid, acetic acid, nitric acid, and water to the substrate,
The changing step is
A substrate processing method , wherein the etching rate of the first film is lowered from the first etching rate to the second etching rate by lowering the mixing ratio of the water in the chemical solution. The substrate has a third film formed in multiple layers spaced apart from each other,
The second film is formed around the third film of each layer so as to cover the third film,
The first film covers the second film and the third film so as to fill a gap between the third films adjacent to each other in the stacking direction,
The first etching step etches the first film,
1 . The second etching step simultaneously etches the first film that fills a gap between the third films adjacent in the stacking direction and the second film formed around the third film. The substrate processing method described in . In the first etching step and the second etching step, the substrate is etched by immersing the substrate in the chemical solution stored in a processing tank;
The changing step is
By discharging a portion of the chemical from the processing tank and supplying a new chemical having a lower mixing ratio of water than the chemical to the processing tank, the etching rate is changed from the first etching rate to the first etching rate. The substrate processing method according to claim 1 or 2 , wherein the etching rate is lowered to the second etching rate. The first etching step includes:
immersing the substrate in a first treatment tank storing a first chemical solution whose etching rate is the first etching rate;
The second etching step includes:
immersing the substrate in a second treatment tank storing a second chemical solution in which the etching rate is the second etching rate;
The changing step is
The substrate processing method according to claim 1 or 2, wherein the etching rate is lowered from the first etching rate to the second etching rate by moving the substrate from the first processing tank to the second processing tank. . A step of etching the first film of a substrate having a first film and a second film covered with the first film, the selectivity ratio of the first film to the second film being greater than 1. a first etching step of etching the first film by supplying a chemical solution containing a plurality of components at a mixing ratio to the substrate;
a changing step of bringing the selection ratio closer to 1 by changing the blending ratio;
a second etching step of simultaneously etching the first film and the second film exposed from the first film by supplying the chemical solution after the changing step to the substrate;
Substrate processing methods, including: 6. The substrate processing method according to claim 5, wherein in the changing step, the mixing ratio is changed so that the selection ratio becomes 1. The substrate has a third film formed in multiple layers spaced apart from each other,
The second film is formed around the third film of each layer so as to cover the third film,
The first film covers the second film and the third film so as to fill a gap between the third films adjacent to each other in the stacking direction,
5. The second etching step simultaneously etches the first film that fills a gap between the third films adjacent to each other in the stacking direction, and the second film formed around the third film. Or the substrate processing method according to 6. The changing step is
8. The substrate processing method according to claim 5 , wherein the compounding ratio is changed before the second film is exposed from the first film. A first film that is one of a tungsten film, a molybdenum film, an osmium film, an iridium film, a ruthenium film, a rhodium film, and a nickel film, and a second film that is one of a titanium nitride film and a tantalum nitride film . a supply unit that supplies a chemical solution to a substrate having
a changing unit that changes conditions for supplying the chemical solution by the supply unit;
a first etching process in which the substrate is etched at a first etching rate using the chemical; and a second etching process in which the etching rate is changed from the first etching rate to a lower etching rate than the first etching rate by controlling the changing part. a control unit that executes a changing process of changing the rate to a second etching rate, and a second etching process of etching the substrate at the second etching rate using the chemical solution ;
In the first etching process and the second etching process, the substrate is etched by supplying a chemical solution containing phosphoric acid, acetic acid, nitric acid, and water to the substrate,
The change process is
A substrate processing apparatus , wherein the etching rate of the first film is lowered from the first etching rate to the second etching rate by lowering the mixing ratio of the water in the chemical solution . The drug solution contains a plurality of components,
The changing unit is capable of changing the blending ratio of the plurality of components in the drug solution,
The control unit includes:
10. The substrate processing apparatus according to claim 9, wherein the etching rate is lowered from the first etching rate to the second etching rate by controlling the changing unit to change the blending ratio of the plurality of components. a first processing tank that stores the first chemical solution, the first chemical solution having the etching rate equal to the first etching rate;
a second treatment tank storing the second chemical solution, the second chemical solution having the etching rate equal to the second etching rate;
The supply unit includes:
a first chemical solution supply unit that supplies the first chemical solution to the first processing tank;
a second chemical solution supply section that supplies the second chemical solution to the second processing tank;
The change section is
The substrate processing apparatus according to claim 9, wherein the substrate processing apparatus is a moving mechanism that moves the substrate from the first processing tank to the second processing tank. a supply unit that supplies a chemical solution to a substrate having a first film and a second film covered with the first film;
a changing unit that changes the blending ratio of a plurality of components mixed in the drug solution;
The process of etching the first film includes supplying the chemical solution containing the plurality of components at the mixing ratio such that the selectivity of the first film to the second film is greater than 1 from the supply unit. a first etching process in which the first film is etched by supplying it to the substrate; a changing process in which the selection ratio approaches 1 by controlling the changing unit to change the blending ratio; and after the changing process. a control unit that performs a second etching process that simultaneously etches the first film and the second film exposed from the first film by supplying the chemical solution from the supply unit to the substrate;
A substrate processing apparatus comprising: A computer-readable storage medium storing a program that runs on a computer and controls a substrate processing apparatus,
A storage medium, wherein the program, when executed, causes a computer to control the substrate processing apparatus so that the substrate processing method according to any one of claims 1 to 8 is performed.

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