KR20090113184A - Film forming apparatus and film forming method - Google Patents

Abstract

PURPOSE: An apparatus and a method for forming a film are provided to stabilize a substrate by absorbing the substrate in a supporting part. CONSTITUTION: An apparatus for forming a film includes a supporting part, a rotation part(104), a heating part, and an exhaust unit. The supporting part supports a substrate. The rotation part rotates the supporting part, and forms a hollow region by covering a top part by the supporting part. The heating part is arranged in the hollow region, and heats the substrate through the supporting part. The exhaust unit exhausts a gas inside the hollow region.

Description

FILM FORMING APPARATUS AND FILM FORMING METHOD}

The present invention relates to a film forming apparatus and a film forming method.

BACKGROUND ART In the past, epitaxial growth techniques have been utilized for the manufacture of semiconductor devices requiring crystal films with relatively thick thicknesses, such as power devices such as IGBTs (Insulated Gate Bipolar Transistors).

In order to produce epitaxial wafers with a high film thickness with high yield, it is necessary to improve the film formation speed by sequentially contacting new source gas with the surface of the uniformly heated wafer. Therefore, epitaxial growth is performed while the wafer is rotated at high speed (see, for example, JP-A-5-152207).

In Japanese Patent Laid-Open No. 5-152207, a susceptor for supporting a wafer is fitted to the susceptor support portion, and the wafer is rotated by rotating the rotation shaft connected to the susceptor support portion. However, since the wafer is only structured on the susceptor, there is a fear that the wafer is shifted when the rotation speed increases.

In addition, when epitaxial growth is performed, the pressure in the deposition chamber is adjusted to a predetermined pressure. However, if the pressure side in the susceptor support substantially sealed through the wafer is high, there is a fear that the wafer is shifted from the susceptor.

The wafer is heated from the back surface to form an epitaxial film on the surface, but is bent in a concave shape toward the surface side by heating. For this reason, when the wafer is rotated at high speed, there is a possibility that the wafer is easily shifted from the susceptor.

As described above, if the wafer is deviated from the susceptor due to the above-described cause, film formation to the wafer cannot be performed and the yield of epitaxial wafers is greatly reduced. Thus, the wafer is deviated from the susceptor. It was urgent to make it difficult.

This invention is made | formed in view of such a subject. That is, an object of the present invention is to provide a film forming apparatus capable of stabilizing a substrate and rotating at high speed.

It is also an object of the present invention to provide a film formation method which can form a film on a substrate while stabilizing the substrate and rotating at high speed.

Other objects and advantages of the present invention will become apparent from the following description.

The first aspect of the present invention

In the film-forming apparatus which performs a film-forming process on the board | substrate carried in a film-forming chamber,

Support for supporting the substrate,

A rotating part which rotates the support and is covered by the support to form a hollow area,

A heating portion disposed in the hollow region and heating the substrate through the support portion, and

And exhaust means for exhausting the gas in the hollow region,

The support part is provided with a plurality of holes in the contact surface with the substrate,

The substrate is adsorbed to the support by exhausting the gas in the hollow region.

In the 1st aspect of this invention, it is preferable that the contact surface with the board | substrate of a support part is concave shape inclined toward the center part from an outer edge part.

The second aspect of the present invention

In the film forming method of forming a film on a substrate placed in a film forming chamber,

Bringing the substrate into the deposition chamber and placing the substrate on a support portion having a plurality of holes provided on its surface;

Heating the substrate while rotating the support portion, and

After the substrate reaches a predetermined temperature, the substrate has a step of adsorbing the substrate to the support by exhausting the gas in the space substantially spaced between the film formation chamber and the support.

In the 2nd aspect of this invention, it is preferable to make predetermined temperature into film-forming temperature.

In the 2nd aspect of this invention, in the process of making a board | substrate adsorb | suck to a support part, it is preferable to depressurize the pressure in space to 90% of the pressure in a maximum film-forming chamber.

According to the first aspect of the present invention, a plurality of holes are provided in the contact surface with the substrate of the support portion, and the substrate is adsorbed to the support portion by evacuating the gas in the hollow region, whereby the substrate can be stabilized and the film can be rotated at high speed. have.

According to the second aspect of the present invention, after the substrate reaches a predetermined temperature, the substrate is adsorbed to the support by exhausting the gas in the space substantially separated from the deposition chamber by the support, so that the substrate is stabilized and rotated at high speed. A film forming method capable of forming a film is provided.

1 is a schematic cross-sectional view of a sheet type film deposition apparatus 100 according to the present embodiment. In this embodiment, the silicon wafer 101 is used as the substrate. However, the present invention is not limited thereto, and a wafer made of another material may be used in some cases.

The film forming apparatus 100 has a chamber 103 as a film forming chamber.

In the upper portion of the chamber 103, a gas supply unit 123 is provided on the surface of the heated silicon wafer 101 to supply source gas for forming a crystal film. The gas supply part 123 is connected to a shower plate 124 in which a plurality of source gas discharge holes are formed. By arranging the shower plate 124 to face the surface of the silicon wafer 101, the source gas can be supplied to the surface of the silicon wafer 101.

In the lower part of the chamber 103, the gas exhaust part 125 which exhausts the raw material gas after reaction is provided. The gas exhaust unit 125 is connected to an exhaust mechanism 128 composed of an adjustment valve 126 and a vacuum pump 127. The exhaust mechanism 128 is controlled by the control mechanism 112 to adjust the inside of the chamber 103 to a predetermined pressure.

In the chamber 103, a receptor 102 as a support part is provided on the rotating part 104. As shown in FIG.

The rotating part 104 has the cylindrical part 104a and the rotating shaft 104b. The rotating shaft 104b is rotated by a motor (not shown), whereby the susceptor 102 rotates through the cylindrical portion 104a.

In FIG. 1, the cylindrical portion 104a has an open top, but the susceptor 102 is provided to form a hollow area (hereinafter, referred to as a P ₂ area) by covering the top. Here, when the inside of the chamber 103 is made into a P ₁ region, the P ₂ region becomes a region substantially separated from the P ₁ region by the susceptor 102.

In the P ₂ region, an injector 120 and an out heater 121 are provided to heat the silicon wafer 101 from the rear surface through the susceptor 102. The surface temperature of the silicon wafer 101 which is changed by heating is measured by the radiation thermometer 122 provided above the chamber 103. In addition, by making the shower plate 124 made of transparent quartz, it is possible to prevent the temperature measurement by the radiation thermometer 122 from being disturbed by the shower plate 124. The measured temperature data is sent to a control mechanism (not shown) and then fed back to the output control of the injector 120 and the out heater 121. Thereby, the silicon wafer 101 can be heated so that the temperature distribution in the surface may become uniform.

The rotating part 104 is connected with the rotating mechanism not shown by the rotating shaft 104b extended to the exterior of the chamber 103, and it rotates by predetermined rotation speed by making the axis the centerline orthogonal to the silicon wafer 41. Thereby, the susceptor 102 can be rotated, and further, the silicon wafer 101 supported by the susceptor 102 can be rotated.

The rotary part 104 is provided with an exhaust pipe 107 which is an exhausting means for exhausting the gas in the P ₂ region. The exhaust pipe 107 passes through the interior of a substantially cylindrical quartz shaft 108 installed in the rotating shaft 104b, and includes an exhaust valve composed of an adjustment valve 109 and a vacuum pump 110 provided outside the chamber 103. And (111).

2 is a cross-sectional view showing a state where the silicon wafer 101 is placed on the susceptor 102. 3 is the figure which looked at the susceptor 102 from upper direction. 4 is a partially enlarged sectional view of the susceptor 102.

As shown in FIGS. 2 to 4, a plurality of holes penetrate the susceptor 102 to communicate with the P ₁ region and the P ₂ region in the contact surface 105 where the susceptor 102 contacts the silicon wafer 101. 106 is provided. When operating the exhaust mechanism 111, the gas exhaust region in the P ₂ the pressure of the area P ₂ becomes lower than the pressure P ₁ in the area. As a result of the pressure difference, the silicon wafer 101 is sucked to the P ₂ region side through the hole 106, and the silicon wafer 101 can be adsorbed to the susceptor 102. Thereby, even if the susceptor 102 rotates at high speed, the silicon wafer 101 can be stabilized and supported. In addition, by connecting the exhaust mechanism 111, the control mechanism 112 to control the pressure P ₁ of the sphere it can be varied along with the pressure P ₂ in the region of the pressure of the area P _1.

In FIG. 3, although the hole 106 was provided centering in the vicinity of the center part of the contact surface 105, you may provide so that it may distribute uniformly in the whole contact surface 105 at equal intervals, or it may be concentric in shape from the center of the contact surface 105. FIG. You may install it. If the diameter of the hole 106 is too large or the number of the holes 106 is too large, it is concerned that the inside of the chamber 103 is contaminated with metal due to various members accommodated in the rotating part 104. Accordingly, the size and number of the holes are determined so that the silicon wafer 101 can be adsorbed to the susceptor 102 while taking this into consideration.

8 is a diagram illustrating an example of the relationship between the pressure difference between the P ₁ region and the P ₂ region and the frictional force between the silicon wafer 101 and the susceptor 102. In this example, the diameter of the hole 106 provided in the susceptor 102 is 2 mm. As can be seen from Fig. 8, when the pressure difference is the same, the larger the number of the holes 106, the greater the frictional force. In addition, when the number of the holes 106 is the same, the larger the pressure difference, the greater the frictional force. The tendency (ratio of increase in frictional force to increase in pressure difference) increases as the number of holes 106 increases. 9 is a diagram showing an example of the relationship between the rotational speed of the silicon wafer 101 and the centrifugal force acting on the silicon wafer 101. As can be seen from FIG. 9, when the rotation speed is the same, the centrifugal force becomes larger as the distance from the rotation center of the rotation part 104 to the center of the silicon wafer 101 becomes larger. In addition, when the distance from the center of rotation of the rotating part 104 to the center of the silicon wafer 101 is the same, the larger the rotation speed, the greater the centrifugal force. And the tendency (ratio of increase of centrifugal force to increase of rotation speed) becomes large, so that the shift amount between the said centers becomes large. In this embodiment, the pressure difference between the P ₁ region and the P ₂ region and the number of the holes 106 are set so that the frictional force> the centrifugal force with reference to FIGS. 8 and 9.

It is preferable that the contact surface 105 has a concave shape inclined from the outer edge to the center as shown in Figs. This takes into account that the silicon wafer 101 is bent by heating at the time of film formation. That is, by making the shape of the contact surface 105 into the shape of the silicon wafer 101 after heating previously, it can prevent that the silicon wafer 101 rises from the susceptor 102 and becomes easy to escape | escape during film-forming. For example, when using an 8-inch (diameter approximately 200 mm) silicon wafer 101, the distance H from the substantially horizontal surface h _{1 of the} outer edge of the susceptor 102 to the deepest central portion h ₂ It is good to make 2 micrometers-30 micrometers. If it is in this range, the surface shape of the contact surface 105 can be harvested on the back surface of the silicon wafer 101 bent by heating.

In FIG. 3, the diameter d ₁ of the substantially circular contact surface 105 is preferably equal to or larger than the diameter d ₂ of the silicon wafer 101 on which it is placed. If d _1? d ₂ , the outer surface of the silicon wafer 101 can be brought into contact with the contact surface 105, thereby further increasing the adhesion to the susceptor 102.

When changing the diameter of the silicon wafer 101, it is preferable to appropriately set the depth H and the diameter d ₁ of the contact surface 105 accordingly.

5 is a flowchart showing the film formation method of the present embodiment. 6 is a graph showing the relationship between the elapsed time of the film forming process, the surface temperature of the silicon wafer 101 and the rotation speed. 7 is the sectional drawing which expands and shows the state which adsorb | sucks the silicon wafer 101 to the susceptor 102 in the film-forming process of this embodiment.

One form of the film-forming method of this embodiment is implemented with the following procedures.

First, as shown in FIG. 2, the silicon wafer 101 is placed on the susceptor 102, and is attached to the rotating unit 104 to rotate the silicon wafer 101 at about 50 rpm (S101).

Next, the silicon wafer 101 is heated by the injector 120 and the out heater 121. For example, it gradually heats up to 1150 degreeC which is film-forming temperature (S102).

After confirming that the temperature of the silicon wafer 101 reaches 1150 degreeC by the measurement by the radiation thermometer 122, the rotation speed of the silicon wafer 101 is gradually raised. When the rotation speed of the silicon wafer 101 exceeds 300 rpm (T ₁ ), the exhaust mechanism 111 is operated to start the pressure reduction of the P ₂ region (S103). Thereafter, the source gas is supplied from the gas supply unit 123 to the surface of the silicon wafer 101 through the shower plate 124.

When the P ₂ region is reduced in pressure with respect to the P ₁ region, downward force as indicated by the arrow in FIG. 7 acts on the silicon wafer 101. As a result, the silicon wafer 101 is adsorbed to the susceptor 120 (S104).

When the temperature of the silicon wafer 101 is maintained at about 1150 ° C, the silicon wafer 101 starts to bend with the back surface convex. At this time, by making the contact surface 105 of the susceptor 102 into a concave shape inclined from the outer edge to the center, the silicon wafer 101 can be brought into close contact with the susceptor 102 smoothly. Therefore, even if the susceptor 102 is rotated at a high speed of 900 rpm or higher, for example, the silicon wafer 101 can be stabilized and supported. Therefore, it is possible to prevent the silicon wafer 101 from shifting from the susceptor 102.

The control structure 112 preferably controls the exhaust mechanism 111 such that the pressure in the P ₂ region is reduced to 90% of the maximum P ₁ region pressure. For example, when the pressure in the P ₁ region is 700 Torr, the pressure in the P ₂ region is reduced to about 630 Torr. As a result, sufficient adsorption force is obtained without applying excessive force to the silicon wafer 101. In addition, disturbance of the flow of the source gas in the P ₁ region can be minimized.

In the above-described state, the epitaxial film can be efficiently formed at a high deposition rate by supplying new source gas to the silicon wafer 101 sequentially from the gas supply unit 123 provided above the chamber 103 through the shower plate 124. It may be (S105).

As described above, when the film forming apparatus and the film forming method of the present embodiment are used, the substrate can be stabilized and rotated even when the number of rotations of the susceptor is increased to improve the film formation speed, so that the epitaxial wafer can be produced at a high yield. It can manufacture.

As mentioned above, embodiment was described, referring a specific example. This invention is not limited to embodiment mentioned above, You may change and implement variously in the range which does not deviate from the summary.

For example, in one embodiment of the present invention described above, the decompression of the P ₂ region is started when the rotation speed of the susceptor 102 exceeds 300 rpm. This is because when the rotation speed of the susceptor 102 is about 300 rpm, the source gas flowing on the silicon wafer 101 is in a laminar flow state, so that the flow of the source gas is not disturbed even when the P ₂ region is reduced in pressure. However, when the process gas such as pressure or temperature in the chamber 103 is changed, and the source gas can be laminar flow on the silicon wafer 101 even if the rotation speed is not the above, the time for depressurizing the P ₂ region ( The timing is not limited to the above example. That is, the pressure reduction of the P ₂ region may be performed at a time when the flow of the source gas supplied to the silicon wafer 101 is not disturbed.

Although an epitaxial growth apparatus has been described as an example of the film forming apparatus of the present invention, the present invention is not limited thereto, and the epitaxial growth apparatus may be any apparatus for vapor-growing a predetermined crystal film on the silicon wafer surface. For example, even if it is a film-forming apparatus aimed at growing a polysilicon film, the effect similar to this invention can be acquired.

In addition, although description is abbreviate | omitted about the part which is not directly required by this invention, such as a structure of a device, a control method, etc., the structure of a required device, a control method, etc. can be selected suitably, and can be used.

In addition, except for the configuration necessary for explanation in the drawings shown for explaining the present invention, the scale and the like have been changed appropriately so as not to match the original size, but to be clearly visible.

In addition, all vapor phase growth apparatuses and elements of the present invention which are equipped with the elements of the present invention and can be appropriately modified by those skilled in the art are included in the scope of the present invention.

1 is a cross-sectional view of the film forming apparatus of this embodiment;

2 is a cross-sectional view showing a state where a wafer is placed on a susceptor in the present embodiment;

3 is a view of the susceptor viewed from above in the present embodiment;

4 is a partially enlarged cross-sectional view of the susceptor of the present embodiment;

5 is a flowchart showing a film forming method of the present embodiment;

6 is a graph showing the relationship between the elapsed time of the film forming step of the present embodiment, the surface temperature of the wafer and the rotation speed;

7 is a cross-sectional view showing a state in which a silicon wafer is adsorbed to a susceptor in the present embodiment;

FIG. 8 is a diagram showing an example of the relationship between the pressure difference between the P ₁ region and the P ₂ region and the frictional force between the silicon wafer and the susceptor in the present embodiment; and

9 is a diagram showing an example of the relationship between the rotational speed of the silicon wafer and the centrifugal force acting on the silicon wafer in the present embodiment.

* Explanation of symbols for the main parts of the drawings

100: film forming apparatus 101: silicon wafer

102: susceptor 103: chamber

104: rotating part 104a: cylindrical part

104b: axis of rotation 105: contact surface

106: hole 107: exhaust pipe

108: shaft 109, 126: adjustment valve

110, 127: vacuum pump 111, 128: exhaust mechanism

112: control mechanism 120: in heater

121: heater 122: radiation thermometer

123: gas supply unit 124: shower plate

125: gas exhaust

Claims (5)

In the film-forming apparatus which performs a film-forming process on the board | substrate carried in a film-forming chamber, A support for supporting the substrate; A rotating part rotating the support part and covered by the support part to form a hollow area; A heating part disposed in the hollow area and heating the substrate through the support part; And Exhaust means for exhausting gas in the hollow region, The support portion is provided with a plurality of holes in the contact surface with the substrate, The substrate is adsorbed on the support part by exhausting the gas in the hollow region. The method of claim 1, The contact surface with the substrate of the support portion is a concave shape inclined from the outer edge toward the center portion. In the film forming method of forming a film on a substrate placed in a film forming chamber, Bringing the substrate into the deposition chamber and placing the substrate on a support portion having a plurality of holes provided on a surface thereof; Heating the substrate while rotating the support; And And adsorbing said substrate to said support portion by exhausting gas in a space substantially separated from said film formation chamber according to said support portion when said substrate reaches a predetermined temperature. The method of claim 3, wherein And the predetermined temperature is a film forming temperature. The method according to claim 3 or 4, And in the step of adsorbing the substrate to the support portion, the pressure in the space is reduced to 90% of the maximum pressure in the film formation chamber.

Images