JP2006012994A - Substrate processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cause a gas to uniformly contact in the surfaces of wafers and between wafers. <P>SOLUTION: A batch type remote plasma CVD apparatus comprises a process tube 31 having a processing chamber 32 formed therein, which houses and processes a boat 25 that holds a group of wafers 1; a gas supply pipe 35 for supplying a processing gas 61 to the processing chamber 32; an exhaust pipe 36 for exhausting the processing chamber 32; a partition 41 provided on the inner peripheral surface of the processing chamber 32 for forming a plasma chamber 40; and a nozzle 42 provided at the partition 41. In the batch type remote plasma CVD apparatus, a pair of partitions 52, 52 having a gas supply pipe side distribution port 53 and an exhaust pipe side distribution port 54 are disposed in the processing chamber 32 concentrically with the boat 25, and the exhaust pipe side distribution port 54 is formed in the shape of a vertically elongated reverse trapezoid. Since the gas issued from the nozzle flows into the inside of the both partitions from the gas supply pipe side distribution port, and uniformly exhausts from the exhaust pipe side distribution port, the gas is distributed uniformly inside the entire partitions, and the gas uniformly contacts in the surfaces of wafers and between wafers. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a substrate processing apparatus, and more particularly to a gas rectification technique. For example, in a method of manufacturing a semiconductor integrated circuit device (hereinafter referred to as IC), a semiconductor wafer (hereinafter referred to as wafer) in which a semiconductor integrated circuit including semiconductor elements is fabricated. Is effective for depositing (depositing) an insulating film or a metal film.

Substrate for removing carbon (C) adhering to the vicinity of the surface of a tantalum pentoxide (Ta ₂ O ₅ ) film for forming a capacitance portion (insulating film) of a capacitor (capacitor) of a DRAM (Dynamic Random Access Memory) As a processing apparatus, a batch type remote plasma processing apparatus has been proposed (for example, see Patent Document 1).
As an example, a pair of electrodes close to each other are disposed in the processing chamber of a process tube having a processing chamber into which a plurality of substrates to be processed are loaded, and high-frequency power is applied between the electrodes. A power supply is connected, and a discharge chamber is formed in the processing chamber including the two electrodes and independent of the processing chamber. The discharge chamber has a gas outlet for supplying processing gas to the processing chamber. There is a batch-type remote plasma processing apparatus that has been established.

JP 2002-280378 A

The above-described batch type remote plasma processing apparatus has the following problems.
Although it is desired to supply the processing gas to the surface of the substrate to be processed, the processing gas is exhausted before it reaches the entire surface of the substrate to be processed. A part of the processing gas blown out from the gas blow-out port flows to the side instead of flowing between the substrates to be processed and is exhausted.

  An object of the present invention is to provide a substrate processing apparatus that can uniformly supply a gas to the surface of a substrate to be processed.

  A substrate processing apparatus according to the present invention includes a processing chamber for storing a substrate holder for holding the substrate in multiple stages and processing the substrate, a heater unit for heating the substrate, and a gas supply for supplying gas into the processing chamber. A partition plate having a gas supply pipe side circulation port and an exhaust pipe side circulation port arranged to surround the substrate in the processing chamber, and an exhaust pipe for exhausting the processing chamber. The exhaust pipe side circulation port extends in the stacking direction of the substrates, and the opening of the cross section parallel to the main surface of the substrate at the exhaust pipe side circulation port is viewed from the flow direction of the gas flowing on the substrate. The diameters of both ends of the exhaust pipe side circulation port in the stacking direction of the substrate are different from each other.

  According to the above means, the gas blown out from the gas supply pipe flows into the space surrounded by the partition plate from the circulation port on the gas supply pipe side of the partition plate, and the gas that has flowed in reaches the entire surface of the substrate and then exhausts the partition plate. The air is exhausted from the pipe side through the exhaust port. At this time, since the opening of the distribution port on the exhaust pipe side of the partition plate is set so that the flow of the gas in the stacking direction is uniform, the gas contacts the entire surface of the substrate in the stacking direction. The treatment is performed uniformly over the entire surface of the substrate.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the present embodiment, the substrate processing apparatus according to the present invention is configured as a batch type vertical hot wall type remote plasma CVD apparatus (hereinafter referred to as a CVD apparatus).
As shown in FIG. 1, the CVD apparatus 10 includes a housing 11, and a cassette transfer unit 12 is installed on the front surface of the housing 11. The cassette transfer unit 12 includes a cassette stage 13 on which two cassettes 2 serving as carriers of the wafer 1 can be placed. Two sets of wafer posture alignment devices 14 are provided below the cassette stage 13. When the cassette 2 transported by an external transport device (not shown) is placed on the cassette stage 13 in a vertical posture (the wafer 1 stored in the cassette 2 is vertical), the wafer posture alignment device 14 is placed. Are aligned so that the notches and orientation flats of the wafers 1 stored in the cassette 2 are the same. The cassette stage 13 is rotated 90 degrees to bring the cassette 2 into a horizontal posture.

  A cassette shelf 15 is provided inside the casing 11 so as to face the cassette delivery unit 12, and a spare cassette shelf 16 is provided above the cassette delivery unit 12. A cassette transfer device 17 is installed between the cassette transfer unit 12 and the cassette shelf 15. The cassette transfer device 17 includes a robot arm 18 that can move back and forth in the front-rear direction, and the robot arm 18 is configured to be able to traverse and move up and down. The robot arm 18 is adapted to convey and transfer the cassette 2 in a horizontal position on the cassette stage 13 to the cassette shelf 15 or the spare cassette shelf 16 by advancing / retreating, raising / lowering and traversing.

  Behind the cassette shelf 15, a wafer transfer device 19 that can transfer a plurality of wafers 1 at a time or to a single wafer is provided so as to be rotatable and liftable. The wafer transfer device 19 includes a wafer holder 20 that can be moved back and forth. A plurality of wafer holding plates 21 are horizontally attached to the wafer holder 20. A boat elevator 22 is installed behind the wafer transfer device 19, and a seal cap 24 as a substrate holder is horizontally installed on the arm 23 of the boat elevator 22.

  As shown in FIGS. 2 to 4, the CVD apparatus 10 includes a process tube 31 formed using a material having high heat resistance such as quartz glass, and one end of the process tube 31 is open. The end is formed in a closed cylindrical shape. The process tube 31 is vertically arranged so that the center line is vertical and is fixedly supported. A cylindrical hollow portion of the process tube 31 forms a processing chamber 32 in which a plurality of wafers 1 are accommodated, and a lower end opening of the process tube 31 forms a furnace port 33 for taking in and out the wafer 1. The inner diameter of the process tube 31 is set to be larger than the maximum outer diameter of the wafer 1 to be handled. A heater unit 34 surrounding the process tube 31 is concentrically provided outside the process tube 31, and the heater unit 34 is configured to heat the processing chamber 32 uniformly or with a predetermined temperature distribution throughout. Yes. The heater unit 34 is installed vertically by being supported by the casing 11 of the CVD apparatus 10.

  One end of a gas supply pipe 35 for supplying a processing gas is connected to a part of the side wall of the process tube 31 near the furnace port 33, and the other end of the gas supply pipe 35 is a gas for supplying the processing gas. Connected to a source (not shown). One end of an exhaust pipe 36 is connected to a portion of the process tube 31 near the furnace port 33 on the side wall 180 degrees opposite to the gas supply pipe 35, and the other end of the exhaust pipe 36 is an exhaust device (not shown). ) So that the processing chamber 32 can be exhausted.

  A seal cap 24 that closes the furnace port 33 is brought into contact with the lower end surface of the process tube 31 from below with a seal ring 24a interposed therebetween. The seal cap 24 is formed in a disk shape having an outer diameter larger than the inner diameter of the furnace port 33, and is lifted and lowered in the vertical direction by the arm 23 of the boat elevator 22 installed vertically outside the process tube 31. It is configured as follows. A rotation shaft 39 is inserted on the center line of the seal cap 24, and the rotation shaft 39 moves up and down together with the seal cap 24 and is rotated by a rotation driving device 38. A boat 25 for holding the wafer 1 as a substrate to be processed is vertically supported on and supported by the upper end of the rotating shaft 39 via a heat insulating cap portion 37.

  The boat 25 includes a pair of end plates 26 and 27 at the top and bottom, and a plurality of (three in this embodiment) holding members 28 provided between the end plates 26 and 27 and arranged vertically. Each holding member 28 is provided with a plurality of holding grooves 29 arranged at equal intervals in the longitudinal direction so as to be opened opposite to each other. Then, by inserting the outer peripheral edges of the wafers 1 between the multiple holding grooves 29 of the holding members 28, the plurality of wafers 1 are aligned horizontally on the boat 25 and aligned with each other. Are to be held. A heat insulating cap portion 37 is formed below the lower end plate 27 of the boat 25.

In a portion of the process tube 31 facing the gas supply pipe 35, a bowl-shaped partition wall 41 is laid so as to extend in the vertical direction in parallel with the inner peripheral surface of the process tube 31, and the partition wall 41 is airtight plasma. The chamber 40 is configured to be formed. A plurality of air outlets 42 are arranged in the partition wall 41 so as to be opposed to each other between upper and lower wafers 1 and 1 held in holding grooves 29 and 29 adjacent to the upper and lower sides of the boat 25. The outlet 42 is set so as to blow out the gas supplied to the plasma chamber 40 evenly.
Inside the plasma chamber 40, a pair of protective tubes 43, 43 are arranged symmetrically on opposite sides of the extended line of the gas supply tube 35, and are laid so as to extend in the vertical direction. Each protective tube 43 is formed in a long and narrow circular pipe shape using a dielectric material and closed at the upper end. The lower end of each protective tube 43 is appropriately bent and penetrates the side wall of the process tube 31 to the outside. Is sticking out. The inside of the hollow portion of each protection tube 43 is communicated with the outside (atmospheric pressure) of the processing chamber 32. A pair of electrodes 44, 44 formed in the shape of elongated rods using a conductive material are concentrically laid in the hollow portions of both protective tubes 43, 43, and high-frequency power is passed between the electrodes 44, 44. A high frequency power supply 45 to be applied is electrically connected via a matching unit 46.

In the processing chamber 32, a pair of partition plates 52, 52 are arranged concentrically on the left and right, and are installed on the side wall of the process tube 31 by a plurality of brackets 51. Both the bracket 51 and the partition plate 52 are formed using transparent quartz (SiO ₂ ) and are connected by welding. The left and right partition plates 52, 52 are each formed in an arcuate curved plate shape whose inner diameter is larger than the outer diameter of the boat 25 and whose length is substantially equal to the overall height of the boat 25. It arrange | positions so that it may become a symmetrical form, and is installed in the side wall of the process tube 31 by the several bracket 51. FIG. The pair of gaps before and after the front and rear edges of the left and right partition plates 52 and 52 are formed respectively extend in the vertical direction, which is the stacking direction of the group of wafers 1, and the gas supply pipe side circulation port 53 and the exhaust pipe side. Each circulation port 54 is configured.

The size of the front opening which is a plane (horizontal plane) opening parallel to the main surface of the wafer 1 in the gas supply pipe side circulation port 53 formed by the front side edges of the left and right partition plates 52, 52 is larger than the lateral width of the partition wall 41. It is set slightly larger and is set equally over the entire height. That is, the shape of the gas supply pipe side circulation port 53 viewed from the horizontal direction (the shape in front view) is a vertically elongated rectangle.
On the other hand, the size of the front opening which is a horizontal plane opening in the exhaust pipe side circulation port 54 formed by the rear side edges of the left and right partition plates 52, 52 is set to be smaller than the diameter of the wafer 1 in the vertical direction. The frontage dimension is set to become smaller as it goes downward. That is, as shown in FIG. 4, the shape of the exhaust pipe side circulation port 54 viewed from the horizontal direction (the shape in the rear view) is formed in a vertically elongated inverted trapezoidal shape.
If the angle formed by the line segment connecting the center of the left and right partition plates 52, 52 and the opening edge of the exhaust pipe side circulation port 54 is the opening degree of the exhaust pipe side circulation port 54, the implementation shown in FIG. In this embodiment, the upper opening degree Θa that is the maximum opening degree of the exhaust pipe side circulation port 54 is set to about 30 degrees, and the lower end opening degree Θb that is the minimum opening degree of the exhaust pipe side circulation port 54. Is set to about 15 degrees.

  A partition plate (hereinafter referred to as a horizontal partition plate) 55 that horizontally partitions the space of the exhaust pipe 36 and the space of the boat 25 is disposed on the heat insulating cap portion 37 so as to be concentric with the boat 25 and horizontally. Is installed. The horizontal partition plate 55 is made of transparent quartz and is formed in a disk shape having a diameter larger than that of the wafer 1 and smaller than that of the process tube 31. An escape portion 55 a that escapes the partition wall 41 is cut out at a portion corresponding to the partition wall 41 of the horizontal partition plate 55.

Next, a method of removing carbon existing near the surface of the Ta ₂ O ₅ film for the capacitance portion of the DRAM capacitor using the CVD apparatus 10 having the above configuration will be described. That is, in the present embodiment, a Ta ₂ O ₅ film (not shown) for forming a capacitance portion of a capacitor is deposited on the wafer 1 supplied to the CVD apparatus 10 in the previous MOCVD process. It is assumed that carbon (not shown) exists near the surface of the Ta ₂ O ₅ film, and this carbon is removed by the CVD apparatus 10.

  As shown in FIG. 2, a plurality of wafers 1 as substrates to be processed by the CVD apparatus 10 are loaded (charged) into the boat 25 by the wafer transfer apparatus 19. The boat 25 loaded with a plurality of wafers 1 is lifted by the boat elevator 22 together with the seal cap 24 and the rotary shaft 39 and is loaded into the processing chamber 32 of the process tube 31 (boat loading).

  As shown in FIG. 5, when the boat 25 holding the group of wafers is loaded into the processing chamber 32 and the processing chamber 32 is sealed by the seal cap 24, the processing chamber 32 is connected to the exhaust pipe 36. The exhaust device exhausts the air to below a predetermined pressure, and the power supplied to the heater unit 34 is increased, whereby the temperature of the processing chamber 32 is increased to a predetermined temperature. Since the heater unit 34 has a hot-wall structure, the temperature of the processing chamber 32 is maintained uniformly throughout the entire structure. As a result, the temperature distribution of the group of wafers held in the boat 25 is uniform over the entire length. At the same time, the in-plane temperature distribution of each wafer 1 is uniform and the same.

  After the temperature of the processing chamber 32 reaches a preset value and stabilizes, the processing gas 61 is introduced. When the pressure reaches a preset value, high-frequency power is applied between the pair of electrodes 44 and 44 by the high-frequency power supply 45 and the matching unit 46 while the boat 25 is rotated by the rotating shaft 39. When the processing gas 61 is supplied to the gas supply pipe 35 and high-frequency power is applied between the electrodes 44, 44, plasma 60 is formed inside the gas supply pipe 35, and the processing gas 61 is in a reaction-active state. Become. 5 and 6, the activated particles (oxygen radicals) 62 of the processing gas 61 are blown out from the respective outlets 42 of the partition wall 41 into the processing chamber 32.

Activated particles (hereinafter referred to as active particles) 62 are blown out from the respective outlets 42, thereby flowing between the wafers 1 and 1 facing each other and coming into contact with the respective wafers 1.
At this time, since the left and right partition plates 52 and 52 are concentrically installed outside the boat 25, the active particles 62 blown out from the respective outlets 42 are guided laterally by the left and right partition plates 52 and 52. Without any leakage to the wafers 1 and 1.
Further, the size of the front end of the exhaust pipe side circulation port 54 is set to be smaller than the diameter of the wafer 1, and the shape of the exhaust pipe side circulation port 54 in the rear view is formed in a vertically elongated inverted trapezoidal shape. The particles 62 diffuse evenly throughout the entire length in the space surrounded by the left and right partition plates 52, 52.
For this reason, the radial contact distribution in the wafer surface of each wafer 1 corresponding to the flow direction of the active particles is uniform, and the contact distribution of the active particles 62 with respect to the whole group of wafers is also uniform over the entire length of the boat 25. become. In addition, since the wafer 1 is rotated by the rotation of the boat 25, the contact distribution within the wafer surface of the active particles 62 flowing between the wafers 1 and 1 becomes uniform in the circumferential direction.

The active particles (oxygen radicals) 62 in contact with the wafer 1 react with the carbon existing near the surface of the Ta ₂ O ₅ film of the wafer 1 to generate CO (carbon monoxide), thereby converting the carbon into Ta _2. Remove from O ₅ film. At this time, as described above, the temperature distribution of the wafer 1 is maintained uniformly over the entire length of the boat 25 and within the wafer plane, and the contact distribution of the active particles 62 with the wafer 1 is within the entire position of the boat 25 and within the wafer plane. Therefore, the action of removing carbon from the wafer 1 due to the thermal reaction of the active particles 62 becomes uniform in all positions of the boat 25 and in the wafer surface.
Incidentally, the processing conditions for removing carbon from the Ta ₂ O ₅ film for forming the capacitance portion of the DRAM capacitor are as follows. The supply flow rate of oxygen gas used as the processing gas is 8.45 × 10 ^{−1 to} 3.38 Pa · m ³ / s, the pressure in the processing chamber is 10 to 100 Pa, and the temperature is 500 to 700 ° C.

When a preset processing time elapses, supply of the processing gas 61, rotation of the rotating shaft 39, application of high-frequency power, heating of the heater unit 34, exhaust of the exhaust pipe 36, and the like are stopped.
Subsequently, the furnace cap 33 is opened by lowering the seal cap 24 by the boat elevator 22, and the group of wafers is carried out of the processing chamber 32 from the furnace port 33 while being held by the boat 25 (boat unloading). Loading).
The group of wafers carried out of the processing chamber 32 is discharged (lowered) from the boat 25 by the wafer transfer device 19.
Thereafter, the plurality of wafers 1 are batch processed by repeating the above-described operation.

  According to the embodiment, the following effects can be obtained.

1) By installing a pair of left and right partition plates concentrically outside the boat, the process gas blown out from each outlet is guided by both partition plates to ensure that it flows between the opposing wafers. Since the entire surface can be diffused in a space surrounded by a plate, the contact distribution in the radial direction of each wafer corresponding to the flow direction of the processing gas and the contact distribution of the processing gas to the entire wafer group are made uniform. Can be made.

2) By setting the front dimension of the exhaust pipe side circulation port formed by the rear side edges of the left and right partition plates to be smaller than the diameter of the wafer, and forming the rear view shape of the front port in a vertically elongated inverted trapezoidal shape Since the processing gas flowing into the space surrounded by the left and right partition plates can be evenly diffused over the entire surface and the entire length in the space surrounded by the left and right partition plates, each wafer corresponding to the flow direction of the processing gas The contact distribution in the radial direction within the wafer surface can be made uniform, and the contact distribution of the processing gas with respect to the entire wafer group can also be made uniform over the entire length of the boat.

3) By arranging the horizontal partition plates under the left and right partition plates, the processing gas blown out from the outlet is prevented from being exhausted directly to the exhaust pipe through the lower space of the left and right partition plates. Therefore, the contact distribution in the radial direction of each wafer corresponding to the flow direction of the processing gas and the contact distribution of the processing gas with respect to the entire wafer group can be made more uniform.

4) By distributing the contact distribution in the radial direction within the wafer surface of each wafer corresponding to the flow direction of the process gas and the contact distribution of the process gas with respect to the entire wafer group, the wafer processing status distribution by the process gas can be reduced. Uniformity can be achieved within the wafer surface and within the wafer group (between each wafer).

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  For example, the partition plate is not limited to being fixed to the process tube, but may be fixed to a housing or a boat.

  The number of outlets of the gas supply pipe is not limited to the number of wafers to be processed, but can be increased or decreased according to the number of wafers to be processed. For example, the air outlets are not limited to be disposed between the upper and lower adjacent wafers, but may be arranged in two or three.

In the above-described embodiment, the case where the carbon intervening in the Ta ₂ O ₅ film of the capacitance portion of the capacitor is removed has been described. However, the batch type remote plasma processing apparatus uses foreign substances (that film) intervening in other film types. It can be applied to the case of removing molecules, atoms, etc. other than seeds), forming a CVD film on a wafer, diffusing, or heat treating.
For example, in a process of nitriding an oxide film for a gate electrode of a DRAM, nitrogen (N ₂ ) gas, ammonia (NH ₃ ), or nitrogen monoxide (N ₂ O) is supplied to a gas supply pipe, and the processing chamber is set to room temperature to By heating to 750 ° C., the surface of the oxide film could be nitrided.
In addition, when the surface of the silicon wafer before the formation of the silicon germanium (SiGe) film is plasma-treated with active particles of hydrogen (H ₂ ) gas, the natural oxide film can be removed and a desired SiGe film is formed. We were able to.
Further, in forming a nitrogen film at a low temperature, ALD (Atomic Layer Deposition atoms) in which DCS (dichlorosilane) and NH ₃ (ammonia) are alternately supplied to form Si (silicon) and N (nitrogen) one by one. In the case of layer formation), when NH ₃ was supplied with NH ₃ activated by plasma when supplied, a high-quality nitride film was obtained.

  Although the batch type remote plasma processing apparatus has been described in the above embodiment, the present invention is not limited to this, and is applicable to other substrate processing apparatuses such as other CVD apparatuses, oxide film forming apparatuses, diffusion apparatuses, and annealing apparatuses. be able to.

  In the above embodiment, the case where the wafer is processed has been described. However, the processing target may be a photomask, a printed wiring board, a liquid crystal panel, a compact disk, a magnetic disk, or the like.

It is a perspective view which shows the CVD apparatus which is embodiment of this invention. It is side surface sectional drawing which shows the principal part. FIG. 3 is a partially cut plan sectional view taken along line III-III in FIG. 2. It is a longitudinal cross-sectional view which follows the IV-IV line of FIG. FIG. 3 is a partially omitted plan cross-sectional view of a main part showing a gas flow. It is side surface sectional drawing similarly.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Wafer (substrate to be processed), 2 ... Cassette, 10 ... CVD apparatus (batch type vertical hot wall type remote plasma CVD apparatus), 11 ... Housing, 12 ... Cassette transfer unit, 13 ... Cassette stage, 14 ... Wafer posture Alignment device, 15 ... cassette shelf, 16 ... spare cassette shelf, 17 ... cassette transfer device, 18 ... robot arm, 19 ... wafer transfer device, 20 ... wafer holder, 21 ... wafer holding plate, 22 ... boat elevator, DESCRIPTION OF SYMBOLS 23 ... Arm, 24 ... Seal cap, 24a ... Seal ring, 25 ... Boat, 26, 27 ... End plate, 28 ... Holding member, 29 ... Holding groove, 31 ... Process tube, 32 ... Processing chamber, 33 ... Furnace port, 34 ... Heater unit, 35 ... Gas supply pipe, 36 ... Exhaust pipe, 37 ... Thermal insulation cap part, 38 ... Rotation drive device, 39 ... Rotating shaft, 4 DESCRIPTION OF SYMBOLS ... Plasma chamber, 41 ... Bulkhead, 42 ... Outlet, 43 ... Protective tube, 44 ... Electrode, 45 ... High frequency power supply, 46 ... Matching device, 51 ... Bracket, 52 ... Partition plate, 53 ... Gas supply pipe side circulation port, 54 ... Exhaust pipe side circulation port, 55 ... Horizontal partition plate, 55a ... Escape part, 60 ... Plasma, 61 ... Processing gas, 62 ... Active particles (processing gas).

Claims (1)

  A processing chamber that accommodates substrate holders that hold the substrate in multiple stages and processes the substrate, a heater unit that heats the substrate, a gas supply pipe that supplies gas into the processing chamber, and an exhaust chamber that exhausts the processing chamber An exhaust pipe, and a partition plate that is disposed so as to surround the substrate in the processing chamber and has a gas supply pipe side circulation port and an exhaust pipe side circulation port, and the exhaust pipe side circulation port is provided on the substrate. The opening of the cross section extending in the stacking direction and parallel to the main surface of the substrate at the exhaust pipe side circulation port is set smaller than the diameter of the substrate when viewed from the flow direction of the gas flowing on the substrate. The substrate processing apparatus is characterized in that the exhaust pipe side circulation port has different sizes at both ends in the substrate stacking direction.

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