JPH07245273A - Substrate treatment device - Google Patents

Abstract

PURPOSE:To make uniform all the heat treatment results of substrates to be treated being mounted on a boat by providing an air-controlling part for forming a cylindrical contour with a peripheral surface section which is in the same shape and has the same size as the peripheral surface section of the cylindrical contour formed by the substrates to be treated and a boat at the reaction pipe feed gas introduction port side of a boat stage. CONSTITUTION:An air-controlling part is made of SiO2 and is formed in one piece with a port stage, four posts for forming plate materials 3 and 4 in opposing state are laid out along the peripheral edge of the plate materials, and a plurality of cuts 5a are formed each. An air-controlling plate in a same diameter is inserted into the cuts 5a over the practically entire range of the plate materials 3 and 4 consisting of for example SiC ceramic materials and the peripheral edge. The outer diameter of the plate materials 3 and 4 is set equally to that of a multiple-stage ring constituting a boat and the peripheral surface section of the cylindrical contour formed by the air-controlling part and the cylindrical contour peripheral surface section at the port side are equal in shape and dimensions, thus preventing swirls from being present near the substrate surface and obtaining a film with a uniform film thickness on the substrate surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing apparatus for performing processing such as thin film formation on the surface of a semiconductor substrate, and a cylindrical reaction tube having an internal space serving as a reaction chamber and a plurality of objects to be processed in the reaction tube. A boat for mounting the substrates in a stacked state of the reaction tubes in the axial direction,
A boat stage that supports the boat and positions the boat at a predetermined axial position in the reaction tube, and heats a substrate to be processed located in the reaction tube to a predetermined temperature, and a raw material for a reaction tube located on the side opposite to the boat stage of the boat stage. The raw material gas is introduced into the reaction tube from the gas inlet at a low pressure to form a thin film on the surface of the substrate to be processed, or the surface of the substrate is oxidized, and impurities or ions are diffused from the surface of the substrate into the inside of the substrate. The present invention relates to a substrate processing apparatus for performing heat treatment such as.

[0002]

2. Description of the Related Art This type of substrate processing apparatus is known as a low pressure CVD apparatus or an oxidation diffusion apparatus, and is constructed, for example, as shown in FIG. The figure shows a vertical type in which the axial direction of the cylindrical reaction tube is the vertical direction, but the basic configuration is the same for horizontal type with the axial direction in the horizontal direction, so here the vertical type is used. Will be explained mainly.

The apparatus shown in FIG. 3 includes a tubular reaction tube 10 usually made of SiO ₂ , a heater 11 surrounding the reaction tube 10, and a boat 12 for mounting a plurality of substrates 12 to be processed in an axially stacked state. A boat stage 14 that moves up and down to position an axial position of the boat 12 inside the reaction tube 10, and a heat shield mechanism 15 that does not let radiant heat supplied from the heater 11 into the reaction tube 10 escape to the outside. A raw material gas introduction pipe 16 for introducing a raw material gas into the reaction tube 10, an exhaust pipe 17 connected to a vacuum exhaust system (not shown), and an untreated substrate 12 inserted into the reaction pipe 10 or a treated substrate 1
2 to take out the reaction tube 10 from the boat stage 14
And a vertical movement mechanism 18 for vertically moving the.

During heat treatment such as thin film formation on the substrate 12,
A plurality of substrates 1 mounted on the boat 13 in an axially stacked state
When 2 is inserted into the reaction tube 10 and heated to a predetermined temperature by the heater 11, the raw material gas is fed from the raw material gas introduction pipe 16 so as to have a pressure of about 1 Torr or less under the operation of the exhaust system. When the pressure of the raw material gas in the reaction tube 10 is lowered in this way, the diffusion of the raw material gas molecules is large,
The raw material gas flowing in the reaction tube 10 in the axial direction can freely flow into the central portion of the substrate, and the in-plane uniformity of the processing result can be improved in any of the thin film formation, oxidation, and diffusion processes.

[0005]

In the substrate processing apparatus constructed and operated as described above, all the substrates are placed in the uniform temperature region in the reaction tube during the processing so that the axial uniformity of the substrate processing result can be obtained. Located. The axial length of the soaking region in the reaction tube varies depending on the method of using the reaction tube. For example, a low temperature region for thin film formation and a high temperature region for annealing treatment after thin film formation are set in the reaction pipe. In order to increase the productivity of the device by continuously performing thin film formation to annealing treatment, the length of each region becomes shorter,
Usually, the boat is manufactured so that the reaction tube for setting both the high temperature region and the low temperature region is targeted for a soaking region having a short axial length. On the other hand, in order to prevent the heat in the reaction tube from escaping to the outside, a heat shield mechanism formed by, for example, filling the SiO ₂ case with SiO ₂ wool reduces the temperature gradient in the reaction tube to achieve the desired level. In order to secure a sufficient length of the heat zone, it is located as low as possible in the reaction tube.Therefore, there is a gap between the heat shield mechanism and the boat stage that supports the bottom of the boat in the soaking zone. The flow of the raw material gas is disturbed in this void portion, and the influence of this disturbance is exerted over ten or more substrates, and the film thickness distribution on these ten or more substrates exceeds ± 5% and is distributed in the range of ± 10% or more. Therefore, these substrates become dummy substrates for obtaining non-defective products, and the number of substrates that should be obtained as non-defective products in one batch is largely reduced, and there is a problem that the throughput of the apparatus is reduced.

An object of the present invention is to provide a heat treatment apparatus having the basic structure described at the beginning without changing the boat, the reaction tube, and the heater in terms of structure, dimensions, or usage.
The heat treatment results of the substrates to be processed mounted on the boat are made uniform in the entire surface, and the apparatus is configured to be capable of performing the processing that is obtained as a non-defective product.

[0007]

In order to solve the above-mentioned problems, in the present invention, a substrate processing apparatus having the basic structure described at the beginning, that is, a cylindrical reaction tube having an internal space as a reaction chamber, and a reaction A boat that mounts a plurality of substrates to be processed in a tube in a stacked state in the axial direction of the reaction tube, and a boat stage that supports the boat and positions the boat at a predetermined axial position in the reaction tube are provided. While heating the processing substrate to a predetermined temperature, the raw material gas is introduced into the reaction tube from the raw material gas introduction port of the reaction tube located on the opposite side of the boat stage to a low pressure in the reaction tube to form a thin film on the surface of the substrate to be processed. A substrate processing apparatus for forming a substrate or performing a heat treatment such as oxidation of a substrate surface or diffusion of impurities or ions from the substrate surface to the inside of the substrate, the reaction tube of a boat stage according to claim 1. A cylinder having a peripheral cross section of the same shape as the peripheral cross section of the tubular contour formed by the substrate to be processed and the boat in the state where only the boat or the substrate to be processed is mounted on the boat at the raw gas introduction port side. The apparatus is provided with an air conditioning section that forms a contour of a shape.

As described in claim 2, a plurality of plate members each having the same shape as the peripheral surface cross section of the tubular contour on the boat side and a peripheral edge of equal size are provided within the area of each plate member. It is preferable to have a structure in which they are integrated so as to be opposed to each other through the positioned columns. Further, in this structure, the pillars that integrate a plurality of plate members in a mutually opposing state are provided in a plurality along the peripheral edge of the plate member between the plate members as described in claim 3, and a protrusion capable of supporting the air conditioning plate. Alternatively, a notch may be provided.

Further, the air conditioning section according to claim 1 is further suitable as a cylindrical body having a cylindrical contour peripheral surface as an outer peripheral surface of a peripheral wall as described in claim 4. .

[0010]

In this way, the peripheral surface of the tubular contour formed by the substrate to be processed and the boat in the state where only the boat or the substrate to be processed is mounted on the boat on the side of the reaction gas source gas introduction port of the boat stage. If the air conditioning section is provided with a tubular contour that has the same shape as the cross section and an equal circumferential cross section, the air conditioning section has the same circumferential contour as the tubular contour on the boat side. A tubular space is formed between the tubular contour from the wall and the smooth inner wall surface of the reaction tube, and the source gas whose flow is disturbed on the upstream side of the boat such as the boat side end of the heat shield mechanism When the vortex that is causing turbulence disappears while traveling in a curved space, and the cylindrical contour peripheral surface of the air conditioning section is not a smooth substantial surface, the remaining flow path is left with a thin layer on the contour peripheral surface side. The cross section becomes laminar and reaches the boat position. A boat is a vertical device, and usually, a plurality of rings are connected by short struts at intervals in the axial direction.
A substrate having a tubular structure as a whole and having a diameter smaller than the outer diameter of the ring is mounted on the ring. Therefore, since the boat is not a smooth tubular body in the axial direction, the thin layer on the boat side does not become a laminar flow in the entire cross section of the flow, but the flow around the boat including this thin layer expands to the central part of the substrate, As a vortex that disturbs the flow, only a minute vortex is generated at the corner of each ring edge of the boat over the entire length of the edge, and the vortex does not reach the substrate. The raw material gas that has expanded or diffused to the central part of the substrate is heated to a high temperature, so that the thin film constituent elements in the raw material gas are absorbed by the substrate and changed to a low density gas, and toward this low density gas. The high-density source gas flowing around the boat diffuses, and the film thickness grows. Thus, the surface of the substrate has a density
In addition, since a vortex whose position is unstable does not occur, a film having a uniform film thickness is formed on the substrate surface over the entire axial length of the boat. Further, in the horizontal type device, the boat normally uses the ring in the vertical type device as a disk, and since the diameter of the disk is larger than the substrate diameter, the substrate surface over the entire axial length of the boat is the same as the above. The film thickness is uniform. Further, in a horizontal device in which the structure of the boat is such that each of the substrates is sandwiched by using a part of the substrate area, a minute vortex is generated at the corner of the peripheral edge of the substrate. Since the width is extremely small, the effect on the thin film area yield can be substantially ignored.

The required axial length of the air conditioning section depends on the flow velocity of the gas around the air conditioning section. If the flow velocity is high, the flow disturbance on the upstream side of the air conditioning section, such as the end of the heat shield mechanism on the boat side, will occur. Since the size and number of vortices are large, the required length of the air conditioning section is long, and the flow velocity is low, the length is short. Since the air conditioning section is provided by utilizing the space on the upstream side of the boat stage, such as between the boat stage and the heat shield mechanism, the upstream side of the heat shield mechanism, etc. is related to the flow rate of the source gas or the film formation speed. It is necessary to devise such as axial movement of the soaking region by changing the fixing position of the insert or adjusting the heating wire of the heater surrounding the reaction tube.

The air conditioning section is provided on the reaction tube raw material gas introduction port side of the boat stage. However, as a substrate processing apparatus, the air conditioning section may be a part of the boat stage. Alternatively, the air conditioning section may be formed separately and integrated with or close to the boat stage. And, the air conditioning section is a structure in which a plurality of plate members having the same shape as the peripheral cross section of the tubular contour on the boat side and having a peripheral edge of equal size are integrated so as to be opposed to each other through the columns located within the area of each plate member. If so, an appropriate number of plate members and columns of an appropriate length form an air conditioning unit, and the air conditioning unit can be easily formed by stacking a number of units corresponding to the flow rate of the raw material gas. can do.

Further, when a protrusion or a notch is provided on a column which integrally integrates a plurality of plate members in a state of being opposed to each other so that the air conditioning plate can be supported, the gas around the air conditioning part is changed depending on the number and position of the air conditioning plates to be used. You can change the flow condition,
It is possible to form a flow that is necessary and sufficient for making the processing result uniform on the surface, such as making the film thickness uniform on all the substrates in the boat. Also,
The air conditioning section has the same cross section as the cross section of the tubular contour on the boat side.
If a cylindrical body with an equal-sized peripheral surface as the outer peripheral surface of the peripheral wall is used, the flow reaches the boat position as a laminar flow over the entire cross section between the cylindrical body with a smooth surface and the inner wall surface of the reaction tube. Therefore, the film thickness on all the substrates in the boat can be made more reliable. Further, since the air conditioning section is used in a high-temperature atmosphere, quartz or heat-resistant ceramics is used as the material, so the air conditioning section can be formed at a lower cost by simplifying the structure using a tubular body. it can.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the invention according to claim 3.
In this embodiment, the air conditioning section is formed as a part of the boat stage, and the plate material 4 side can be considered as the air conditioning section in the boat stage from the middle of the thickness of the plate material 3. The air conditioning section is integrated with the original boat stage (reference numeral 14 in FIG. 3) using SiO ₂ as a constituent material, and the support column 5 that integrates the plate members 3 and 4 in a facing state is formed along the peripheral edge of the plate member in this example. A plurality of cuts 5a are formed in each of the four slits, and air-conditioning plates made of, for example, a SiC-based ceramic material and having the same diameter are inserted into the cuts 5a over substantially the entire range of the peripheral edges. The outer diameters of the plate members 3 and 4 are set to be equal to the outer diameters of the multi-stage rings forming the boat, and the peripheral surface section of the tubular contour formed by the air conditioning section and the cylindrical contour peripheral section on the boat side are shaped,
The dimensions are the same. Reference numeral 3a in the drawing is a boss for fixing a rod body that moves the boat stage in the axial direction, and reference numeral 3b is a hole for positioning the boat on the boat stage surface. It should be noted that the dimensions in the figure show an example intended for an actual device.

FIG. 2 shows a state in which the boat is supported by the boat stage having the air conditioning section shown in FIG. 1, in comparison with the conventional boat stage. It can be seen that the air conditioning section is provided by utilizing the gap between the conventional boat stage 1 and the heat shield mechanism 6. In the figure, the multi-stage ring of the boat is omitted in order to make the figure easier to see. Using the boat stage 2 shown in FIG. 1, a SiO ₂ film was formed under the following conditions.

Film-forming temperature: 690 [° C.] Raw material (the following three are normal liquid materials, and the vapor is used as a raw material gas for film formation): TEOS [Tetra-Ortho-Silicate, Si (OC ₂ H ₅₎ ) ₄ ]:
50 [SCCM] TMOP [Trimehyl Phosphate, PO (OCH ₃ ) ₃ ]: 1
5 [SCCM] TEB [Triethyl Borate, B (OC ₂ H ₅ ) ₄ ]: 4 [S
CCM] In addition to these vapors, O ₂ : 300 [SCCM] Pressure during film formation: 0.5 [Torr] As a result of repeatedly forming a SiO ₂ film having a film thickness of 6000 Å under the conditions above, the lower part of the quartz boat Even the Si substrate located at
The turbulence of the flow is stopped by the air conditioning section with the air conditioning plate inserted,
There was no turbulence in the raw material gas flowing into the central part of the substrate, and a film thickness distribution of ± 5% or less could be stably obtained.

[0017]

As described above, according to the present invention, the substrate processing apparatus having the basic configuration described in the beginning is provided on the side of the reaction gas source gas introducing port of the boat stage, and only the boat or the substrate to be processed is towered on the boat. Since the apparatus is provided with an air conditioning unit that forms a cylindrical contour having the same circumferential cross section as that of the cylindrical contour formed by the substrate to be processed and the boat in the mounted state, Even if there is turbulence in the flow of the raw material gas flowing from the raw material gas inlet side in the tube toward the boat, after reaching the air conditioning section, the flow is tubular between the peripheral surface of the contour of the air conditioning section and the inner wall surface of the reaction tube. The vortices that make up the turbulence disappear along with the flow, and after reaching the boat position, the remainder is made laminar, leaving a thin layer on the air conditioning section or the boat peripheral surface side. The source gas is uniformly distributed around the substrate. Since a film is formed by diffusion, near the substrate surface, there is no vortex whose density is light and dark and whose position is unstable, and even in the substrate located upstream of the boat, Thus, a film having a uniform film thickness can be obtained on the surface of the substrate, and the throughput of the device can be improved.

By providing the air conditioning section having the above effect with the structure according to the second aspect of the invention, it becomes easy to form the air conditioning portion having a height corresponding to the flow rate of the raw material gas, and the third aspect of the invention. With this structure, it is easy to adjust the number of air rectifying plates and position of the air rectifying plate, and thus it is possible to form a flow necessary and sufficient for uniforming the film thickness distribution on all the substrates in the boat.

Further, since the air conditioning section has the structure according to the fourth aspect, the flow of the raw material gas becomes a laminar flow in the entire cross section and reaches the boat position, so that the film thickness can be made more reliable. Be seen. Further, the structure of the air conditioning section is simplified, and the air conditioning section can be formed at low cost.

[Brief description of drawings]

1A and 1B are views showing an embodiment of an air conditioning unit according to claim 3, wherein FIG. 1A is a top view and FIG. 1B is a front view.

FIG. 2 is a view showing a normal state when a boat is supported on a boat stage equipped with the air conditioning section shown in FIG. 1, in comparison with the case of a conventional boat stage, and FIG. Figure showing the state of supporting the boat on the boat stage of
FIG. 2B is a view showing a state in which the boat is supported on the boat stage having the air conditioning unit shown in FIG.

FIG. 3 is a cross-sectional view showing a conventional configuration example of a substrate processing apparatus targeted by the present invention.

[Explanation of symbols]

 1 Boat Stage 2 Boat Stage 3 Plate Material 4 Plate Material 5 Support 7 Boat 10 Reaction Tube 11 Heater 12 Substrate (Processing Substrate) 13 Boat 14 Boat Stage 15 Heat Shielding Mechanism 16 Raw Material Gas Introducing Pipe

Claims (4)

[Claims] 1. A cylindrical reaction tube having an internal space as a reaction chamber,
Located in the reaction tube is equipped with a boat that mounts a plurality of substrates to be processed in the reaction tube in an axially stacked state of the reaction tube, and a boat stage that supports the boat and positions the boat at a predetermined axial position in the reaction tube. While heating the substrate to be processed to a predetermined temperature, the raw material gas is introduced from the raw material gas inlet of the reaction tube located on the side opposite to the boat stage into the reaction tube to a low pressure inside the reaction tube, and then the surface of the substrate to be processed is introduced. In a substrate processing apparatus that forms a thin film or performs heat treatment such as oxidation of the substrate surface or diffusion of impurities or ions from the substrate surface to the inside of the substrate, only the boat or the treated object at the reaction gas source gas inlet side of the boat stage Provided with an air conditioning section that forms a cylindrical contour having the same peripheral surface cross section as the cylindrical contour formed by the substrate to be processed and the boat while the substrate is mounted on the boat. A substrate processing apparatus, characterized by that. 2. The apparatus according to claim 1, wherein the air conditioning section forming a tubular contour having a peripheral cross-section of the same shape and equal size as the peripheral cross-section of the tubular contour on the boat side is the contour. Substrate processing having a structure in which a plurality of plate materials having the same shape as the peripheral cross-section and a peripheral edge of equal size are integrated so as to face each other via a pillar located within the area of each plate material. apparatus. 3. The apparatus according to claim 2, wherein a plurality of support columns that integrate a plurality of plate members in a mutually opposing state are provided along the peripheral edge of the plate members so as to support the air conditioning plate. A substrate processing apparatus comprising a protrusion or a notch. 4. The apparatus according to claim 1, wherein the air conditioning section forming a tubular contour having a circumferential cross-section having the same shape and equal size as the circumferential cross-section of the boat-side tubular contour is the circumferential contour. A substrate processing apparatus, characterized in that it is a cylindrical body whose surface is an outer peripheral surface of a peripheral wall.