JP3021026B2 - In-line film forming equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object processing apparatus, and more particularly, to a technique for measuring a transfer speed of a substrate tray and a technique for obtaining a uniform film thickness in an in-line type film forming apparatus. About.

[Prior art] An in-line type apparatus connects a plurality of chambers such as a charging chamber, an unloading chamber, and a heating / cooling chamber in addition to a processing chamber for forming a film on a substrate, such as sputtering or CVD. Thus, the substrate is continuously processed.

A substrate to be processed is often conveyed by a tray for mounting a workpiece. In this case, Japanese Patent Application Laid-Open
As described in Japanese Patent No. 9165, the transfer speed when transferring the tray horizontally is measured by measuring the number of rotations of a rotating body such as a roller for transfer, and indirectly determining the transfer speed of the tray from the measured value. I'm asking.

Also, in the vertical transport for transporting the tray vertically,
As described in JP-A-1-240660, a method of transporting a tray by a rack and pinion is used.

In the vertical transport, it is difficult to transport only by contact with the rollers due to its structure, so the rack and pinion system is used. In this rack and pinion method, a large amount of dust is generated in the galling portion of the rack and pinion, and it is necessary to perform rack processing for each tray. For this reason, when a large number of trays are continuously transported by the in-line apparatus, troubles are caused and the cost is increased.

For the above reason, in general, in the case of horizontal transfer, a transfer method based on only contact between a rotating body such as a roller and a tray is often adopted.

[Problems to be Solved by the Invention] In the transfer method using the rotating body in the horizontal transfer, the transfer speed of the tray often varies due to slippage between the rotating body and the tray.

For this reason, in a device that transports a tray and continuously processes an object to be processed, for example, in an in-line film forming device, when a film is formed while the rotation speed of a rotating body and other process conditions are all the same. However, there is a problem that a large variation occurs in the film thickness.

The present invention is a technology for directly measuring the transport speed of the workpiece mounting tray, the transport speed measuring technique of the workpiece mounting tray, and even if the transport speed of the tray varies due to slippage, each It is an object of the present invention to provide a technique in which processing contents between trays are constant.

In addition, since the transport speed of each tray often fluctuates in a certain tendency, the purpose of observing this tendency is to prevent transport troubles and improve the reliability of the equipment. I do.

[Means for Solving the Problems] The object of the present invention is to provide a detecting means for detecting a plurality of reference positions of an object mounting tray, a detection signal of one reference position output from the detecting means and a next reference signal. This can be achieved by an in-line film forming apparatus configured to include means for calculating the transport speed of the workpiece mounting tray using the time interval between the position detection signal and the distance between the reference positions.

Further, an object of the present invention is to measure a time interval until detecting one reference position and another reference position of the processing object mounting tray, a distance between the two reference positions, and the time interval. Is used to calculate the transport speed of the tray for loading the workpiece, calculate the deviation between the transport speed and a predetermined speed, and control the processing conditions of the workpiece based on the calculation result. This can be achieved by the processing method of the processed material.

[Operation] At least two reference positions such as holes or grooves serving as marks for position confirmation are formed on each tray.

A mechanism for detecting the mark by an optical method such as an optical sensor or a proximity switch is provided at a fixed point in the chamber through which the tray passes.

The actual transport speed of the tray can be measured by measuring the time from when one mark passes through the fixed point until the next mark passes.

Further, from the actual transport speed, the tendency of the variation in the transport speed can be grasped, and the tendency of the variation is fed back to the processing conditions, so that the variation in the processing between the trays can be minimized.

In addition, since the trays are used repeatedly, the transfer speed is managed for each tray, and when processing the workpiece mounted on each tray, processing is performed according to the actual transfer speed measured last time. By adjusting the condition by applying feedback, it is possible to more reliably control the processing of the object to be processed.

Embodiment An embodiment of the present invention will be described with reference to FIGS.

The present embodiment is an inline film forming apparatus which is a continuous apparatus for forming a thin film on a substrate mounted on a tray.

Referring to FIG. 3, an in-line film forming apparatus according to the present embodiment will be described.
100 will be described.

As shown in FIG.
Preparation room 31, heating room 32, intermediate room 33, film formation room 11, cooling room 34,
It is configured to include processing chambers having different functions, such as the extraction chamber 35.

The plurality of substrate trays 2 are continuously transported from the preparation chamber 31 to the respective chambers, and undergo predetermined processing in the respective chambers.

In the film forming chamber 11, a film is formed on the substrate by sputtering while the substrate tray 2 is being conveyed. After each processing, the substrate tray 2 carried out of the unloading chamber 35 is returned to its original state by the ascending elevator 36 (b), the tray return 37, and the descending elevator 36 (a). The processed substrate is collected by the substrate attaching / detaching robot 38, and at the same time, a new substrate is mounted, and the same processing is repeated.

Next, a technique for measuring the transfer speed of the tray will be described with reference to FIG.

FIG. 1 is an enlarged explanatory view showing the film forming chamber 11 shown in FIG. 3. FIG. 1 (a) is a view for explaining the above-mentioned technology.
FIG. 2B is an explanatory view of the film forming chamber 11 in which the substrate tray 2 is placed, as viewed from above. FIG. 2B is an explanatory view as viewed from the direction of travel of the substrate tray 2, and FIG. FIG. 9 is an explanatory diagram for explaining reference positions such as 4;

As shown in FIGS. 1 (a), 1 (b) and 1 (c), the substrate tray 2 has an arrow 20 between two side walls 3 forming a film forming chamber.
Transported in the direction of

The substrate tray 2 has two substrates 1 mounted thereon.

The substrate tray 2 has a plurality of transport rollers 7 indicated by broken lines.
Conveyed by the rotation of. The transport roller 7 is rotated at a constant speed via a drive shaft 8 by a chain 14 provided outside and a rotary drive system (not shown).

The substrate tray 2 has grooves 4 for measuring the transfer speed.
Have in several places. The groove 4 is provided at right angles to the traveling direction 20 of the substrate tray 2. In order to detect the position of the groove 4, an optical means such as a transmission type optical sensor 5 is used.
It is provided on 11 side walls 3.

In the film forming chamber 11, the target electrode 9
Has been fixed. The target electrode 9 holds a target 12 and an earth shield 13, and a sputter power is supplied to the target electrode 9 and the target 12 from a sputter power supply (not shown).

By the gas introduced from the sputtering gas inlet 15,
Discharge occurs between the target 12 and the substrate tray 2, and the target 12 is sputtered to form a film on the substrate 1 held on the substrate tray 2. During the sputtering, the substrate tray 2 is transported in the direction of arrow 20 by the rotation of the transport roller 7.

The substrate tray 2 forms a film while being transported.
The film thickness formed thereon depends on the time required for the substrate 1 to pass over the target 12 and the sputtering power.

Next, a technique for measuring the transport speed of each substrate tray 2 will be described.

The rotation of the rotation roller 7 causes the substrate tray 2 to move in the direction indicated by the arrow 20.
Transported in the direction of As the substrate tray 2 advances, the groove 4 provided in the substrate tray 2 passes in front of the transmission type optical sensor 5.

Although the light of the transmission type optical sensor 5 is blocked at a place where the groove 4 is not formed, at the position of the groove 4, the light passes and the position of the groove 4 can be detected.

Since the detection of the position of the groove 4 is performed at a certain fixed point provided in the film forming chamber 11, the time from the passage of one groove 4 to the passage of the next groove 4 is determined by a sequencer for controlling the entire apparatus or another computer. The transfer speed of the substrate tray 2 in the film forming chamber 11 can be determined from the distance between the grooves 4.

In the above-described method of measuring the transfer speed, the actual movement of the substrate tray 2 is measured, so that even if slippage occurs between the rotary roller 7 and the transfer of the substrate tray 2, an accurate transfer speed can be measured. .

Further, the transfer speed of the substrate tray 2 can be measured if there are at least two grooves 4, but the more the number, the more accurate the speed can be measured.

Further, a plurality of optical sensors may be provided with one reference position such as the groove 4. Further, a plurality of reference positions and sensors may be provided.

The light sensor may be affected by light emission from the plasma, but by measuring in the horizontal direction above the substrate tray 2 as in this embodiment, the light sensor is hardly affected by light emission from the plasma. Can be

Next, a technique for making the film thickness formed on the substrate constant will be described with reference to FIG. 2, FIG. 4, and FIG.

This technology detects a deviation between the above-described substrate tray transport speed and a target transport speed (hereinafter, referred to as a speed control value), and feeds back the deviation to sputtering power to make the film thickness constant. is there.

FIG. 2A is a block diagram showing a configuration of an apparatus for the above-described technology, FIG. 2B is an explanatory diagram illustrating a groove of a substrate tray, and FIG. 2C is a flowchart.

As shown in FIG. 1A, the apparatus is connected to a film forming chamber 11 of an in-line film forming apparatus 100, and detects a position of a substrate tray 2 in the film forming chamber.
An arithmetic unit 32 for measuring the speed of the substrate tray 2 from the signal of the tray position detection sensor 31 and calculating a deviation from the speed management value; and a film forming chamber based on the signal from the arithmetic unit 32.
Sputter power supply 9 for supplying power to target 12 in 11
And a power supply controller 30 for controlling the power supply.

The configuration of the arithmetic unit 32 is shown in a two-dot chain line in FIG. 3A, and detects the tray position and stores the interval between the groove 4 and the tray position detecting means 41 for starting a built-in timer. Tray groove interval storage means 42, calculating means 43 for calculating the time interval from the previous tray position detection time to the current tray position detection time, and calculating the transport speed of the tray from the time interval and the tray groove interval. Tray actual speed calculating means 44, speed management value storage means 45 for storing a speed management value, and calculating a deviation between the tray actual speed and the speed management value,
Deviation calculation means for sending the result to the power supply controller 30 as a signal.

Next, a method for detecting a deviation between the transfer speed of the substrate tray and the speed control value and feeding back the deviation to the sputtering power to make the film thickness constant is described in the second method.
This will be described with reference to FIGS.

As shown in FIG. 2 (b), the substrate tray
Five grooves 4-1 to 4-5 are provided, and the distance between the grooves is d.

As shown in FIG. 2 (c), a tray groove is detected (step 21), and a timer is started (step 22).

Next, the next tray groove is detected (step 23), and the timer count is stopped (step 24), and at the same time, the timer count is reset and restarted (step 25).

Next, the tray actual speed S is calculated from the groove interval d and the time interval from the timer (step 26).

Next, the tray actual speed S and the speed control value Sr (step
27) and calculate the speed deviation DS by calculating
28).

Next, the power of the power supply 9 is corrected based on the speed deviation DS (step 29).

To make this correction, the power supply power P shown in FIG.
And the relationship between the tray transport speed S and the film thickness d.

FIG. 3A shows the relationship between the power supply power P and the film thickness d.

 The vertical axis indicates the film thickness d, and the horizontal axis indicates the power supply power P.

As shown in the drawing, the film thickness d and the power supply power P are in direct proportion.

FIG. 2B shows the relationship between the tray transport speed S and the film thickness d.

 The vertical axis indicates the film thickness d, and the horizontal axis indicates the tray transport speed S.

As shown in the figure, the film thickness d and the tray transport speed S are in an inversely proportional relationship.

Accordingly, as shown in FIG. 3C, the film thickness d can be expressed as a function of the ratio between the power supply power P and the tray conveyance speed S, and the film thickness d and the ratio P / S are directly proportional. It is in.

That is, if the tray conveyance speed S is halved and the power supply power P is doubled, the film thickness d is constant.

According to the in-line film forming apparatus according to the present embodiment, the film thickness can be controlled to be constant by eliminating the variation in the film thickness due to the variation in the transfer speed of the substrate tray, so that the product yield can be improved and the device reliability can be improved. Improvement can be achieved.

 Next, the above effects will be described with reference to FIG.

In FIG. 5, the horizontal axis represents the continuous sputtering time T, and the vertical axis represents the film thickness d.
7 is a graph showing a comparison of the film thickness between the present embodiment and the conventional example in the case where.

The thickness 52 of the conventional example gradually increases with the passage of time, for example, because the transport speed of the tray gradually decreases.

In contrast, the in-line film forming apparatus according to the present embodiment
Even if the transfer speed of the tray changes, the power supply power is controlled according to the change, so that the film thickness d53 always falls within the fixed widths 52 and 54 of the management value.

In this embodiment, an example in which the groove provided in the substrate tray is detected by a method using an optical sensor has been described. However, as a method for detecting the position of the groove, a method using a proximity switch or a method using a reflection type optical sensor may be used. A method and the like can be considered, and the present invention is not limited to this embodiment.

Also, in the processing on the substrate tray side, hole processing may be considered in addition to the groove.

In addition to directly processing a substrate tray, a method of holding a jig for tray position confirmation on the tray may be considered.

Further, according to the present embodiment, the actual transfer speed of each substrate tray can be monitored and stored, so that the correlation with the film thickness of each substrate tray or substrate can be clearly grasped, and the production management can be improved. In addition, it is possible to greatly contribute to improvement of device reliability.

Further, when the transport speed varies, it is determined that there is an abnormality in the transport system, and an alarm is issued to prevent trouble.

[Effects of the Invention] According to the present invention, the transport speed of the tray for mounting the workpiece can be directly measured, so that the difference between the processing content of the workpiece and the transport speed of the tray for mounting the workpiece can be measured. The correlation becomes clear, and the reliability of the device can be improved in production management.

In addition, the processing speed can be controlled within a certain range by applying feedback to the process conditions according to the degree of the variation due to the variation in the transport speed of the tray for loading the workpiece. Reliability can be improved.

Further, when a variation in the transport speed occurs, an alarm is issued, thereby preventing a transport trouble beforehand, thereby improving the operation rate of the apparatus and improving the reliability.

[Brief description of the drawings]

1 (a) is an explanatory view of a film forming chamber containing a substrate tray as viewed from above, FIG. 1 (b) is an explanatory view of the substrate tray as viewed from the traveling direction, and FIG. 1 (c) is a substrate tray. FIG. 2 (a) is an explanatory view for explaining a reference position of a groove or the like machined into a groove.
2 is a block diagram showing the configuration of the apparatus, FIG. 2 (b) is an explanatory view for explaining the grooves of the substrate tray, FIG. 2 (c) is a flow chart for making the film thickness uniform, and FIG. FIG. 4 (a) is a graph showing the relationship between power supply power P and film thickness d, and FIG. 4 (b) is the relationship between tray transport speed S and film thickness d. FIG. 4C is a graph showing that the film thickness d and the ratio P / S are in direct proportion, and FIG. 5 is a graph showing the continuous sputtering time T on the horizontal axis and the film thickness d on the vertical axis. 7 is a graph showing a comparison of the film thickness between the example and the conventional example in the case. 1 ... substrate, 2 ... substrate tray, 3 ... side wall, 4 ...
Groove, 5 ... Photoelectric sensor, 7: Transport roller, 8: Drive shaft, 9: Target electrode, 10: Insulator, 12: Target.

Claims (5)

(57) [Claims] 1. A detecting means for detecting a plurality of reference positions of a workpiece mounting tray, and a time interval between a detection signal of one reference position and a detection signal of a next reference position output from the detecting means. An in-line film forming apparatus comprising: means for calculating a transfer speed of a tray for mounting a workpiece using the distance between the reference positions. 2. A plurality of detecting means for detecting one reference position of a workpiece mounting tray, a reference position detection signal output from one of the detecting means, and a reference signal output from the next detecting means. Means for calculating the transport speed of the tray for mounting the workpiece using the time interval between the position detection signal and the distance between the two detection means. 3. A tray reference position detection sensor for detecting a reference position of a workpiece mounting tray, a speed of a substrate tray measured from a signal output from the tray reference position detection sensor, and a predetermined speed. An object processing apparatus comprising: a calculating means for calculating a deviation; and a control means for controlling a processing condition of the object based on a signal from the calculating device. 4. The arithmetic unit detects a reference position of the workpiece mounting tray and simultaneously starts a timer, and a reference position interval storage unit that stores an interval between the two reference positions. Calculating means for calculating a time interval from the previous tray reference position detection time to the current tray reference position detection time; and a tray transfer speed for calculating a tray transfer speed using the time interval and the reference position interval. Calculation means; speed management value storage means for storing a predetermined constant speed; deviation calculation means for calculating a deviation between the tray conveyance speed and the constant speed and sending the result as a signal to the control means The object processing apparatus according to claim 3, comprising: 5. A time interval between detection of one reference position and another reference position of the workpiece mounting tray is measured, and a distance between the two reference positions and the time interval are measured. ,
Calculating a transport speed of the tray for mounting the workpiece; calculating a deviation between the transport speed and a predetermined speed; and controlling a processing condition of the workpiece based on the calculation result. Processing method of the object.