CN110804732A

CN110804732A - Plasma CVD apparatus

Info

Publication number: CN110804732A
Application number: CN201910523742.5A
Authority: CN
Inventors: 洪丽; 赵月; 公占飞
Original assignee: Hushang Industrial Development Group Co Ltd
Current assignee: Hushang Industrial Development Group Co Ltd
Priority date: 2019-06-17
Filing date: 2019-06-17
Publication date: 2020-02-18
Anticipated expiration: 2039-06-17
Also published as: CN110804732B

Abstract

The invention discloses a plasma CVD device, wherein a cylindrical cavity is fixed on a working platform of a frame, a microwave converter is arranged at the top of the cavity, an annular air inlet channel and an annular air exhaust channel which surround the cavity are arranged on the outer wall of the cavity, a plurality of observation windows are arranged on the periphery of the middle part of the cavity, an opening is arranged at the lower part of the cavity, a lifting mechanism is arranged on the frame and comprises a lifting table and a lifting flange which is arranged on the lifting table and used for sealing the opening of the cavity, a buffer mechanism is arranged between the lifting table and the lifting flange, an intracavity table for placing a substrate is fixed on the lifting table through a support tube, the intracavity table is positioned above the lifting flange and corresponds to the opening of the cavity, and a leakage-proof device is arranged at the lower. The plasma CVD device has the advantages of simple structure, good sealing performance of the cavity, less microwave leakage and long service life, and has very high practical value.

Description

Plasma CVD apparatus

Technical Field

The invention belongs to the technical field of chemical vapor deposition equipment, and particularly relates to a plasma CVD device.

Background

Chemical Vapor Deposition (CVD) is widely used in diamond synthesis, in which a mixture of gases (hydrogen, oxygen, nitrogen, methane, etc.) is heated in a chamber to form a carbon plasma in the chamber, and the carbon in the plasma is continuously deposited on a substrate (carbon substrate) in the chamber, and gradually accumulates and hardens to form a diamond film or sheet. The microwave CVD equipment in the prior art has a complex structure, a buffer mechanism is not arranged between the lifting mechanism and the cavity, and the lifting flange is in rigid hard contact with the cavity when the cavity is closed, so that the service life of the lifting mechanism (comprising a motor) or the sealing property of the cavity is easily influenced. In addition, when microwaves are used as a heat source, the conventional cavity structure easily causes leakage of the microwaves. Chinese patent publication No. CN 104053816a, publication No. 9/17/2014, discloses a CVD reactor and a substrate holder for a CVD reactor, having a reactor housing and a process chamber into which a process gas can be introduced by means of a gas inlet mechanism; having a substrate support, the upper side of which has one or more recesses, which is designed such that the substrate rests only on a support region which is raised relative to the base of the recess; the substrate holder has a heater which is spaced apart from the underside of the substrate holder by a gap, the underside of the substrate holder being designed in a central region below a central region of the recess in terms of heat transfer from the heater to the substrate holder differently than a peripheral region surrounding the central region below a region of the recess which is close to the edge. The heater is designed as a substantially flat heat source and the gas flushing device flushes the gap with the aid of a flushing gas. The gap has a gap height such that when a first purge gas having a first thermal conductivity is replaced with a second purge gas having a second thermal conductivity, a change in heat transfer from the heater to the substrate support in the peripheral region is different than in the central region. The substrate support structure of such CVD reactors is too complex.

Disclosure of Invention

The invention aims to solve the problems of the plasma CVD device in the prior art, and provides the plasma CVD device which has the advantages of simple structure, good cavity tightness, less microwave leakage and long service life.

The technical scheme adopted by the invention for solving the technical problems is that a plasma CVD device is arranged on a frame, a cylindrical cavity is fixed on a working platform of the frame, a microwave converter for guiding microwaves into the cavity is arranged at the top of the cavity, the microwave converter comprises an inner conductor extending into the cavity, a sealing medium plate for sealing the upper part of the cavity is arranged below the inner conductor, an annular air inlet channel surrounding the cavity is arranged on the outer wall of the cavity below the sealing medium plate and communicated with the cavity through an air inlet hole arranged around the cavity, a plurality of observation windows are arranged on the periphery of the middle part of the cavity, an opening is arranged at the lower part of the cavity, a cavity flange is arranged at the opening, an annular air exhaust channel surrounding the cavity is arranged on the outer wall of the cavity above the cavity flange, and is communicated with the cavity through an air exhaust hole arranged around the cavity, be equipped with elevating system in the frame, elevating system includes a elevating platform and sets up and be used for the sealed cavity open-ended lifting flange on the elevating platform, be equipped with buffer gear between elevating platform and the lifting flange, the intracavity platform for settling the substrate passes through the stay tube to be fixed on the elevating platform, the intracavity platform is located the top of lifting flange and corresponds with the opening of cavity, the lower part of intracavity platform is equipped with prevents leaking the device, when the elevating platform rose, the intracavity platform was located the cavity middle part, lifting flange and cavity flange butt and sealed cavity, when the elevating platform dropped, the intracavity platform shifted out outside the cavity through the opening.

The plasma CVD device comprises a cylindrical cavity, wherein a microwave converter is arranged at the upper part of the cavity to provide a heat source for chemical vapor deposition in the cavity, when the cavity is vacuumized and mixed gas (hydrogen, oxygen, nitrogen, methane and the like) is fed, carbon plasma is formed in the cavity, and carbon in the carbon plasma is continuously deposited on a base material (a carbon bottom layer) in the cavity and gradually accumulated and hardened, so that a diamond film or sheet is formed; the lifting mechanism is arranged below the cavity, so that the base materials in the cavity can be conveniently placed and taken out, and the whole structure is simple. And a buffer mechanism is arranged between the lifting platform and the lifting flange, so that when the cavity platform rises into the cavity, the lifting flange is in contact with the cavity flange, direct collision can be avoided, impact on the lifting mechanism and a motor caused by hard collision is avoided, and the service life of the lifting mechanism is prolonged. Meanwhile, the elastic buffering force of the buffering mechanism can enable the lifting flange and the cavity flange to be combined more tightly, so that possible looseness between the lifting flange and the cavity flange is avoided, and the sealing performance of the plasma cavity is ensured. In addition, the lower part of the cavity inner table is provided with a leakage-proof device, so that the leakage of the microwave can be effectively prevented. The plasma CVD device has the advantages of simple structure, good sealing performance of the cavity, less microwave leakage and long service life, and has very high practical value.

Preferably, an isolation flange is arranged above the sealed medium plate, a medium window plate is arranged on the isolation flange, a window hole is arranged in the center of the medium window plate, the diameter of the window hole is 4-5 times of the diameter of the inner conductor, heat dissipation holes are arranged on the periphery of the isolation flange, the diameter of each heat dissipation hole is smaller than one twentieth of the wavelength of the microwave, and sealing rings are arranged on the upper surface and the lower surface of the sealed medium plate. The isolation flange is used for pressing the medium sealing plate, the window hole and the reasonable size of the window hole are used for perfecting the shape of a microwave radiation field in the cavity, perfecting a plasma distribution structure in the cavity and facilitating chemical vapor deposition in the cavity; the small heat dissipation holes can avoid microwave leakage.

Preferably, the outer wall of the cavity is provided with a water cooling mechanism, and the water cooling mechanism comprises an annular cooling cavity arranged between the sealing medium plate and the annular air inlet channel and a cylindrical cooling cavity arranged above the medium window plate and below the annular air inlet channel; the water inlet and the water outlet of the annular cooling cavity are arranged in parallel, and a partition plate is arranged between the water inlet and the water outlet; the water inlet of the cylindrical cooling cavity is positioned at the lower part of the cylindrical cooling cavity, and the water outlet is positioned at the upper part of the cylindrical cooling cavity. The water cooling mechanism is arranged on the outer wall of the cavity and used for cooling the cavity.

Preferably, spiral partition plates surrounding the cavity are arranged in the cylindrical cooling cavity, and spiral water channels are formed among the spiral partition plates. The spiral water channel can ensure that the periphery of the cavity is uniformly cooled, and the phenomenon that the heat dissipation of the cavity is not uniform due to the fact that the water flow of the cylindrical water channel of the integral structure is not uniform is avoided.

Preferably, the upper end and the lower end of the isolation flange are connected with the connecting surface of the cavity body through grooves, reeds for preventing microwave leakage are arranged in the grooves, and the reeds are made of beryllium bronze and are subjected to surface gold plating treatment. The elastic spring can ensure the effective contact of the cavities on the two sides of the spring, thereby preventing the microwave leakage.

Preferably, the cavity platform is hollow structure, and the bottom is equipped with the opening, and the opening part is connected the stay tube, the stay tube includes outer tube and the inner tube of coaxial setting, and the opening part in cavity platform bottom is fixed on the top of outer tube, and the top of inner tube is close to the hollow structure top and the periphery of cavity platform and is equipped with the board that expands water of outside extension, and the lower extreme of inner tube is equipped with the water inlet, and the lower extreme of outer tube is equipped with the delivery port. The supporting tube is used for supporting the cavity inner platform and is used as a cooling pipeline of the cavity inner platform, cooling water enters from the bottom of the inner tube and upwards reaches the upper part of the water expansion plate during actual work, and the cavity inner platform is fully cooled and then downwards flows from the outer tube and flows out from the bottom of the outer tube; the water expansion plate is arranged, so that cooling water can be in full contact with the inner cavity platform, and the heat dissipation effect is improved.

Preferably, the cavity is a three-section stepped structure with a small top and a large bottom, the inner conductor and the sealing medium plate are positioned at the upper section of the cavity, the air inlet and the observation window are positioned at the middle section of the cavity, the air exhaust hole is positioned at the lower section of the cavity, and the inner wall of the middle section of the cavity and the inner wall of the lower section of the cavity are in conical surface transition. The conical surface between the inner wall of the middle section of the cavity and the inner wall of the lower section of the cavity is beneficial to the in-and-out of the cavity, and the collision is avoided when the cavity enters the cavity.

Preferably, the intracavity platform is big end down's stair structure, including the roof that is located the top and the base that is located the roof below, the external diameter of base and the internal diameter looks adaptation in cavity middle section, the junction of base upper portion and roof is equipped with the undergauge portion, prevents leaking the device including setting up at base middle part periphery and lower extreme open-ended microwave absorption ring cavity, the lower part periphery of base is equipped with the ring channel, is equipped with the reed that prevents the microwave leakage in the ring channel, when the elevating platform rose, reed and the middle section lower part inner wall butt of cavity. The diameter reducing part is arranged below the top plate, so that the length of the edge surface can be increased, an electromagnetic field in the cavity is concentrated above the top plate, plasma is formed above the top plate, and chemical vapor deposition in the cavity is concentrated on the base material of the top plate. The cross section of the microwave absorbing ring cavity is L-shaped and arranged around the cavity, the opening width of the microwave absorbing ring cavity is smaller than the wavelength of microwaves, so that the microwave absorbing ring cavity has the effect of preventing microwave leakage, and the reed at the lower part is abutted against the inner wall of the lower part of the middle section of the cavity when the lifting platform is lifted, so that the lower part of the inner platform of the cavity is connected with the cavity, and the effect of preventing microwave leakage is achieved.

Preferably, the lifting mechanism comprises a guide rail vertically arranged on the rack, a lifting seat is arranged on the guide rail, the lifting platform is fixed on the lifting seat, a screw rod threaded sleeve is arranged on the lifting seat and is in threaded connection with a vertically arranged lifting screw rod, the lower end of the lifting screw rod is connected with a motor fixed on the rack through a coupler, and the upper end of the screw rod is pivoted on a working platform of the rack. The motor drives the screw rod to rotate, so that the screw rod thread sleeve screwed on the screw rod moves up and down to drive the lifting seat on the guide rail to lift.

Preferably, the buffer mechanism comprises 3-6 guide pillars fixed on the bottom surface of the lifting flange, a spring is sleeved on each guide pillar, a guide sleeve corresponding to each guide pillar is arranged on the lifting platform, each guide pillar penetrates through the guide sleeve, the lower end of each guide pillar is fixed on an upper fixing ring arranged below the lifting platform, and a sealing ring is arranged on the lifting flange. When the lifting flange rises to abut against the cavity flange, the limit switch on the lifting mechanism is supposed to act that the motor should stop rotating immediately, but the motor is influenced by the rotation inertia, the manufacturing error and the like, and the situation that hard collision occurs or the lifting flange rises to be not tightly combined with the cavity flange can occur when the lifting flange actually rises to abut against the cavity flange; according to the invention, the buffer spring is arranged below the lifting flange, so that the motor can rotate for a certain angle when the lifting flange is lifted to abut against the cavity flange in actual control, and the hard collision between the lifting flange and the cavity flange is avoided by means of spring compression, so that the untight combination between the lifting flange and the cavity flange can be avoided, and the sealing of the cavity can be ensured.

Preferably, the lifting mechanism is provided with an intracavity platform height fine-tuning device, the intracavity platform height fine-tuning device comprises 3-5 guide rods and a manual lead screw, the guide rods are arranged on the bottom surface of the lifting platform, a lead screw seat is arranged below the lifting platform, a lead screw nut and a guide rod sleeve are arranged on the lead screw seat, the manual lead screw is in threaded connection with the lead screw nut, the upper end of the manual lead screw is pivoted on the lifting platform, the lower end of the manual lead screw is provided with a handle, the guide rods penetrate through the guide rod sleeve, and the lower end of the guide rods is fixed on a lower fixing ring arranged below the lead screw seat; the center of the bottom surface of the lifting flange is provided with a bellows upper flange, the screw rod seat is provided with a bellows lower flange, and a leakage-proof bellows is fixed between the bellows upper flange and the bellows lower flange. When the manual screw rod rotates, the screw rod seat can be driven to move up and down together with the intracavity platform; the height of the inner cavity platform relative to the lifting platform can be finely adjusted through the manual screw rod, and the position of the inner cavity platform in the cavity is accurate when the lifting flange is abutted to the cavity flange; the anti-leakage corrugated pipe is used for preventing microwave leakage at the position due to the fact that the lifting flange is of a slidable structure relative to the supporting pipe.

Preferably, the observation windows comprise four horizontal observation windows and two inclined observation windows, the six observation windows are symmetrically arranged in pairs, the two pairs of horizontal observation windows are respectively arranged on two different heights of the middle part of the cavity, the central lines of the observation windows are mutually vertical, and the pair of inclined observation windows is arranged between the two horizontal observation windows of the middle part of the cavity; temperature measuring holes are symmetrically arranged on the cavity. The observation window is used for observing the deposition condition on the base material in the cavity; the temperature measuring hole is used for arranging a temperature probe and is used for detecting the temperature in the cavity so as to ensure that the temperature in the cavity is within the range of the process requirement.

Preferably, one end of the microwave converter is connected with the three-screw adapter, and the other end of the microwave converter is connected with the short-circuit piston. The three-screw tuner is used for matching the microwave source with the microwave converter; the short-circuiting piston is used to reflect the microwaves at the other end of the converter, maximizing the efficiency of the microwave converter.

The invention has the beneficial effects that: the plasma CVD device has the advantages of simple structure, good sealing performance of the cavity, less microwave leakage and long service life, and has high practical value.

Drawings

FIG. 1 is a schematic view of a structure of a plasma CVD apparatus according to the present invention;

FIG. 2 is a schematic view of a portion of the structure of FIG. 1;

fig. 3 is a partial structural schematic view of fig. 1.

In the figure: 1. the device comprises a frame, 2, a working platform, 3, a cavity, 4, a microwave converter, 5, an inner conductor, 6, a sealing medium plate, 7, an annular air inlet channel, 8, an air inlet hole, 9, an observation window, 10, a cavity flange, 11, an annular air pumping channel, 12, an air pumping hole, 13, a lifting platform, 14, a lifting flange, 15, an inner cavity platform, 16, an isolation flange, 17, a medium window plate, 18, a window hole, 19, a heat dissipation hole, 20, a sealing ring, 21, an annular cooling cavity, 22, a cylindrical cooling cavity, 23, an outer tube, 24, an inner tube, 25, a water expansion plate, 26, a top plate, 27, a base, 28, a reducing part, 29, a microwave absorption ring cavity, 30, a reed, 31, a guide rail, 32, a lifting seat, 33, a threaded sleeve, 34, a lifting lead screw, 35, a coupler, 36, a motor, 37, a guide post, 38, a spring, 39, an upper fixing ring, 41, a guide rod, 43. the corrugated pipe comprises a screw rod seat, 44 screw rod nuts, 45 guide rod sleeves, 46 handles, 47 lower fixing rings, 48 corrugated pipe upper flanges, 49 corrugated pipe lower flanges and 50 leakage-proof corrugated pipes; 51. a temperature measuring hole; 52. a three-screw tuner; 53. short-circuiting piston, 54, pipe joint, 55, sleeve.

Detailed Description

The following provides a further description of embodiments of the present invention by way of examples and with reference to the accompanying drawings.

Example 1

In embodiment 1 as shown in fig. 1, fig. 2 and fig. 3, a plasma CVD apparatus is arranged on a frame 1, a cylindrical cavity 3 is fixed on a working platform 2 of the frame, a microwave converter 4 for guiding microwaves into the cavity is arranged at the top of the cavity, the front end of the microwave converter is connected with a microwave source through a three-screw adapter 52, and the rear end of the microwave converter is connected with a short-circuit piston 53; the invention adopts high-power microwave with the frequency of 2450MHz, and is connected with a microwave source through a waveguide tube of WR-340. The microwave converter comprises an inner conductor 5 extending into the cavity, a sealing medium plate 6 used for sealing the upper part of the cavity is arranged below the inner conductor, the sealing medium plate is a quartz glass plate, an annular air inlet channel 7 surrounding the cavity is arranged on the outer wall of the cavity below the sealing medium plate, the annular air inlet channel is communicated with the cavity through an air inlet hole 8 uniformly distributed around the cavity, an observation window 9 is arranged on the periphery of the middle part of the cavity and comprises four horizontal observation windows and two inclined observation windows, the six observation windows are symmetrically arranged in pairs, two pairs of horizontal observation windows with larger openings are respectively arranged on two different heights of the middle part of the cavity, the central lines of the observation windows are mutually vertical, and a pair of inclined observation windows with smaller openings are arranged between the two horizontal observation windows of the middle part of the; two temperature measuring holes 51 are symmetrically arranged on the cavity; the lower part of the cavity is provided with an opening for the inlet and outlet of the inner platform 15, the opening is provided with a cavity flange 10, the outer wall of the cavity above the cavity flange is provided with an annular air exhaust passage 11 surrounding the cavity, the annular air exhaust passage is communicated with the cavity through an air exhaust hole 12 arranged around the cavity, and the air exhaust passage is connected with a vacuum pump through a port. The lifting mechanism is arranged on the frame and comprises a lifting platform 13 and a lifting flange 14 arranged on the lifting platform and used for sealing an opening of the cavity, a buffer mechanism is arranged between the lifting platform and the lifting flange and comprises 4 guide pillars 37 fixed on the bottom surface of the lifting flange, a spring 38 is sleeved on each guide pillar, a guide sleeve 39 corresponding to each guide pillar is arranged on the lifting platform, each guide pillar penetrates through the corresponding guide sleeve, the lower end of each guide pillar is fixed on an upper fixing ring 40 arranged below the lifting platform, and a sealing ring 20 is arranged on the lifting flange. An intracavity platform for settling the substrate is fixed on the elevating platform through the stay tube, and the intracavity platform is located the top of lift flange and corresponds with the opening of cavity, and when the elevating platform rose, the intracavity platform was located the cavity middle part, and lift flange and cavity flange butt and sealed cavity, when the elevating platform dropped, the intracavity platform shifted out outside the cavity through the opening.

An isolation flange 16 is arranged above the sealed medium plate, a medium window plate 17 is arranged on the isolation flange, the medium window plate is made of quartz glass, a window hole 18 is arranged in the center of the medium window plate, the diameter of the window hole is 4-5 times of the diameter of the inner conductor, heat dissipation holes 19 are arranged on the periphery of the isolation flange, the diameter of each heat dissipation hole is smaller than one twentieth of the wavelength of the microwave, and sealing rings are arranged on the upper surface and the lower surface of the sealed medium plate. The upper end and the lower end of the isolation flange are connected with the connecting surface of the cavity, grooves are formed in the connecting surfaces of the upper end and the lower end of the isolation flange and the cavity, reeds for preventing microwave leakage are arranged in the grooves, and the reeds are made of beryllium bronze and subjected to surface gold plating treatment.

The outer wall of the cavity is provided with a water cooling mechanism, and the water cooling mechanism comprises an annular cooling cavity 21 arranged between the sealing medium plate and the annular air inlet channel and a cylindrical cooling cavity 22 arranged above the medium window plate and below the annular air inlet channel; the water inlet and the water outlet of the annular cooling cavity are arranged in parallel, and a partition plate is arranged between the water inlet and the water outlet to form an annular water flow cooling channel; the water inlets of the upper cylindrical cooling cavity and the lower cylindrical cooling cavity are both positioned at the lower part of the cylindrical cooling cavity, the water outlets of the upper cylindrical cooling cavity and the lower cylindrical cooling cavity are positioned at the upper part of the cylindrical cooling cavity to form a water flow cooling channel for water inflow from the lower part and water outflow from the upper part, and all the water inlets and the water outlets are connected with a cooling water circulation system through pipe joints 54.

The cavity inner table is of a hollow structure, the bottom of the cavity inner table is provided with an opening, the opening is connected with the supporting tube, the supporting tube comprises an outer tube 23 and an inner tube 24 which are coaxially arranged, the top end of the outer tube is fixed at the opening at the bottom of the cavity inner table, and the opening of the outer tube is communicated with the cavity inner table; the hollow structure top and the periphery that the top of inner tube is close to the intracavity platform are equipped with the board 25 that expands that outwards extends, and the lower extreme of inner tube is equipped with the water inlet, and the lower extreme of outer tube is equipped with the delivery port, and the bottom of inner tube gets into during the actual operation cooling water, upwards reachs the top of expanding the board, and it is downward by the outer tube after fully cooling to the intracavity platform, flows from the bottom of outer tube.

The cavity is of a three-section stepped structure with a small upper part and a large lower part, the inner conductor and the sealing medium plate are positioned at the upper section of the cavity, the air inlet is positioned at the upper part of the middle section of the cavity, the observation window is positioned at the middle section of the cavity, the air exhaust hole is positioned at the lower section of the cavity, and the inner wall of the middle section of the cavity and the inner wall of the lower section of the cavity are in conical surface transition. The intracavity platform is big end down's stair structure, including being located the roof 26 on top and being located the base 27 of roof below, the external diameter of base and the internal diameter looks adaptation in cavity middle section, the junction of base upper portion and roof is equipped with undergauge portion 28, prevent leaking the device including setting up at base middle part periphery and lower extreme open-ended microwave absorption ring cavity 29, the lower part periphery of base is equipped with the ring channel, be equipped with the reed 30 that prevents the microwave leakage in the ring channel, when the elevating platform rose, the reed and the middle section lower part inner wall butt of cavity, the reed is beryllium bronze material and surface gold-plating and handles.

Elevating system includes vertical setting guide rail 31 in the frame, is equipped with lifting seat 32 on the guide rail, the elevating platform fix on lifting seat, be equipped with the lead screw swivel nut 33 on the lifting seat, the lead screw swivel nut is connected with the 34 spiro unions of the lift lead screw of vertical setting, the lower extreme of lift lead screw passes through shaft coupling 35 and is connected with the motor 36 of fixing in the frame, the upper end pin joint of lead screw is on the work platform of frame, elevating system still includes limit switch, limit switch connects the motor. When the motor rotates, the lifting seat, the lifting flange and the cavity inner table are driven to move up and down through the screw rod thread sleeve, when the lifting seat is lifted up, the lifting flange is used for sealing the cavity, and the substrate on the cavity inner table enter the middle part of the cavity; when the lifting seat descends, the inner platform of the cavity leaves the cavity, so that the base material on the inner platform of the cavity can be replaced conveniently.

The lifting mechanism is provided with an intracavity platform height fine-tuning device, the intracavity platform height fine-tuning device comprises 3 guide rods 41 arranged on the bottom surface of the lifting platform and a manual lead screw 42, a lead screw seat 43 is arranged below the lifting platform, a lead screw nut 44 and a guide rod sleeve 45 are arranged on the lead screw seat, the manual lead screw is in threaded connection with the lead screw nut, the upper end of the manual lead screw is pivoted on the lifting platform, the lower end of the manual lead screw is provided with a handle 46, the guide rod penetrates through the guide rod sleeve, and the lower end of the guide rod is fixed on a lower fixing ring 47 arranged below the lead screw seat; the center of the bottom surface of the lifting flange is provided with an upper corrugated pipe flange 48, a sleeve 55 made of polytetrafluoroethylene is arranged between the lifting flange and the upper corrugated pipe flange and the outer pipe, a sealing ring is arranged between a lower corrugated pipe flange and the supporting pipe, a lower corrugated pipe flange 49 is arranged on the screw rod seat, and a leakage-proof corrugated pipe 50 is fixed between the upper corrugated pipe flange and the lower corrugated pipe flange.

Example 2

The cylindrical cooling cavity of example 2 is provided with spiral partition plates (not shown) surrounding the cavity, and spiral water channels are formed between the spiral partition plates, which are otherwise the same as those of example 1.

In addition to the above embodiments, the technical features or technical data of the present invention may be reselected and combined to form new embodiments within the scope of the claims and the specification of the present invention, which are all realized by those skilled in the art without creative efforts, and thus, the embodiments of the present invention not described in detail should be regarded as specific embodiments of the present invention and are within the protection scope of the present invention.

Claims

1. A plasma CVD device is arranged on a frame (1) and is characterized in that a cylindrical cavity (3) is fixed on a working platform (2) of the frame, a microwave converter (4) for guiding microwaves into the cavity is arranged at the top of the cavity, the microwave converter comprises an inner conductor (5) extending into the cavity, a sealing medium plate (6) for sealing the upper part of the cavity is arranged below the inner conductor, an annular air inlet channel (7) surrounding the cavity is arranged on the outer wall of the cavity below the sealing medium plate, the annular air inlet channel is communicated with the cavity through an air inlet (8) arranged around the cavity, a plurality of observation windows (9) are arranged on the periphery of the middle part of the cavity, an opening is arranged at the lower part of the cavity, a cavity flange (10) is arranged at the opening, an annular air exhaust channel (11) surrounding the cavity is arranged on the outer wall of the cavity above the cavity flange, and the annular air, be equipped with elevating system in the frame, elevating system includes a elevating platform (13) and sets up and be used for sealed cavity open-ended lift flange (14) on the elevating platform, be equipped with buffer gear between elevating platform and the lift flange, intracavity platform (15) for settling the substrate are fixed on the elevating platform through the stay tube, the intracavity platform is located the top of lift flange and corresponds with the opening of cavity, the lower part of intracavity platform is equipped with prevents leaking the device, when the elevating platform rose, the intracavity platform was located the cavity middle part, lift flange and cavity flange butt and sealed cavity, when the elevating platform descended, the intracavity platform shifted out outside the cavity through the opening.

2. A plasma CVD apparatus according to claim 1, wherein an isolation flange (16) is provided above the sealing medium plate, a medium window plate (17) is provided on the isolation flange, a window hole (18) is provided in the center of the medium window plate, the diameter of the window hole is 4 to 5 times the diameter of the inner conductor, heat radiating holes (19) are provided in the periphery of the isolation flange, the diameter of the heat radiating holes is smaller than one twentieth of the wavelength of the microwave, and sealing rings (20) are provided on both the upper and lower surfaces of the sealing medium plate.

3. A plasma CVD apparatus according to claim 1, wherein a water cooling mechanism is provided on an outer wall of the chamber, and the water cooling mechanism includes an annular cooling chamber (21) provided between the sealing medium plate and the annular inlet, and a cylindrical cooling chamber (22) provided above the medium window plate and below the annular inlet; the water inlet and the water outlet of the annular cooling cavity are arranged in parallel, and a partition plate is arranged between the water inlet and the water outlet; the water inlet of the cylindrical cooling cavity is positioned at the lower part of the cylindrical cooling cavity, and the water outlet is positioned at the upper part of the cylindrical cooling cavity.

4. A plasma CVD apparatus according to claim 1, wherein the inner chamber has a hollow structure, and an opening is formed at the bottom of the hollow structure, and the opening is connected to the support tube, and the support tube comprises an outer tube (23) and an inner tube (24) coaxially disposed, wherein the top end of the outer tube is fixed at the opening at the bottom of the hollow structure, the top end of the inner tube is close to the top of the hollow structure of the inner chamber, and the outer circumference of the inner tube is provided with a water expansion plate (25) extending outwards, the lower end of the inner tube is provided with a water inlet, and the.

5. The plasma CVD apparatus of claim 1, wherein the chamber has a three-section stepped structure with a small top and a large bottom, the inner conductor and the sealing medium plate are located at the top of the chamber, the air inlet and the observation window are located at the middle of the chamber, the air exhaust hole is located at the bottom of the chamber, and the inner wall of the middle of the chamber and the inner wall of the bottom of the chamber are in conical surface transition.

6. A plasma CVD apparatus according to claim 5, wherein the chamber is a stepped structure having a small top and a large bottom, and includes a top plate (26) at a top end and a susceptor (27) below the top plate, an outer diameter of the susceptor is adapted to an inner diameter of a middle section of the chamber, a diameter reduction portion (28) is provided at a junction between an upper portion of the susceptor and the top plate, the leakage preventing means includes a microwave absorbing ring chamber (29) provided at a periphery of the middle portion of the susceptor and having an opening at a lower end thereof, an annular groove is provided at a periphery of a lower portion of the susceptor, a reed (30) for preventing leakage of microwaves is provided in the annular groove, and the reed abuts against an inner wall of the.

7. A plasma CVD apparatus according to claim 1, characterized in that the elevating mechanism comprises a guide rail (31) vertically arranged on the frame, a lifting base (32) is provided on the guide rail, the elevating platform is fixed on the lifting base, a screw sleeve (33) is provided on the lifting base, the screw sleeve is screwed with a vertically arranged lifting screw (34), the lower end of the lifting screw is connected with a motor (36) fixed on the frame through a coupling (35), and the upper end of the screw is pivoted on the working platform of the frame.

8. A plasma CVD apparatus according to claim 1, wherein the buffer mechanism includes 3 to 6 guide posts (37) fixed to a bottom surface of the elevating flange, the guide posts are provided with springs (38) around the guide posts, the elevating platform is provided with guide sleeves (39) corresponding to the guide posts, the guide posts pass through the guide sleeves, lower ends of the guide posts are fixed to an upper fixing ring (40) provided below the elevating platform, and the elevating flange is provided with a sealing ring.

9. A plasma CVD apparatus according to claim 1, wherein the elevating mechanism is provided with an in-chamber stage height fine-adjusting means, the in-chamber stage height fine-adjusting means comprises 3-5 guide rods (41) and a manual lead screw (42) arranged on the bottom surface of the elevating platform, a lead screw base (43) is arranged below the elevating platform, a lead screw nut (44) and a guide rod sleeve (45) are arranged on the lead screw base, the manual lead screw is screwed with the lead screw nut, the upper end of the manual lead screw is pivoted on the elevating platform, the lower end of the manual lead screw is provided with a handle (46), the guide rod passes through the guide rod sleeve, and the lower end of the guide rod is fixed on a lower fixing ring (47) arranged below the lead screw base; the center of the bottom surface of the lifting flange is provided with a bellows upper flange (48), the screw rod seat is provided with a bellows lower flange (49), and a leakage-proof bellows (50) is fixed between the bellows upper flange and the bellows lower flange.

10. A plasma CVD apparatus according to any one of claims 1 to 9, wherein the observation windows include four horizontal observation windows and two inclined observation windows, the six observation windows are arranged two by two symmetrically, two pairs of the horizontal observation windows are respectively arranged at two different heights in the middle of the chamber and the center lines of the observation windows are perpendicular to each other, and one pair of the inclined observation windows is arranged between the two horizontal observation windows in the middle of the chamber; temperature measuring holes (51) are symmetrically arranged on the cavity; one end of the microwave converter is connected with the three-screw adapter (52), and the other end of the microwave converter is connected with the short-circuit piston (53).