JP3531466B2 - Semiconductor device manufacturing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing apparatus, and more particularly to a semiconductor device manufacturing apparatus having members for plasma etching processing, film forming processing, etc. using plasma with excellent uniformity. is there.

[0002]

2. Description of the Related Art A conventional semiconductor device manufacturing apparatus is shown in FIG. 11 (JP-A-7-14822). 11, the plasma reaction chamber 101 is provided, and the plasma reaction chamber 10
Wafer 1 on the bottom electrode 102 installed at the bottom of
No. 03 is installed, and the counter electrode 106 including the gas introduction pipe 104 and the dispersion plate 105 is provided above the plasma reaction chamber 101. Further, the plasma reaction chamber 101 is provided with a plurality of exhaust ports 107, and the exhaust ports 107 are connected to a vacuum pump to keep the plasma reaction chamber 101 in a vacuum state. Further, the etching gas is supplied from the gas introduction pipe 104 to the dispersion plate 10
5 is supplied into the plasma reaction chamber 101. Further, by applying a high frequency power supply 108 to the counter electrode 106, plasma is generated in the plasma reaction chamber 101 to perform plasma etching processing or the like.

[0003]

However, in the structure of the conventional plasma reaction apparatus, since the reaction gas is supplied from above the wafer and the reaction gas passes through the plasma for a long time, dissociation of the reaction gas by the plasma occurs. Be promoted. As a result, regarding the etching process, the etching rate of the resist film, which is the pattern mask used for manufacturing the semiconductor device, increases, and the ratio of the etching rate of the resist film and the etching rate of the film to be etched such as an oxide film to the resist selection The ratio is 2 to 3, which makes etching difficult, which requires a high resist-to-resist selection ratio.

According to the present invention, when an etching apparatus for introducing a reaction gas from the bottom of the plasma reaction chamber near the wafer is used, the uniformity of the etching rate in the plane of the wafer, and the selectivity to the resist and the in-plane uniformity thereof are used. It is an object of the present invention to provide an apparatus for manufacturing a semiconductor device having a member capable of changing the position of the gas introduction hole, which can cope with the difference between the etching gas species and the etching target film species.

[0005]

In order to solve this problem, the member supplied to the semiconductor device manufacturing apparatus of the present invention has a mechanism capable of changing the position of the gas inlet hole of the apparatus. .

As a result, the gas flow rate and gas density in the plasma reactor are made uniform, the distribution of the etching characteristics of the generated plasma in the wafer surface is made uniform, and it is optimized for the type of film to be etched and the type of gas. The characteristics of uniform etching rate and selective ratio to resist are obtained.

According to the present invention, with respect to a plurality of gas introduction holes fixed in the reaction chamber arranged around the wafer installation position, some of the gas introduction holes are completely aligned with the above gas introduction hole positions and the remaining gas introduction holes remain. By using a gas introduction plate with the gas holes closed and changing the position of the gas introduction plate to close the gas holes, the gas flow rate and gas density in the plasma reaction chamber can be adjusted with respect to the type of film to be etched and the type of etching gas. It has the effect of homogenizing and improving the in-plane uniformity of the etching rate and resist selectivity with respect to the wafer.

The present invention comprises a plurality of gas introducing holes fixed around the wafer installation position and fixed to the reaction chamber, and a groove for completely covering the gas introducing hole and connecting the gas introducing holes. By using a gas introduction plate provided with a plurality of gas holes connected to the groove on the surface opposite to the grooved surface, by arbitrarily changing the gas blowing position of the gas introduction plate, Make the gas flow rate and gas density uniform,
It has the effect of improving the uniformity of the etching rate and the resist selectivity with respect to the wafer surface.

According to the present invention, by using a gas introduction plate in which gas holes are locally arranged and the positions of the gas holes are made coarse and dense, the gas introduction plate is rotated or exchanged to arbitrarily change the gas blowing position. This has the effect of making the gas flow rate and gas density in the plasma reaction chamber uniform and improving the in-plane uniformity of the etching rate and resist selectivity with respect to the wafer.

In the present invention, the gas blowing area is 0.1 to 2
Using a gas introduction plate with multiple gas holes doubled, by rotating or replacing the gas introduction plate and arbitrarily changing the gas blowing position, the gas flow rate and gas density in the plasma reaction chamber are made uniform, and etching is performed. It has the effect of improving the uniformity of speed and resist selectivity with respect to the wafer surface.

The present invention uses a circular gas introduction plate which can change the position of the gas introduction hole fixed to the reaction chamber, rotates the gas introduction plate, and arbitrarily changes the gas blowing position to change the type of film to be etched. Also, it has the effect of making the gas flow rate and gas density in the plasma reaction chamber uniform with respect to the type of etching gas, and improving the in-plane uniformity of the etching rate and resist selectivity with respect to the wafer.

According to the present invention, a gas introducing plate made of quartz, silicon nitride, silicon carbide or aluminum nitride is used, the etching resistance of the gas introducing plate is enhanced, and the gas introducing plate is etched. It has the effect of reducing particles and extending the life of the gas introducing plate.

According to the present invention, a quartz ring, which is arranged around a wafer and made of quartz, has no holes penetrating through the upper surface and the lower surface. Since it cannot be removed by etching, it has the effect of extending the service life of the push-up pin and suppressing particles.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION << First Embodiment >> A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an etching apparatus utilizing the plasma reaction of the present invention.

In FIG. 1, a plasma induction coil 21 is wound around the side wall of the plasma reaction chamber 11 in multiple layers. The first high frequency power supply 22 is electrically connected to one end of the plasma induction coil 21, and the other end is grounded. A lower electrode 12 is installed at the bottom of the plasma reaction chamber 11, and a second high frequency power supply 23 is electrically connected to the lower electrode 12. An upper electrode 15 is arranged above the plasma reaction chamber 11, and the upper electrode 15 is an electrode facing the lower electrode 12. A wafer 13 is installed on the lower electrode 12.

A plurality of gas introduction holes 14 fixed to the apparatus are provided near the wafer 13 at the bottom of the plasma reaction chamber 11.
To induce the etching gas into the plasma reaction chamber 11. An exhaust port 19 is provided at one end of the outer periphery of the bottom of the plasma reaction chamber 11.
And a vacuum pump 20 is connected to the exhaust port 19.

A plasma reaction chamber 1 is provided around the wafer 13.
In order to protect the bottom of 1 from etching, a base plate 24 made of quartz and covering the bottom of the plasma reaction chamber 11 except for the lower electrode 12 is provided. The base plate 24 has a gas hole 25 in which a part of the hole is closed and the rest is completely aligned with the position of the gas introduction hole 14. The gas introduction position and the number of gas can be changed by changing the closing position of the gas hole.

A quartz ring 16 is installed on the outer periphery of the lower electrode 12, and a silicon ring 17 is placed on the quartz ring 16.
Is installed. Quartz ring 16 and silicon ring 1
Reference numeral 7 denotes a plurality of push-up pins 18 at the bottom of the plasma reaction chamber 11, which can be moved up and down by being pushed up through holes in the base plate.

In FIG. 2, the base plate 24 and the gas holes 25 are shown.
The top view and sectional drawing of and the gas introduction hole 14 are shown. The double circle shown in the top view of the base plate 24 is the gas hole 25 of the base plate 24 and the gas introduction hole 14 fixed to the plasma reaction chamber 11, and indicates that they are completely aligned. The dashed circles shown in the top view of the base plate 24 do not have the gas holes 25 in the base plate 24,
Only the gas introduction hole 14 of the plasma reaction chamber 11 is shown. Therefore, the gas introduction position to the plasma reaction chamber 11 can be changed by changing the closing position of the gas hole 25.

The operation of the etching apparatus having the above structure will be described below.

First, the silicon wafer 13 is carried on the lower electrode 12 in the plasma reaction chamber 11. Next, the inside of the plasma reaction chamber 11 is 10 mTorr by the vacuum pump 20.
A vacuum degree of about rr is maintained. Next, the wafer 13 and the lower electrode 12 are electrostatically coupled, and the wafer 13 is fixed to the lower electrode 12.

Next, etching gas such as C ₂ F ₆ gas or C ₄ F ₈ gas is used for gas introduction holes 14 near the wafer at the bottom and gas holes 25 other than the closed gas holes 25 of the base plate 24.
50 to 150 scc in the plasma reaction chamber 11 through
Introduced about m. Next, power of about 2000 W at 2.0 MHz is applied to the plasma induction coil 21 by the first high frequency power source 22 to generate plasma in the plasma reaction chamber 11. In addition, the second high frequency power supply 23
Then, power of about 1200 W is applied at 1.8 MHz to promote anisotropic etching and plasma etching is performed.

As described above, according to the present embodiment, by partially blocking the gas holes 25 of the base plate 24 and changing and optimizing the gas ejection portion, the plasma reaction which is locally biased due to gas exhaustion or the like. The gas flow rate and the gas density in the chamber 11 can be relaxed, and the degree of gas dissociation by plasma can be made uniform, so that the etching rate in the wafer surface and the uniformity of the resist selection ratio in the surface can be improved.

3 (a), 3 (b), 3 (c), and 3 (d), the base plate 24, the gas holes 25 in the base plate 24, and the closing positions of the gas holes 25, Four examples of the positional relationship of the exhaust ports 19 will be shown. The etching gas is a mixed gas of C ₄ F ₈ , CH ₂ F ₂ , Ar, and CO, and the flow rate ratio is 1: 1.5: 2.5: 3.5, and the silicon oxide film is formed using the resist as a mask. Is etching.

3 (a), 3 (b) and 3 are shown in FIG. 4 (a).
3C shows a change in etching rate with respect to the closed position of the gas hole 25 in FIG. The vertical axis of FIG. 4A is standardized with the etching rate of FIG. Than this,
As shown in FIG. 3B, when two gas holes 25 on the gas exhaust port 19 side are closed with respect to the position of the gas exhaust port 19, the etching rate becomes about 40% slower.

3 (a), 3 (b), 3
3C shows the change in the uniformity of the etching rate with respect to the closed position of the gas hole 25 in FIG. The vertical axis of FIG. 4B is standardized with the uniformity of the etching rate of FIG. Further, it is shown that the larger the vertical axis is, the worse the uniformity is. Therefore, as shown in FIG. 3B or FIG. 3C, when two gas holes 25 on the gas exhaust port 19 side or the gas exhaust port 19 opposite side are closed with respect to the gas exhaust port 19 position, the etching rate is The uniformity deteriorates by about 60%.

3 (a), 3 (b), 3
FIG. 3C shows a change in resist selectivity with respect to the closing position of the gas hole 25 of the base plate 24 in FIG. Figure 4
The vertical axis of (c) is normalized with the resist selection ratio with respect to FIG. As a result, when two gas holes on the gas exhaust port 19 side are closed with respect to the position of the gas exhaust port 19 as shown in FIG. 3B, the resist selectivity with respect to the resist deteriorates to about 10%. On the other hand, as shown in FIG. 3 (d), the gas hole 2 on the side opposite to the gas exhaust port 19
When one hole of 5 is closed, the selection ratio to resist is improved by about 10%. Further, the closed position of the gas hole 25 in FIG. 3 (d) is left with the gas exhaust port 19 facing up, but the same result is obtained with the right position.

3 (a), 3 (b), 3
3C shows the change in the uniformity of the resist selection ratio with respect to the closing position of the gas hole 25 of the base plate 24 in FIG. 3D. The vertical axis of FIG. 4D is standardized with the uniformity of the resist selection ratio with respect to FIG. Further, it is shown that the larger the vertical axis is, the worse the uniformity is. As a result, when two gas holes on the gas exhaust port 19 side are closed with respect to the position of the gas exhaust port 19 as shown in FIG. 3B, the uniformity of the resist selection ratio is deteriorated by about 50%. On the other hand, when two gas holes 25 on the opposite side of the gas exhaust port 19 are closed as shown in FIG. 3C, the uniformity of the resist selection ratio with respect to the resist is improved by about 30%. Further, as shown in FIG. 3D, the gas holes 2 on the side opposite to the gas exhaust port 19 are provided.
When 5 holes are closed by 1 hole, the uniformity of the resist selection ratio is improved by about 40%. Further, the closed position of the gas hole 25 in FIG. 3 (d) is left with the gas exhaust port 19 facing up, but the same result is obtained with the right position.

Therefore, under the etching conditions used in this experiment, as shown in FIG. 3D, the configuration of the positions of the gas exhaust port 19 and the gas hole 25 (the gas hole farthest from the gas exhaust port 19) Is a structure in which the etching rate and the uniformity are excellent, the selectivity with respect to the resist is improved, and the uniformity with respect to the resist is improved.

Although the base plate 24 is made of quartz in the above invention, it may be made of silicon nitride, silicon carbide or aluminum nitride.

<< Second Embodiment >> A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 shows a sectional view of the etching apparatus of the plasma reactor of the present invention. 11 to 25 in FIG.
The configuration and operation of are the same as the configuration and operation of 11 to 25 of FIG. 1 shown in the first embodiment, and therefore description thereof will be omitted. The only difference is the gas introduction plate 26 made of quartz.
Is installed. The configuration and operation of the gas introduction plate 26 will be described below.

FIG. 6 shows a top view and a sectional view of the gas introducing plate 26. The gas introduction plate 26 is a ring-shaped member that is installed on the upper portion of the base plate 24 and completely covers the gas holes 25 of the base plate 24. A double circle (a ring-shaped region surrounded by a dotted line) indicated by a broken line along the gas introduction plate 26 shown in the top view of FIG. 6 is a ring-shaped groove 27 that connects all the gas holes 25 of the base plate 24. Is. Also, the groove 2
A plurality of gas outlets 28 connected to the grooves 27 are provided on the surface opposite to the surface on which 7 is located. As a result, by using the gas introduction plate 26, it is possible to arbitrarily change the position of the gas outlet 28 without modifying the gas holes 25 fixed to the plasma reaction chamber 11.

As described above, according to the present embodiment, by opening the gas blowout port 28 of the gas introduction plate 26 at an arbitrary position to change the gas blowout position and the number of gas blowouts, and optimizing the gas blowout port, the gas exhaust or the like can be performed. The gas flow rate and the gas density in the plasma reaction chamber 11 that are locally biased are relaxed, the degree of gas dissociation by plasma is made uniform, and the etching rate in the wafer surface and the uniformity of the resist selection ratio are improved. be able to.

FIG. 7 (a) shows an example of the gas introducing plate 26 in which the position of the gas outlet 28 of the gas introducing plate 26 is biased. The gas blowing positions are formed on the circumference at a predetermined interval, but the number of gas blowing ports is reduced at a position where the amount of gas in the plasma chamber is desired to be reduced. FIG. 7B shows an example of the gas introducing plate 26 in which the sizes of the gas outlets 28 of the gas introducing plate 26 are biased. In this case, the size of the gas outlet at the position where the amount of gas in the plasma chamber is desired to be reduced is reduced.

As an example of the uniformity of the etching rate and the resist selectivity with respect to the resist by changing the gas blowing position by the gas introducing plate 26, FIG. 3 shown in the first embodiment.
The base plate 24 of (a), (b), (c), and (d) is replaced with a gas introduction plate 26, and the gas holes 25 are replaced with gas outlets 28.
The same effect can be obtained by replacing with.

By rotating the circular gas introducing plate 26 shown in FIGS. 7 (a) and 7 (b), the same gas introducing plate 26 can be obtained.
The gas introduction position can be easily changed with the plasma reaction chamber 11
The gas flow rate and gas density in the inside can be made uniform, and the etching rate and the uniformity of the resist selection ratio can be improved. Therefore, FIGS. 3B and 3C can be realized by the same gas introduction plate 26. Further, the closed position of one gas hole 25 in FIG. 3D can be moved to a position completely opposite to the gas exhaust port 19.

By connecting a stepping motor to the bottom of the circular gas introducing plate 26 shown in FIGS. 7 (a) and 7 (b) so that the rotating operation of the gas introducing plate 26 can be remotely controlled, By changing and optimizing the gas introduction position without opening and closing the plasma reaction chamber 11, the gas flow rate and gas density in the plasma reaction chamber 11 that are locally biased due to gas exhaust, etc. can be relaxed, and the gas generated by the plasma can be reduced. The degree of dissociation can be made uniform to improve the etching rate and the uniformity of the resist selection ratio.

FIG. 8 shows a top view and a sectional view of an example of a circular gas introducing plate 26 whose rotary operation can be remotely controlled. In FIG. 8, a gear groove 29 is dug on the outer circumference or the inner circumference of the groove 27 for rotation, and the rotating portion of the stepping motor 30 is connected to the gear groove 29. By rotating the rotating part of the stepping motor 30, the gear rotates and the gas introduction plate 26 rotates. As a result, the gas flow rate and the gas density in the plasma reaction chamber 11 which are locally biased due to gas exhaust, etc. are alleviated, the dissociation degree of the gas by the plasma is made uniform, and the uniformity of the etching rate and the resist selection ratio is improved. can do.

In the above invention, the gas introduction plate 2
Although the material of 6 is quartz, the material of the gas introducing plate 26 may be silicon nitride, silicon carbide, or aluminum nitride.

In the above invention, the silicon ring 17 shown in FIGS. 1 and 5 is used to reduce the fluorine component in the reaction gas, suppress the abrasion of the resist, and improve the selectivity ratio to the resist. Therefore, the CF ratio (ratio of the amount of C to F) which is the composition ratio of carbon and fluorine such as C ₄ F ₈ gas and C ₅ F ₈ gas in the etching gas is 0.
In the case of etching using a gas of 5 or more, the selectivity to resist can be obtained to some extent even if the silicon ring 17 is removed. FIG. 9 compares the etching characteristics with and without the silicon ring 17. The vertical axis is standardized with 1 when the silicon ring 17 is present.

FIG. 9A shows a comparison of etching rates with and without the silicon ring 17. The etching rate is about 10% faster without the silicon ring.

FIG. 9B shows a comparison of etching rate uniformity with and without the silicon ring 17. The vertical axis indicates that the larger the value, the worse the uniformity. The uniformity of the etching rate is improved by about 30% without the silicon ring 17.

FIG. 9C shows a comparison of the resist selection ratio with respect to the presence or absence of the silicon ring 17. There is no particular change in the resist selection ratio with respect to the presence or absence of the silicon ring 17.

FIG. 9D shows a comparison of uniformity of resist selection ratio with and without the silicon ring 17. The vertical axis indicates that the larger the value, the worse the uniformity. The uniformity of the resist selection ratio is about 25% worse without the silicon ring 17.

From this, it is effective to remove the silicon ring 17 in order to improve the uniformity of the etching rate. Further, it can be seen that the silicon ring 17 is preferable in the case of improving the resist selection ratio.

When the silicon ring 17 is not used, the quartz ring 16 having no holes is used above the quartz ring 16 of FIGS. 1 and 2. FIG. 10 shows an example of the quartz ring 16 having no holes at the top.

The broken line circle in the top view of the quartz ring 16 in FIG. 10 is a hole into which the push-up pin 18 having no hole up to the upper part is inserted. By using the quartz ring 16, the upper portion of the push-up pin 18 for pushing up the quartz ring 16 cannot be removed by etching, so that the service life of the push-up pin 18 can be extended and particles can be suppressed. In addition, the quartz ring 16 with no holes on the top
Can be used with or without a silicon ring.

[0050]

According to the present invention, by providing a gas introduction plate capable of introducing gas to a predetermined position of the plasma chamber without changing the position of the gas introduction hole fixed to the plasma chamber, The gas introduction position can be changed without the need to process the gas introduction part, and even if the composition of the reaction chamber, the film type to be etched, the etching gas type and the processing conditions are changed, the gas flow rate and gas in the plasma reaction chamber are changed. It is possible to realize an excellent semiconductor device manufacturing apparatus capable of making the density uniform and improving the etching rate and the uniformity of the resist selection ratio. (1) Localize the arrangement of gas holes in the base plate,
By giving a distribution to the gas blowing area, the gas flow rate and gas density in the plasma reaction chamber 11 which are locally biased due to gas exhaustion, etc. are alleviated, the degree of gas dissociation by plasma is made uniform, and the etching rate and pairing are improved. The uniformity of the resist selection ratio can be improved. (2) By using the gas introduction plate, the gas introduction position can be easily changed and the above effect can be obtained. (3) By remotely rotating the gas introducing plate, the gas blowing position can be easily changed and optimized without breaking the vacuum degree of the chamber. (4) By using quartz, silicon nitride, silicon carbide, or aluminum nitride as the material of the gas introducing plate, it is possible to extend the life of the gas introducing plate and reduce particles. (5) By using a quartz ring that does not have a hole penetrating from the upper surface to the lower surface, particles can be suppressed because the pins that push up the quartz ring are not etched.

[Brief description of drawings]

FIG. 1 is a configuration cross-sectional view of an etching apparatus according to a first embodiment of the present invention.

2A and 2B are a top view and a cross-sectional view showing a positional relationship among a base plate, a gas introduction hole, and a push-up pin according to the first embodiment of the present invention.

FIG. 3 is a top view showing a positional relationship among a base plate, a gas hole, a gas introduction hole, and an exhaust port according to the first embodiment of the present invention.

FIG. 4 is a characteristic diagram of uniformity of etching rate and resist selectivity with respect to four examples of the positional relationship between gas holes and exhaust ports shown in FIG. 3 in the first embodiment of the present invention.

FIG. 5 is a sectional view of an etching apparatus equipped with a gas introducing plate according to a second embodiment of the present invention.

FIG. 6 is a top view and a sectional view of a gas introducing plate according to a second embodiment of the present invention.

FIG. 7 is a top view of a gas introducing plate having a biased gas blowing position and a gas introducing plate having a biased gas blowing port size according to the second embodiment of the present invention.

8A and 8B are a top view and a cross-sectional view of a gas introduction plate in which a groove is formed on an outer peripheral portion of the groove of the gas introduction plate according to the second embodiment of the present invention.

FIG. 9 is a characteristic diagram showing changes in characteristics of etching rate and uniformity of resist selection ratio with and without a silicon ring in the second embodiment of the present invention.

FIG. 10 is a top view and a cross-sectional view showing the positional relationship among the quartz ring, the base plate, and the push-up pin according to the second embodiment of the present invention.

FIG. 11 is a sectional view of a conventional semiconductor device manufacturing apparatus.

[Explanation of symbols]

11 Plasma reaction chamber 12 Lower electrode 13 wafers 14 Gas introduction hole 15 Upper electrode 16 quartz ring 17 Silicon Ring 18 Push-up pin 19 exhaust port 20 vacuum pump 21 Plasma induction coil 22 First high frequency power supply 23 Second high frequency power supply 24 base plate 25 gas holes 26 Gas introduction plate 27 grooves 28 Gas outlet 29 gear groove 30 stepper motor 101 plasma reaction chamber 102 lower electrode 103 wafers 104 gas inlet pipe 105 Dispersion plate 106 counter electrode 107 exhaust port 108 high frequency power supply

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-7-45594 (JP, A) JP-A-6-53147 (JP, A) JP-A-8-45910 (JP, A) JP-A-5- 335280 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/3065 H01L 21/205

Claims (5)

(57) [Claims] 1. A plasma reaction chamber and the plasma reaction chamber
When viewed from above with multiple gas inlet holes fixed inside
Part of the gas introduction hole is blocked and remains
Is provided with a gas hole corresponding to the position of the gas introduction hole
A base plate and a gas outlet are provided, and the gas introduction hole has a structure in which the gas hole farthest from the gas outlet is closed, and the base plate closes a part of the gas introduction hole.
Depending on the structure, the gas introduction position and number can be changed to change the gas holes.
To localize the arrangement of the gas and give a distribution to the gas blowing area
A semiconductor device manufacturing apparatus characterized in that 2. A plasma reaction chamber and the plasma reaction chamber
Multiple gas inlet holes fixed inside, and gas holes are provided
A base plate and a gas outlet, and a groove on the upper side of the base plate that completely covers all the gas holes of the base plate and connects all the gas holes of the base plate, and a groove opposite to the surface with the groove. further example Bei the gas introducing plate having a plurality of gas outlet that is connected to the groove on the surface, the base plate closes a portion of the pores of the gas inlet hole
Depending on the structure, the gas introduction position and number can be changed to change the gas holes.
To localize the arrangement of the gas and give a distribution to the gas blowing area
A semiconductor device manufacturing apparatus characterized in that 3. The semiconductor device manufacturing apparatus according to claim 2 , wherein the gas introduction plate is biased in the gas blowing position. 4. The semiconductor device manufacturing apparatus according to claim 2 , wherein the gas introducing plate has a mechanism that is rotatable and that can change the position of the gas introducing hole. 5. The semiconductor device manufacturing apparatus according to claim 2, wherein the base plate and the gas introduction plate are made of at least one of quartz, silicon nitride, silicon carbide and aluminum nitride.