JP2007208194A - Gas supply apparatus and method, and substrate processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas supply apparatus capable of obtaining a desired in-surface uniformity with simple pipe construction, and shortening time required for supplying the addition gas by a simple control. <P>SOLUTION: Prior to processing of a wafer, a processing gas from a processing gas supply means 210 is distributed to a second branch pipes 204 and 206 at a first prescribed voltage dividing ratio, and subsequently a supply of the processing gas is started, with a flow rate of addition gas set at a first-out flow rate larger than previously set flow rate by an addition gas supply control, and the processing gas is supplied, with the flow rate of the addition gas set at a set flow rate after prescribed time is elapsed. <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.

  Further, an additional gas supply system is provided separately from the gas supply system, and the gas supplied to the gas chamber of the processing chamber is added by adding a predetermined amount of additional gas from the additional gas supply system to the gas of the gas supply system. It is also conceivable to adjust the ingredients. However, for example, when the amount of the additional gas is very small (for example, several sccm), the pressure of the additional gas supply system piping does not increase easily, so it takes time for the additional gas to reach the processing chamber through the additional gas supply system piping. Take it. For this reason, it takes time until the gas concentration is stabilized in the processing chamber, which may reduce the throughput.

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

  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 process gas supply flow path for flowing a process gas from the process gas supply means, a first branch flow path branched from the process gas supply flow path and connected to different parts of the process chamber, and A second branch flow path, a flow rate adjusting means for adjusting the flow rate of the process gas branched from the process gas supply flow path to each branch flow path based on the pressure in each branch flow path, and a predetermined flow rate An additional gas supply means for supplying an 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 downstream from the partial flow rate adjusting means; and the substrate to be processed Prior to the processing of A process gas supply control by a physical gas supply means and a control means for performing an additional gas supply control by the additional gas supply means, wherein the additional gas supply control has a flow rate of the additional gas higher than a preset flow rate. There is provided a gas supply apparatus including control for starting supply at a large advance flow rate and supplying the additional gas at the set flow rate after a predetermined time has elapsed.

  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; and a processing gas supply passage for supplying 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, respectively, and branched from the processing gas supply channel to the branch channels A partial flow rate adjusting means for adjusting a partial flow rate of the processed 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. The flow rate adjusting means An additional gas supply flow path that merges with the second branch flow path on the downstream side, and the control means controls the process gas supply control by the process gas supply means and the additional flow prior to processing the substrate to be processed. The additional gas supply control is performed by the gas supply means. The additional gas supply control starts supply with the advance gas flow rate larger than the preset flow rate set in advance, and the flow rate of the additional gas after a predetermined time elapses. The substrate processing apparatus is characterized in that it includes a control for supplying at a set flow rate.

  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 flow path for flowing a processing gas from the processing gas supply means, and a branching from the processing gas supply flow path differing in the processing chamber The first branch flow path and the second branch flow path connected to each part, and the flow rate of the processing gas branched from the processing gas supply flow path to each branch flow path is set to the pressure in each branch flow path. A partial flow rate adjusting means that adjusts based on the flow rate, an additional gas supply means that supplies a predetermined additional gas, and an additional gas from the additional gas supply means that joins the second branch flow path downstream from the partial flow rate adjusting means. Additional gas supply flow path Prior to the processing of the substrate to be processed, a step of controlling the processing gas supply means to supply a processing gas having a preset set flow rate, and the flow rate of the additional gas from a preset set flow rate And a step of controlling the supply of the additional gas at the set flow rate after a predetermined time elapses after the predetermined time has elapsed.

  According to the present invention, the processing gas from the processing gas supply means is divided into the first and second branch flow paths by the processing gas supply control. Then, by the additional gas supply control, the additional gas from the additional gas supply means is joined to the second branch flow path via the additional gas supply flow path. Thus, the processing gas from the processing gas supply means is supplied to the processing chamber as it is from the first branch flow path, and a predetermined additional gas is added from the second branch flow path to adjust the gas component and flow rate of the processing gas. After that, it is 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 necessary minimum number of pipes is sufficient, and a simple pipe configuration is possible. The desired in-plane uniformity can be achieved with simple flow rate control.

  Further, when supplying the additional gas, the supply is started with a flow rate of the additional gas that is larger than a preset flow rate, and the flow rate of the additional gas is supplied after the predetermined time has elapsed. Therefore, even when the set flow rate of the additional gas is very small, the pressure of the additional gas supply channel can be increased immediately. As a result, the additional gas can easily flow into the second branch flow path at an early stage, the time required for supplying the additional gas can be shortened, and a decrease in throughput can be prevented as much as possible.

  The advance flow rate is calculated based on the volume of the additional gas supply channel for flowing the additional gas and the pressure of the second branch channel through which the additional gas flows from the additional gas supply channel. Preferably. For example, the pressure of the additional gas supply flow path is preferably a value calculated as the maximum flow rate required to reach the pressure of the second branch flow path within the predetermined time. According to this, since it is possible to calculate the optimum first-out flow rate that can increase the pressure of the additional gas supply flow path to the pressure of the second branch flow path in a short time, the additional gas from the additional gas supply flow path can be calculated. Can flow into the second branch flow path, reach the processing chamber, and shorten the time until the pressure stabilizes.

  The additional gas supply means includes an additional gas line to which an additional gas supply source is connected, and the additional gas supply control is performed when the calculated advance flow rate exceeds the maximum allowable flow rate of the additional gas line. The maximum permissible flow rate may be a first-out flow rate, and control may be included to increase the predetermined time accordingly. In this case, the predetermined time is, for example, a time required for the pressure of the additional gas supply channel to reach the pressure of the second branch channel when the additional gas is supplied with the maximum allowable flow rate as the first flow rate. It is preferable that it is calculated. According to this, the first-out process can be performed with the optimal first-out time according to the configuration of the substrate processing apparatus, and the optimum additional gas supply control can be executed within a range not exceeding the maximum allowable flow rate of the additional gas line. .

  Further, it is preferable that the volume of the additional gas supply channel is at least smaller than the volume of the second branch channel. By doing so, even when the set flow rate of the additional gas is very small compared to the set flow rate of the processing gas, the pressure of the additional gas supply channel can be increased in a shorter time.

  The first branch flow path is arranged 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, and the second branch flow path is , It is preferable that the processing gas flowing through the flow path is disposed 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.

  In order to solve the above-described problems, according to another 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 processing gas supplying the processing substrate being supplied A processing gas supply means, a processing gas supply flow path for flowing a processing gas from the processing gas supply means, and a first branch flow path branched from the processing gas supply flow path and connected to different parts of the processing chamber. And a second branch flow path, and a partial flow rate adjusting means for adjusting the flow rate of the process gas branched from the process gas supply flow path to each branch flow path based on the pressure in each branch flow path, and A plurality of additional gas lines respectively connected to the gas supply sources, wherein the plurality of additional gas lines are configured to merge downstream; and the additional gas from the additional gas supply means is supplied to the divided flow rate From adjustment means An additional gas supply channel that joins the second branch channel on the flow side, a processing gas supply control by the processing gas supply unit, and an additional gas supply by the additional gas supply unit prior to the processing of the substrate to be processed Control means for performing control, wherein the additional gas supply control starts supply with a flow rate of the additional gas in each additional gas line being set to a first flow rate larger than a preset flow rate, and is added after a predetermined time has elapsed. There is provided a gas supply apparatus including control for supplying a gas flow rate at the set flow rate.

  According to this, even when the additional gas supply means is constituted by a plurality of additional gas lines, the additional gas supply control is performed at the advance flow rate for each additional gas line, thereby shortening the time required for the additional gas supply. It is possible to prevent a decrease in throughput as much as possible.

  The advance flow rate in each additional gas line is calculated in advance as the maximum flow rate necessary for the pressure in the additional gas supply flow path to reach the pressure in the second branch flow path within the predetermined time. It is preferable that the total flow rate is a value obtained by distributing at the same ratio as the set flow rate ratio of each additional gas line. Thereby, additional gas supply control can be performed at the first-out flow rate according to the ratio of the set flow rate of each additional gas line.

  In addition, when the additional gas supply control includes a first flow rate in each of the additional gas lines that exceeds the maximum allowable flow rate of the additional gas line, the maximum allowable flow rate is set as the first flow rate of the additional gas line. A control for recalculating the advance flow rate of the other additional gas line and the predetermined time may be included. According to this, optimal additional gas supply control can be executed within a range not exceeding the maximum allowable flow rate of each additional gas line. Thus, the first-out process can be performed with the optimal first-out time according to the configuration of the substrate processing apparatus.

  As described above, according to the present invention, it is possible to provide a gas supply device and the like that can achieve desired in-plane uniformity with a simple piping configuration and can reduce the time required to supply additional gas with simple control. It can be done.

  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 flow path. From the processing gas supply pipe 202, the first branch pipe 204 and the second branch flow path that constitute the first branch flow path are connected. The 2nd branch piping 206 which comprises 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 to form the second buffer chamber. It is supplied toward the edge portion of the wafer W via 163b. 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.

(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. 2 is a block diagram illustrating a specific configuration example of the gas supply device 200. Here, the case where an additional gas supply means is comprised by one additional gas line is demonstrated.

  The processing gas supply means 210 is constituted by a gas box in which a plurality of (for example, three) processing gas lines (1), (2), (3) are accommodated as shown in FIG. Gas supply sources 212a, 212b, and 212c are respectively configured upstream of the processing gas lines (1), (2), and (3). Further, the downstream sides of the processing gas lines (1), (2), and (3) are joined and connected to the processing gas supply pipe 202. These processing gas lines (1), (2), and (3) are respectively provided with mass flow controllers 214a, 214b, and 214c for adjusting the flow rate of gas from the gas supply sources 212a, 212b, and 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 and flow out to the processing gas supply pipe 202, and the first and second branch pipes 204, 206 are mixed. To be diverted to

For example, as shown in FIG. 2, a fluorocarbon-based fluorine compound, CF ₄ , C ₄ F ₆ , C ₄ F ₈ , C ₅ F ₈ or other C _X F _Y gas as an etching gas is sealed in the gas supply source 212a. 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 unit 210 is not limited to the example shown in FIG. 2, and may be one, two, or four or more.

  On the other hand, the additional gas supply means 220 is constituted by a gas box in which one additional gas line is accommodated, for example, as shown in FIG. A gas supply source 222a is connected to the upstream side of the additional gas line. The downstream side of the additional gas line is connected to the additional gas supply pipe 208. The additional gas line is provided with a mass flow controller 224a for adjusting the flow rate of the gas from the gas supply source 222a. According to such additional gas supply means 220, the gas from the gas supply source 222 a flows out to the additional gas supply pipe 208 and is supplied to the second branch pipe 206 on the downstream side of the partial flow rate adjusting means 230.

For example, C _X F _Y gas (for example, CF ₄ gas) that can promote etching is sealed in the gas supply source 222a. The gas supply source 222a may be filled with, for example, O ₂ gas that can control the deposition of CF-based reaction products. Further, the number of gas supply sources of the additional gas supply means 220 is not limited to the example shown in FIG. 2, and for example, two or more gas supply sources may be provided.

  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 so that the additional gas having a set flow rate is supplied from the beginning, it takes time until the additional gas reaches the processing chamber through the additional gas supply pipe 208. For example, since the processing gas already flows through the second branch pipe 206 into which the additional gas flows, a certain amount of pressure is generated. For this reason, when the set flow rate of the additional gas is very small (for example, several sccm), the additional gas hardly flows because the pressure difference between the additional gas supply pipe 208 and the second branch pipe 206 is large immediately after the additional gas supply is started. In this case, since the additional gas is gradually filled into the additional gas supply pipe 208, the pressure in the additional gas supply pipe 208 also increases little by little, and the pressure difference between the additional gas supply pipe 208 and the second branch pipe 206 becomes smaller. It becomes easy to flow into the second branch pipe 206 and is also supplied to the processing chamber 110. In this way, when the additional gas having a set flow rate is supplied from the beginning, it takes time to supply the additional gas.

Therefore, in the present invention, as shown in FIG. 3, the additional gas flow rate is larger than the preset flow rate fa as shown in FIG. 3 so that the pressure of the additional gas supply pipe 208 can be increased as soon as possible immediately after the additional gas supply. Supply is started at the flow rate Fa (t ₀ ), and after a predetermined time T (for example, several seconds), an additional gas supply control (addition gas supply process) is performed to supply the additional gas at the set flow rate fa. As a result, the pressure of the additional gas supply pipe 208 can be immediately increased, so that the additional gas can easily flow into the second branch pipe 206. As a result, the time required to supply the additional gas, that is, the time from the start of the supply of the additional gas until the additional gas reaches the processing chamber and the pressure (gas concentration) stabilizes in the processing chamber can be shortened. Reduction can be prevented as much as possible.

FIG. 4 and FIG. 5 show the results of experiments for supplying additional gas by changing the advance flow rate Fa through such additional gas supply processing. 4 and 5 show experimental results when the first flow rate Fa is 21 sccm and 50 sccm, respectively, when the additional gas set flow rate fa is 7 sccm. The time T during which the first flow rate Fa is flowed is 1 sec. 4 and 5, using O ₂ gas as additional gas, which attach the gas concentration measuring device to the gas inlet of the processing chamber 110, shows the results of detecting the concentration of O ₂ gas in the graph ya1, yb1 It is. 4 and 5, the vertical axis represents gas concentration, and the horizontal axis represents time. According to this, since the concentration of O ₂ gas changes according to the flow rate of O ₂ gas that has reached the gas inlet of the processing chamber, the change in flow rate at which the additional gas reaches the processing chamber due to this gas concentration change. Recognize.

  According to the experimental results shown in FIGS. 4 and 5, the gradient of the gas concentration change increases as the advance flow rate Fa increases. As a result, it can be seen that the larger the advance flow rate Fa, the shorter the time during which the additional gas reaches the processing chamber and the gas concentration is stabilized. When the time (addition gas supply time) from when the additional gas supply starts to the processing chamber until the additional gas concentration is stabilized is detected (addition gas supply time), it is about 26.1 sec in the case of FIG. 4 and about 20 in the case of FIG. 2 seconds. On the other hand, since it took tens of seconds to supply the additional gas at the set flow rate from the beginning, the additional gas supply time can be greatly shortened by performing the additional gas supply processing according to the present invention. all right.

  As described above, the volume of the additional gas supply pipe 208 may be reduced in order to increase the pressure of the additional gas supply pipe 208 as soon as possible immediately after the supply of the additional gas. Further, since the volume of the additional gas supply pipe 208 depends on the pipe diameter and the pipe length, the pressure of the additional gas supply pipe 208 can be increased more quickly by reducing the pipe diameter and the pipe length.

  Here, FIG. 6 and FIG. 7 show the results of the experiment of the additional gas supply process performed by changing the pipe diameter and the pipe length of the additional gas supply pipe 208. FIGS. 6 and 7 show the experimental results when the additional gas is supplied at the first-out flow rate shown in FIGS. 4 and 5, respectively.

  6 and 7 are specific examples in the case where a pipe having a pipe diameter of 1/2 is used with reference to the additional gas supply pipe 208 used in FIG. 4 and FIG. FIGS. 6 and 7 are specific examples when a filter having a shorter length is used with reference to a filter attached in the middle of the additional gas supply pipe used in FIGS. 4 and 5.

  6 and 7 are specific examples in the case where the above-described short filter is used while the pipe having the pipe diameter of 1/2 is used. In this way, in this experiment, the length of the pipe is changed by changing the length of the filter provided in the middle of the additional gas supply pipe 208.

  In this experiment, the time (addition gas supply time) from the start of the supply of the additional gas until the additional gas reaches the processing chamber 110 and the gas concentration is stabilized is represented by ya2, ya3, and ya4 shown in FIG. The cases were approximately 19.4 sec, approximately 21 sec, and approximately 13.9 sec, respectively. In the case of yb2, yb3, and yb4 shown in FIG. 7, they were approximately 10.9 sec, approximately 10 sec, and approximately 5.6 sec, respectively.

  According to the experimental results shown in FIGS. 6 and 7, it can be seen that the additional gas supply time becomes shorter as the pipe diameter of the additional gas supply pipe 208 is smaller and as the filter length (pipe length) is shorter. Moreover, the additional gas supply time becomes shorter when the advance flow rate Fa is increased, the pipe diameter is further reduced, and the filter length (pipe length) is shortened.

  Therefore, it is preferable to make the volume of the additional gas supply pipe 208 smaller by adjusting the pipe diameter, pipe length, and the like. For example, by making the volume of the additional gas supply pipe 208 smaller than the volume of the second branch pipe 206, the additional gas can be added in a shorter time even when the additional gas set flow rate fa is smaller than the set flow rate fm of the processing gas. The pressure in the gas supply channel 208 can be increased.

  As described above, when the advance flow rate Fa of the additional gas is increased, the pressure in the additional gas supply pipe 208 increases quickly and the additional gas flows more easily. Therefore, the overshoot temporarily exceeds the set flow rate fa. Then, the flow rate becomes stable at the set flow rate fa (for example, yb4 shown in FIG. 7). When such overshoot occurs, the time until the gas concentration stabilizes becomes shorter. Moreover, as the advance flow rate Fa increases, the overshoot increases and the time until the gas concentration stabilizes also decreases.

  However, if this overshoot becomes too large, it may take time for the gas concentration to stabilize. For example, if the pressure of the additional gas supply pipe 208 becomes too high compared to the pressure of the second branch pipe 206 into which the additional gas flows, the additional gas tends to flow all at once, so the overshoot also increases and the gas concentration becomes stable. It takes time.

  Therefore, in the present invention, before supplying the gas to the processing chamber 110, the additional gas supply process is performed after calculating the optimum value of the advance flow rate Fa of the additional gas. The optimum value of the advance flow rate Fa is preferably the maximum flow rate at which the pressure of the additional gas supply pipe 208 reaches the pressure of the second branch pipe 206 within a predetermined time, for example. Thereby, since the optimal first-out flow rate Fa according to the piping configuration of the gas supply device can be calculated, the additional gas supply time can be further shortened.

  Hereinafter, the additional gas supply process according to the present invention will be described in detail. Such an additional gas supply process is executed, for example, in a series of gas supply processes for supplying the processing gas and the additional gas to the processing chamber 110. Such a gas supply process is executed by a program stored in the control unit 300, for example.

(Configuration example of control unit)
First, a specific configuration example of the control unit 300 that performs the gas supply process as described above will be described with reference to the drawings. FIG. 8 is a block diagram illustrating a configuration example of the control unit 300. As shown in FIG. 8, 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.

  In the storage unit 350, for example, processing programs for executing various processes (for example, gas supply processing, first-out processing of additional gas, etc.) of the substrate processing apparatus 100, information necessary for executing the processing programs (for example, gas Supply processing data) and the like are stored. 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, the CPU 310 executes a gas supply process for supplying a predetermined gas into the processing chamber 110 prior to processing the wafer. In this gas supply processing, first, processing for calculating the advance flow rate of the additional gas is performed, and then processing gas supply processing (processing gas supply control) and additional gas supply processing (additional gas supply control) are started. Such a gas supply process is executed based on the gas supply process data 352 stored in the storage unit 350.

  The gas supply processing data 352 is constituted by a data table as shown in FIG. 9, for example. In this data table, at least data of processing gas and additional gas is stored. In the data table shown in FIG. 9, for example, set flow rates fm (1) to fm (3) of the processing gas lines (1) to (3) as the processing gas data, a total processing gas flow rate fm ( = Fm (1) + fm (2) + fm (3)), a storage area for storing each data of the flow rate ratio C: E of the first and second processing gases is provided. If the flow rate ratio C: E of the first and second process gases is expressed as a percentage with respect to the total process gas flow rate fm, for example, the flow rate ratio E of the second process gas can be easily obtained by E = 100−C. The data table shown in FIG. 9 stores, as additional gas data, for example, additional gas line set flow rate fa, additional gas first flow rate Fa, and first advance time T which is a predetermined time for flowing the first advance flow rate Fa. A storage area is provided.

  Among these gas supply process data 352, the set flow rate for the process gas and the additional gas can be set in advance by operating the operation means 340 by the operator, for example. On the other hand, the advance flow rate Fa of the additional gas is calculated by the advance flow rate calculation process described later. The advance time T is set in advance to a default value (for example, 1 sec). Note that the advance time T can be changed, for example, by an operation of the operation means 340 by an operator.

  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.

(Additional gas advance flow rate calculation processing)
In such a gas supply process performed by the control unit 300, the first-out flow rate of the additional gas is calculated prior to the actual gas supply to the processing chamber 110. A specific example of this advance flow rate calculation process is shown in FIG. As shown in FIG. 10, the control unit 300 first determines the second based on the total processing gas flow rate fm acquired from the gas supply processing data 352 and the flow rate ratio C: E between the first and second processing gases in step S110. The flow rate fe of the processing gas is calculated. Specifically, the flow rate fe of the second processing gas is calculated based on the following mathematical formula (1-1).

  fe = [Ne · E / (Nc · C + Ne · E)] · fm (1-1)

  In the above equation (1-1), C is a flow rate ratio of the first processing gas, and E is a flow rate ratio of the second processing gas. Nc and Ne are known parameters depending on the configuration of the substrate processing apparatus 100 (for example, the configuration of the upper electrode 134). Specifically, Nc is the number of gas ejection holes 160a in the center portion, that is, the first buffer chamber 163a, Ne. Is the number of gas ejection holes 160a in the edge portion, that is, the second buffer chamber 163b.

  Next, in step S120, the set flow rate fa of the additional gas is acquired from the gas supply processing data 352, and in step S130, the total gas flow rate Fe flowing through the second branch pipe (= the flow rate fe of the second process gas + the set flow rate of the additional gas). fa) is calculated.

  In step S140, the pressure Pe in the second branch pipe 206 is calculated based on the total gas flow rate Fe. Specifically, for example, when the set flow rate fa of the additional gas is less than a predetermined pressure (for example, 500 sccm), it can be obtained by the following mathematical formula (1-2). In this mathematical formula (1-2), p1 and p2 are parameters, and are pressure conversion coefficients in the second branch pipe. On the other hand, when the set flow rate fa of the additional gas is equal to or higher than a predetermined pressure (for example, 500 sccm), it can be obtained by the following formula (1-3). In this mathematical formula (1-3), q1 and q2 are parameters, which are pressure conversion coefficients in the second branch pipe.

Pe = p1 · b ^p2 (1-2)

  Pe = q1 · b + q2 (1-3)

  Next, in step S150, the advance flow rate Fa of the additional gas is calculated and stored. Specifically, first advance time T is fixed to a predetermined time (for example, 1 sec), and first advance flow rate Fa is calculated based on the calculated second branch pipe internal pressure Pe by, for example, the following formula (1-4). According to this mathematical formula (1-4), the advance flow rate Fa is based on the volume of the additional gas supply pipe 208 for flowing the additional gas and the pressure of the second branch pipe 206 into which the additional gas flows from the additional gas supply pipe 208. Can be calculated.

  Fa = α · (Pe / P) · β · 60 · v / (T−γ) (1-4)

  In the above formula (1-4), P is atmospheric pressure (760 Torr), and v is the pipe volume of the additional gas supply pipe 208. α, β, and γ are parameters depending on the configuration of the substrate processing apparatus 100, α is a parameter for each apparatus related to the pressure ratio of the first and second processing gases, β is a parameter for each apparatus related to the piping volume, and γ is This is a parameter for each device related to the offset. Note that α and β may be collectively represented by one parameter, but by dividing into α and β, finer adjustment for each device is possible.

  According to the mathematical formula (1-4), the first flow rate Fa is set as the maximum flow rate required for the pressure in the additional gas supply pipe to reach the second branch pipe pressure Pe within the first time (predetermined time) T. Can be calculated. That is, it is possible to calculate the optimum first-out flow rate Fa that can increase the pressure of the additional gas supply pipe 208 to the second branch pipe internal pressure Pe in a short time (here 1 sec). Thereby, it is possible to shorten the time until the additional gas from the additional gas supply pipe 208 flows into the second branch pipe and reaches the processing chamber 110 to stabilize the pressure.

  Then, the advance flow rate Fa of the additional gas calculated as described above is stored. Specifically, it is stored in the storage area of the advance flow rate Fa in the gas supply processing data 352. When the first-out flow rate Fa of the additional gas is obtained in this way, the first-out flow rate calculation process is terminated, and then each gas is actually supplied to the processing chamber 110 and the wafer processing is executed.

  Here, a specific example of the processing performed after the advance flow rate calculation processing is shown in FIG. As shown in FIG. 11, first, necessary data (processing gas data and additional gas data) are acquired from the gas supply processing data 352 in step S210.

Next, in step S220, the processing gas supply unit 210 starts processing gas supply processing (processing gas supply control). Specifically, the respective gases are supplied from the respective processing gas lines (1) to (3) in the processing gas supply means 210 at the set flow rates fm (1) to fm (3). For example, the C _X F _Y gas, O ₂ gas, and Ar gas from the gas supply sources 212a to 212c are started to be supplied at the set flow rates fm (1), fm (2), and fm (3), and the gases are mixed. A mixed gas composed of C _X F _Y gas, O ₂ gas and Ar gas having a predetermined mixing ratio is generated, and the mixed gas flows into the processing gas supply pipe 202 as a processing gas.

  At this time, the controller 300 causes the partial flow rate adjusting means 230 to adjust the partial flow rate of the processing gas by, for example, pressure ratio control. Specifically, when the control unit 300 issues a pressure ratio control command, the partial flow rate adjusting means 230 adjusts the opening / closing degrees 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, Adjustment is made so that the pressure ratio of the first and second branch pipes 204 and 206 becomes 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 S230, it is determined whether or not the pressures in the first and second branch pipes 204 and 206 are stable. When it is determined that each pressure has stabilized, the additional gas supply process (additional gas supply control) is started in steps S240 to S270.

  That is, first, in step S240, the gas from the additional gas line in the additional gas supply means 220 is supplied at the first flow rate Fa. Then, in step S250, it is determined whether or not the advance time T (here 1 sec) has elapsed.

  If it is determined in step S250 that the advance time T has elapsed, the flow rate of the additional gas is supplied at the set flow rate fa in step S260. According to such an additional gas supply process, the additional gas from the additional gas supply means 220 is supplied to the second branch pipe 206 via the additional gas supply pipe 208 and reaches the processing chamber 110 at an early stage, and thereafter. The set flow rate fa is supplied to the processing chamber 110 together with the second processing gas.

Thus, for example, C _X F _Y gas (for example, CF ₄ gas) that can promote etching is supplied from the additional gas supply means 220 at the set flow rate fa from the gas supply source 222a, merges with the second branch pipe 206, and the second It is supplied to the second buffer chamber 163b through the 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. Thereby, the gas component and flow rate of the processing gas supplied to the second buffer chamber 163b are determined.

In step S270, 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 S270 that each pressure has stabilized, wafer processing is performed in step S280. 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. 11, 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 additional gas is supplied at a first flow rate Fa that is larger than the set flow rate fa at the first advance time T (for example, 1 sec), and is then supplied at the set flow rate fa. For this reason, since the pressure of the additional gas supply pipe 208 increases faster than when the additional gas is supplied from the beginning at a small set flow rate fa, the additional gas can easily flow into the second branch pipe 206. As a result, it is possible to shorten the time (addition gas supply time) from when the additional gas is supplied until it flows into the processing chamber 110 and the pressure (gas concentration) is stabilized. Furthermore, since the first-out flow rate Fa of the additional gas is an optimum value calculated based on the volume and pressure of the additional gas supply pipe 208, the first-out processing is performed with the optimum first-out flow rate Fa according to the configuration of the substrate processing apparatus. Can do. Thereby, it can optimize so that additional gas supply time may become the shortest for every substrate processing apparatus.

Here, FIG. 12 shows a result of an experiment for supplying an additional gas by the additional gas supply process described above. In this experiment, Ar gas was supplied from the processing gas supply unit 210 and O ₂ gas was supplied from the additional gas supply unit 220 to check the arrival status of each gas to the processing chamber 110. Specifically, first flowing Ar gas at a predetermined flow rate 1100Sccm, after then _{O 2} gas is flowed best first-out flow 49.9sccm at from _{t 0} predetermined time 1 sec, and the flow rate of _{O 2} gas to the set flow rate 7sccm . FIG. 12 is a graph showing the results of detecting the concentrations of Ar gas and O ₂ gas by attaching a gas concentration measuring device to the gas inlet of the processing chamber 110. The vertical axis in FIG. 12 represents the gas concentration, and the horizontal axis represents time. According to this, since the concentrations of Ar gas and O ₂ gas change according to the flow rates of Ar gas and O ₂ gas reaching the gas inlet of the processing chamber, Ar gas and O ₂ gas are changed by this gas concentration change. It can be seen that the flow rate reaches the processing chamber 110.

According to the experimental results shown in FIG. 12, the concentration of O ₂ gas is stable after time M has elapsed from the start of O ₂ gas supply t ₀ . The time M corresponding to the additional gas supply time was 4.5 sec. In contrast, when the O ₂ gas is supplied at a set flow rate from the beginning, the additional gas supply time is several tens of seconds. Therefore, by performing the additional gas supply processing according to the present invention, the additional gas supply time is increased. It can be seen that it is greatly shortened.

  Prior to the supply of the additional gas, the partial flow rate adjusting means 230 may be configured to adjust the partial flow rate of the processing gas by the constant pressure control. Specifically, when the control unit 300 issues a constant pressure control command, the partial flow rate adjusting means 230 adjusts the opening / closing degrees 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.

  According to this, even when the additional gas is supplied to the second branch pipe 206, the processing gas that should flow into the second branch pipe 206 flows into the first branch pipe 204 even if the pressure in the second branch pipe 206 varies. This can be prevented. For this reason, it is possible to prevent the flow rate ratio (diversion ratio) of the processing gas diverted to the branch pipes 204 and 206 before and after the supply of additional gas from being lost, and the processing gas diverted at the desired flow rate ratio can be prevented. It can be supplied to different areas on the surface. Thereby, desired in-plane uniformity can be realized.

(Additional gas supply processing considering the maximum allowable flow rate of the additional gas line)
Next, an additional gas supply process in consideration of the maximum allowable flow rate of the additional gas line of the additional gas supply means 220 will be described. In the additional gas advance flow rate calculation processing shown in FIG. 10, the advance flow rate Fa is calculated with the advance time T fixed at a predetermined time (for example, 1 sec), so that depending on the value of the advance flow rate Fa, the advance gas flow may be caused to flow in the additional gas line. It is also conceivable that the maximum allowable flow rate fmax can be exceeded. In such a case, the advance flow rate Fa cannot flow.

  Therefore, in such a case, it is preferable to perform correction by setting the maximum allowable flow rate fmax as the first-out flow rate Fa and extending the first-out time T by that amount. When supplying the additional gas, it is possible to execute the optimal additional gas supply process within a range not exceeding the maximum allowable flow rate fmax by causing the maximum allowable flow rate fmax to flow at the corrected first-out time T. it can. As a result, the additional gas supply process can be performed with the optimum first-out time T according to the configuration of the substrate processing apparatus.

  Here, a specific example of the advance flow rate calculation process in consideration of the maximum allowable flow rate fmax of the additional gas line will be described with reference to FIG. The advance flow rate calculation process shown in FIG. 13 is the same as that shown in FIG. 10 from step S110 to step S150.

  Thereafter, it is determined whether or not the advance flow rate Fa calculated in step S160 exceeds the maximum allowable flow rate fmax of the additional gas line. When it is determined that the advance flow rate Fa does not exceed the maximum allowable flow rate fmax of the additional gas line, a series of advance flow rate calculation processes are terminated, and when it is determined that the advance flow rate Fa exceeds the maximum allowable flow rate fmax of the additional gas line, Correction processing of the advance time T after step S170 is performed.

  Specifically, in step S170, the advance flow rate Fa is set to the maximum allowable flow rate fmax of the additional gas line and stored in the data table of the gas supply process data 352. Next, the advance time T is corrected and stored in step S180. That is, first, the advance flow rate Fa is fixed as the maximum allowable flow rate fmax of the additional gas line, and the advance time T is calculated based on the following formula (1-5). This formula (1-5) is obtained by modifying the formula (1-4) into a formula for obtaining the advance time T.

  T = α · (Pe / P) · β · 60 · v / Fa + γ (1-5)

  According to the above formula (1-5), it is necessary for the pressure of the additional gas supply pipe 208 to reach the pressure of the second branch flow path 206 when the additional gas is supplied with the maximum allowable flow rate fmax as the first flow rate Fa. The advance time T can be calculated as time. According to this, the first-out process can be performed with the optimum first-out time T according to the configuration of the substrate processing apparatus, and the optimum additional gas supply control is executed within a range not exceeding the maximum allowable flow rate fmax of the additional gas line. Can do. In this case, since the maximum allowable flow rate smaller than the advance flow rate before correction is used as the advance flow rate after correction, the advance time T is increased by that amount. In comparison, the additional gas supply time can be shortened sufficiently. The corrected advance-out time T calculated in this way is stored in the data table of the gas supply process data 352, and the series of advance-out flow rate calculation processes ends.

(Other specific configuration examples of the gas supply device)
Next, a specific configuration example of each part of the gas supply device 200 will be described. FIG. 14 is a block diagram illustrating another specific configuration example of the gas supply device 200. Here, the case where an additional gas supply means is comprised by several additional gas lines is demonstrated.

  As shown in FIG. 14, the additional gas supply means 220 shown in FIG. 14 includes a gas box in which a plurality of (for example, two) additional gas lines (1) and (2) are accommodated. Gas supply sources 222a and 222b are connected to the upstream side of the additional gas lines (1) and (2), respectively. Further, the downstream sides of the additional gas lines (1) and (2) merge and are connected to the additional gas supply pipe 208. Each additional gas line (1), (2) is provided with mass flow controllers 224a, 224b for adjusting the flow rate of gas from the gas supply sources 222a, 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. . Note that the number of gas supply sources of the additional gas supply means 220 is not limited to the example shown in FIG. 14, and may be three or more, for example.

  When the additional gas supply means is constituted by a plurality of additional gas lines as described above, it is necessary to calculate the advance flow rate Fa for each additional gas line also in the additional gas supply processing. The gas supply process data 352 for executing such an additional gas supply process is constituted by a data table as shown in FIG. 15, for example. In this data table, at least data of processing gas and additional gas is stored.

  The processing gas data in the data table shown in FIG. 15 is the same as that shown in FIG. In the data table shown in FIG. 15, as additional gas data, for example, the set flow rates fa (1) and fa (2) of the additional gas lines (1) and (2) and the total additional gas flow rate fa (= fa (1)). + Fa (2)), each first-out flow rate Fa (1), Fa (2) and first-out total flow rate Fa (= Fa (1) + Fa (2)), additional gas line (1), (2), each first-out flow rate Fa (1) A storage area is provided for storing each data of the advance time T, which is the time to flow Fa (2).

  Among these gas supply process data 352, the set flow rate for the process gas and the additional gas can be set in advance by operating the operation means 340 by the operator, for example. On the other hand, each advance flow rate Fa (1), Fa (2) and advance total flow rate Fa of the additional gas is calculated by a advance flow rate calculation process shown in FIG. The advance time T is set in advance to a default value (for example, 1 sec). The advance time T can be changed by operating the operating means 340 by an operator, for example.

(Additional gas advance flow rate calculation processing)
Based on such gas supply process data 352, the control unit 300 executes the advance flow rate calculation process of the additional gas as shown in FIG. 16, for example. As shown in FIG. 16, the control unit 300 first sets the second flow rate based on the total processing gas flow rate fm acquired from the gas supply processing data 352 and the flow rate ratio C: E between the first and second processing gases in step S310. The flow rate fe of the processing gas is calculated. The flow rate fe of the second process gas is calculated in the same manner as in step S110, for example.

  Next, in step S320, a set total flow rate fa that is the sum of the set flow rates of the additional gas lines is acquired from the gas supply processing data 352, and in step S330, the total gas flow rate Fe (= second processing) flowing through the second branch pipe. The gas flow rate fe + the set total flow rate fa) of the additional gas is calculated.

  Subsequently, in step S340, the pressure Pe in the second branch pipe 206 is calculated based on the total gas flow rate Fe. This pressure Pe is calculated in the same manner as in step S140, for example. Next, in step S350, a first-out total flow rate Fa, which is the sum of the first-out flow rates of the additional gas lines, is calculated and stored. The advance total flow rate Fa is calculated in the same manner as in step S150.

  Next, in step S360, advance flow rates Fa (1) and Fa (2) are calculated and stored for each of the additional gas lines (1) and (2). The advance flow rates Fa (1) and Fa (2) are calculated so as to have the same ratio as the set flow rates fa (1) and fa (2) of the additional gas lines (1) and (2). Specifically, it is calculated using the following mathematical formula (1-6).

  Fa (x) = Fa · (f (x) / fa) (1-6)

  In the above mathematical formula (1-6), x represents the number of the additional gas line. For example, the additional gas line (1) is x = 1, and the additional gas line (2) is x = 2. fa is a set total flow rate, and Fa is a first-out total flow rate. For example, when the set flow rate of the additional gas line is fa (1) = 10 sccm and fa (2) = 20 sccm, the set total flow rate is fa = 30 sccm. Therefore, if the preceding total flow rate is calculated as Fa = 60 sccm, The advance flow rate of each additional gas line is calculated as Fa (1) = 20 sccm and Fa (2) = 40 sccm, respectively.

  In this way, when the advance flow rate of each additional gas line is calculated, a series of advance flow rate calculation processing ends. According to this, the optimum value of the advance flow rate can be calculated with the set flow rate ratio of each additional gas line.

(Additional gas supply processing considering the maximum allowable flow rate of the additional gas line)
Next, an additional gas supply process in consideration of the maximum allowable flow rate of each additional gas line of the additional gas supply means 220 will be described. In the advance flow rate calculation processing shown in FIG. 16, the advance flow time Fa (1) and Fa (2) of each additional gas line is calculated by fixing the advance time T when supplying the additional gas to a predetermined time (for example, 1 sec). Therefore, depending on the additional gas line, the calculated advance flow rate may exceed the maximum allowable flow rate fmax that can be passed through the additional gas line. In such a case, the calculated advance flow rate cannot flow. For example, even if the advance flow rate Fa (1) does not exceed the maximum allowable flow rate fmax (1), the advance flow rate Fa (2) may exceed the maximum allowable flow rate fmax (2).

  In such a case, the advance flow rate Fa (2) is fixed to the maximum allowable flow rate fmax (2), the other advance flow rate Fa (1) is corrected, and the advance time is set according to the maximum allowable flow rate fmax (2). T is corrected. When supplying the additional gas, the first flow rates Fa (1) and Fa (2) corrected by the corrected first time T are allowed to flow so that the maximum allowable flow rate fmax is not exceeded in all the additional gas lines. An optimal additional gas supply process can be executed. As a result, the additional gas supply process can be performed with the optimum first-out time T according to the configuration of the substrate processing apparatus. Thereby, it can optimize so that additional gas supply time may become the shortest for every substrate processing apparatus.

  Here, a specific example of the advance flow rate calculation process in consideration of the maximum allowable flow rate fmax of each additional gas line will be described with reference to FIG. The advance flow rate calculation process shown in FIG. 17 is the same as that shown in FIG. 16 from step S310 to step S360.

  Thereafter, of the first-out flow rates Fa (1) and Fa (2) of the additional gas lines (1) and (2) calculated in step S370, the maximum allowable flow rates fmax (1) and fmax (2) of the additional gas line are calculated. ). When it is determined that none of the first flow rates Fa (1) and Fa (2) exceed the maximum allowable flow rate of the additional gas line, the series of first flow rate calculation processes is terminated and the maximum allowable flow rate of the additional gas line is determined. If it is determined that there is an excess, the first advance flow rate Fa (1), Fa (2) and the advance time T are corrected in step S380.

  Specifically, in step S380, each advance flow rate Fa (1), Fa (2) and advance time T are recalculated and stored in accordance with the maximum allowable flow rate of the additional gas line where the advance flow rate exceeds the maximum allowable flow rate. In the same specific example as described above, when the set flow rate of the additional gas line is fa (1) = 10 sccm and fa (2) = 20 sccm, if the first total flow rate is calculated as Fa = 60 sccm, each additional flow rate is calculated. The advance flow rate of the gas line is calculated as Fa (1) = 20 sccm and Fa (2) = 40 sccm, respectively. In this case, if the maximum allowable flow rate fmax (2) of the additional gas line (2) is 30 sccm, it is impossible to flow Fa (2) = 40 sccm, so the first flow rate Fa (2) = fmax (2) = Set to 30 sccm. Accordingly, when the advance flow rate Fa (1) is recalculated so as to be the same ratio as the set flow rate ratio, Fa (1) = 15 sccm. Therefore, since the first advance total flow rate Fa = 30 sccm + 15 sccm = 45 sccm, the advance time T can be calculated by substituting this value into the equation (1-5).

  The corrected first-out flow rates Fa (1), Fa (2), first-out total flow rate Fa, and first-out time T are stored in the data table of the gas supply process data 352, and a series of first-out flow rate calculation processes is completed. . In the advance flow rate calculation process shown in FIGS. 16 and 17 described above, the case where the advance flow rates of the two additional gas lines (1) and (2) are calculated has been described. Each advance flow rate is calculated according to the number of additional gas lines provided in the supply means 220.

  In the advance flow rate calculation process (FIGS. 10, 13, 16, and 17) described in the above embodiment, for example, the wafer process is composed of a plurality of steps, and the set flow rate of the additional gas is different for each step. For this reason, it is preferable to calculate the advance flow rate of the additional gas for each step. Thereby, the additional gas supply process according to the wafer processing step can be performed.

  Further, the second branch flow path 206 in the above embodiment is constituted 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 gas supply apparatus concerning the embodiment. It is a figure which shows the supply control timing of the additional gas in the case of performing the additional gas supply process concerning the embodiment. It is a graph which shows the experimental result which performed additional gas supply processing with a certain advance flow rate. It is a graph which shows the experimental result which performed the additional gas supply process with the advance flow volume different from FIG. It is a graph which shows the experimental result which changed the piping diameter etc. and performed the additional gas supply process by the advance flow volume of FIG. It is a graph which shows the experimental result which changed the piping diameter etc. and performed the additional gas supply process by the advance flow volume of FIG. It is a block diagram which shows the structural example of the control part concerning the embodiment. It is a figure which shows the structural example of the data table of the gas supply process data shown in FIG. It is a flowchart which shows the specific example of the advance flow volume calculation process concerning the embodiment. It is a flowchart which shows the specific example of the process performed after the advance flow volume calculation process. Results of experiment to supply additional gas by additional gas supply processing according to the embodiment It is a flowchart which shows the specific example of the advance flow volume calculation process at the time of considering the maximum permissible flow volume of an additional gas line. It is a block diagram which shows the other structural example of the gas supply apparatus concerning the embodiment. It is a figure which shows the other structural example of the data table of the gas supply process data shown in FIG. It is a flowchart which shows the other specific example of the advance flow volume calculation process concerning the embodiment. It is a flowchart which shows the other specific example of the advance flow volume calculation process at the time of considering the maximum permissible flow volume of an additional gas line.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Substrate processing apparatus 110 Processing chamber 111 Ground conductor 112 Insulating plate 114 Susceptor support stand 116 Susceptor 118 Electrostatic chuck 120 Electrode 122 DC power supply 124 Focus ring 126 Inner wall member 128 Refrigerant chamber 130a, 130b Pipe 132 Gas supply line 134 Outer electrode 136 Outer Upper electrode 138 Inner upper electrode 142 Dielectric material 144 Insulating shielding member 146 Matching device 148 Upper power supply rod 150 Connector 152 Power supply tube 156 Insulating member 160 Electrode plate 160a Gas ejection hole 162 Electrode support body 163 Buffer chamber 163a First buffer chamber 163b First Two buffer chambers 164 Annular partition member 170 Lower feed cylinder 172 Variable capacitor 174 Exhaust port 176 Exhaust pipe 178 Exhaust device 180 Matching unit 184 Low pass filter 186 High pass filter 200 Gas supply Apparatus 202 Processing 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 controller 220 Additional gas supply means 222a and 222b Gas supply source 224a, 224b Mass flow controller 230 Minute flow rate adjusting means 232, 234 Pressure adjusting 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 352 Gas supply processing data 360 Interface W Wafer

Claims (15)

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 channel 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 branched from the processing gas supply flow channel to each branch flow channel based on a pressure in each branch flow channel;
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 the processing of the substrate to be processed, a processing gas supply control by the processing gas supply means, and a control means for performing additional gas supply control by the additional gas supply means,
The additional gas supply control includes control for starting supply with the advance gas flow rate larger than a preset set flow rate and supplying the additional gas flow rate with the set flow rate after a predetermined time has elapsed. A gas supply device. The advance flow rate is a value calculated in advance based on the volume of the additional gas supply channel through which the additional gas flows and the pressure in the second branch channel through which the additional gas flows from the additional gas supply channel. The gas supply device according to claim 1, wherein the gas supply device is provided. The advance flow rate is a value calculated in advance as a maximum flow rate required for the pressure of the additional gas supply channel to reach the pressure of the second branch channel within the predetermined time. The gas supply device according to claim 2. The additional gas supply means includes an additional gas line to which an additional gas supply source is connected,
The additional gas supply control includes a control in which, when the calculated advance flow rate exceeds the maximum allowable flow rate of the additional gas line, the maximum allowable flow rate is set as the advance flow rate, and the predetermined time is increased by that amount. The gas supply device according to claim 2 or 3, wherein The predetermined time is calculated as a time required for the pressure of the additional gas supply channel to reach the pressure of the second branch channel when the additional gas is supplied with the maximum allowable flow rate as the first flow rate. The gas supply device according to claim 4, wherein: The gas supply device according to any one of claims 1 to 5, wherein a volume of the additional gas supply channel is at least smaller than a volume of the second branch channel. 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. 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 channel 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 branched from the processing gas supply flow channel to each branch flow channel based on a pressure in each branch flow channel;
A plurality of additional gas lines that respectively connect the additional gas supply sources, and the additional gas supply means configured to join the plurality of additional gas lines downstream;
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 the processing of the substrate to be processed, a processing gas supply control by the processing gas supply means, and a control means for performing additional gas supply control by the additional gas supply means,
In the additional gas supply control, the supply of the additional gas in each additional gas line is started with a first-out flow rate larger than a preset set flow rate, and after a predetermined time has elapsed, the additional gas flow rate is set to the set flow rate. A gas supply device comprising a supply control. The first-out flow rate in each additional gas line is the first-out total flow rate calculated in advance as the maximum flow rate necessary for the pressure in the additional gas supply flow path to reach the pressure in the second branch flow path within the predetermined time. The gas supply device according to claim 8, wherein the value is distributed at the same ratio as the set flow rate ratio of each additional gas line. In the additional gas supply control, when there is a pre-flow rate in each additional gas line that exceeds the maximum allowable flow rate of the additional gas line, the maximum allowable flow rate is set as the previous flow rate of the additional gas line. The gas supply apparatus according to claim 9, further comprising a control for recalculating the advance flow rate of the additional gas line and the predetermined time. 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 includes a processing gas supply means for supplying a processing gas for processing the substrate to be processed, a processing gas supply flow path for supplying a processing gas from the processing gas supply means, and a branch from the processing gas supply flow path The first branch channel and the second branch channel respectively connected to different parts of the processing chamber, and the partial flow rates of the processing gas branched from the processing gas supply channel to each branch channel are A partial flow rate adjusting means for adjusting the pressure based on the pressure in the branch flow path, an additional gas supply means for supplying a predetermined additional gas, and the additional gas from the additional gas supply means on the downstream side of the partial flow rate adjusting means. An additional gas supply channel that joins the second branch channel;
The control means performs processing gas supply control by the processing gas supply means and additional gas supply control by the additional gas supply means prior to processing of the substrate to be processed,
The additional gas supply control includes control for starting supply with the advance gas flow rate larger than a preset set flow rate and supplying the additional gas flow rate with the set flow rate after a predetermined time has elapsed. A substrate processing apparatus. The advance flow rate is a value calculated in advance based on the volume of the additional gas supply passage through which the additional gas flows and the pressure of the second branch passage through which the additional gas flows from the additional gas supply passage. The substrate processing apparatus according to claim 11, wherein the substrate processing apparatus is provided. The advance flow rate is a value calculated in advance as a maximum flow rate required for the pressure of the additional gas supply channel to reach the pressure of the second branch channel within the predetermined time. The substrate processing apparatus according to claim 12. 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 includes a processing gas supply means for supplying a processing gas for processing the substrate to be processed, a processing gas supply flow path for supplying a processing gas from the processing gas supply means, and a branch from the processing gas supply flow path The first branch channel and the second branch channel respectively connected to different parts of the processing chamber, and the partial flow rates of the processing gas branched from the processing gas supply channel to each branch channel are A partial flow rate adjusting means for adjusting the pressure based on the pressure in the branch flow path, an additional gas supply means for supplying a predetermined additional gas, and the additional gas from the additional gas supply means on the downstream side of the partial flow rate adjusting means. An additional gas supply channel that joins the second branch channel;
Prior to processing of the substrate to be processed, performing a control of supplying a processing gas having a preset flow rate by the processing gas supply means;
Starting the supply with the advance flow rate larger than the preset flow rate set in advance and supplying the additional gas flow rate with the set flow rate after a predetermined time; and
A gas supply method comprising: Before the step of performing the control to supply the processing gas,
Based on the volume of the additional gas supply flow path through which the additional gas flows and the pressure of the second branch flow path through which the additional gas flows from the additional gas supply flow path, the additional gas supply flow path within a predetermined time. The gas supply method according to claim 14, further comprising a step of calculating, as a first-out flow rate, a maximum flow rate necessary for the pressure to reach the pressure of the second branch flow path.

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