JP2004193396A - Method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device by which a warpage due to film lamination on a dummy substrate can be prevented when it is placed instead of a depositing substrate during precoating in prior to film formation of the depositing substrate and furthermore the generation of particles accompanying the warpage can be suppressed or prevented. <P>SOLUTION: While a dummy substrate 11 is placed on a substrate holding plate 2, a cleaning gas is introduced into a substrate processing chamber 50 to clean the inside thereof, and while the dummy substrate 11 is still placed on the substrate holding plate 2, a film formation processing gas is supplied into the substrate processing chamber 50 to perform precoating. Then, while a product substrate 1 is placed on the substrate holding plate 2, the film formation processing gas is supplied into the substrate processing chamber 50 to form a film. A dummy substrate whose surface is uneven is used as the dummy substrate 11, preventing the warpage of the dummy substrate due to a stress of a film made by precoat film formation. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a semiconductor manufacturing apparatus for forming a thin film on a substrate, doping impurities, performing surface treatment, and the like. The present invention relates to a method of manufacturing a semiconductor device using a semiconductor manufacturing apparatus having a heater unit of a type which is mounted and heated, and which removes a reaction product deposited in a substrate processing chamber by dry etching with a cleaning gas.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, prior to a process of forming a film on a product substrate, a pre-coating process is performed by flowing a processing gas into a processing chamber in order to suppress particles and metal contamination and prepare an atmosphere in the substrate processing chamber. This precoating process was performed with the dummy substrate placed on the substrate holding plate.
[0003]
[Problems to be solved by the invention]
When a pre-coating process is performed by flowing a processing gas for film formation in a state where the dummy substrate is mounted on the substrate holding plate, a film is similarly deposited on the dummy substrate. However, no film is deposited on the surface of the dummy substrate in contact with the substrate holding plate. If the film deposited on one side of the dummy substrate becomes thicker, the dummy substrate warps due to the film stress, film deposition on the substrate holding plate, and film deposition on the backside of the dummy substrate, resulting in the generation of particles. I was
[0004]
A main object of the present invention is to provide a semiconductor device that can suppress warpage due to film deposition on a dummy substrate and thereby suppress or prevent the generation of particles due to warpage.
[0005]
[Means for Solving the Problems]
According to the present invention,
A step of supplying a processing gas into the processing chamber and performing pre-coating (empty film formation) with a dummy substrate having irregularities on the surface mounted on a substrate holding plate in the processing chamber;
Supplying a processing gas into the processing chamber in a state where a product substrate is placed on the substrate holding plate to form a film, thereby providing a method of manufacturing a semiconductor device.
[0006]
As described above, since the dummy substrate having the unevenness on the surface is used, the warpage of the dummy substrate due to the stress of the film due to the pre-coat film formation is suppressed, thereby suppressing or preventing the generation of particles due to the warpage. it can.
[0007]
By providing a pre-coating step before the step of forming a film on a product substrate, particles and metal contamination can be suppressed and the atmosphere in the substrate processing chamber can be adjusted.
[0008]
Preferably, before the pre-coating step, the method further includes a step of introducing a cleaning gas into the processing chamber with the dummy substrate placed on the substrate holding plate to clean the processing chamber.
[0009]
Since the processing chamber is cleaned by introducing a cleaning gas into the processing chamber in a state where the dummy substrate is placed on the substrate holding plate, the substrate holding plate can be protected at the time of cleaning, and is separated by the substrate holding plate. The cleaning gas can be prevented from entering the space other than the substrate processing space.
[0010]
By providing the pre-coating step after such a cleaning step, the atmosphere of the substrate processing chamber after cleaning can be adjusted in addition to suppressing particles and metal contamination.
[0011]
The dummy substrate placed on the substrate holding plate at the time of cleaning is used as a dummy substrate placed on the substrate holding plate at the time of subsequent precoating, so that the process from cleaning to precoating can be performed by one dummy substrate. Since it becomes possible, a substrate for pre-coating, which had to be separately prepared until now, becomes unnecessary, and cost reduction is expected. Further, since the two processes of cleaning and precoating can be fully automated as an integrated process, the downtime of the apparatus can be reduced.
[0012]
Further, the dummy substrate on which the film is formed by the above-mentioned pre-coating step can be used in the next cleaning step and / or empty film forming step.
[0013]
When the cover substrate formed by the precoat is used in the next cleaning, the deposited film is removed by the cleaning. Therefore, by depositing the film again by the precoat, the cover substrate can be used semipermanently.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
FIGS. 1, 2 and 3 are schematic vertical sectional views for explaining a substrate processing apparatus used in an embodiment of the present invention. FIG. 1 shows a state when an elevating mechanism 10 described later is lowered. FIG. 2 shows a state at the time of preliminary heating, and FIG. 3 shows a state at the time of substrate processing when the elevating mechanism 10 is raised. FIG. 4 is a schematic longitudinal sectional view for explaining a temperature measuring method in the substrate processing apparatus used in one embodiment of the present invention, and FIG. 5 is a diagram showing a dummy substrate used in one embodiment of the present invention. FIG. 3 is a schematic plan view for explaining.
[0015]
A thermal CVD thin film forming apparatus will be described as an example of the substrate processing apparatus 30 shown in FIGS. 1 to 3, and a semiconductor silicon substrate will be described as an example of a substrate to be processed.
[0016]
The substrate processing apparatus 30 is a cold-wall type single-wafer thermal CVD film forming apparatus, and includes a substrate processing chamber 50 for accommodating a processing substrate (semiconductor wafer) 1 to be processed, and a processing substrate 1 in the substrate processing chamber 50. Alternatively, a substrate holding plate (susceptor) 2 for supporting the dummy substrate 11, a resistance heater 3 for heating the processing substrate 1 or the dummy substrate 11, a heater unit 20 including the substrate holding plate 2 and the resistance heating heater 3, a processing substrate 1 or a dummy. The substrate insertion port 8 for carrying the substrate 11 into the substrate processing chamber 50 of the substrate processing apparatus 30, an opening / closing valve (gate valve) 9 for opening and closing the substrate insertion port 8, and the processing substrate 1 or the dummy substrate 11 being used as the substrate holding plate 2. When mounted on the substrate, the substrate support 4 for temporarily supporting the processing substrate 1 or the dummy substrate 11 and the heater unit 20 can be raised and lowered in the substrate processing chamber 50 by multi-step adjustment. The lifting mechanism 10 (in the drawing, the lifting mechanism itself is not shown, only the vertical movement distance range is indicated by a two-way arrow), an exhaust port 7 for exhausting the inside of the substrate processing chamber 50, and a gas in the substrate processing chamber 50. And a gas distribution plate 5 for uniform supply of gas to the processing surface of the processing substrate 1.
[0017]
The substrate support 4 is made up of quartz pins. The substrate holding plate 2 (susceptor) supports the processing substrate 1 and plays a role in quickly and uniformly transferring heat from the resistance heater 3 to the processing substrate 1 or the dummy substrate 11. The gas supply port 6 is for supplying a desired gas species into the substrate processing chamber 50 at a desired gas flow rate and gas ratio. The supply of the gas to the processing surface of the processing substrate 1 is made uniform by a gas dispersion plate. Has been The exhaust port 7 is for exhausting unreacted gas and gas generated during the reaction process. As shown in FIG. 4, the temperature of the resistance heater 3 is measured by a thermocouple 62, and the temperature of the substrate holding plate 2 is measured by a radiation thermometer 61.
[0018]
The substrate processing apparatus 30 enables processing of each single substrate at a high temperature of 400 ° C. or more and 850 ° C. or less and a pressure of 100,000 Pa.
[0019]
In the substrate processing apparatus 30 having the above structure, gas cleaning and pre-coating are performed in the following steps.
[0020]
The cleaning dummy substrate 11 is transported to the substrate processing chamber 50 by a transport mechanism (not shown) provided in the substrate transport chamber 40 connected to the substrate processing chamber 50 through the substrate insertion opening 8, and the space between the substrate holding plate 2 and the space is removed. It is placed on the substrate support 4 so as to be separated and parallel (see FIG. 1)
[0021]
The on-off valve 9 is closed after the dummy substrate 11 is inserted to isolate the substrate transfer chamber 40 and the substrate processing chamber 50 during gas cleaning and precoating.
[0022]
The temperature of the substrate processing chamber 50 is lowered while being controlled by the resistance heater 3 to a temperature arbitrarily determined by the characteristics of the cleaning gas.
[0023]
The heater unit 20 is moved up from the transfer position shown in FIG. 1 to the substrate processing position shown in FIG. When the heater unit 20 rises, the distance between the cleaning dummy substrate 11 on the substrate support 4 and the substrate holding plate 2 gradually narrows, and after the preheating state shown in FIG. The dummy substrate 11 is directly heated by being placed on the substrate holding plate 2.
[0024]
A gas for removing a reaction product attached during substrate processing, for example, NF ₃ gas radicalized by remote plasma is introduced into the substrate processing chamber 50.
[0025]
After removing the reaction products in the substrate processing chamber 50 by cleaning, a cycle purge is performed to exhaust a cleaning gas atmosphere remaining in the substrate processing chamber 50. The cycle purge means that the inside of the substrate processing chamber 50 is evacuated, then an inert gas such as nitrogen or hydrogen is introduced into the substrate processing chamber 50, and the inside of the substrate processing chamber 50 is evacuated. This is a method of purging the substrate processing chamber 50 by repeating the exhaust of the substrate processing chamber 50 and the introduction of an inert gas such as nitrogen or hydrogen into the substrate processing chamber 50.
[0026]
After purging the cleaning gas from the substrate processing chamber 50, the substrate holding plate 2 is heated by the resistance heater 3 to the substrate processing temperature. At this time, the cleaning dummy substrate 11 is placed on the substrate holding plate 2.
[0027]
When the substrate holding plate 2 is heated to the substrate processing temperature, it is introduced from the upper gas supply port 6 and diffused by the gas dispersion plate 5 so as to be evenly distributed on the processing surface. The inside of the substrate processing chamber 50 is precoated with an arbitrary thickness of about 1.0 μm. At this time, a film is naturally deposited on the cleaning dummy substrate 11 as well.
[0028]
After the precoating process, the heater unit 20 descends to the transport position (see FIG. 1). At the time of lowering, the substrate support 4 pushes up the cleaning dummy substrate 11 again, and creates a space for transport with the substrate holding plate 2.
[0029]
The dummy substrate 11 is carried out from the substrate insertion opening 8 to the transfer chamber 40 by a transfer mechanism (not shown).
[0030]
In this embodiment, the surface of the cleaning dummy substrate 11 is provided with irregularities in order to relieve the stress of the film that causes the warp when the film is deposited on one surface where the warp is likely to occur. The irregularities on the surface of the cleaning dummy substrate 11 are arbitrarily selected depending on the type of the film to be deposited and the thickness of the deposited film. For example, as shown in FIG. Thereby, the stress of the film deposited on the surface of the cleaning dummy substrate 11 can be reduced, and the warpage can be suppressed. It goes without saying that the material of the cleaning dummy substrate 11 is also arbitrarily selected depending on the type of the film to be deposited and the thickness of the deposited film. In the present embodiment, Carbon is used as the cleaning dummy substrate 11. In addition, other than this, SiC and SiO ₂ can be used. However, depending on the cleaning temperature, SiC and SiO ₂ may be etched by the cleaning gas. Therefore, the material of the cleaning dummy substrate 11 is preferably a material such as Carbon which is not easily etched. The thickness of the cleaning dummy substrate is arbitrarily selected from 0.5 mm to 1.5 mm.
[0031]
In this embodiment, it is possible to perform the process from cleaning to pre-coating with a single cleaning dummy substrate, so that a pre-coating substrate that had to be separately prepared until now is not required, and cost reduction is expected. You. In addition, since cleaning and precoating can be performed in an integrated manner and cleaning can be fully automated, downtime of the apparatus can be reduced.
[0032]
Next, a method of forming a film on the processing substrate 1 as one step of a semiconductor device manufacturing process using the apparatus 30 will be described. In the present embodiment, first, the heater unit 20 is moved to the substrate transfer position (the position shown in FIG. 1), and the on-off valve 9 is moved downward to open the substrate insertion port 8. The processing substrate 1 is moved through the substrate insertion opening 8 by a transfer mechanism (not shown) provided in a substrate transfer chamber 40 (only the position is shown in the figure) connected to the substrate processing chamber 50 and the substrate insertion opening 8. Thereafter, the substrate is carried into the substrate processing chamber 50 and placed on the substrate support 4 so as to be parallel to the substrate holding plate 2 with a space therebetween. FIG. 1 shows this state.
[0033]
Next, in order to isolate the substrate transfer chamber 40 and the substrate processing chamber 50 during the substrate processing, the substrate insertion port 8 is closed by the on-off valve 9.
[0034]
Next, the heater unit 20 is lifted by the elevating mechanism 10 and then stopped until the substrate preheating position, that is, until the distance between the processing substrate 1 and the substrate holding plate 2 reaches a predetermined distance. As a result, a state where the processing substrate 1 is separated from the substrate holding plate 2 by a predetermined distance, that is, the substrate preheating state shown in FIG. 2 is realized. By maintaining this state for a predetermined time, the processing substrate 1 is preheated by radiant heat transfer from the substrate holding plate 2 and gas-phase heat transfer.
[0035]
In this case, the predetermined distance is such a distance that the processing substrate 1 does not contact the substrate holding plate 2 even when the processing substrate 1 warps due to heat transfer from the substrate holding plate 2 by the end of the preheating. The predetermined time means that the average temperature of the processing substrate 1 is equal to the temperature between the processing substrate 1 and the substrate holding plate 2 when the processing substrate 1 is placed on the substrate holding plate 2 after the predetermined time has elapsed. This is the time required to reach a temperature at which the processing substrate 1 does not warp due to the difference. The above-mentioned predetermined distance is short, for example, 1 mm, and even if the processing substrate 1 is warped immediately after the start of the preheating, the temperature non-uniformity in the processing substrate 1 is improved during the preheating and the warping is caused. If the processing substrate 1 is not warped even if the processing substrate 1 is placed on the substrate holding plate 2 after the preheating, the average temperature of the processing substrate 1 is increased, and no trouble occurs.
[0036]
The predetermined distance and the predetermined time are not uniquely determined, but may be adjusted arbitrarily. The above-mentioned predetermined distance is preferably 0.5 mm or more and 10 mm or less, and the predetermined time is preferably 10 seconds or more and 120 seconds or less. In the present embodiment, the predetermined distance is set to 3 mm or more and 5 mm or less, and the predetermined time is set to 30 seconds or more and 90 seconds or less.
[0037]
Next, the heater unit 20 is moved up from the preheating position (the position shown in FIG. 2) to the substrate processing position (the position shown in FIG. 3) by the elevating mechanism 10. When the heater unit 20 rises, the distance between the processing substrate 1 on the substrate support 4 and the substrate holding plate 2 gradually decreases, and before the heater unit 20 reaches the substrate processing position, when the distance disappears, The substrate holding plate 2 holds the processing substrate 1 instead of the substrate support 4, and moves up further to stop at the position (substrate processing position) in FIG. The processing substrate 1 is heated by direct heat transfer from the substrate holding plate 2 which is heated by the resistance heater 3 and has a high temperature.
[0038]
Next, in the state shown in FIG. 3, a monosilane (SiH ₄ ) gas as a film formation gas and a nitrogen ( N ₂ ) gas. Further, a hydrogen (H ₂ ) gas is supplied together with the carrier gas N ₂ . The SiH ₄ gas, the N ₂ gas, and the H ₂ gas are supplied by being diffused by the gas dispersion plate 5 so as to be even on the processing surface of the processing substrate 1. As a result, a thermal CVD reaction occurs, and a polysilicon film is formed on the processing substrate 1. The film forming temperature is, for example, 550 to 780 ° C., and the pressure is, for example, 6000 to 50,000 Pa.
[0039]
After the above-described substrate processing (after the formation of the polysilicon film on the processing substrate 1), the heater unit 20 descends to the substrate loading position (the position shown in FIG. 1). When descending, the substrate support 4 pushes up and supports the processing substrate 1 on the substrate holding plate 2 again, and creates a space between the processing substrate 1 and the substrate holding plate 2 for transporting the processing substrate 1.
[0040]
Next, the substrate insertion slot 8 is opened, and the processing substrate 1 is carried out of the substrate insertion slot 8 to the substrate transfer chamber 40 by a transfer mechanism (not shown) in the substrate transfer chamber 40.
[0041]
【The invention's effect】
According to the present invention, there is provided a semiconductor device manufacturing method capable of suppressing warpage due to film deposition on a dummy substrate and thereby suppressing or preventing the generation of particles due to warpage.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view for explaining a substrate processing apparatus used in an embodiment of the present invention.
FIG. 2 is a schematic longitudinal sectional view for explaining a substrate processing apparatus used in an embodiment of the present invention.
FIG. 3 is a schematic longitudinal sectional view for explaining a substrate processing apparatus used in one embodiment of the present invention.
FIG. 4 is a schematic longitudinal sectional view for explaining a temperature measuring method in the substrate processing apparatus used in one embodiment of the present invention.
FIG. 5 is a schematic plan view for explaining a dummy substrate used in one embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Processing substrate 2 ... Substrate holding plate 3 ... Resistance heater 4 ... Substrate support 5 ... Gas dispersion plate 6 ... Gas supply port 7 ... Exhaust port 8 ... Substrate insertion port 9 ... Open / close valve 10 ... Elevating mechanism 11 ... Dummy substrate Reference Signs List 20 heater unit 30 substrate processing apparatus 40 substrate transfer chamber 50 substrate processing chamber 61 radiation thermometer 62 thermocouple 111 groove

Claims (2)

A step of supplying a processing gas into the processing chamber in a state where a dummy substrate having irregularities on the surface is mounted on a substrate holding plate in the processing chamber to perform pre-coating,
Supplying a processing gas into the processing chamber in a state where a product substrate is mounted on the substrate holding plate to form a film. 2. The method according to claim 1, further comprising a step of introducing a cleaning gas into the processing chamber with the dummy substrate placed on the substrate holding plate to clean the processing chamber before the precoating step. A manufacturing method of the semiconductor device according to the above.

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