JP2007184329A - Gas supply apparatus, substrate processing apparatus, gas supply method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve desired in-plane uniformity by supplying gas from a plurality of portions in a processing chamber through a simple piping system by simple control without being affected by pressure variation. <P>SOLUTION: Prior to processing a wafer, pressure ratio control for regulating the amount of shunt is performed such that the pressure ratio in each branch channel becomes a target pressure ratio for an amount of shunt regulation means 230. When processing gas from a processing gas supply means 210 is shunted to first and second branch lines 204 and 206 and pressure in each branch channel is stabilized, control for the amount of shunt regulation means is switched to pressure constant control for regulating the amount of shunt such that the pressure in the first branch channel at the time of stable pressure is sustained, and then additional gas is supplied by an additional gas supply means 220 to the second branch line 206. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a gas supply apparatus, a substrate processing apparatus, and a gas supply method for supplying a gas into a processing chamber.

  This type of substrate processing apparatus supplies a predetermined gas into a processing chamber, and performs predetermined film formation, etching, etc. on a substrate to be processed such as a semiconductor wafer or a liquid crystal substrate (hereinafter simply referred to as “substrate”). Processing is to be performed.

  For example, a plasma processing apparatus is known as such a substrate processing apparatus. The plasma processing apparatus includes, for example, a lower electrode that also serves as a mounting table for placing a substrate in a processing chamber, and an upper electrode that also serves as a shower head that ejects gas toward the substrate. In such a parallel plate type plasma processing apparatus, film formation or etching is performed by generating plasma by applying high-frequency power between both electrodes while a predetermined gas is supplied from a shower head onto a substrate in a processing chamber. The predetermined process is performed.

JP-A-8-158072 JP-A-9-45624

  By the way, when performing predetermined processing such as film formation and etching on the substrate, the processing characteristics such as the etching rate, the etching selectivity, and the film formation rate are made uniform in the substrate surface, and the in-plane uniformity of the substrate processing is improved. Improving has been an important issue from the past.

  From such a viewpoint, for example, in Patent Documents 1 and 2, the interior of the shower head is partitioned into a plurality of gas chambers, and gas supply pipes are independently connected to each gas chamber, and any kind or It has been proposed to supply process gas at an arbitrary flow rate. According to this, the gas concentration in the substrate surface can be locally adjusted to improve the in-plane uniformity of the etching substrate treatment.

  The gas used for actual substrate processing is, for example, a processing gas directly involved in substrate processing, a carrier for controlling deposition (deposition) of reaction products generated by such processing, an inert gas carrier, etc. The gas is composed of a combination of a plurality of gases such as a gas, and the gas species is appropriately selected and used according to the material to be processed on the substrate and the process conditions. For this reason, for example, as shown in Patent Document 2, it is necessary to provide a mass flow controller for each gas supply pipe connected to each gas chamber of the shower head to perform flow control.

  However, in such a conventional configuration, a gas supply system is provided for each gas supplied from each gas chamber even if a common gas type is included in the gas used, and flow control is performed separately. As a result, the piping configuration is complicated and the flow rate control of each piping is complicated, so that, for example, a large piping space is required, and the control burden increases.

  Even if the gas can be supplied from a plurality of parts in the processing chamber with simple control, for example, the flow rate ratio (diversion ratio) of the processing gas supplied from each part due to a change in pressure when the gas is introduced. In such a control that fluctuates), the desired in-plane uniformity cannot be realized. For this reason, it is also important to control the gas supply so as not to be affected by pressure fluctuations.

  Therefore, the present invention has been made in view of such problems, and the object of the present invention is to supply gas from a plurality of parts in the processing chamber with a simple piping configuration and simple control. An object of the present invention is to provide a gas supply device or the like that can realize desired in-plane uniformity.

  In order to solve the above problems, according to an aspect of the present invention, a gas supply apparatus that supplies a gas into a processing chamber that processes a substrate to be processed, the process supplying a processing gas that processes the substrate to be processed. A gas supply means, a processing gas supply path for flowing a processing gas from the processing gas supply means, a first branch flow path and a second branch flow branching from the processing gas supply path and connected to different parts of the processing chamber, respectively. A branch flow channel, a flow rate adjusting means for adjusting the flow rate of the process gas branched from the process gas supply channel to each branch flow channel based on the pressure in each branch flow channel, and a predetermined additional gas. An additional gas supply means for supplying, an additional gas supply flow path for joining the additional gas from the additional gas supply means to the second branch flow path downstream from the partial flow rate adjusting means, and for processing the substrate to be processed Prior to the processing, A processing gas is supplied by a supply means, and pressure ratio control is performed to adjust the flow rate so that the pressure ratio in each branch flow path becomes a target pressure ratio with respect to the flow rate adjustment means, and each branch flow is controlled. When the pressure in the passage is stabilized, the control for the partial flow rate adjusting means is switched to constant pressure control for adjusting the partial flow rate so as to maintain the pressure in the first branch flow path when the pressure is stable, and then the additional gas There is provided a gas supply device comprising control means for supplying additional gas by the supply means.

  In order to solve the above problems, according to another aspect of the present invention, a processing chamber for processing a substrate to be processed, a gas supply device for supplying a gas into the processing chamber, and a control means for controlling the gas supply device A substrate processing apparatus comprising: a processing gas supply means for supplying a processing gas for processing the substrate to be processed; a processing gas supply path for supplying a processing gas from the processing gas supply means; , A first branch flow path and a second branch flow path branched from the process gas supply path and connected to different parts of the process chamber, and a process branched from the process gas supply path to the branch flow paths A partial flow rate adjusting means for adjusting a partial flow rate of the gas based on a pressure in each branch flow path; an additional gas supply means for supplying a predetermined additional gas; and an additional gas from the additional gas supply means for supplying the partial flow rate Downstream from adjustment means And an additional gas supply flow path that merges with the second branch flow path, and the control means supplies a process gas by the process gas supply means prior to processing the substrate to be processed, and the partial flow rate adjustment When the pressure ratio control for adjusting the divided flow rate is performed so that the pressure ratio in each branch flow path becomes the target pressure ratio, and the pressure in each branch flow path is stabilized, the divided flow rate adjusting means The additional gas is supplied by the additional gas supply means after the control is switched to the constant pressure control for adjusting the partial flow rate so as to maintain the pressure in the first branch flow path when the pressure is stable. A substrate processing apparatus is provided.

  In order to solve the above problems, according to another aspect of the present invention, there is provided a gas supply method using a gas supply device for supplying a gas into a processing chamber for processing a substrate to be processed. A processing gas supply means for supplying a processing gas for processing a substrate to be processed; a processing gas supply path for supplying a processing gas from the processing gas supply means; and a branch from the processing gas supply path to a different part of the processing chamber. The first branch channel and the second branch channel connected to each other, and the partial flow rate of the processing gas branched from the processing gas supply channel to each branch channel are adjusted based on the pressure in each branch channel. Additional gas supply means for supplying a predetermined additional gas, and additional gas for joining the additional gas from the additional gas supply means to the second branch flow path downstream from the partial flow rate adjusting means. With supply flow path Prior to the processing of the substrate to be processed, a processing gas is supplied by the processing gas supply means, and the partial flow rate is adjusted so that the pressure ratio in each branch flow path becomes the target pressure ratio with respect to the partial flow rate adjusting means. If the pressure in each branch flow path is stabilized by the pressure ratio control and the pressure ratio control in the first branch flow path when the pressure is stable. And a step of supplying an additional gas by the additional gas supply means after switching to a constant pressure control for adjusting the partial flow rate so as to maintain the gas flow rate.

  According to the present invention, the processing gas from the processing gas supply means is divided into the first and second branch flow paths, and the processing gas from the processing gas supply means is directly supplied to the processing chamber from the first branch flow path. A predetermined additional gas is added from the second branch flow path and the gas component and flow rate of the processing gas are adjusted, and then supplied to the processing chamber. As a result, the processing gas having a common gas component in each branch flow path is supplied from the common processing gas supply means, and an additional gas is added to the processing gas flowing in the second branch flow path as necessary. Since the components and flow rate can be adjusted, the minimum number of pipes is sufficient, and a simple pipe configuration can be made correspondingly, and flow control can be simplified.

  Further, since the diversion control of the diversion flow adjusting means is switched from the pressure ratio control to the constant pressure control before the additional gas supply, the pressure in the second branch flow path varies when the additional gas is supplied to the second branch flow path. However, it is possible to prevent the processing gas that should flow into the second branch flow path from flowing into the first branch flow path. For this reason, it is possible to prevent the flow rate ratio (diversion ratio) of the processing gas divided into each branch flow path before and after the supply of the additional gas from being lost, and the processing gas divided at the desired flow rate ratio is prevented from flowing on the substrate surface. Can be supplied to different areas. Thereby, desired in-plane uniformity can be realized.

  In addition, when the pressure in each branch passage is stabilized after the supply of the additional gas is started, the control means sets the pressure ratio in each branch passage when the pressure is stabilized as a new target pressure ratio, and The control for the partial flow rate adjusting means may be switched to pressure ratio control for adjusting the partial flow rate so that the pressure ratio in each branch flow path becomes the new target pressure ratio. In this way, by returning the control of the partial flow rate adjusting means from the constant pressure control to the pressure ratio control, even if the conductance of the gas ejection holes changes in the subsequent substrate processing, the pressure in each branch channel is changed. Since both fluctuate, the pressure ratio does not change. Therefore, the pressure ratio control can be performed so that the pressure ratio in each branch channel does not collapse. Thereby, even if the conductance of the gas ejection hole changes with time, it is possible to prevent the flow rate ratio of the processing gas diverted to each branch flow path from collapsing.

  The partial flow rate adjusting means includes, for example, a valve for adjusting the flow rate of the processing gas flowing through each branch channel and a pressure sensor for measuring the pressure in each branch channel. The flow rate ratio of the processing gas from the processing gas supply flow path is adjusted by adjusting the degree of opening and closing of the valve based on the detected pressure from the processing gas.

  The processing gas supply means may include a plurality of gas supply sources, and supply the processing gas mixed at a predetermined flow rate from the gas supply sources to the processing gas supply path. The additional gas supply means includes a plurality of gas supply sources, and supplies the additional gas selected from the gas supply sources or mixed at a predetermined gas flow ratio to the additional gas supply path. Good. According to this, the processing gas supply means supplies a processing gas in which a plurality of gas components common to each branch flow path are mixed, and an additional gas is added to the processing gas flowing through the second branch flow path as necessary. In addition, since the gas component and flow rate are adjusted, the number of pipes can be reduced and a simpler pipe configuration can be realized.

  Further, the first branch flow path is disposed so that, for example, the processing gas flowing through the flow path is supplied toward a central region on the surface of the substrate to be processed in the processing chamber, and the second branch flow path is For example, the processing gas flowing through this flow path is arranged so as to be supplied toward the outer peripheral region on the surface of the substrate to be processed. Thereby, the uniformity of processing in the central region and the outer peripheral region of the substrate to be processed can be improved.

  The second branch flow path includes a plurality of branch flow paths branched from the processing gas supply path, and is configured to be able to supply additional gas from the additional gas supply means to the second branch flow paths. Also good. According to this, it is possible to divide the outer peripheral region of the substrate to be processed into a plurality of regions and supply the processing gas to each region. Can be controlled more finely.

  As described above, according to the present invention, it is possible to supply a gas supply device and the like that can supply gas from a plurality of parts in the processing chamber with a simple piping configuration and simple control, and achieve desired in-plane uniformity. It can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

(Configuration example of substrate processing equipment)
First, a substrate processing apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of the substrate processing apparatus according to the present embodiment. Here, the substrate processing apparatus is configured as a parallel plate type plasma etching apparatus.

  The substrate processing apparatus 100 has a processing chamber 110 constituted by a substantially cylindrical processing container. The processing container is made of, for example, an aluminum alloy and is electrically grounded. The inner wall surface of the processing vessel is covered with an alumina film or an yttrium oxide film.

  A susceptor 116 that constitutes a lower electrode that also serves as a mounting table on which a wafer W as a substrate is mounted is disposed in the processing chamber 110. Specifically, the susceptor 116 is supported on a columnar susceptor support 114 provided via an insulating plate 112 at the bottom center in the processing chamber 110. The susceptor 116 is made of, for example, an aluminum alloy.

  An electrostatic chuck 118 that holds the wafer W is provided on the susceptor 116. The electrostatic chuck 118 has an electrode 120 inside. A DC power source 122 is electrically connected to the electrode 120. The electrostatic chuck 118 can attract the wafer W on the upper surface thereof by a Coulomb force generated when a DC voltage is applied to the electrode 120 from the DC power supply 122.

  A focus ring 124 is provided on the upper surface of the susceptor 116 so as to surround the periphery of the electrostatic chuck 118. A cylindrical inner wall member 126 made of, for example, quartz is attached to the outer peripheral surfaces of the susceptor 116 and the susceptor support base 114.

  A ring-shaped refrigerant chamber 128 is formed inside the susceptor support 114. The refrigerant chamber 128 communicates with a chiller unit (not shown) installed outside the processing chamber 110 via pipes 130a and 130b, for example. A refrigerant (refrigerant liquid or cooling water) is circulated and supplied to the refrigerant chamber 128 via the pipes 130a and 130b. Thereby, the temperature of the wafer W on the susceptor 116 can be controlled.

  A gas supply line 132 passing through the inside of the susceptor 116 and the susceptor support 114 is connected to the upper surface of the electrostatic chuck 118. A heat transfer gas (backside gas) such as He gas can be supplied between the wafer W and the electrostatic chuck 118 via the gas supply line 132.

  Above the susceptor 116, an upper electrode 134 facing the susceptor 116 constituting the lower electrode is provided. A plasma generation space PS is formed between the susceptor 116 and the upper electrode 134.

  The upper electrode 134 includes a disk-shaped inner upper electrode 138 and a ring-shaped outer upper electrode 136 that surrounds the outer side of the inner upper electrode 138. A ring-shaped dielectric 142 is interposed between the outer upper electrode 136 and the inner upper electrode 138. A ring-shaped insulating shielding member 144 made of alumina, for example, is airtightly interposed between the outer upper electrode 136 and the inner peripheral wall of the processing chamber 110.

  A first high-frequency power source 154 is electrically connected to the outer upper electrode 136 via a power supply tube 152, a connector 150, an upper power supply rod 148, and a matching unit 146. The first high frequency power supply 154 can output a high frequency voltage having a frequency of 40 MHz or more (for example, 60 MHz).

  The power supply cylinder 152 is formed in, for example, a substantially cylindrical shape having an open bottom surface, and a lower end portion is connected to the outer upper electrode 136. A lower end portion of the upper power supply rod 148 is electrically connected to the central portion of the upper surface of the power supply tube 152 by a connector 150. The upper end of the upper power feed rod 148 is connected to the output side of the matching unit 146. The matching unit 146 is connected to the first high-frequency power source 154, and can match the internal impedance of the first high-frequency power source 154 with the load impedance.

  The outside of the power supply tube 152 is covered with a cylindrical ground conductor 111 having a side wall having substantially the same diameter as the processing chamber 110. A lower end portion of the ground conductor 111 is connected to an upper portion of the side wall of the processing chamber 110. The upper power feed rod 148 described above passes through the center portion of the upper surface of the ground conductor 111, and an insulating member 156 is interposed at the contact portion between the ground conductor 111 and the upper power feed rod 148.

  The inner upper electrode 138 constitutes a shower head that ejects a predetermined gas onto the wafer W placed on the susceptor 116. The inner upper electrode 138 includes a circular electrode plate 160 having a large number of gas ejection holes 160a, and an electrode support 162 that detachably supports the upper surface side of the electrode plate 160. The electrode support 162 is formed in a disk shape having substantially the same diameter as the electrode plate 160.

  Inside the electrode support 162, a buffer chamber 163 composed of a disk-shaped space is formed. An annular partition member 164 is provided in the buffer chamber 163, and the annular partition member 164 surrounds the first buffer chamber 163 a and the first buffer chamber 163 a inside the disk-shaped space. It is partitioned into an outer second buffer chamber 163b made of a ring-shaped space. The annular partition member 164 is composed of, for example, an O-ring.

  Here, if divided into the central region (center portion) of the wafer W on the susceptor 116 and the outer peripheral region (edge portion) surrounding the central region, the first buffer chamber 163a is located at the center portion of the wafer W. The second buffer chamber 163b is configured to face the edge portion of the wafer W.

  The gas ejection holes 160a communicate with the lower surfaces of the buffer chambers 163a and 163b. A predetermined gas can be ejected from the first buffer chamber 163a to the center portion of the wafer W, and a predetermined gas can be ejected from the second buffer chamber 163b to the edge portion of the wafer W. A predetermined gas is supplied from the gas supply device 200 to each of the buffer chambers 163a and 163b.

  A lower feeding cylinder 170 is electrically connected to the upper surface of the electrode support 162 as shown in FIG. The lower power feeding tube 170 is connected to the upper power feeding rod 148 via the connector 150. A variable capacitor 172 is provided in the middle of the lower power supply tube 170. By adjusting the capacitance of the variable capacitor 172, the electric field strength formed immediately below the outer upper electrode 136 when a high frequency voltage is applied from the first high frequency power supply 154 and formed directly below the inner upper electrode 138. It is possible to adjust the relative ratio with the electric field strength.

  An exhaust port 174 is formed at the bottom of the processing chamber 110. The exhaust port 174 is connected to an exhaust device 178 provided with a vacuum pump or the like via an exhaust pipe 176. By exhausting the inside of the processing chamber 110 by the exhaust device 178, the inside of the processing chamber 110 can be decompressed to a desired degree of vacuum.

  A second high frequency power source 182 is electrically connected to the susceptor 116 via a matching unit 180. The second high frequency power source 182 can output a high frequency voltage having a frequency in the range of 2 MHz to 20 MHz, for example, 2 MHz, for example.

  A low pass filter 184 is electrically connected to the inner upper electrode 138 of the upper electrode 134. The low-pass filter 184 cuts off the high frequency from the first high frequency power source 154 and passes the high frequency from the second high frequency power source 182 to the ground. On the other hand, a high pass filter 186 is electrically connected to the susceptor 116 constituting the lower electrode. The high-pass filter 186 is for passing the high frequency from the first high frequency power supply 154 to the ground.

(Gas supply device)
Next, the gas supply device 200 will be described with reference to the drawings. FIG. 1 shows a first processing gas (center portion processing gas) for supplying a processing gas toward the center portion of the wafer W in the processing chamber 110 and a second processing gas (for processing toward the edge portion of the wafer W). This is an example in the case of branching into two of the edge processing gas. Note that the present invention is not limited to the case where the processing gas is divided into two as in the present embodiment, but may be divided into three or more.

  For example, as shown in FIG. 1, the gas supply apparatus 200 includes a processing gas supply means 210 for supplying a processing gas for performing a predetermined processing such as film formation and etching on the wafer, and an additional gas for supplying a predetermined additional gas. Supply means 220. The processing gas supply means 210 is connected to a processing gas supply pipe 202 that constitutes a processing gas supply path, and the processing gas supply pipe 202 constitutes a first branch pipe 204 and a second branch path that constitute a first branch flow path. The second branch pipe 206 is branched. The first and second branch pipes 204 and 206 may be branched inside the divided flow rate adjusting unit 230 or may be branched outside the divided flow rate adjusting unit 230.

  These first and second branch pipes 204 and 206 are connected to different parts of the upper electrode 134 of the processing chamber 110, for example, the first and second buffer chambers 163a and 163b of the inner upper electrode 138, respectively.

  The gas supply device 200 further adjusts the partial flow rates of the first and second process gases flowing through the first and second branch pipes 204 and 206 based on the pressure in the first and second branch pipes 204 and 206. Adjustment means (flow splitter) 230 is provided. The additional gas supply means 220 is connected to the middle of the second branch pipe 206 via the additional gas supply pipe 208 on the downstream side of the flow rate adjusting means 230.

  According to such a gas supply device 200, the processing gas from the processing gas supply unit 210 is divided into the first branch pipe 204 and the second branch pipe 206 while the divided flow rate is adjusted by the divided flow rate adjusting unit 230. . The first processing gas flowing through the first branch pipe 204 is supplied toward the center portion of the wafer W via the first buffer chamber 163a, and the second processing gas flowing through the second branch pipe 206 is supplied to the second buffer chamber 163b. To the edge portion of the wafer W.

  At this time, when the additional gas is supplied from the additional gas supply means 220, the additional gas flows through the additional gas supply pipe 208 to the second branch pipe 206 and is mixed with the second processing gas. The additional gas is supplied to the edge portion of the wafer W through the second buffer chamber 163b together with the second processing gas. A specific configuration example of the gas supply device 200 will be described later.

  The substrate processing apparatus 100 is connected to a control unit 300 that controls each unit. For example, the control unit 300 controls the DC power source 122, the first high frequency power source 154, the second high frequency power source 182 and the like in addition to the processing gas supply unit 210, the additional gas supply unit 220, the partial flow rate adjustment unit 230, and the like in the gas supply apparatus 200. It has come to be.

(Configuration example of control unit)
Here, a configuration example of the control unit 300 will be described with reference to the drawings. FIG. 2 is a block diagram illustrating a configuration example of the control unit 300. As shown in FIG. 2, the control unit 300 includes a CPU (central processing unit) 310 constituting the control unit main body, a RAM (random access memory) provided with a memory area used for various data processing performed by the CPU 310, and the like. Memory) 320, display means 330 including a liquid crystal display for displaying an operation screen, a selection screen, and the like, input of various data such as input and editing of a process recipe by an operator, and process recipes and processes to a predetermined storage medium An operation unit 340, a storage unit 350, and an interface 360 configured with a touch panel or the like capable of outputting various data such as log output are provided.

  The storage unit 350 stores, for example, a processing program for executing various processes of the substrate processing apparatus 100, information (data) necessary for executing the processing program, and the like. The storage unit 350 is configured by a memory, a hard disk (HDD), or the like, for example. The CPU 310 reads program data and the like as necessary and executes various processing programs. For example, prior to processing the wafer, the CPU 310 executes a gas supply process for controlling the gas supply device 200 into the processing chamber 110 to supply a predetermined gas.

  The interface 360 is connected to various components such as a partial flow rate adjusting unit 230, a process gas supply unit 210, and an additional gas supply unit 220 that are controlled by the CPU 310. The interface 360 is configured by a plurality of I / O ports, for example.

  The CPU 310, the RAM 320, the display means 330, the operation means 340, the storage means 350, the interface 360, and the like are connected by a bus line such as a control bus or a data bus.

(Specific configuration example of gas supply device)
Next, a specific configuration example of each part of the gas supply device 200 will be described. FIG. 3 is a block diagram illustrating a specific configuration example of the gas supply device 200. For example, as shown in FIG. 3, the processing gas supply unit 210 includes a gas box in which a plurality of (for example, three) gas supply sources 212 a, 212 b, and 212 c are accommodated. The pipes of the gas supply sources 212a to 212c are connected to a processing gas supply pipe 202 where the gases from these gas sources merge. Mass flow controllers 214a to 214c for adjusting the flow rates of the respective gases are provided in the pipes of the respective gas supply sources 212a to 212c. According to such a processing gas supply means 210, the gases from the gas supply sources 212a to 212c are mixed at a predetermined flow rate ratio, flow out to the processing gas supply pipe 202, and the first and second branch pipes 204, The current is diverted to 206.

For example, as shown in FIG. 3, the gas supply source 212a is filled with C _X F _Y gas such as fluorocarbon fluorine compound, CF ₄ , C ₄ F ₆ , C ₄ F ₈ , C ₅ F ₈ as an etching gas. The The gas supply source 212b is filled with, for example, O ₂ gas as a gas for controlling the deposition of a CF-based reaction product, and the gas supply source 212c is filled with a rare gas such as Ar gas as a carrier gas. ing. Note that the number of gas supply sources of the processing gas supply means 210 is not limited to the example shown in FIG. 3, and may be one, two, or four or more, for example.

  On the other hand, the additional gas supply means 220 is constituted by a gas box in which a plurality of (for example, two) gas supply sources 222a and 222b are accommodated as shown in FIG. The pipes of the gas supply sources 222a and 222b are connected to an additional gas supply pipe 208 through which the gases from these sources join. Mass flow controllers 224a and 224b for adjusting the flow rate of each gas are provided in the pipes of the gas supply sources 222a and 222b, respectively. According to such additional gas supply means 220, the gas from each gas supply source 222a, 222b is selected or mixed at a predetermined gas flow ratio, and flows out to the additional gas supply pipe 208 to adjust the partial flow rate. It is supplied to the second branch pipe 206 on the downstream side of the means 230.

For example, C _X F _Y gas capable of promoting etching is sealed in the gas supply source 222a, and O ₂ gas capable of controlling the deposition of a CF-based reaction product is sealed in the gas supply source 222b, for example. . The number of gas supply sources of the additional gas supply means 220 is not limited to the example shown in FIG. 3, and may be one, for example, or three or more.

  The partial flow rate adjusting unit 230 includes a pressure adjusting unit 232 that adjusts the pressure in the first branch pipe 204 and a pressure adjusting unit 234 that adjusts the pressure in the second branch pipe 206. Specifically, the pressure adjustment unit 232 includes a pressure sensor 232a that detects the pressure in the first branch pipe 204 and a valve 232b that adjusts the degree of opening and closing of the first branch pipe 204, and the pressure adjustment unit 234 includes the second branch pipe. A pressure sensor 234a for detecting the pressure in 206 and a valve 234b for adjusting the opening / closing degree of the second branch pipe 206 are provided.

  The pressure adjusting units 232 and 234 are connected to the pressure controller 240, and the pressure controller 240 is configured to control the valves 232b and 234b based on the detected pressures from the pressure sensors 232a and 234a in response to a command from the control unit 300. Adjust the degree of opening and closing. For example, the control unit 300 controls the divided flow rate adjusting means 230 by pressure ratio control. In this case, the pressure controller 240 adjusts the pressure in the first and second branch pipes 204 and 206 to the target pressure ratio so that the first and second process gases have a target flow rate ratio according to a command from the control unit 300. Thus, the opening / closing degree of each valve 232b, 234b is adjusted. The pressure controller 240 may be incorporated as a control board in the divided flow rate adjusting means 230, or may be configured separately from the divided flow rate adjusting means 230. The pressure controller 240 may be provided in the control unit 300.

  In such a substrate processing apparatus 100, for example, a predetermined gas is supplied into the processing chamber 110 by the gas supply apparatus 200 before performing processing such as etching on the wafer. Specifically, supply of the processing gas from the processing gas supply unit 210 is started first, and the partial flow rate adjusting unit 230 is pressure ratio controlled. Then, after the pressure ratio in the first and second branch pipes 204 and 206 is adjusted to the target pressure ratio, the additional gas from the additional gas supply means 220 is supplied to the second branch pipe 206.

  In this case, if the additional gas is supplied to the second branch pipe 206 while the pressure ratio control is controlled with respect to the partial flow rate adjusting means 230, the following problem occurs. That is, when the additional gas is supplied to the second branch pipe 206, the pressure in the second branch pipe 206 rises higher than the pressure in the first branch pipe 204, and the pressure ratio collapses. An attempt is made to automatically adjust the degree of opening and closing of the valves 232b and 234b so as to achieve the target pressure ratio. For this reason, there is a problem that the first process gas flows more than the second process gas, and the flow rate ratio of the first and second process gases collapses before and after the supply of the additional gas.

  At this point, when the pressure ratio in the first and second branch pipes 204 and 206 is adjusted to the target pressure ratio and the respective pressures are stabilized, the valves 232b and 234b of the divided flow rate adjusting means 230 are fixed, and then the additional gas If the additional gas is supplied, the valves 232b and 234b are not automatically moved even if the additional gas is supplied, so that the flow rate ratio of the first and second process gases can be prevented from being lost.

  However, since the pressure in the second branch pipe 206 increases due to the supply of the additional gas, if the valves 232b and 234b of the diversion flow adjusting means 230 are fixed as described above, the processing gas is supplied to the second branch pipe 206. It becomes difficult to flow to the side, and accordingly flows into the first branch pipe 204 side. Therefore, even if the valves 232b and 234b of the divided flow rate adjusting means 230 are fixed, the flow rate ratio of the first and second process gases is lost before and after the additional gas supply.

  Therefore, in the gas supply process according to the present invention, the diversion control of the diversion flow adjusting means 230 is performed before the additional gas is supplied, and the pressure ratio for maintaining the pressure in the first and second branch pipes 204 and 206 at the target pressure ratio. The control is switched to the constant pressure control for keeping the pressure in the first branch pipe 204 constant. Then, supply of additional gas is started.

  According to this, even when the additional gas is supplied, the pressure in the first branch pipe 204 is kept constant, so even if the pressure in the second branch pipe 206 fluctuates, for example, the second branch pipe 206 Since it is possible to prevent the processing gas to flow into the first branch pipe 204, it is possible to prevent the flow rate ratio of the first and second processing gases from being lost before and after the additional gas supply.

(Specific examples of gas supply processing)
Here, a specific example of the gas supply process according to the embodiment of the present invention will be described. FIG. 4 is a flowchart showing a specific example of the processing of the substrate processing apparatus including the gas supply processing according to the present embodiment. First, in step S <b> 110, the control unit 300 starts supplying the processing gas by the processing gas supply unit 210. As a result, a preset gas in the processing gas supply means 210 is caused to flow through the processing gas supply pipe 202 at a predetermined flow rate. Specifically, for example, when the supply of C _X F _Y gas, O ₂ gas and Ar gas from the gas supply sources 212a to 212c is started at a predetermined flow rate, the gases are mixed and C _X F having a predetermined mixing ratio is mixed. _A mixed gas composed of _Y gas, O ₂ gas and Ar gas is generated, and the mixed gas flows to the processing gas supply pipe 202 as a processing gas.

  Next, in step S120, the control unit 300 causes the partial flow rate adjusting means 230 to adjust the partial flow rate of the processing gas by pressure ratio control. Specifically, for example, when the control unit 300 issues a pressure ratio control command, the flow rate adjusting means 230 adjusts the opening / closing degree of the valves 232b and 234b based on the measured pressures of the pressure sensors 232a and 234a under the control of the pressure controller 240. The pressure ratio between the first and second branch pipes 204 and 206 is adjusted to the target pressure ratio. As a result, the flow ratios of the first and second process gases supplied to the first and second buffer chambers 163a and 163b via the first and second branch pipes 204 and 206 are determined.

  In step S130, it is determined whether or not the pressures in the first and second branch pipes 204 and 206 are stable. If it is determined that each pressure is stable, the control unit 300 causes the partial flow rate adjusting unit 230 to adjust the partial flow rate of the processing gas by the constant pressure control in step S140.

  Specifically, for example, when the control unit 300 issues a constant pressure control command, the divided flow rate adjusting means 230 adjusts the degree of opening and closing of the valves 232b and 234b based on the measured pressures of the pressure sensors 232a and 234a under the control of the pressure controller 240. The pressure of the first processing gas in the first branch pipe 204 is adjusted to be constant. At this time, the second buffer chamber 163b is supplied with a mixed gas of at least the same gas component as the first buffer chamber 63a (a mixed gas capable of the same etching process).

  Next, in step S150, the controller 300 starts supply of additional gas by the additional gas supply means 220. As a result, a preset additional gas is supplied from the additional gas supply means 220 to the second branch pipe 206 through the additional gas supply pipe 208 at a predetermined flow rate.

In this case, for example, C _X F _Y gas (for example, CF ₄ gas) capable of accelerating etching is supplied from the additional gas supply means 220 at a predetermined flow rate from the gas supply source 222a, and is joined to the second branch pipe 206. It is supplied to the second buffer chamber 163b through the second branch pipe 206. As a result, the second buffer chamber 163b is supplied with a processing gas containing more CF ₄ gas than the first buffer chamber 163a. Thus, the gas component and the flow rate of the processing gas supplied to the second buffer chamber 163b are determined.

In step S160, it is determined whether or not the pressures in the first and second branch pipes 204 and 206 are stable. If it is determined in step S160 that each pressure has stabilized, wafer processing is executed in step S200. With such a gas supply process, in the substrate processing apparatus 100, the mixed gas from the first buffer chamber 163 a is supplied near the center of the wafer W on the susceptor 116 under a reduced pressure atmosphere, and the outer peripheral portion of the wafer W is supplied. Is supplied with a mixed gas containing a large amount of CF ₄ gas from the second buffer chamber 163b. As a result, the etching characteristics at the outer peripheral portion of the wafer W are adjusted relative to the central portion of the wafer W, and the in-plane etching characteristics of the wafer W can be made uniform.

  According to the processing shown in FIG. 4, the processing gas from the processing gas supply unit 210 is divided into the first and second branch pipes 204 and 206, and from the first branch pipe 204 from the processing gas supply unit 210. The processing gas 110 is supplied to the processing chamber 110 as it is, and a predetermined additional gas is added from the second branch pipe 206 to adjust the gas component and flow rate of the processing gas and then supplied to the processing chamber 110. As a result, a processing gas having a gas component common to the branch pipes 204 and 206 is supplied from the processing gas supply means 210, and an additional gas is added to the processing gas flowing through the second branch pipe 206 as necessary. Gas component and flow rate are adjusted. For this reason, for example, when the number of gas components common to each branch pipe is large, the number of pipes is smaller than when a processing gas source is provided for each branch pipe. Thus, since the number of pipes of the gas supply device 200 can be minimized, the gas supply device 200 can be configured with a simpler pipe configuration. In addition, since the partial flow rate of the processing gas is adjusted based on the pressures of the branch pipes 204 and 206, the gas can be supplied from a plurality of parts in the processing chamber 110 with simple control.

  Further, the simple control of switching the flow rate adjusting means 230 from the pressure ratio control to the constant pressure control before supplying the additional gas causes the pressure ratio of the first and second branch pipes 204 and 206 to change due to the start of the additional gas supply. However, since the flow rate adjusting means 230 adjusts the valves 232b and 234b so that the pressure of the first branch pipe 204 becomes constant by the constant pressure control, a part of the processing gas that should flow to the second branch pipe 206 is reduced. It can prevent flowing into the first branch pipe 204. As a result, it is possible to prevent the flow rate ratio of the first and second process gases from the partial flow rate adjusting means 230 from being lost before and after the additional gas supply, so that desired in-plane uniformity can be realized.

  In the process shown in FIG. 4, an example has been given in which the wafer processing is performed in step S140 while the control for the partial flow rate adjusting unit 230 is switched to the constant pressure control. You may make it return control of 230 to pressure ratio control again.

  For example, while a single wafer process or a continuous process of a plurality of wafers is being performed, for example, the temperature of the upper electrode 134 gradually increases, and the conductance of the gas ejection holes 160a changes to make it difficult for the gas to flow. is there.

  In such a case, both the pressures in the first and second branch pipes 204 and 206 rise. Therefore, if the control for the partial flow rate adjusting means 230 is left at a constant pressure control, the first branch pipe is set. Since the valves 232b and 234b are adjusted so that only the pressure of 204 is constant, as a result, the ratio of the second processing gas flowing to the second branch pipe 206 is the first processing gas flowing to the first branch pipe 204. As a result, the flow rate ratio of the first and second process gases collapses.

  This phenomenon can be prevented by returning to pressure ratio control before processing the wafer. In other words, by returning to the pressure ratio control, even if the conductance of the gas ejection hole 160a changes, the pressure ratio does not change because the pressure in the first and second branch pipes 204 and 206 both fluctuate. The pressure ratio in the second branch pipes 204 and 206 can be controlled so as not to collapse. Thereby, even if the conductance of the gas ejection hole changes with time, it is possible to prevent the flow rate ratio of the first and second processing gases from collapsing.

  Specifically, for example, as shown in FIG. 5, the processes of step S170 and step S180 are added before the process of step S200. That is, in the process shown in FIG. 5, if it is determined in step S160 that the pressures in the first and second branch pipes 204 and 206 are stable, the control unit 300 controls the flow rate adjusting means 230 in step S170. To pressure ratio control. Specifically, the pressure ratio in the first and second branch pipes 204 and 206 when the pressure is stable is set as a new target pressure ratio, and the control for the flow rate adjusting means 230 is controlled in the first and second branch pipes 204 and 206. Switch to pressure ratio control to adjust the flow rate so that the pressure ratio becomes the new target pressure ratio. The reason why the pressure ratio in the first and second branch pipes 204 and 206 at the time of pressure stabilization is set as a new target pressure ratio is to supply the additional gas to the second branch pipe 206 and to the second branch pipe accordingly. Since the pressure in 206 changes, by controlling the pressure ratio in consideration of the fluctuation in pressure due to the supply of the additional gas, the flow rate adjusting means 230 does not change the flow rate ratio of the first and second process gases. This is to adjust the partial flow rate.

  Next, in step S180, it is determined whether or not the pressures of the first and second branch pipes 204 and 206 are stable. If it is determined in step S180 that the pressures are stable, wafer processing is performed in step S200.

  According to the process shown in FIG. 5, even when the conductance of the gas ejection hole 160a of the upper electrode 134 changes during the wafer process, the flow rates of the first and second process gases are changed. Wafer processing can be performed while preventing fluctuations in the ratio.

  Note that the second branch flow path 206 in the above embodiment is configured by a plurality of branch flow paths branched from the processing gas supply pipe 202, and the additional gas from the additional gas supply means 220 is supplied to each of the second branch flow paths. You may comprise. According to this, it is possible to further divide the outer peripheral area of the wafer into a plurality of areas and supply the processing gas to each area, so that the processing uniformity in the outer peripheral area of the wafer can be controlled more finely. can do.

  In the above-described embodiment, the case where the processing gas supplied from the gas supply apparatus 200 is ejected from the upper portion of the processing chamber 110 toward the wafer W is not limited to this. The processing gas may be ejected from other portions of 110, for example, from the side surface of the plasma generation space PS in the processing chamber 110. According to this, since the predetermined process gas can be supplied from the upper part and the side part of the plasma generation space PS, the gas concentration in the plasma generation space PS can be adjusted. Thereby, the in-plane uniformity of wafer processing can be further improved.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above embodiment, the case where the branch flow rate of the branch pipe is adjusted by the pressure adjustment unit has been described as an example. However, the present invention is not limited to this, and the mass flow controller is used to adjust the branch flow rate of the branch pipe. May be. Although the case where the present invention is applied to a plasma etching apparatus as a substrate processing apparatus has been described, the present invention is applied to a film forming apparatus such as a plasma CVD apparatus, a sputtering apparatus, or a thermal oxidation apparatus to which a processing gas is supplied. You may apply. Further, the present invention can be applied to other substrate processing apparatuses such as FPD (Flat Panel Display), photomask mask reticles, and MEMS (micro electro mechanical system) manufacturing apparatuses other than wafers as substrates to be processed.

  The present invention is applicable to a gas supply apparatus, a substrate processing apparatus, and a gas supply method for supplying a gas into a processing chamber.

It is sectional drawing which shows the structural example of the substrate processing apparatus concerning embodiment of this invention. It is a block diagram which shows the structural example of the control part shown in FIG. It is a block diagram which shows the structural example of the gas supply apparatus concerning the embodiment. It is a flowchart which shows an example of a process of the substrate processing apparatus concerning the embodiment. It is a flowchart which shows the other example of a process of the substrate processing apparatus concerning the embodiment.

Explanation of symbols

100 substrate processing apparatus 110 processing chamber 111 ground conductor 112 insulating plate 114 susceptor support base 116 susceptor 118 electrostatic chuck 120 electrode 122 DC power supply 124 focus ring 126 inner wall member 128 refrigerant chamber 130a, 130b piping 132 gas supply line 134 upper electrode 136 outside Upper electrode 138 Inner upper electrode 142 Dielectric material 144 Insulating shielding member 146 Matching device 148 Upper power feeding rod 150 Connector 152 Power feeding cylinder 156 Insulating member 160 Electrode plate 160a Gas ejection hole 162 Electrode support 163 (163a, 163b) Buffer chamber 164 Annular Partition member 170 Lower feed cylinder 172 Variable capacitor 174 Exhaust port 176 Exhaust pipe 178 Exhaust device 180 Matching device 184 Low pass filter 186 High pass filter 200 Gas supply device 202 Process gas supply Pipe 204 First branch pipe 206 Second branch pipe 208 Additional gas supply pipe 210 Processing gas supply means 212a to 212c Gas supply sources 214a to 214c Mass flow controllers 222a and 222b Gas supply sources 224a and 224b Mass flow controller 230 Minute flow rate adjusting means 232 234 Pressure adjustment unit 232a, 234a Pressure sensor 232b, 234b Valve 240 Pressure controller 300 Control unit 310 CPU
320 RAM
330 Display means 340 Operation means 350 Storage means 360 Interface W Wafer

Claims (11)

A gas supply device for supplying a gas into a processing chamber for processing a substrate to be processed,
A processing gas supply means for supplying a processing gas for processing the substrate to be processed;
A processing gas supply path for flowing a processing gas from the processing gas supply means;
A first branch channel and a second branch channel branched from the processing gas supply channel and connected to different parts of the processing chamber;
A partial flow rate adjusting means for adjusting a partial flow rate of the processing gas diverted from the processing gas supply path to each branch flow path based on a pressure in each branch flow path;
An additional gas supply means for supplying a predetermined additional gas;
An additional gas supply flow path for joining the additional gas from the additional gas supply means to the second branch flow path on the downstream side of the partial flow rate adjusting means;
Prior to processing the substrate to be processed, a processing gas is supplied by the processing gas supply means, and the partial flow rate is adjusted so that the pressure ratio in each branch flow path becomes a target pressure ratio with respect to the partial flow rate adjusting means. When the pressure ratio control to be adjusted is executed and the pressure in each of the branch flow paths is stabilized, the control of the flow rate adjusting means is performed so that the flow rate in the first branch flow path is maintained so that the pressure in the first branch flow path is maintained. Control means for supplying additional gas by the additional gas supply means after switching to constant pressure control to be adjusted;
A gas supply device comprising: When the pressure in each branch passage is stabilized after the supply of the additional gas is started, the control means sets the pressure ratio in each branch passage when the pressure is stabilized as a new target pressure ratio, and 2. The gas supply device according to claim 1, wherein the control for the adjusting means is switched to pressure ratio control for adjusting a partial flow rate so that a pressure ratio in each of the branch flow paths becomes the new target pressure ratio. The partial flow rate adjusting means includes a valve for adjusting the flow rate of the processing gas flowing through each branch channel and a pressure sensor for measuring the pressure in each branch channel,
The flow rate ratio of the processing gas from the processing gas supply flow path is adjusted by adjusting the degree of opening and closing of the valve based on the detected pressure from each pressure sensor. Gas supply device. The process gas supply means includes a plurality of gas supply sources, and supplies the process gas mixed at a predetermined flow rate from each gas supply source to the process gas supply path. The gas supply device according to claim 1. The additional gas supply means includes a plurality of gas supply sources, and supplies the additional gas selected from the gas supply sources or mixed at a predetermined gas flow rate ratio to the additional gas supply path. Item 5. The gas supply device according to any one of Items 1 to 4. The first branch flow path is disposed so that the processing gas flowing through the flow path is supplied toward a central region on the surface of the substrate to be processed in the processing chamber,
The said 2nd branch flow path is arrange | positioned so that the process gas which flows through this flow path may be supplied toward the outer peripheral part area | region on the said to-be-processed substrate surface. The gas supply device described in 1. The second branch flow path includes a plurality of branch flow paths branched from the processing gas supply path, and is configured to be able to supply additional gas from the additional gas supply means to the second branch flow paths. The gas supply device according to any one of claims 1 to 6. A substrate processing apparatus comprising a processing chamber for processing a substrate to be processed, a gas supply device for supplying a gas into the processing chamber, and a control means for controlling the gas supply device,
The gas supply device branches from a processing gas supply means for supplying a processing gas for processing the substrate to be processed, a processing gas supply path for supplying a processing gas from the processing gas supply means, and the processing gas supply path. A first branch channel and a second branch channel connected to different parts of the processing chamber; and a branch flow rate of the processing gas branched from the processing gas supply channel to each branch channel. A partial flow rate adjusting means for adjusting based on the internal pressure, an additional gas supply means for supplying a predetermined additional gas, and an additional gas from the additional gas supply means downstream of the second flow rate adjusting means in the second branch An additional gas supply channel that joins the channel,
Prior to the processing of the substrate to be processed, the control means supplies a processing gas by the processing gas supply means, and a pressure ratio in each branch flow path becomes a target pressure ratio with respect to the partial flow rate adjusting means. When the pressure ratio control for adjusting the partial flow rate is executed and the pressure in each branch flow path is stabilized, the pressure in the first branch flow path is maintained when the pressure is stabilized. Thus, the substrate processing apparatus is characterized in that the additional gas is supplied by the additional gas supply means after switching to the constant pressure control for adjusting the partial flow rate. When the pressure in each branch passage is stabilized after the supply of the additional gas is started, the control means sets the pressure ratio in each branch passage when the pressure is stabilized as a new target pressure ratio, and The process for the substrate to be processed is started after the control for the adjusting means is switched to the pressure ratio control for adjusting the partial flow rate so that the pressure ratio in each branch flow path becomes the new target pressure ratio. The substrate processing apparatus according to claim 8. A gas supply method using a gas supply device for supplying a gas into a processing chamber for processing a substrate to be processed,
The gas supply device branches from a processing gas supply means for supplying a processing gas for processing the substrate to be processed, a processing gas supply path for supplying a processing gas from the processing gas supply means, and the processing gas supply path. A first branch channel and a second branch channel connected to different parts of the processing chamber; and a branch flow rate of the processing gas branched from the processing gas supply channel to each branch channel. A partial flow rate adjusting means for adjusting based on the internal pressure, an additional gas supply means for supplying a predetermined additional gas, and an additional gas from the additional gas supply means downstream of the second flow rate adjusting means in the second branch An additional gas supply channel that joins the channel,
Prior to processing the substrate to be processed, a processing gas is supplied by the processing gas supply means, and the partial flow rate is adjusted so that the pressure ratio in each branch flow path becomes a target pressure ratio with respect to the partial flow rate adjusting means. Executing the pressure ratio control to be adjusted;
When the pressure in each branch flow path is stabilized by the pressure ratio control, the control for the flow rate adjusting means controls the partial flow rate so as to maintain the pressure in the first branch flow path when the pressure is stable. A step of supplying an additional gas by the additional gas supply means after switching to control;
A gas supply method comprising: When the pressure in each branch flow path is stabilized after the supply of the additional gas is started, the pressure ratio in each branch flow path at the time of the pressure stabilization is set as a new target pressure ratio, and the control for the flow rate adjusting means is performed. The gas supply method according to claim 10, further comprising a step of switching to pressure ratio control for adjusting a partial flow rate so that a pressure ratio in each of the branch flow paths becomes the new target pressure ratio.

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