JPS6329523A - Semiconductor manufacture apparatus - Google Patents

Abstract

PURPOSE:To obtain a semiconductor manufacturing apparatus, which can achieve the uniform quality and thickness of a grown film, by constituting the apparatus by an electrode plate, on the main surface of which a wafer is mounted, and an electrode plate, through which gas is blown to the wafer, and providing exhausting ports in the outer surface of a sample stage at an equal interval. CONSTITUTION:Gas 8 on the main surface of a sample stage 4 flows from the center of the main surface of the sample stage 4 to the periphery of the sample stage 4. Exhausting ports 10 are provided in the outer surface of the sample stage 4. Therefore, not only the gas, which is reacted between a pair of electrode plates 2, but also the gas, which is not reacted, are sucked into the exhausting ports 10 and exhausted to the outside of an apparatus. In this exhausting system structure, the gas 8 flows in the crawling manner on the main surface of the sample stage 4, turns around the outer surface of the sample stage and, is sucked into the exhausting ports 10. Therefore, the gas flows uniformly on the main surface of the sample stage 4. A homogeneous, uniform plasma CVD film is grown on a wafer 3, which is mounted on the main surface of the sample stage 4.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a semiconductor manufacturing device, particularly a semiconductor manufacturing device having a parallel plate electric bridge in a chamber. CVD for forming various films
(ChemicafL Va-por Depos
tion) equipment, plasma CVD equipment, spunter equipment, or other film forming equipment, or plasma etching equipment that etches a film provided on the main surface of a wafer, or etching equipment such as Svanta etching equipment. .

[Conventional technology]

In the manufacture of semiconductor devices, silicon oxide film (Si
Oz 11! J), IJ7SilJ Kategary
S film (PSG film), nitride film (S i NIIA
) etc. on the main surface of a wafer (semiconductor thin plate) is plasma CVD technology. plasma CVD
For more information, please refer to "Monthly Semiconductor World" published by Press Journal Co., Ltd.
r World) J June 1982 issue, published May 15, 1982, pages 53 to 57. As one of the plasma CVD equipment that performs plasma CVD,
As described in the above-mentioned literature, a structure in which parallel plate electrodes are arranged in a chamber having a vacuum evacuation system is known. A plasma CVD apparatus with this structure uses one of the parallel plate electrodes, that is, the lower electrode plate, as a susceptor (sample stage) to place a wafer as a workpiece, and generates plasma between the parallel plate electrodes to mount the wafer. It has a structure in which a desired coating is formed on the main surface.

(Point B to be solved by the invention) A plasma CVD apparatus having a structure having parallel plate electrodes has, for example, a structure as shown in FIGS. 6 and 7, if the structure is conceptually illustrated. That is, plasma C
The VD device has a pair of electrode plates 2 arranged in parallel to each other in a chamber (reaction chamber) l, and has a parallel plate electrode structure. One of the electrode plates 2, that is, the lower electrode plate 2 also serves as a sample stage (susceptor) 4 on which a wafer (semiconductor thin plate) 3 is placed. This sample stage 4 has a built-in heater 5 that heats the wafer 3 placed thereon to a desired temperature, and also heats the wafer 3 to a desired temperature. ! It is designed to rotate when placed in the second position.

On the other hand, a plurality of gas ejection holes 7 are provided on the lower surface of the upper electrode plate 2, also known as the shower electrode 6, that is, on the surface facing the wafer 3. ! Gas (processing gas) 8 is evenly blown out onto the wafers 3 placed on the wafers 3. Further, the chamber 1 is provided with an exhaust port 10 connected to a vacuum exhaust system (exhaust system) 9.

In this plasma CVD apparatus, after the wafer 3 is placed on the sample stage 4, the inside of the chamber 1 is brought to a desired degree of vacuum by the evacuation system 9, the wafer 3 is heated and rotated, and the gas The gas 8 is blown out from the ejection hole 7, and the high frequency power source 11 is applied to the pair of electrode plates 2 to turn the gas 8 between the electrode plates 2 into plasma, thereby forming a plasma CVD film on the main surface of the wafer 3. There is. Note that the arrows in the figure indicate the flow of gas such as processing gas or carrier gas. Further, 12 in FIG. 6 is an exhaust adjustment valve 12.

However, since the plasma CVD apparatus has a single exhaust port 10, the gas 8 introduced into the chamber 1 from the gas nozzle 7 flows toward the single exhaust port 10, so that the gas 8 is removed from the sample. The inventor of the present invention has clarified that the thickness and thickness distribution of the formed film vary due to non-uniformity for each wafer 3 on the table 4. Also,
In the example of the plasma CVD apparatus shown in FIGS. 6 and 7, the single exhaust port 10 is provided on the side wall of the chamber 1, so that the non-uniform flow of the gas is noticeable. However, even in a structure in which a large number of exhaust ports 10 are provided, or in a structure in which the exhaust ports 10 are provided at the bottom of the chamber 1, the gas 8 flows directly toward each exhaust port 10, so that the above-mentioned problem occurs. The phenomenon of non-uniform gas flow occurs even to a low degree.

On the other hand, in conventional plasma CVD mounting, as mentioned above, the gas 8 is exhausted from the exhaust port 10 provided on the peripheral wall of the chamber 1. There are many opportunities for contact. Further, the temperature of the wall surface of the chamber 1 is lower than that of the center portion of the chamber 1. Therefore, since the gas 8 comes into contact with the inner wall of the chamber 1, the rate of deposition of reaction products or unreacted gas on the inner wall increases. These deposits attached to the inner wall surface of the chamber 1 fall off and cause flakes (particles). The flakes adhere to the main surface of the wafer 3 and cause foreign matter adhesion defects (foreign matter defects), which causes a decrease in quality and a decrease in yield.

An object of the present invention is to provide a semiconductor manufacturing apparatus having a parallel plate electrode structure in which gas flows uniformly over the main surface of a workpiece.

Another object of the present invention is to provide a semiconductor manufacturing apparatus that can achieve uniformity in film quality and thickness.

Another object of the present invention is to provide a semiconductor manufacturing apparatus that can perform highly accurate etching.

Another object of the present invention is to provide a semiconductor manufacturing apparatus having a structure in which less deposits are deposited on the inner wall surface of the chamber.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Means for solving problems]

A brief summary of typical inventions disclosed in this application is as follows.

That is, the plasma CVD apparatus of the present invention is composed of an electrode plate that also serves as a sample stage on which a wafer is placed f2 on its main surface, and an electrode plate that faces the sample stage and also serves as a shower electrode that sprays gas onto the wafer. In addition, exhaust ports are provided at equal intervals on the circumferential surface of the sample stage. The exhaust ports are in communication with an exhaust system connected to the outside of the apparatus through the center of the interior of the sample stage, through the interior of a rotating shaft that supports the sample stage, and to the outside of the apparatus.

[Effect]

According to the above-mentioned method, the gas flowing on the sample stage is sucked into the exhaust port provided on the circumferential surface of the sample stage for exhaustion, so that the gas flows along the main surface of the sample stage. Because of this, the gas flows uniformly over the main surface of each wafer on the sample stage, resulting in high-quality plasma CV with uniform film thickness distribution.
D film is produced. Furthermore, the gas blown onto the sample stage flows along the main surface of the sample stage, reaches the periphery of the sample stage, and then changes its flow downward along the circumferential surface of the sample stage. Since the gas is exhausted from the exhaust port, there is less chance of the gas adhering to the inner wall of the chamber, and the frequency of flakes is also reduced.This reduces the occurrence of defects caused by foreign particles adhering to the wafer, and improves quality1. It can be achieved.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing the main parts of a plasma CVD apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing the flow of gas. and the second
As shown in the figure, a pair of electrode plates 2 are arranged in parallel to each other in a chamber 1, forming a parallel plate electrode structure. One of the electrode plates 2, that is, the lower electrode plate 2, also serves as a sample stage (susceptor) 4 on which a wafer 3, which is a workpiece, is placed R on its main surface. This sample stage 4 has a built-in heater 5 that heats the wafer 3 placed thereon to a desired temperature, and also heats the wafer 3 to a desired temperature. ! It will rotate when it is fixed.

On the other hand, the upper electrode plate 2 becomes a shower electrode 6, and its lower surface, that is, the surface facing the wafer 3, has gas injection holes 7.
A plurality of gases (processing gas) 8 are provided so as to uniformly blow out a gas (processing gas) 8 onto the wafer 3 placed on the sample stage 4. A plasma nitride film (Si
When forming monosilane (S 1H
4) Ammonia (NH, ) and nitrogen (N2) are sent between the pair of electrode plates 2. Further, a high frequency power source 11 is applied to the pair of electrode plates 2, plasma is generated between the pair of electrode plates 2, and a desired plasma CVD is applied to the main surface of the wafer 3.
Forms a film.

On the other hand, exhaust ports 10 each having a diameter of 2Q mm or more are provided on the circumferential surface of the sample stage 40. These exhaust ports 10 are arranged at 90 degree intervals, as also shown in FIG.
Each one is towards the center. The rotating shaft 13 that supports the sample stage 4 is a tube. This rotating shaft 13 is connected to the sample stage 4.
It communicates with the exhaust port 10 at the center of the interior thereof, and the exhaust port 10 communicates with a vacuum exhaust system (exhaust system) 9 outside the plasma CVD apparatus. Further, the heater 5 in the sample stage 4 is provided on the main surface side of the sample stage 4, that is, above the exhaust port 10, and efficiently heats the wafer 3 heated to the main surface of the sample stage 4. It is now possible to do so.

In such a plasma CVD apparatus, after the wafer 3 is placed on the sample stage 4, the inside of the chamber 1 is brought to a desired degree of vacuum by the exhaust system 9.

Thereafter, the wafer 3 is heated to a desired temperature by a heater 5 built into the electrode plate 2 and rotated. Further, as described above, gas 8 such as monosilane, ammonia, nitrogen, etc. is blown out from the gas blowing hole 7 toward the wafer 3 on the sample stage 4. Furthermore, a high frequency voltage is applied to the parallel plate electrodes. As a result, plasma is generated between the pair of electrode plates 2, and a nitride film is formed on the main surface of the wafer 3.

At this time, the gas 8 on the main surface of the sample stage 4 flows radially from the center of the main surface of the sample stage 4 to the periphery of the sample stage 4, as shown by the arrows in FIG. In addition, since the exhaust ports 10 are provided at regular intervals on the circumferential surface of the sample stage 4, not only the gas that has reacted between the pair of electrode plates 2 but also the unreacted gas that has not been subjected to the reaction can be collected. , are sucked into these exhaust ports 10 and exhausted to the outside of the device. Due to such an exhaust system structure, the gas 8 flows along the main surface of the sample stage 4 and wraps around the circumferential surface of the sample stage 4 until it reaches the exhaust port 10.
gas 8 is evenly distributed on the main surface of the sample stage 4.
flows, and a homogeneous and uniform plasma CVD film is generated on the wafer 3 placed on the main surface of the sample stage 4.

In addition, as mentioned above, this plasma CV DHy flows as the gas 8 crawls along the main surface of the sample stage 4, wraps around the circumferential surface of the sample stage 4, and is sucked into the exhaust port 10. There are fewer opportunities for the gas 8 to come into direct contact with the inner peripheral wall surface of the chamber 1, making it difficult for reaction products and unreacted gases to accumulate on the inner peripheral wall surface of the chamber 1.As a result,
Flakes (particles) are less likely to be generated on the inner circumferential wall surface of the chamber 1, and based on the falling off of the flakes, foreign matter defects caused by the flakes adhering to the main surface of the wafer 3 are less likely to occur, and the yield is improved.

According to such an embodiment, the following effects can be obtained.

(1) According to the plasma CVD apparatus with the parallel plate electrode structure of the present invention, since the exhaust ports are provided at each part of the circumferential surface of the sample stage, the gas is discharged from the center of the sample stage in conjunction with the rotation of the sample stage. Since the plasma uniformly flows radially toward the periphery, a uniform plasma CVD film can be generated on the main surface of the wafer, resulting in the effect that highly accurate film formation can be achieved.

(2) According to the above (1), according to the plasma CVD apparatus of the present invention, the gas that has come out between the pair of electrode plates is sequentially exhausted from the exhaust port provided on the circumferential surface of the electrode plate that also serves as the sample stage. Because of this, there are fewer chances for gas to come into contact with the chamber (
Therefore, it is possible to suppress the generation of flakes on the inner circumferential wall surface of the chamber, which causes foreign matter adhesion failure.

(3) According to (2) above, according to the plasma CVD apparatus of the present invention, gas passes through the inside of the sample stage in a heated state and is exhausted, so gas that does not react during this passage causes a reaction. Since it is a reaction product gas, it does not deteriorate equipment such as pumps in the exhaust system, which has the effect of extending the life of the exhaust system and reducing the frequency of replacing pump oil in the vacuum exhaust system. It will be done.

(4) According to 2) above, according to the plasma CVD apparatus of the present invention, since the gas flows along the main surface of the sample stage, most of the gas is used to generate the film formed on the main surface of the wafer. Therefore, there is no waste in the use of gas, and there is an effect that cost reduction can be achieved by reducing gas consumption.

(5) According to (1) to (4) above, the plasma C of the present invention
According to the VD apparatus, since the occurrence of defects due to foreign matter adhesion is suppressed and gas is used efficiently, a synergistic effect can be obtained in that a plasma CVD film of excellent quality can be formed with good reproducibility (and at low cost).

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. For example, as shown in FIG. 3, the sample stage 4 has a structure in which two discs 14.
A groove 16 extending in eight directions from the center of the disk 14 on the main surface of the disk 14.
, and by overlapping the flat main surface of the disk 5 on the main surface of the disk 14, the exhaust port 10 may be formed in the overlapped portion. According to this structure, when cleaning the exhaust port 10, the portion constituting the exhaust port 10 is removed by removing the disk 15 from the disk 14 and cleaning the main surfaces of the circular plate 14 and the disk 15. Easy to clean.

A tubular rotating shaft 13 is attached to the center of the lower surface of the disc 14, and the rotating shaft 13 and the intersections of the grooves 16 at the center of the disc 14 communicate with each other, as indicated by the arrows. The gas 8 sucked into the groove 16 (exhaust port 10) is directed toward the rotating shaft 1 as shown by the arrow indicated by the two-dot chain line.
Exhaust from 3.

Further, as shown in FIG. 4, an exhaust pipe 17 is provided outside the rotating shaft 13 that supports the sample stage 4 and is concentric with the rotating shaft 13. Even if the exhaust pipe 17 is used to perform exhaustion, the same effects as in the embodiment described above can be obtained.

Further, as shown in FIG. 5, the rotating shaft 13 supporting the sample stage 4 is made into a tube body 18, and the upper main surface of the rotating shaft 13, that is, the part of the rotating shaft 13 near the sample stage 4 has an exhaust port. 10 is provided, the gas 8 is sucked into the exhaust port 10, and the gas 8 is exhausted by passing through the rotary shaft 13. The same effect as in the embodiment described above can be obtained.

The above explanation has mainly been about the case where the invention made by the present inventor is applied to the plasma CVD technology, which is the background field of application, but the invention is not limited thereto. , low-pressure epitaxial growth equipment, sputtering equipment, and other film forming equipment, or plasma etching equipment that etches a film provided on the main surface of a wafer, sputter etching equipment, and the like.

The present invention can be applied at least to semiconductor manufacturing technology having a parallel plate electrode structure.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

The plasma CVD apparatus of the present invention includes an electrode plate that also serves as a sample stage on which a wafer is placed on its main surface, and an electrode plate that faces the sample stage and also serves as a shower electrode that sprays gas onto the wafer. In addition, exhaust ports are provided at equal intervals on the circumferential surface of the sample stage. The exhaust ports are in communication with an exhaust system connected to the outside of the apparatus through the center of the interior of the sample stage, through the interior of a rotating shaft that supports the sample stage, and to the outside of the apparatus. Therefore, the gas flowing on the sample stage is
Since the structure is such that the gas is sucked in for exhaust into the exhaust port provided on the circumference of the sample stand, the gas flows along the main surface of the sample stand, so that the main surface of each wafer on the sample stand is Gas flows uniformly, and a high-quality plasma CVD film with a uniform film thickness distribution is produced. In addition, the gas blown onto the sample stage flows along the main surface of the sample stage, reaches the periphery of the sample stage, and is exhausted from the exhaust port, so the gas has no chance of coming into contact with the inner wall surface of the chamber. This reduces the frequency of flakes, suppresses the occurrence of foreign matter adhesion defects on wafers, and improves quality and yield.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing the main parts of a plasma CVD apparatus according to an embodiment of the present invention, FIG. FIG. 4 is a perspective view showing a sample stage in a plasma CVD apparatus; FIG. 4 is a sectional view showing an exhaust port portion of a plasma CVD apparatus according to another embodiment of the present invention; FIG. 4 is a plasma CVD apparatus according to another embodiment of the present invention. Figure 6 is a cross-sectional view showing the exhaust port of the conventional plasma CVD apparatus.
, Figure 7 is the same (schematic diagram). 1...chamber, 2...electrode plate, 3...wafer, 4...sample stage, 5...heater, 6...shower electrode , 7... Gas outlet, 8... Gas, 9... Vacuum exhaust system (exhaust system), 10... Exhaust port 1.11...
High frequency power supply, 12... Exhaust adjustment valve, 13... Rotating shaft, 14° 15... Disc, 16... Groove, 17...
・Exhaust agent Patent attorney Katsuma Ogawa (37 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A semiconductor manufacturing apparatus having a pair of parallel plate electrodes facing each other, one of which serves as a sample stage, and a workpiece is placed on the main surface thereof, wherein a processing gas flows over the sample stage. 1. A semiconductor manufacturing apparatus characterized in that the exhaust gas is concentrated on the side of a rotating shaft supporting the sample table on the back side of the sample table. 2. The scope of claims characterized in that a plurality of exhaust ports are provided on the circumferential surface of the sample stage, each of which communicates with an exhaust system extending from the center of the interior of the sample stage through the interior of the rotating shaft to the outside of the apparatus. 2. The semiconductor manufacturing apparatus according to item 1. 3. The feature set forth in claim 1, wherein an exhaust pipe is arranged concentrically around the outer circumference of the rotating shaft, and an exhaust port is provided above the rotating shaft on the back surface of the sample stage. Semiconductor manufacturing equipment.