JP2008205327A - Substrate processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the uniformity of a raw gas flowing on a wafer surface and to improve the uniformity of wafer processing and processing quality in a substrate processing apparatus for processing a substrate using plasma. <P>SOLUTION: The apparatus includes a processing chamber 21 for housing the substrate 20 and performing prescribed processing by the plasma, a substrate mounting base 8 provided in the processing chamber for mounting the substrate, exhaust chambers 25 and 26 positioned below the substrate mounting base, and a buffer plate 22 provided so as to surround the periphery of the substrate mounting base and partitioning the exhaust chambers and the processing chamber. The buffer plate is a porous plate where many vent holes are perforated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a substrate processing apparatus that performs processing such as generation of a thin film, diffusion of impurities, etching, or ashing on the surface of a substrate such as a silicon wafer or a glass substrate.

  In the process of manufacturing a semiconductor device, a thin film is formed on a substrate such as a glass substrate or a silicon wafer (hereinafter referred to as a wafer), an etching process for forming a circuit pattern on the wafer, or the resist on the wafer is removed after etching. There are ashing processes to be performed, and examples of processes for processing such processes include a plasma CVD apparatus, a plasma etching apparatus, and a substrate processing apparatus such as an ashing apparatus.

  The substrate processing apparatus has a processing chamber for performing predetermined processing on the wafer, and the thin film generation, etching, ashing, etc. are performed on the wafer stored in the processing chamber using plasma generated by predetermined means. Perform the process.

  For example, an ashing apparatus, which is one of substrate processing apparatuses, has a cylindrical quartz reaction tube and a metal chamber connected to the reaction tube in an airtight manner, and the reaction tube is surrounded by the reaction tube. A coil for converting the discharged gas into plasma is provided, a wafer is placed in the chamber, and a substrate placing table (susceptor) for heating the placed wafer is provided.

  A wafer is placed on the susceptor, heated, high-frequency power is applied to the coil, plasma is generated by introducing a processing gas into the reaction tube, and the ionized gas is brought into contact with the wafer as required. Processing is done. The treated gas is exhausted from an exhaust port provided below the chamber.

  The uniformity of wafer processing is affected by the state of the gas flowing over the surface of the wafer. Therefore, in order to improve the wafer processing uniformity, it is necessary for the processing gas to flow uniformly over the entire wafer surface. However, the gas flow depends on the flow path resistance in the gas flow path. For example, more processing gas flows in the shortest path from the chamber to the exhaust port, and the processing gas non-uniformity flows on the wafer surface. Cause.

JP 2002-93783 A

  In view of such circumstances, the present invention improves the uniformity of the processing gas flowing on the wafer surface and improves the uniformity and processing quality of the wafer processing.

  The present invention includes a processing chamber for storing a substrate and performing a predetermined process using plasma, a substrate mounting table provided in the processing chamber on which the substrate is mounted, an exhaust chamber positioned below the substrate mounting table, A substrate processing apparatus comprising a buffer plate provided so as to surround the substrate mounting table and partitioning the exhaust chamber and the processing chamber, wherein the buffer plate is a perforated plate having a large number of vent holes. It is related to.

  According to the present invention, a processing chamber for storing a substrate and performing a predetermined process using plasma, a substrate mounting table provided in the processing chamber on which a substrate is mounted, and an exhaust chamber positioned below the substrate mounting table And a buffer plate that surrounds the periphery of the substrate mounting table and partitions the exhaust chamber and the processing chamber, and the buffer plate is a perforated plate having a large number of ventilation holes. The exhaust gas is uniformly exhausted from the periphery of the substrate mounting table, and as a result, the gas flow distribution becomes uniform, and excellent effects such as improvement in wafer processing uniformity and processing quality are exhibited.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 schematically shows an ashing apparatus as an example of a substrate processing apparatus according to the present invention.

  In the figure, reference numeral 1 denotes a cylindrical quartz reaction tube. The reaction tube 1 is airtightly installed in a chamber 2 which is a metal hermetic container, and the reaction tube 1 and the chamber 2 are arranged in the chamber 2. It communicates with the opening 3 formed on the upper surface. The upper end of the reaction tube 1 is hermetically closed by the reaction tube ceiling plate 4, and the reaction tube ceiling plate 4 is preferably provided with a processing gas introduction hole 5 at the center, and the processing gas introduction hole 5 is not shown in the drawing. It is connected to a gas supply source so that a process gas whose flow rate is adjusted is supplied.

  A coil 6 for generating plasma is provided around the reaction tube 1, and the coil 6 is covered with a coil cover 7. A high frequency power source (not shown) is connected to the coil 6, and a high frequency current for generating plasma is applied to the coil 6 by the high frequency power source.

  A substrate mounting table (susceptor) 8 supported by a plurality of (for example, four) columns 10 is provided on the bottom surface of the chamber 2. The susceptor 8 includes a substrate heating unit 9 and a substrate mounting plate 11. .

  An exhaust plate 12 is disposed below the susceptor 8. The exhaust plate 12 is supported by a bottom substrate 14 via a guide shaft 13, and the bottom substrate 14 is airtightly provided on the lower surface of the chamber 2. .

  An elevating board 15 is provided so as to freely move up and down using the guide shaft 13 as a guide, and at least three lift rods 16 are erected on the elevating board 15. The lift rod 16 penetrates the susceptor 8, and a lift pin 17 is attached to the upper end of the lift rod 16.

  The lift pins 17 extend in the center direction of the susceptor 8, the wafer 20 is placed on the upper surface, and the wafer 20 is placed on the susceptor 8 or lifted by the lift rod 16. It is like.

  An elevating shaft 18 of an elevating drive unit (not shown) is hermetically penetrated through the bottom substrate 14, the elevating shaft 18 is connected to the elevating substrate 15, and the elevating drive unit raises and lowers the elevating shaft 18. Thus, the lift pins 17 are lifted and lowered via the lift board 15 and the lift rod 16.

  The reaction tube 1 defines a reaction chamber 19 in which plasma is generated, and the chamber 2 defines a processing chamber 21 in which a wafer 20 is accommodated. A first exhaust chamber 25 is defined between the susceptor 8 and the exhaust plate 12, and a second exhaust chamber 26 is defined between the exhaust plate 12 and the bottom substrate 14.

  A cylindrical buffer plate 22 is provided on the susceptor 8 so as to surround the first exhaust chamber 25. As shown in FIG. 2, the buffer plate 22 is composed of a perforated plate (for example, a punching metal made of aluminum or stainless steel) having a large number of vent holes 23 formed uniformly. Accordingly, the first exhaust chamber 25 is partitioned from the inside of the chamber 2 by the buffer plate 22, and communicates with the inside of the chamber 2 by the vent hole 23.

  An exhaust communication hole 24 is formed in the center of the exhaust plate 12, and the first exhaust chamber 25 and the second exhaust chamber 26 are communicated with each other by the exhaust communication hole 24. The exhaust system that does not work is in communication.

  A wafer loading / unloading port (not shown) is formed on the side wall of the chamber 2, and the wafer loading / unloading port is opened by a gate valve (not shown) and can be airtightly closed. Yes. The wafer 20 is carried into and out of the chamber 2 through the wafer carry-in / out port, and the wafer 20 is placed on the lift pins 17 in cooperation with the raising and lowering of the lift pins 17, and the wafers from the lift pins 17. 20 payouts are made.

  Hereinafter, an operation of the substrate processing apparatus, for example, an ashing process will be described.

  With the lift pins 17 raised, the wafer 20 is loaded into the processing chamber 21 from the wafer loading / unloading port by a substrate transfer machine (not shown), and the wafer 20 is placed on the lift pins 17. The substrate transfer machine moves backward and the wafer loading / unloading port is closed. The lift pins 17 are lowered by the lift shaft 18 via the lift substrate 15 and the lift rod 16, and the wafer 20 is placed on the susceptor 8.

  The wafer 20 is heated to a predetermined processing temperature by the substrate heating unit 9. Further, the resist used in the etching process, which is the previous process, is attached to the surface of the wafer 20.

  The process gas whose flow rate is controlled is introduced into the reaction chamber 19 through the process gas introduction hole 5. The processing gas is, for example, a mixed gas obtained by adding a fluorine-based gas to oxygen gas.

  A high-frequency current is supplied to the coil 6 from the high-frequency power source (not shown), discharge occurs in the processing gas, and radical oxygen (radical oxygen) or the like is generated, and a plasma region is formed in the reaction chamber 19. The

  A processing gas containing radical oxygen descends in the reaction chamber 19 and is supplied to the processing chamber 21, passes through the buffer plate 22, and enters the first exhaust chamber 25, the exhaust communication hole 24, and the second exhaust chamber 26. And exhausted as exhaust gas by the exhaust means (not shown).

  In the process gas exhaust process, the process gas flowing down the reaction chamber 19 diffuses radially along the surface of the wafer 20 and passes through the buffer plate 22 from the entire circumference of the susceptor 8 to the first exhaust chamber. 25.

  Since the buffer plate 22 is provided so as to surround the entire circumference of the susceptor 8, it has a large surface area. Further, since a large number of the vent holes 23 are equally formed, the buffer plate 22 provides an appropriate flow path resistance, and further, a radial flow (radial flow) in which exhaust gas flows into the first exhaust chamber 25. Therefore, the flow velocity does not increase locally.

  Therefore, the uniformity of the velocity distribution of the processing gas flowing along the surface of the wafer 20 can be obtained, and the processing uniformity and the processing quality can be improved.

  The gas exhaust means exhausts exhaust gas at a predetermined flow rate, and the exhaust resistance is adjusted by the buffer plate 22, whereby the pressure in the reaction chamber 19 and the processing chamber 21 is adjusted to a predetermined processing pressure. . In FIG. 3, an arrow 28 indicates the gas flow.

  The radical oxygen in the processing gas comes into contact with the wafer 20, and the resist on the wafer 20 is oxidized by the radical oxygen. The resist becomes carbon dioxide, water, etc., and is removed from the wafer 20 and exhausted from the processing chamber 21 together with the exhaust gas. Is done.

  As an example of the processing chamber temperature, gas flow rate, and processing chamber pressure in the above-described ashing, the processing chamber temperature is 250 ° C., and the gas flow rate is 3 L / min or more, preferably 8 L / min to 13 L / min. min, the processing chamber pressure is 200 Pa to 600 Pa.

  It should be noted that the size and density (the number of holes per unit area) of the vent holes 23 formed in the buffer plate 22 can be changed as appropriate, and the density varies depending on the location according to the flow conditions. May be.

It is a schematic sectional drawing which shows the substrate processing apparatus which concerns on embodiment of this invention. It is a perspective view of the buffer plate used for this substrate processing apparatus. It is explanatory drawing which shows the flow of the gas in this substrate processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reaction tube 2 Chamber 5 Process gas introduction hole 6 Coil 8 Susceptor 9 Substrate heating part 19 Reaction chamber 20 Wafer 21 Processing chamber 22 Buffer plate 25 1st exhaust chamber 26 2nd exhaust chamber

Claims (1)

  A processing chamber for storing a substrate and performing a predetermined process using plasma, a substrate mounting table provided in the processing chamber on which the substrate is mounted, an exhaust chamber positioned below the substrate mounting table, and the substrate mounting table And a buffer plate that divides the exhaust chamber and the processing chamber, and the buffer plate is a perforated plate having a large number of ventilation holes. apparatus.

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