JP3426866B2 - Apparatus and method for manufacturing semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing apparatus and method for flattening the surface of a semiconductor wafer, for example, and in particular, polishing processing and cleaning of the wafer surface (surface to be polished) after polishing. It is used for post-treatment.

[0002]

2. Description of the Related Art In recent years, in the field of manufacturing semiconductor devices, various fine processing techniques have been researched and developed in accordance with higher density and finer semiconductor devices. Among them, the chemical mechanical polishing (hereinafter, simply referred to as CMP) method is indispensable because it is difficult to perform when flattening an interlayer insulating film, forming a plug, forming a buried metal wiring, and separating a buried element. Has become the technology of.

Now, in the CMP method of polishing a wafer by rubbing it with a polishing cloth coated with a polishing agent,
After polishing, separate the wafer from the surface of the polishing cloth, wash with ultrapure water to wash away the polishing agent, and then perform physical cleaning such as brush cleaning or chemical cleaning using a chemical solution, and attach particles to the surface to be polished. To remove.

This is, for example, single crystal silicon (Si).
When the wafer is separated from the surface of the polishing cloth, such as polycrystalline silicon, or the like, the active surface appears by polishing and the surface (surface to be polished) becomes hydrophobic. This is to prevent the rest of the polishing agent such as SiO2 contained in 1) from remaining in a shape (so-called water glass) after repelling water when dried.

Particles adhering to the active surface of Si or polycrystalline Si cannot be completely removed by cleaning with only ultrapure water because the active surface is hydrophobic, and chemical solution cleaning must be performed as a post-treatment.

As a method for preventing the adhesion of particles,
It is known that it is effective to make the polished wafer surface hydrophilic before exposing it to the atmosphere. However, in order to make the surface of the active surface hydrophilic, it is conceivable to form an organic film using a surfactant, but in the case of using a surfactant, there is a risk of organic contamination, There were problems such as not being kind to him.

[0007]

As described above, in the past, in order to prevent particles from adhering to the wafer surface after polishing, the surface of the active surface is formed by forming an organic film with a surfactant. In the case of the method of making the polymer hydrophilic, there is a concern that it may be contaminated with organic substances and is not environmentally friendly.

Therefore, according to the present invention, the surface to be polished of the semiconductor substrate is made hydrophilic without the problem of organic contamination, and at the same time,
An object of the present invention is to provide a semiconductor device manufacturing apparatus and manufacturing method that can be cleaned.

[0009]

In order to achieve the above object, in a semiconductor device manufacturing apparatus of the present invention, a polishing apparatus for polishing a semiconductor substrate and a polishing surface plate of this polishing apparatus are provided close to each other. The cleaning liquid for cleaning the surface to be polished of the semiconductor substrate polished by the polishing device with a cleaning liquid has a height of the polishing cloth surface on the polishing surface plate.
; And a cleaning device comprising a cleaning tank that is filled to substantially the same height, the semiconductor substrate, the surface to be polished before
By moving the polishing cloth while it is in contact with the surface of the polishing cloth,
The cleaning device without exposing the surface to be polished to the atmosphere.
It is configured to be supplied into the cleaning tank .

Further, in the semiconductor device manufacturing apparatus of the present invention, the holding portion for holding the semiconductor substrate, the rotating mechanism for rotating the holding portion, and the holding portion rotated by the rotating mechanism are pressurized. A pressing mechanism and the semiconductor substrate held by the holding section by the pressing mechanism,
By contacting the surface of the polishing cloth to which the polishing liquid is supplied,
A rotatably provided polishing surface plate for polishing the semiconductor substrate, and a polishing surface plate provided in proximity to the polishing surface plate before polishing.
Serial for cleaning the polished surface of the semiconductor substrate, as well as have a cleaning brush that is rotatably provided, the cleaning liquid before
Up to almost the same height as the polishing cloth surface on the polishing surface plate
A cleaning tank that Tasa, a supply passage for supplying the cleaning liquid to the cleaning tank, the filled the cleaning tank by the cleaning liquid supplied from the supply path, by sliding the holding portion , The semiconductor substrate after polishing ,
Exposed to the atmosphere with the surface to be polished in contact with the surface of the polishing cloth.
It is composed of a moving mechanism for supplying without being carried out.

Further, in the method of manufacturing a semiconductor device of the present invention, a polishing step for polishing the semiconductor substrate, and the surface to be polished of the semiconductor substrate polished in this polishing step are polished.
Slide it while it is in contact with the polishing cloth surface on the polishing table.
By doing so, the surface to be polished can be washed without exposing it to the atmosphere.
Washing with the cleaning liquid filled to a height almost equal to the surface of the polishing cloth.
The cleaning process includes a moving process of moving the cleaning device into the cleaning tank, and a cleaning process of cleaning the surface to be polished of the semiconductor substrate slid into the cleaning tank by the moving process.

Further, in the method of manufacturing a semiconductor device of the present invention, the step of holding the semiconductor substrate, the step of rotating the held semiconductor substrate, and the pressurization of the rotated semiconductor substrate, A step of polishing the semiconductor substrate by bringing it into contact with a polishing cloth surface on a rotatably provided polishing platen to which a polishing liquid is supplied; The surface to be polished can be enlarged by sliding it while it is in contact with the surface of the polishing cloth.
The cleaning liquid is almost the same as the polishing cloth surface without exposing it to the air.
It comprises a step of moving into a cleaning tank of a cleaning device filled to the height and a step of brush-cleaning the surface to be polished of the semiconductor substrate moved into the cleaning tank.

According to the semiconductor device manufacturing apparatus and manufacturing method of the present invention, before the semiconductor substrate after polishing is dried,
A natural oxide film can be formed on the surface to be polished of the semiconductor substrate.

Further, when alkaline ionized water is used, since the cleaning water whose potential is controlled is used, it is possible to carry out brush cleaning in an environment where particles are unlikely to adhere, and it is easy to remove residual particles. In this case, even though the concentration of the chemical liquid is low, a cleaning liquid having a strong oxidizing property is used, which is environmentally friendly.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a semiconductor manufacturing apparatus according to an embodiment of the present invention. It should be noted that FIG. 7A is a plan view of the main part of the semiconductor manufacturing apparatus, and FIG.

That is, the polishing platen 11 can rotate about the shaft 12 in the direction of arrow a at a constant speed.
A polishing cloth (polishing cloth) 13 is attached to the upper surface of the polishing platen 11.

Above the polishing platen 11, a wafer holding plate (holding part) is provided at a position off the center of the polishing platen 11.
14 are arranged. The wafer holding plate 14 can be rotated at a constant speed in the direction of the arrow b in the figure about the rotating shaft 15 by a rotating mechanism 21 including a motor.

On the lower surface of the wafer holding plate 14, single crystal silicon (Si) or polycrystalline Si (Po) is used.
A semiconductor wafer (semiconductor substrate) 16 made of ly-Si can be held by a vacuum chuck method or the like.

The wafer holding plate 14 is supported by a pressurizing mechanism 22 such as a hydraulic cylinder so as to be able to move up and down with respect to the upper surface of the polishing platen 11, and when performing polishing (planarizing) processing. The surface to be polished of the semiconductor wafer 16 to be held can be pressed against the cross surface of the polishing cloth 13 with a predetermined pressure.

The pressing mechanism 22 is capable of pressing the surface to be polished of the semiconductor wafer 16 held by the cleaning brush with a predetermined pressure when performing a cleaning process described later. Further, the wafer holding plate 14 is configured to be freely movable between the polishing platen 11 and the cleaning tank 31 of the cleaning device by a moving mechanism 23 including a horizontal shaft.

A supply device 17 is provided above the polishing platen 11.
Is provided. The supply device 17 is provided with a polishing agent 1 containing SiO2 or the like near the center of rotation of the polishing cloth 13 where the outer peripheral portion of the semiconductor wafer 16 is located and at a position on the upstream side corresponding to the semiconductor wafer 16.
7a is supplied.

In this semiconductor manufacturing apparatus, the above-mentioned respective parts, that is, the polishing surface plate 11, the wafer holding plate 14, the supply device 17, the rotating mechanism 21, the pressing mechanism 22, and the moving mechanism 23. A polishing device is configured by the above.

On the other hand, a cleaning device for cleaning the surface to be polished of the semiconductor wafer 16 polished by the polishing device is provided adjacent to the side of the polishing device.

That is, a cleaning tank 31 is provided near the polishing platen 11. The cleaning tank 31 includes an inner tank 31a for storing a cleaning liquid or ultrapure water and an inner tank 3a.
It is composed of an outer tank 31b for receiving the cleaning liquid overflowing from 1a.

The inner tank 31a and the outer tank 3 of the cleaning tank 31
The surface of the lapping plate 1b facing the polishing surface plate 11 has an arc shape along the outer periphery of the polishing surface plate 11. A supply path 32 for supplying a cleaning liquid or ultrapure water into the inner tank 31 a is connected to the cleaning tank 31, and the cleaning liquid or ultrapure water flowing through the supply path 32 is supplied via a supply port 33 to the tank. It will be supplied inside.

The cleaning tank 31 includes the inner tank 31.
A discharge passage 35 for discharging the cleaning liquid or the ultrapure water in a and the outer tank 31b through the discharge port 34 is connected.

As the cleaning liquid, for example, ultrapure water or acidic ionized water produced by electrolyzing pure water, or ozone water is used. The acidic ionized water or ozone water is very clean, has a strong oxidizing property, and has the ability to remove contamination by metals and organic substances.

On the other hand, the inner tank 31a is controlled by a height adjusting mechanism 36 including a hydraulic cylinder or the like so that the outer tank 3a is
The height position with respect to 1b can be adjusted arbitrarily.

Further, in the inner tank 31a, a cleaning brush 38 which is rotated in the direction of arrow c in the drawing by a drive mechanism 37 including a motor is provided. The cleaning brush 38 is made of PVA (Poly Vinyl Alcohol) or the like, and is configured to be able to clean itself by contact with a brush cleaning device 39 provided at the bottom of the inner tank 31a.

Further, the inner tank 31a is arranged with a gap of about 5 mm between it and the polishing platen 11. The gap between the inner tank 31a and the polishing platen 11 is filled with the surface tension of the cleaning liquid supplied to the inner tank 31a when the cleaning liquid overflows from the inner tank 31a.

That is, by adjusting the height position of the inner tank 31a, the inner tank 31a and the polishing platen 1
By forming a bridge of cleaning water having a height substantially the same as the cross surface of the polishing cloth 13 on the polishing surface plate 11 with the polishing surface plate 1, the semiconductor wafer 16 is exposed without exposing the surface to be polished to the atmosphere. It can be moved from above the polishing cloth 13 into the inner tank 31a of the cleaning tank 31.

Next, the operation of the above configuration will be described. FIG. 2 schematically shows such an operation. First, the semiconductor wafer 16 held by the wafer holding plate 14 is rotated by the rotating mechanism 21 and is brought into contact with the cross surface of the polishing cloth 13 on the polishing platen 11 by the pressing mechanism 22.

At this time, the polishing platen 11 is rotated and the polishing agent 17a is supplied from the supply device 17, so that the surface to be polished of the semiconductor wafer 16 is polished ((a) in the figure). Then, when the polishing process of the semiconductor wafer 16 is completed, the supply of the polishing agent 17a from the supply device 17 is stopped, the rotation of the polishing platen 11 and the wafer holding plate 14 is kept as it is, and the moving mechanism 23 moves the wafer. The position of the holding board 14 is moved.

As a result, the semiconductor wafer 16 is slid on the cross surface of the polishing cloth 13 and moved to the position of the cleaning tank 31 of the cleaning device. At this time, the cleaning tank 31 has already been filled with the cleaning liquid, and the semiconductor wafer 16 is exposed from the polishing cloth 13 to the cleaning tank 3 without exposing the surface to be polished of the semiconductor wafer 16 to the atmosphere.
Moved to 1.

That is, when the semiconductor wafer 16 that has undergone the polishing process is moved to the cleaning device, the cleaning tank 31 is
The position of the inner tank 31a is adjusted in advance by the height adjusting mechanism 36, and the height of the wall is set to be lower than the cross surface of the polishing cloth 13 by about 2 to 5 mm.

Then, it is supplied through the supply port 33,
The cleaning liquid from the supply passage 32 overflows from the inner tank 31a,
Due to the surface tension of the overflowing cleaning liquid, the inner tank 31
The gap between a and the polishing platen 11 is the polishing platen 1
It is embedded at almost the same height as the cross surface of the polishing cloth 13 on 1.

As a result, by moving the wafer holding plate 14 so that the semiconductor wafer 16 slides on the polishing cloth 13, the semiconductor wafer 16 does not expose the surface to be polished to the atmosphere and the cloth of the polishing cloth 13 is exposed. It is moved so as to slide on the surface of the cleaning liquid in the cleaning tank 31 from above the surface.

When the semiconductor wafer 16 after polishing is moved to the cleaning tank 31, the pressure mechanism 22 further lowers the position of the semiconductor wafer 16 held by the wafer holding plate 14, The surface to be polished of the semiconductor wafer 16 is brought into contact with the cleaning brush 38 ((b) of the same figure).

Then, the surface to be polished of the semiconductor wafer 16 is cleaned and, at the same time, the surface to be polished is made hydrophilic. That is, before the semiconductor wafer 16 after polishing is dried, a natural oxide film uniformly grows on the surface of the surface to be polished due to the strong oxidizing property of the cleaning solution, and the rotation mechanism 21 rotates and drives the semiconductor wafer 16. The rotation of the cleaning brush 38 by the mechanism 37 removes particles on the surface to be polished.

In this way, after the cleaning process is performed for about 1 to 3 minutes, the supply of the cleaning liquid from the supply passage 32 is stopped.
Further, the pressing mechanism 22 presses the semiconductor wafer 16 against the cleaning brush 38.

The semiconductor wafer 16 after cleaning is cleaned in the cleaning tank 3
After the cleaning liquid in 1 is discharged from the discharge port 34 via the discharge passage 35, it is rinsed with ultrapure water from the supply passage 32 supplied via the supply port 33, if necessary.

The semiconductor wafer 16 after cleaning is raised by the pressing mechanism 22 so that the wafer holding plate 14 is raised.
Moved to a position higher than the cross surface of the polishing cloth 13,
Further, as the wafer holding plate 14 is moved by the moving mechanism 23, it is transferred to the next process.

After cleaning the semiconductor wafer 16, the cleaning brush 38 rotated by the drive mechanism 37 while supplying the ultrapure water from the supply path 32 into the inner tank 31a.
By bringing the brush into contact with the brush cleaner 39, the brush itself is cleaned.

As described above, before the semiconductor wafer after polishing is dried, the natural oxide film can be formed on the surface to be polished of the semiconductor wafer. That is, the surface to be polished of the polished semiconductor wafer can be supplied to the cleaning device without being exposed to the atmosphere. This makes it possible to make the active surface hydrophilic before the semiconductor wafer dries, so it is possible to use acidic ionic water or ozone water, which is highly oxidizing and clean, as a cleaning liquid for the formation of the natural oxide film. It will be possible. Therefore, it is a very environmentally friendly process that does not cause the problem of organic contamination.

Moreover, since acidic ionized water and ozone water have the ability to remove contamination by metals and organic substances, it becomes possible to form a natural oxide film and at the same time sufficiently clean the polished surface of a semiconductor wafer.

Moreover, since acidic ionized water and ozone water easily return to neutral water, there is no fear of corrosion of the apparatus.
Since it is cheaper than a surfactant, it can be very advantageous in terms of cost.

In the above-described embodiment of the present invention, the position of the inner tank is adjusted by the height adjusting mechanism before the semiconductor wafer after the polishing process is moved to the cleaning device. However, the present invention is not limited to this, and for example, the gap between the inner tank and the polishing surface plate is always kept at almost the same height as the cross surface of the polishing cloth on the polishing surface plate by the cleaning liquid overflowing from the inner tank. The inner tank may be arranged in advance at a position where it can be embedded, and its height position may be finely adjusted by the height adjusting mechanism when the semiconductor wafer after polishing is moved. Of course, various modifications can be made without departing from the scope of the invention.

[0048]

As described above in detail, according to the present invention, there is no problem of organic contamination, and the surface of the semiconductor substrate to be polished is made hydrophilic, and at the same time, it is possible to clean the semiconductor device manufacturing apparatus. A manufacturing method can be provided.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a semiconductor manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a semiconductor manufacturing apparatus similarly shown for explaining the operation.

[Explanation of symbols]

11 ... Polishing surface plate 12 ... Axis 13 ... Polishing cloth 14 ... Wafer holder 15 ... Rotation axis 16 ... Semiconductor wafer 17 ... Feeding device 17a ... Abrasive 21 ... Rotation mechanism 22 ... Pressure mechanism 23 ... Moving mechanism 31 ... Washing tank 31a ... inner tank 31b ... Outer tank 32 ... Supply path 33 ... Supply port 34 ... Discharge port 35 ... Discharge path 36 ... Height adjustment mechanism 37 ... Drive mechanism 38 ... Cleaning brush 39 ... Brush washer

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/304 B24B 37/00

Claims (16)

(57) [Claims] 1. A polishing apparatus for polishing a semiconductor substrate, and a polishing surface of the polishing apparatus, which is provided in the vicinity of a polishing platen, for cleaning a surface to be polished of the semiconductor substrate polished by the polishing apparatus.
For cleaning with a cleaning liquid, the cleaning liquid is the polishing platen.
The height is almost equal to the height of the upper polishing cloth surface.
And a cleaning device having a cleaning tank, the semiconductor substrate having a surface to be polished abutting against the polishing cloth surface.
The surface to be polished is moved by moving it in this state.
It is used in the cleaning tank of the cleaning device without being exposed to the atmosphere.
Supplying equipment for semiconductor devices. Wherein said cleaning apparatus, the inside of the cleaning tank filled with the cleaning solution, the semiconductor device according to claim 1, characterized in that a cleaning brush which is rotatable Manufacturing equipment. 3. The semiconductor device according to claim 1 , wherein the cleaning liquid is electrolyzed ionic water generated by electrolyzing ultrapure water or pure water, or ozone water. Manufacturing equipment. 4. The polishing apparatus comprises a holding unit for abutting against a polishing cloth surface on the polishing platen, which slides on the polishing platen while rotating the semiconductor substrate. The semiconductor device manufacturing apparatus according to claim 1, further comprising a moving mechanism that moves the position to a position. 5. A holding unit for holding a semiconductor substrate, a rotating mechanism for rotating the holding unit, a pressure mechanism for applying pressure to the holding unit rotated by the rotating mechanism, and the holding mechanism by the pressure mechanism. A rotatably provided polishing surface plate for polishing the semiconductor substrate by bringing the semiconductor substrate held by the unit into contact with a polishing cloth surface to which a polishing liquid is supplied, and a polishing surface plate close to the polishing surface plate. and provided, for cleaning the polished surface of the semiconductor substrate after polishing, as well as have a cleaning brush that is rotatably provided, the washing liquid is the polishing constant
Filled to a height almost equal to the height of the polishing cloth surface on the board
A cleaning tank that are a supply passage for supplying the cleaning liquid to the cleaning tank, the filled the cleaning tank by the cleaning liquid supplied from the supply path, by sliding the holding portion, polished The semiconductor substrate of
An apparatus for manufacturing a semiconductor device, comprising: a moving mechanism that supplies the polishing cloth while being in contact with the polishing cloth without being exposed to the atmosphere . 6. The semiconductor device manufacturing apparatus according to claim 5, wherein the cleaning liquid is ultrapure water or electrolytic ion water generated by electrolyzing pure water, or ozone water. 7. The semiconductor device according to claim 5, wherein the cleaning tank comprises an inner tank for storing the cleaning solution and an outer tank for receiving the cleaning solution overflowing from the inner tank. Manufacturing equipment. 8. A polishing step of polishing a semiconductor substrate, and a step of polishing the semiconductor substrate polished in this polishing step with the surface to be polished being in contact with a polishing cloth surface on a polishing surface plate.
Exposing the surface to be polished to the atmosphere by
The cleaning liquid to the same height as the polishing cloth surface.
And a cleaning step of cleaning the surface to be polished of the semiconductor substrate slid into the cleaning tank by the moving step. Manufacturing method. Wherein said washing step is in the cleaning tank filled with the cleaning solution, a method of manufacturing a semiconductor device according to claim 8, characterized in that it is carried out by cleaning brush rotatably provided. 10. The semiconductor device according to claim 8 , wherein the cleaning liquid is electrolyzed ionic water generated by electrolyzing ultrapure water or pure water, or ozone water. Manufacturing method. Wherein said polishing step, said while rotating the holding portion for holding the semiconductor substrate, the semiconductor substrate held by the holding unit, the polishing cloth surface of the polishing platen polishing liquid is supplied 9. The method for manufacturing a semiconductor device according to claim 8, wherein the semiconductor device is brought into contact with the semiconductor device. 12. The moving step, the the polishing cloth surface of the polishing platen for polishing a semiconductor substrate, while keeping contact with the surface to be polished of the semiconductor substrate, the cleaning tank direction < The method for manufacturing a semiconductor device according to claim 8, wherein the method is sliding. 13. A step of holding a semiconductor substrate, a step of rotating the held semiconductor substrate, a step of pressurizing the rotated semiconductor substrate, and a polishing liquid being supplied to the semiconductor substrate. Polishing by bringing it into contact with a polishing cloth surface on a polishing surface plate which is provided, and sliding the semiconductor substrate after polishing with the surface to be polished being in contact with the polishing cloth surface. The above-mentioned
Without exposing the polishing surface to the atmosphere, the cleaning liquid
A semiconductor device comprising: a step of moving into a cleaning tank of a cleaning device filled to almost the same height; and a step of brush-cleaning a surface to be polished of the semiconductor substrate moved into the cleaning tank. Manufacturing method. 14. The method of manufacturing a semiconductor device according to claim 13, wherein the cleaning liquid is electrolyzed ionic water generated by electrolyzing ultrapure water or pure water, or ozone water. 15. The semiconductor device according to claim 13, wherein the cleaning tank comprises an inner tank for storing the cleaning solution and an outer tank for receiving the cleaning solution overflowing from the inner tank. Production method. 16. When the semiconductor substrate is moved into the cleaning tank, the cleaning liquid is temporarily overflowed from the inner tank of the cleaning tank.
16. The process is performed in a state in which a gap between the inner tank and the polishing cloth on the polishing platen is filled.
A method of manufacturing a semiconductor device according to item 1.