JPH04109526U - plasma generator - Google Patents

Abstract

(57) [Summary] [Purpose] To make it possible to change the position of a porous reflector for generating stable plasma, and to optimize the processing conditions of wafers. [Structure] A cylindrical surface is formed above the wafer table 19 in the wafer processing chamber 31, and a plurality of spacers 28,
29, 30, and 31 are fitted, and the porous reflector 32 is held between the spacers or at the upper end of the upper spacer or the lower end of the lower spacer, and the holding position of the porous reflector is adjusted. By selecting, the distance between the porous reflector and the wafer is changed. Depending on the position of the porous reflector, wafer processing conditions can be optimized.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention generates plasma by introducing microwaves into the wafer processing chamber. A plasma generator, especially a porous reflector provided in a processing chamber of the plasma generator. This invention relates to a position adjustment structure.

0002

[Conventional technology]

One type of semiconductor manufacturing equipment uses plasma to process the surface of wafers. There is also a method in which plasma generation is performed by introducing microwaves into the wafer processing chamber.

0003 FIG. 2 shows the entire microwave plasma generator.

0004 A microwave generation unit 2 is provided on the upper part of the frame 1. A wafer processing chamber 3 is provided below the cut 2. The microwave generation unit The microwave generated in the chamber 2 is transmitted to the wafer processing chamber 3 by a waveguide unit 4. It's like being guided.

[0005] The waveguide unit 4 includes a waveguide 5 having a rectangular cross section, a matching device 6, and a circular cross section. It consists of a circular waveguide 7 etc. having a planar shape.

[0006] A conventional plasma generator will be explained with reference to FIG.

[0007] A lower container 9 is provided on the base 8, and a ring plate 10 is connected to the lower container 9. A hole reflecting plate 11 is provided, a trunk ring 12 is provided on the ring plate 10, and the trunk ring 12 is provided on the ring plate 10. A quartz discharge plate 13 is attached to the ring 12. Further, at the upper end of the trunk ring 12, a guide is provided. The circular waveguide 7 of the wavetube unit 4 is attached. The lower container 9 and phosphorus At the joints such as the joint with the quartz discharge plate 13 and the trunk ring 12, etc. is provided with heat-resistant O-rings 14, 15, and 16, and the inside of the processing chamber 3 is kept airtight. It has become. Further, a required number of reaction gas introduction holes 18 are bored around the body ring 12. The reactant gas is supplied from a reactant gas supply source (not shown).

[0008] The base 8 is provided with a wafer mounting table 19, and the wafer mounting table 19 is used for processing. A wafer 20 to be processed is placed thereon.

[0009] Microwaves are guided into the processing chamber 3 via the waveguide unit 4 . Guidance The input microwave is reflected by the porous reflection plate 11, and is reflected by the quartz discharge plate 13. It is possible to excite the reactive gas between the porous reflectors 11 and stably generate plasma. Wear. The surface treatment of the wafer 20 is performed by this generated plasma. .

0010

[Problem that the idea aims to solve]

Wafer processing is also achieved by the assist effect of ions in the plasma that have passed through the holes. This is done by radicals (neutral active species) in the plasma that have passed through the holes. pass through the hole If the distance to the wafer is short, the ions will reach the wafer as ions, but If the distance to the wafer is long, it will become neutralized before reaching the wafer. that distance varies depending on processing conditions such as the type of reaction gas and the pressure inside the processing chamber. For that reason, In order to increase the processing speed of the wafer, it is possible to bring the porous reflector closer to the wafer, but Receives damage from radiation. Entire wafer uniformity with less damage caused by radicals In order to achieve uniform processing, it is possible to move the porous reflector away from the wafer, but this slows down the processing speed. Chiru. Therefore, we selected the position of the porous reflector that was considered optimal under each processing condition. There must be.

[0011] However, in the conventional plasma generator mentioned above, the porous reflector is fixedly installed. Therefore, it is difficult to optimally adjust the position of the porous reflector according to the processing conditions. I could not do it.

0012 In view of this situation, the present invention is designed to allow the position of the porous reflector to be easily changed. It is.

[0013]

[Means to solve the problem]

The present invention forms a cylindrical surface above the wafer table in the wafer processing chamber, and A plurality of spacers are fitted to the surface, and an upper spacer is fitted between the spacers or the upper spacer. It is configured to hold the porous reflector at either the upper end or the lower end of the lower spacer. It is characterized by:

[0014]

[Effect]

By selecting the holding position of the porous reflector, the distance between the porous reflector and the wafer can be changed. It is said that it will be changed. Therefore, depending on the processing conditions, the wafer processing speed and in-wafer processing Enables wafer processing with optimal uniformity and damage.

[0015]

【Example】

Hereinafter, one embodiment of the present invention will be described based on the drawings.

[0016] In FIG. 1, the wafer placement table is omitted. A donner is placed at the upper end of the processing chamber container 23. The top cover 24 in the form of a disk is airtightly attached, and a ring is formed on the top surface of the top cover 24 concentrically with the top cover 24. The seat 25 is fixed airtight. A cylindrical space holder 26 is installed on the lower surface of the upper lid 24. Install. The space holder 26 has a flange 27 at its lower end that projects toward the center. There is. The inner diameters of the space holder 26, the upper lid 24, and the ring seat 25 are the same diameter. A spacer 28 is attached to the cylindrical surface formed by the space holder 26, the upper cover 24, and the ring seat 25. , 29, 30, and 31. The spacers 28, 29, 30, 31 are The lengths in the axial direction are different. Moreover, the spacers 28, 29, 30, 31 The stacked length in the axial direction is slightly lower than the upper end surface of the ring seat 25.

[0017] Then, the porous reflector 32 is placed between the spacers and between the spacer and the quartz discharge plate holder. It is interposed between the plate 33 or between the spacer and the collar 27.

[0018] The holder plate 33 having substantially the same shape as the ring seat 25 is fixed to the upper surface of the ring seat 25. wear it. A stepped portion 34 for holding the quartz discharge plate 46 is provided on the inner diameter side of the holder plate 33. Further, a groove 35 is carved in the bottom surface of the stepped portion 34.

[0019] An annular groove 36 is carved on the bottom surface of the holder plate 33, and the annular groove 36 and the inside of the annular seat 25 are A required number of communication holes 37 communicating with the peripheral surface are bored along the radial direction. Also, the annular groove A guide hole 38 bored from the outer peripheral surface side of the ring seat 25 is communicated with the guide hole 36. 8 is connected to a reaction gas supply source (not shown) via a supply pipe 39.

[0020] O-rings are provided on the upper surface of the ring seat 25 and on the inner and outer diameter sides of the ring groove 36, respectively. rings 40, 40 are provided to airtightly seal the annular groove 36.

[0021] A cooling pipe 41 is buried on the upper surface of the holder plate 33 and along the stepped portion 34. Ru.

[0022] The quartz discharge plate 46 has its peripheral end fitted into the stepped portion 34, and the holder plate 3 It is held between the presser plate 43 fixed to the upper surface of 3 and the holder plate 33. It will be done. Further, in the groove 35, there is an O-ring 44 for sealing, and a synthetic resin for holding the quartz discharge plate. A greasy cushion ring 45 is embedded, and the upper peripheral edge of the quartz discharge plate 46 and the presser plate are A cushion ring 47 is interposed between the plate 43 and the plate 43.

[0023] A plurality of ventilation holes 48 are bored in the holding plate 43 at a required pitch in the radial direction. ing. A circular waveguide 49 is fixed to the holding plate 43. The circular waveguide 4 A nitrogen gas supply pipe 50 is connected to the upper surface of 9, and the nitrogen gas supply pipe 50 is not shown. Connected to a nitrogen gas source.

[0024] The action will be explained below.

[0025] The microwave generated by the microwave generation unit 2 is guided to the waveguide unit 4. and introduced into the processing chamber 3. Through the supply pipe 39, the annular groove 36, and the communication hole 37 A reaction gas is supplied into the processing chamber 3. The microwave is reflected by the porous reflector 32. , plasma is generated between the quartz discharge plate 46 and the porous discharge plate 32. this plasma The wafer (not shown) is processed by the quartz discharge plate 46, and the quartz discharge plate 46 is heated.

[0026] On the other hand, during operation, the inside of the circular waveguide 49 passes through the nitrogen gas supply pipe 50. Nitrogen gas at approximately room temperature is supplied, and the nitrogen gas is exhausted to the outside through the ventilation hole 48. Served. During this nitrogen gas distribution process, nitrogen gas flows onto the surface of the quartz discharge plate 46. More heat is removed and the quartz discharge plate 46 is cooled.

[0027] Further, the exhaust path 48 is provided near the surface of the quartz discharge plate 46 and along the periphery thereof. Therefore, there is no stagnation in the flow of the nitrogen gas on the surface of the quartz discharge plate 46, and cooling is performed by the quartz discharge plate 46. This is effectively carried out over the entire surface of the plate 46.

[0028] Furthermore, a refrigerant such as water is made to flow through the cooling pipe 41 through the holder plate 33. The O-ring 40 is cooled.

[0029] Since the quartz discharge plate 46 itself is cooled with nitrogen gas, the quartz discharge plate 46 is cooled by The heat transmitted from the discharge plate 46 can be suppressed, and the O-ring 44 itself can also be connected to the cooling pipe 4. 1 is cooled by a refrigerant flowing through it.

[0030] Regarding the porous reflecting plate 32, in FIG. 1, the uppermost spacer 31 and the holder plate If you want to change the position of the porous reflector plate 32, use the Between the collar 27 of the pace holder 26 and the lowermost spacer 28, or between the spacer 28 29, between the spacer 29 and the spacer 30, between the spacer 30 and the spacer 31 The porous reflector plate 32 can be sandwiched between the reflector plate 32 and the porous reflector plate 32. The distance between the porous reflector 32 and the wafer can be adjusted using the .

[0031] Furthermore, when the porous reflective plate 32 is sandwiched between the spacers, the spacer The distance can also be adjusted by changing the arrangement order.

[0032] In the above example, the lengths of the spacers in the axial direction were different, but the lengths were the same. You can also do this. Furthermore, the number of spacers is not limited to the above embodiment.

[0033]

[Effect of the idea]

As described above, according to the present invention, the position of the porous reflector is adjusted and the wafer processing conditions are adjusted. The distance between the wafer and the porous reflector can be set to the optimum distance depending on the situation, and the wafer processing It is possible to optimize processing speed, uniformity of processing within a wafer, etc.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an overall view of a plasma generator in which the embodiment is implemented.

FIG. 3 is a sectional view showing a conventional example.

[Explanation of symbols]

3 Processing room 19 Wafer placement stand 23 Processing chamber container 28 Spacer 29 Spacer 30 Spacer 31 Spacer 32 Porous reflector 33 Holder plate 43 Presser plate

Claims (1)

[Scope of utility model registration request] 1. A cylindrical surface is formed above a wafer table in a wafer processing chamber, and a plurality of spacers are fitted to the cylindrical surface, and a plurality of spacers are formed between the spacers or at the upper end of the upper stage spacer and the lower end of the lower stage spacer. A plasma generating device characterized in that it is configured to sandwich a porous reflector at either position.