JPH05160111A - Semiconductor manufacturing equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to measure the particles inside the equipment by preventing contamination by reaction products of the observation windows used in CVD equipment and etching equipment and keeping the window glass clean at all times. In addition, yield improvement and high throughput are realized in the semiconductor manufacturing process. [Structure] An auxiliary vacuum chamber having a gas inlet pipe and a gas outlet small hole is provided between the surface of the window glass and the wall surface of the reaction container, and a clean gas flows from the auxiliary vacuum chamber into the reaction container due to a pressure difference. I chose [Effect] Since the surface of the window glass can be prevented from being contaminated by the reaction product, it becomes easy to introduce light into the reaction vessel from the outside of the semiconductor manufacturing apparatus through the window glass and to detect a signal from the inside of the reaction vessel. It becomes possible to measure the fine particles and the like, and it is possible to improve the yield and increase the throughput in the semiconductor manufacturing process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus,
In particular, CVD in which the inside of the reaction vessel is contaminated by reaction products, etc.
The present invention relates to a semiconductor manufacturing apparatus suitable for measuring minute dust in a vacuum atmosphere such as an apparatus and an etching apparatus.

[0002]

2. Description of the Related Art From 16 MDRAM to 64 MDRA
With the rapid increase in the integration of semiconductor elements toward M, many semiconductor manufacturing apparatuses such as etching apparatuses and CVD apparatuses are
Etching and CVD processes have come to be performed in a vacuum atmosphere. The biggest problem in these manufacturing processes is the decrease in yield due to the occurrence of product defects caused by the adhesion of fine dust to the wafer surface due to the reaction products generated in the manufacturing process, and the decrease in throughput due to the stoppage of device operation for device cleaning. It is prevention of deterioration. In order to realize this, it is necessary to directly detect dust and the like due to reaction products in the reaction container generated in these manufacturing processes, and prevent wafer contamination by the dust in advance.

However, the literature "Aerosol Technology;
As described on pages 328 to 329 of "Kazuya Hayakawa (Inoue Shoin)", try to measure with a particle counter (laser dust monitor) that uses a light scattering method that is often used for particle measurement. Gas containing dust in the area to be filled (atmospheric pressure)
Is sampled and irradiated with light such as a highly densified laser to detect scattered light generated by fine particles, and the particle size of dust is measured from the scattered light intensity, and the number is measured from the number of times of occurrence. Therefore, in order to apply this method to measurement of dust floating in a vacuum atmosphere such as in a reaction vessel of a semiconductor manufacturing apparatus, dust floating in the vacuum atmosphere must be sampled and measured.

However, it has not been realized because it is difficult to sample dust floating in a vacuum atmosphere in an atmospheric pressure atmosphere, and there are problems such as adhesion of dust on the piping surface and response in the sampling process. is the current situation. Further, in the direct measurement of fine particles in a reaction container of a semiconductor manufacturing apparatus such as a CVD apparatus or an etching apparatus using the light scattering method, there is a problem that a window for light introduction or signal detection is contaminated with a reaction product. , Not realized.

[0005]

In a semiconductor manufacturing apparatus, especially a CVD apparatus, a raw material gas such as SiH ₄ or TEOS is reacted in a vacuum (reaction) container to form SiO on the wafer surface.
Form a thin film such as ₂ . In this process, many fine particles are generated by the reaction product. By detecting and controlling the generation of the fine particles, it is possible to improve the yield and increase the throughput in the semiconductor manufacturing process. But,
In such an apparatus, in order to measure the fine particles in the reaction vessel by using the light scattering method, light (for example, laser light) is used.
It is indispensable to introduce an observation window into the reaction vessel to detect light scattered by the fine particles.
In an apparatus or the like, since the reaction product adheres to the observation window in the form of a thin film or particles, the window glass of the observation window is contaminated with the reaction product, and the light transmittance of the window glass changes every moment. Therefore, there is a big problem that the intensity of incident light is reduced and the intensity of scattered light from the fine particles of the same size in the reaction vessel is also reduced.

An object of the present invention is to prevent contamination by thin films and fine particles due to the reaction product of the window glass, thereby enabling fine particle measurement in a semiconductor manufacturing apparatus such as a CVD apparatus or an etching apparatus, which occurs in the semiconductor manufacturing process. Wafer manufacturing defects due to adhered fine particles are reduced, yield is improved and throughput is increased.

[0007]

In order to achieve the above object, the present invention provides a semiconductor manufacturing apparatus having an observation window for observing the inside of a reaction vessel in a vacuum state, wherein the observation window and the inside of the reaction vessel are provided between the observation window and the inside of the reaction vessel. An auxiliary vacuum chamber for flowing clean gas into the reaction vessel is interposed.

Further, in a semiconductor manufacturing apparatus having an observation window for observing a plasma state in a reaction vessel in a vacuum state, or for introducing light for optical measurement and detecting a signal, the surface of the window glass of the observation window and the reaction An auxiliary vacuum chamber having a clean gas inlet pipe and a small outflow hole is provided between the wall surface of the container and the clean gas is discharged from the auxiliary vacuum chamber into the reaction container by a pressure difference. To do.

[0009]

According to the above construction, the reactive gas in the reaction vessel is prevented from flowing into the auxiliary vacuum chamber due to the diffusion or flow of the gas flow by the clean gas (for example, Ar or He) introduced from the outside. Since it is possible to prevent reaction products and reactive gases from directly contacting the window glass surface, it is possible to prevent the window glass surface from being contaminated and keep the window glass surface clean at all times. You can Therefore, the intensity of the light introduced into the reaction container can be kept constant, and the influence of the window glass on the detection of the optical signal can be reduced as much as possible. As a result, light is introduced into the reaction vessel from outside the semiconductor manufacturing apparatus such as the CVD apparatus or the etching apparatus through the window glass,
The signal can be easily detected from the reaction container, and the direct measurement of fine particles in the reaction container can be performed easily and accurately, and the wafer contamination by the fine particles of the reaction product generated in the reaction container can be prevented in advance. .. Therefore, it is possible to improve the yield and increase the throughput in the semiconductor manufacturing process.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to FIGS. FIG. 1 shows a first embodiment of the present invention. As shown in FIG. 1, the observation window 1 includes a window glass 2, a cylinder 4, a flange 5, an auxiliary vacuum chamber 3 including a gas introduction pipe 13 and an O-ring 6, and a gas cylinder 9.
And a clean gas supply system including a valve 8.

The observation window 1 is connected to the reaction container 11 of the semiconductor manufacturing apparatus.
It is attached to the wall surface 10 of. Usually, several T is in the reaction vessel 11.
It is held at a few millimeters Torr from orr. Therefore,
When clean gas is introduced into the auxiliary vacuum chamber 3 by the gas cylinder 9, the clean gas enters the reaction container 11 through the small holes 7 of the auxiliary vacuum chamber 3 due to the pressure difference between the auxiliary vacuum chamber 3 and the reaction container 11. It flows as shown by arrow 12 and flows out into the reaction vessel. The pressure in the auxiliary vacuum chamber 3 is always the reaction vessel 1
By adjusting the valve 8 so as to be higher than the pressure in 1, the reactive gas and reaction products in the reaction vessel 11 will not reach the surface of the window glass 2 by diffusion or flow. Therefore, it is possible to always keep the surface of the window glass 2 in a clean state.

For example, assuming that the diameter of the small hole 7 is 3 mm, the pressure in the reaction vessel 11 is 0.1 Torr, and the pressure in the auxiliary vacuum chamber 3 is 1 Torr, the pressure in the reaction vessel 1 passes through the small hole 7.
The flow rate of the gas flowing into 1 is about 100 cc / min (0
(° C, 1 atm), and the flow velocity is about 100 m / sec.

The type of gas supplied from the gas cylinder 9 is
The same gas as the carrier gas of the raw material gas used in the semiconductor manufacturing apparatus is used. For example, He, N ₂ , Ar, etc., and have little influence on the reaction.

FIG. 2 shows a second embodiment of the present invention. As shown in FIG. 2, the observation window 1 includes an auxiliary vacuum chamber 3 including a window glass 2, a cylinder 4, a flange 5, a gas introduction pipe 13 and an O-ring 6, and a reaction product attachment plate 60.
It is composed of a heating power source 61 and a clean gas supply system including a gas cylinder 9 and a valve 8.

The observation window 1 is connected to the reaction container 11 of the semiconductor manufacturing apparatus.
It is attached to the wall surface 10 of. As described above, the inside of the reaction vessel 11 is normally maintained at several Torr to several millimeters Torr, and the pressure inside the auxiliary vacuum chamber 3 becomes higher than the pressure inside the reaction vessel 11 by adjusting the valve 8. , Clean gas passes through the small hole 7 of the auxiliary vacuum chamber 3 and the reaction container 11
Since it flows out into the inside, the reactive gas and the reaction product do not reach by diffusion or flow, and it is possible to always keep the glass surface clean.

In addition, in this embodiment, the reaction product attaching plate 60 is attached to the small hole 7. This allows
Most of the reactive gas and reaction products in the reaction vessel 11 flowing toward the small holes 7 collide with and adhere to the reaction product attachment plate 60. Furthermore, by heating the reaction product adhering plate 60 with the heating power source 61, it is possible to make it difficult for the reaction product that has once adhered to come off, so that the surface of the window glass 2 can always be kept in a clean state. become.

FIG. 3 shows a third embodiment of the present invention. As shown in FIG. 3, in this embodiment, the cylinder 18
The observation window in which the light source 15 held by the above and the optical system 16 held by the cylinder 19 are integrated with the observation window 1 shown in the first embodiment is attached to the wall surface 10 of the reaction vessel 11 of the semiconductor manufacturing apparatus. There is. Light source 15 and optical system 16
Is structured to be fixed in the cylinder 17 by the holding plate 20.

As described above, the pressure inside the auxiliary vacuum chamber 3 becomes higher than the pressure inside the reaction container 11, and the reactive gas and reaction products do not reach the glass surface by diffusion or flow. It will always be possible to keep it clean.

In such a state, the light 21 from the light source 15 (for example, laser) passes through the window glass 2 through the optical system 16, passes through the small hole 7, and is introduced into the reaction vessel 11. It is possible to introduce light into the reaction container 11 without being affected by the reduction in the transmittance due to the contamination of the reaction product of the window glass 2.

FIG. 4 shows a fourth embodiment of the present invention. In this embodiment, the light source 15 of the observation window in the third embodiment is changed to the photodetector 22 and the observation window in which the optical system 16 is changed to the optical filter 23 is the reaction container 1 of the semiconductor manufacturing apparatus.
1 is attached to the wall surface 10. The photodetector 22 and the optical filter 23 are attached to the cylinder 17 by the pressing plate 20.
The structure is fixed inside.

Also in this embodiment, as described above, the glass surface can always be kept clean due to the pressure difference between the auxiliary vacuum chamber 3 and the reaction vessel 11.

In such a state, the light 25 generated in the reaction vessel 11 is passed through the small holes 7 and the optical filter 23 is used, so that only the light of the required wavelength is contaminated with the reaction products of the window glass 2. The light can be detected by the photodetector 22 without being affected by the reduction of the transmittance due to.

FIG. 5 shows a fifth embodiment of the present invention. In this embodiment, in the observation window shown in the third embodiment, the observation window in which the window glass 2 is attached at an attachment angle θ smaller than 90 degrees with respect to the traveling direction of light is the reaction container 11 of the semiconductor manufacturing apparatus. It is attached to the wall surface 10 of. The light source 15 and the optical system 16 are structured to be fixed in the cylinder 27 by the holding plate 20.

Also in this case, as described above, the reactive gas and the reaction products do not reach the glass surface due to the pressure difference.

In such a state, the light 26 from the light source 15 (for example, a laser) passes through the window glass 2 through the optical system 16, passes through the small hole 7, and is introduced into the reaction vessel 11.
For example, when the wavelength of the laser light is 632.8 nm and the mounting angle θ of the window glass 2 is 57 degrees 39 minutes (generally called Brewster's angle), the plane of polarization parallel to the electric field from the light source 15 (usually P polarization). The reflection of the laser light having the above-mentioned) on the surface of the window glass 2 can be made substantially zero.
About 4% is reflected without such a structure.

Similarly, the window glass 2 in the fourth embodiment shown in FIG. 4 can be tilted. By doing so, the plane of polarization parallel to the electric field (usually called P-polarized light)
It is possible to selectively detect only the light having.

FIG. 6 shows a sixth embodiment of the present invention. As shown in FIG. 6, in this embodiment, an observation window in which an optical fiber 63 is integrated with the observation window 1 shown in the first embodiment is attached to the wall surface 10 of the reaction container 11 of the semiconductor manufacturing apparatus. ..

Also in the case of the present embodiment, since the clean gas flows out into the reaction vessel 11 as described above, the surface of the window glass 2 is always kept clean.

Therefore, (1) the light from the light source (for example, laser) provided at the other end of the optical fiber 63 is not affected by the reduction of the transmittance due to the contamination of the reaction product of the window glass 2, etc. The glass 2 can be passed through, passed through the small holes 7, and introduced into the reaction vessel 11.

(2) On the contrary, the optical signal generated in the reaction vessel 11 can be detected through the optical fiber 63.

FIG. 7 shows a seventh embodiment of the present invention. In this embodiment, a plurality of observation windows having the structure shown in the above embodiment are attached to a CVD device for manufacturing a semiconductor device.

As shown in FIG. 7, in the CVD apparatus, the gate valve 37, the turbo molecular pump 36, the valves 38, 3 are used.
The inside of the reaction container 30 is brought to a low pressure state by using a vacuum exhaust system including the rotary pump 40 and the exhaust gas treatment device 41. Then, a raw material gas such as SiH ₄ or TEOS is introduced into the reaction container 30 by using a gas supply device 31, and a voltage is applied between the lower electrode 32 and the upper electrode 34 by a plasma power source 35 to lower the lower electrode 32. Plasma is generated between the upper electrode 34 and the upper electrode 34.

As a result, the raw material gas reacts and the wafer 3
A SiO ₂ thin film or the like is formed on the three surfaces. In this process, an unnecessary film adheres to the wall surface 42 of the reaction container 30. This film causes the wall surface 42 to vibrate or change due to changes in the wall surface temperature.
Peeled off, and again floated in the low-pressure reaction container 30, and some of them reattach to the surface of the wafer 33. This causes a decrease in yield and a decrease in throughput in the semiconductor manufacturing process.

Therefore, in this embodiment, for example, the observation window 43 of the third embodiment and the observation windows 44 and 45 of the fourth embodiment are attached to the wall surface of the reaction vessel 30. Then, clean gas is supplied to each observation window from the gas cylinder 46 by adjusting valves 47, 48 and 49 so that the pressure in the auxiliary vacuum chamber of each observation window becomes higher than the pressure in the reaction vessel 30. Thereby, the window glass of the observation window is protected from contamination by the reaction products.

Laser light 50 emitted from the observation window 43
However, the observation window 43 is installed on the wall surface on the opposite side so as to enter the observation window 44. By doing this, the observation window 4
Since the laser light 50 emitted from the laser light source 3 is scattered by the reaction product generated in the reaction container 30, the light detection cell 4
The intensity of the laser light 50 reaching 4 is attenuated. By detecting this attenuation amount and using the signal processing device 51, it is possible to detect fine particles floating in the reaction container 30.

At the same time, the observation window 45 detects the scattered light due to the fine particles floating in the reaction container 30, and the signal processing device 52 can be used to detect the fine particles generated in the reaction container 30. Can be effectively cleaned. As a result, manufacturing defects due to the adhesion of dust to the wafer can be reduced, so that the yield and the throughput in the semiconductor manufacturing process can be improved.

[0037]

As described above, according to the present invention,
It has the following effects.

(1) It is possible to prevent contamination of the window glass surface of the observation window of the semiconductor manufacturing apparatus having the observation window with the reactive gas or the reaction product.

(2) The number and particle size of fine dust floating in a vacuum atmosphere such as in a CVD device or an etching device can always be detected accurately.

(3) Since it is possible to know the abnormal occurrence of dust during the operation of these semiconductor manufacturing apparatuses, it is possible to effectively clean the apparatus.

(4) As a result, manufacturing defects due to the adhesion of dust to the wafer can be reduced, so that the yield and throughput in the semiconductor manufacturing process can be improved.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram showing a configuration of a semiconductor manufacturing apparatus according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram showing a configuration of a semiconductor manufacturing apparatus according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing a configuration of a semiconductor manufacturing apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram showing a configuration of a semiconductor manufacturing apparatus according to a fifth embodiment of the present invention.

FIG. 6 is a configuration diagram showing a configuration of a semiconductor manufacturing apparatus according to a sixth embodiment of the present invention.

FIG. 7 is a block diagram showing a seventh embodiment of the present invention.

[Explanation of symbols]

 1 Observation window 2 Window glass 3 Auxiliary vacuum chamber 4 Cylinder 5 Flange 6 O-ring 7 Small hole 8 Valve 9 Gas cylinder 10 Wall surface 11 Reaction vessel 12 Gas flow 13 Gas introduction tube 14 Light introduction cell 15 Light source 16 Optical system 17, 18, 19 Cylinder 20 Holding plate 21 Light 22 Photodetector 23 Optical filter 24 Photodetection cell 25, 26 Light 27 Cylinder 30 Reaction vessel 31 Gas supply device 32 Lower electrode 33 Wafer 34 Upper electrode 35 Plasma power supply 36 Turbo molecular pump 37 Gate valve 38, 39 valve 40 rotary pump 41 exhaust gas treatment device 42 wall surface 43 light introduction cell 44, 45 light detection cell 46 gas cylinder 47, 48, 49 valve 50 laser light 51, 52 signal processing device 60 reaction product attachment plate 61 heating power source 63 optical fiber

Claims (8)

[Claims] 1. A semiconductor manufacturing apparatus having an observation window for observing the inside of a reaction vessel in a vacuum state, wherein an auxiliary vacuum chamber for flowing a clean gas into the reaction vessel is provided between the observation window and the inside of the reaction vessel. A semiconductor manufacturing apparatus characterized by being interposed. 2. A semiconductor manufacturing apparatus having an observation window for observing a plasma state in a reaction vessel in a vacuum state, or for introducing light for optical measurement or detecting a signal, wherein the reaction is performed between the window glass surface of the observation window and the reaction. Between the wall surface of the container, an auxiliary vacuum chamber having a clean gas inlet pipe and a small outflow hole is provided.
A semiconductor manufacturing apparatus, wherein the clean gas is flown out of the auxiliary vacuum chamber into the reaction container due to a pressure difference. 3. The semiconductor manufacturing apparatus according to claim 1, wherein a reaction product adhering member is integrated with the gas outlet small hole portion of the auxiliary vacuum chamber. 4. The semiconductor manufacturing apparatus according to claim 1 or 2, wherein a light source and an optical system are added to and integrated with the auxiliary vacuum chamber. 5. The semiconductor manufacturing apparatus according to claim 1, wherein a photodetector and an optical filter are added to and integrated with the auxiliary vacuum chamber. 6. The semiconductor manufacturing apparatus according to claim 1 or 2, wherein the window glass of the observation window is attached at an angle other than a right angle with respect to a traveling direction of light. 7. The semiconductor manufacturing apparatus according to claim 1 or 2, wherein an optical fiber is brought close to and integrated with the window glass of the observation window. 8. A semiconductor manufacturing apparatus, wherein a plurality of observation windows having the structure used in the semiconductor manufacturing apparatus according to claim 1 are provided.