JP2684192B2 - CVD apparatus and heater cover position adjusting method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a CVD apparatus and a heater cover position adjusting method in the apparatus. More specifically, the present invention relates to a heater cover position adjusting method that can reduce variations in film thickness.

[Prior art] One of the thin film formation methods generally used in the semiconductor industry is chemical vapor deposition (CVD: Ch).
emical Vapor Deposition). CVD means that a gaseous substance is converted into a solid substance by a chemical reaction and deposited on a substrate.

The feature of CVD is that various thin films can be obtained at a deposition temperature much lower than the melting point of the thin film to be grown, and
Since the grown thin film has high purity and stable electrical characteristics even when grown on Si or a thermal oxide film on Si, it is widely used as a passivation film on a semiconductor surface.

Thin film formation by CVD is performed by, for example, reacting a gas (for example, SiH ₄ + O ₂ , or S) on a wafer heated to about 400 ° C to 500 ° C.
iH ₄ + PH ₃ + O ₂ ) is supplied. The above reaction gas is blown onto the wafer in the reaction furnace (belja) to form a thin film of SiO ₂ or phosphosilicate glass (PSG) or borosilicate glass (BSG) on the surface of the wafer. Also, a two-layer film formation of SiO ₂ and PSG or BSG may be performed.

An example of an apparatus conventionally used for performing such a thin film forming operation by CVD is shown in FIG.

In FIG. 3, a reaction furnace 1 has a conical buffer 2 in the furnace, and a disk-shaped wafer sample stage 4 can be rotationally driven and / or revolved by a drive mechanism 5 around the buffer 2. It is arranged.

Immediately below the wafer sample stage 4 is provided a heating means 10 via a slight gap to heat the wafer 6 to a predetermined temperature (for example, about 500 ° C.).

A heater cover 14 supported by columns 12 is mounted adjacent to the outer peripheral edge of the sample table 4 and rotates while revolving.

[Problems to be Solved by the Invention] However, when a film is formed on the surface of a silicon wafer by the CVD apparatus having the above-described structure, the film thickness varies, and the yield cannot be increased.

In the structure of the reaction furnace, there is a sample table 4 that revolves around its own axis, and a heater cover 14 is mounted around it and rotates around it. The gap between the sample table 4 and the heater cover 14 is about 3 mm, and the gap between the heater cover 14 and the furnace wall 16 is about 2.5 mm.
There is ~ 3mm. However, when the sample stage is heated for film formation and the temperature is raised, this gap expands due to thermal expansion,
The value is not as designed. Therefore, the flow of the reaction gas in the vicinity of the sample table becomes non-uniform, causing variations in the film thickness.

Therefore, it is an object of the present invention to provide a heater cover position adjusting method capable of minimizing the variation in film thickness.

[Means for Solving the Problems] As means for achieving the object, in the present invention,
In a CVD apparatus in which a heater cover surrounding a side surface of a sample table is mounted on an upper end surface of a horizontal support arm of a substantially T-shaped support column for the heater cover, the heater cover is engaged with the heater cover. A CVD apparatus characterized in that it is mounted on the support arm via a slide member, and the slide member is fixed to the support arm together with the heater cover so that its position can be changed in the radial direction. provide.

Further, as a means for achieving the above object, in the present invention, a heater cover surrounding the side surface of the sample table is mounted on the upper end surface of the horizontal support arm of the substantially T-shaped support column for the heater cover. In the existing CVD device, a long hole along the radial direction for screw escape at an appropriate location on the heater cover,
A through hole for the engaging pin is formed adjacent to this,
At least one screw hole is cut in the upper end surface of the bearing arm at a position corresponding to the screw escape long hole of the heater cover. Inverted U-shaped slide member drilled along the direction,
The pin is engaged with a pin engaging hole of the heater cover so as to straddle the bearing arm, and the slide arm can be unfastened from the upper surface of the heater cover through the screw escape long hole. There is provided a heater cover position adjusting method characterized in that the heater cover is screwed to the heater cover.

[Operation] As described above, in the CVD apparatus of the present invention, the position of the heater cover can be easily adjusted even when the temperature rises to 400 ° C or higher.

Therefore, even if the gap between the sample table and the heater cover and the gap between the heater cover and the furnace wall deviate from the design values due to thermal expansion, the heater cover is displaced to keep the gap between each member to a predetermined design value. Can be maintained within the range of.

As a result, the variation in film thickness is minimized and the yield is improved.

[Example] Hereinafter, an example of the CVD apparatus and the heater cover position adjusting method of the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a partial schematic perspective view showing a specific example of the CVD apparatus and the heater cover position adjusting method of the present invention.

In the apparatus of the present invention, the heater cover 14 is basically mounted on the support arm 20 of the support column 12.

Unlike conventional devices, the device of the present invention has a heater cover
A slide member 22 is interposed between 14 and the support arm 20.
As shown, the slide member 22 has an inverted U-shaped cross section and can be mounted on the support arm 20. The upper surface of the bearing arm portion on which the slide member 22 is seated is lower by one step and is cut out horizontally. Thus, when the slide member 22 straddles, the upper end surface of the slide member 22 and the radially inward upper end surface of the support arm 22 are flush with each other. Screw holes 26, 26 are threaded into the notched flat surface portion 24 of the support arm at predetermined intervals.

Screw 3 on the upper surface of slide member 22
A radially long hole 28 having a width slightly larger than the diameter of 2, 32 is bored. Further, an engagement pin 30 is bored in the radially inner portion of the same upper surface.

A screw escape hole 34 and an engagement hole 36 of an engagement pin 30 are formed in the heater cover portion corresponding to the straddling position of the slide member 22. The screw escape hole 34 has an inner diameter larger than the maximum outer diameter of the heads of the screws 32, 32. If washers or spring washers 40 are used, they have an inner diameter greater than their maximum outer diameter.

FIG. 2 shows a partial cross-sectional view of a state in which the slide member 22 is engaged with the heater cover 14 and the supporting arm 20 is laid across.

As shown in FIG. 2, from the outer peripheral edge of the screws 32, 32 to the outer and inner ends of the elongated hole of the slide member 22, "d" mm
There is a space for adjustment only. The slide member 22 is fixed to the support arm 20 from the upper surface of the heater cover 14 with screws 32, 32. Therefore, when adjusting the clearance between the heater cover and the sample table and / or the furnace wall, loosen the screws 32, 32. The slide member 22 is slid inward or outward in the radial direction together with the heater cover 14 to determine the clearance, and then the screws 32, 32 are stopped again and the slide member is supported by the arm 20.
If it is fixed to, it is possible to adjust the deviation of ± dmm between the heater cover, the sample table and / or the furnace wall. This d can be, for example, about 2 mm. The number of screws for fixing the slide member may be one. When the number of screws for fixing the slide member is one, the shapes of the screw escape hole 34 of the heater cover and the elongated hole 28 of the slide member can be changed to one.

The material itself of the slide member 22 and the fixing screw 32 is not an essential requirement of the present invention. It is preferably composed of heat-resistant and corrosion-resistant metal such as stainless steel. Other materials can also be used.

The CVD device of the present invention is a batch type atmospheric pressure type CVD similar to the conventional one.
Device.

[Effects of the Invention] As described above, in the CVD apparatus of the present invention, the temperature is 4
The position of the heater cover can be easily adjusted even when the temperature rises above 00 ° C.

Therefore, even if the gap between the sample table and the heater cover and the gap between the heater cover and the furnace wall deviate from the design values due to thermal expansion, the heater cover is displaced to keep the gap between each member to a predetermined design value. Can be maintained within the range of.

As a result, the variation in film thickness is suppressed to a minimum and the yield is improved.

[Brief description of the drawings]

FIG. 1 is a partial schematic perspective view showing a specific example of a CVD apparatus and a heater cover position adjusting method of the present invention, and FIG. 2 shows a state in which a slide member is engaged with the heater cover and a supporting arm is laid across. FIG. 3 is a partial sectional view, and FIG. 3 is a conventional CVD.
It is a partial schematic sectional drawing of an example of an apparatus. 12 …… Heater cover support column, 14 …… Heater cover, 20 ……
Bearing arm, 22 …… Slide member, 26 …… Screw hole, 28 ……
Slotted hole, 30 …… Engagement pin, 32 …… Screw, 34 …… Screw relief hole, 36
...... Engagement hole.

Claims (3)

(57) [Claims] 1. A CVD apparatus in which a heater cover surrounding a side surface of a sample table is mounted on an upper end surface of a horizontal support arm of a substantially T-shaped support column for the heater cover, wherein the heater cover is the heater. It is mounted on the support arm via a slide member that is engaged with the cover, and the slide member is fixed to the support arm together with the heater cover so that its position can be changed in the radial direction. And CVD equipment. 2. The CV according to claim 1, which is a batch type atmospheric pressure type.
D equipment. 3. A CVD apparatus in which a heater cover surrounding a side surface of a sample table is mounted on an upper end surface of a horizontal support arm of a substantially T-shaped support column for the heater cover, at an appropriate location of the heater cover. A long hole extending in the radial direction for screw escape and a through hole for an engaging pin are formed adjacent to this hole, and the upper end surface of the bearing arm at a position corresponding to the long hole for screw escape of the heater cover. An inverted U-shaped slide member having at least one screw hole cut in its upper surface, a pin formed on the upper surface thereof, and an elongated hole having a width for loosely fitting the screw formed along the longitudinal direction. It engages with the pin engaging hole of the heater cover, straddles the supporting arm, and is screwed to the supporting arm so that the slide member can be released from the upper surface of the heater cover through the elongated hole for screw escape. A heater characterized by Bar position adjustment method.