Substrate processing apparatus and substrate processing method

Abstract

The invention relates to a substrate processing apparatus and a substrate processing method. A control unit of a substrate processing apparatus adjusts an opening degree of a needle valve on the basis of a difference between pre-processing film thickness profile data and post-processing target film thickness profile data, performs ejection of a chemical solution from a nozzle to an ejection destination other than a substrate, and after completion of the ejection, performs ejection of the chemical solution from the nozzle to the target film thickness profile data. The first raw material liquid and the second raw material liquid remain in a portion of the liquid flow path between the first shutoff valve and the nozzle and between the second shutoff valve and the nozzle at a ratio corresponding to the opening degree of the needle valve. The first stop valve and the second stop valve are opened in a state in which the substrate is rotated by the substrate holding and rotating part and the nozzle is positioned above the central part of the substrate. The etching process of the film to be etched is started by supplying a mixed solution of the first raw material solution and the second raw material solution remaining in a portion of the liquid flow path between the first and second shutoff valves and the nozzle to the central portion of the substrate.

Description

Technical Field

[0001] The present disclosure relates to a substrate processing device and a substrate processing method. Background Art

[0002] The manufacturing of semiconductor devices includes the following steps: a substrate (semiconductor wafer, etc.) is held in a horizontal position by a substrate holding rotating part called a rotating holding plate, etc. and the substrate is rotated around a vertical axis, and a chemical solution such as SPM (a mixture of sulfuric acid and hydrogen peroxide) is supplied from a nozzle to the surface of the rotating substrate to wet-etch a metal film (such as a TiN film) on the surface of the substrate. In such wet etching, the management of the etching profile has become increasingly important recently.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-899836 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The present disclosure provides a technology that can control an etching profile of the substrate by controlling a liquid supply mechanism that is ejected immediately before the mixed liquid is ejected from a nozzle toward the substrate when a mixed liquid is ejected from a nozzle toward the substrate.

[0008] Solutions for solving problems

[0009] According to one embodiment of the present disclosure, there is provided a substrate processing apparatus comprising:

[0010] a substrate holding and rotating portion that holds a substrate and rotates the substrate;

[0011] a nozzle configured to eject a liquid obtained by mixing at least a first raw material liquid and a second raw material liquid toward the substrate held by the substrate holding portion;

[0012] a nozzle arm that supports the nozzle and moves the nozzle;

[0013] A liquid medicine supply mechanism supplies the liquid medicine to the nozzle, the liquid medicine supply mechanism comprising:

[0014] a first raw material liquid flow path, which is used to supply the first raw material liquid;

[0015] a second raw material liquid flow path, which is used to supply the second raw material liquid;

[0016] a liquid medicine flow path connected to the first raw material liquid flow path and the second raw material liquid flow path, and connected to the nozzle;

[0017] A first stop valve, which is provided in the first raw material liquid supply path and is constituted by a pneumatic valve;

[0018] a second stop valve, which is provided in the second raw material liquid supply path;

[0019] an air passage connected to the first stop valve and configured to allow at least the air exhausted from the stop valve to flow when the first stop valve is switched from an open valve state to a closed valve state;

[0020] a needle valve disposed in the air passage and capable of adjusting a closing speed of the stop valve by adjusting an exhaust resistance of air exhausted from the stop valve; and

[0021] an actuator for adjusting the opening of the needle valve; and

[0022] a control unit for controlling the operation of the substrate processing device,

[0023] The control unit is configured to cause the substrate processing device to perform the following processing:

[0024] acquiring pre-processing film thickness profile data representing a film thickness distribution in a radial direction of the substrate of an etching target film existing on the first substrate before processing;

[0025] adjusting the opening of the needle valve to a first opening by means of the actuator based on a difference between post-processing target film thickness profile data representing a target value of film thickness distribution in the radial direction of the substrate of the etching target film present on the first substrate after processing and the pre-processing film thickness profile data;

[0026] Before ejecting the chemical liquid from the nozzle toward the first substrate, ejecting the chemical liquid from the nozzle toward an ejection destination different from the first substrate, and stopping ejecting the chemical liquid from the nozzle in a state where the opening of the needle valve is adjusted to the first opening, thereby causing the first raw material liquid and the second raw material liquid to remain in the chemical liquid flow path and the first raw material liquid flow path between the first shut-off valve and the nozzle and in the chemical liquid flow path and the second raw material liquid flow path between the second shut-off valve and the nozzle at a ratio corresponding to the opening of the needle valve; and

[0027] After stopping the spraying of the chemical liquid from the nozzle to the spraying destination different from the first substrate, the first stop valve and the second stop valve are opened while the substrate is rotated by the substrate holding rotating part and the nozzle is located above the center of the first substrate, thereby supplying a mixed solution of the first raw material liquid and the second raw material liquid remaining in the chemical liquid flow path and the first raw material liquid flow path between the first stop valve and the nozzle and in the chemical liquid flow path and the second raw material liquid flow path between the second stop valve and the nozzle to the center of the first substrate from the nozzle, thereby starting the etching process of the etching object film on the first substrate.

[0028] Effects of the Invention

[0029] According to one embodiment of the present disclosure described above, the etching profile when the mixed chemical liquid is ejected onto the substrate to etch the substrate can be controlled by controlling the chemical liquid supply mechanism when the liquid is ejected from the nozzle immediately before the mixed chemical liquid is ejected from the nozzle toward the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic cross-sectional view of a substrate processing system according to an embodiment of a substrate processing apparatus.

[0031] Figure 2 is set at Figure 1 A schematic longitudinal cross-sectional view of a processing unit of a substrate processing system.

[0032] Figure 3 This is a piping structure diagram of a chemical liquid supply mechanism that supplies a mixed chemical liquid to a processing unit.

[0033] Figure 4 This is a graph showing the experimental results of investigating the relationship between the opening degree of the needle valve and the pressure detected by the pressure gauge.

[0034] Figure 5 This is a graph showing the temporal change in the temperature of the mixed solution of sulfuric acid and hydrogen peroxide supplied to the wafer W immediately after the actual processing of the wafer W is started, for each opening degree of the needle valve.

[0035] Figure 6 This is a graph showing the radial distribution (etching profile) of the etching amount after the actual processing of the wafer W for each opening degree of the needle valve.

[0036] Figure 7 Graph showing the relationship between the liquid draining time and the etching amount at the center of the wafer W.

[0037] Figure 8This is a graph showing the relationship between the attenuation rate and the liquid drain time when the opening degree of the needle valve is changed to various values. DETAILED DESCRIPTION

[0038] Hereinafter, one embodiment of a substrate processing apparatus will be described with reference to the drawings.

[0039] Figure 1 1 is a diagram showing a schematic configuration of a substrate processing system according to the present embodiment. In order to clarify the positional relationship, mutually orthogonal X-axis, Y-axis, and Z-axis are defined, and the positive direction of the Z-axis is defined as the vertical upward direction.

[0040] like Figure 1 As shown, the substrate processing system 1 includes a loading / unloading station 2 and a processing station 3. The loading / unloading station 2 and the processing station 3 are provided adjacent to each other.

[0041] The loading / unloading station 2 includes a carrier placement unit 11 and a conveying unit 12. A plurality of carriers C for accommodating a plurality of substrates, in this embodiment, semiconductor wafers (hereinafter referred to as wafers W) in a horizontal state are placed on the carrier placement unit 11.

[0042] The conveying unit 12 is disposed adjacent to the carrier placement unit 11, and includes a substrate conveying device 13 and a delivery unit 14 inside the conveying unit 12. The substrate conveying device 13 includes a wafer holding mechanism for holding the wafer W. In addition, the substrate conveying device 13 can move in the horizontal direction and the vertical direction and rotate around the vertical axis, and uses the wafer holding mechanism to convey the wafer W between the carrier C and the delivery unit 14.

[0043] The processing station 3 is provided adjacent to the conveying unit 12. The processing station 3 includes a conveying unit 15 and a plurality of processing units 16. The plurality of processing units 16 are arranged on both sides of the conveying unit 15.

[0044] A substrate transport device 17 is provided inside the transport section 15. The substrate transport device 17 includes a wafer holding mechanism for holding the wafer W. The substrate transport device 17 is capable of moving in the horizontal direction and the vertical direction and rotating around the vertical axis, and transports the wafer W between the interface 14 and the processing unit 16 using the wafer holding mechanism.

[0045] The processing unit 16 performs predetermined substrate processing on the wafer W transferred by the substrate transfer device 17 .

[0046] In addition, the substrate processing system 1 includes a control device 4. The control device 4 is, for example, a computer, and includes a control unit 18 and a storage unit 19. The storage unit 19 stores programs for controlling various processes performed in the substrate processing system 1. The control unit 18 controls the operation of the substrate processing system 1 by reading and executing the programs stored in the storage unit 19.

[0047] In addition, the program may be recorded in a computer-readable storage medium and installed from the storage medium to the storage unit 19 of the control device 4. Examples of computer-readable storage media include a hard disk (HD), a floppy disk (FD), a compact disk (CD), a magneto-optical disk (MO), and a memory card.

[0048] In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 of the loading / unloading station 2 takes out the wafer W from the carrier C mounted on the carrier mounting portion 11, and places the taken-out wafer W on the delivery portion 14. The wafer W placed on the delivery portion 14 is taken out from the delivery portion 14 by the substrate transfer device 17 of the processing station 3 and carried into the processing unit 16.

[0049] After being processed by the processing unit 16, the wafer W is carried out from the processing unit 16 by the substrate transfer device 17 and placed on the delivery unit 14. Then, the processed wafer W placed on the delivery unit 14 is returned to the carrier C of the carrier placement unit 11 by the substrate transfer device 13.

[0050] Next, refer to Figure 2 , to illustrate a structural example of the processing unit 16. Figure 2 This is a diagram schematically showing a configuration example of the processing unit 16 .

[0051] like Figure 2 As shown, the processing unit 16 includes a chamber 20 , a substrate holding and rotating unit 30 , a nozzle 40 , and a recovery cup 50 .

[0052] The chamber 20 accommodates the substrate holding rotating unit 30 , the nozzle 40 , and the recovery cup 50 . A fan filter unit (FFU) 21 is provided on the top of the chamber 20 . The FFU 21 is used to form a downflow in the chamber 20 .

[0053] The substrate holding and rotating unit 30 includes a substrate holding unit 31 and a rotation driving unit 33. The substrate holding unit 31 holds the wafer W horizontally. The rotation driving unit 33 rotates the substrate holding unit 31 and the wafer W held by the substrate holding unit 31 around a vertical axis via a rotation shaft 32.

[0054] The nozzle 40 discharges the processing liquid supplied from the processing liquid supply unit (processing liquid supply mechanism) 70 toward the wafer W held and rotated by the substrate holding unit 31. Thus, the wafer W is processed by the processing liquid.

[0055] The recovery cup 50 is configured to surround the holding portion 31 and capture the processing liquid scattered from the wafer W due to the rotation of the holding portion 31. A drain port 51 is formed at the bottom of the recovery cup 50, and the processing liquid captured by the recovery cup 50 is discharged to the outside of the processing unit 16 from the drain port 51. In addition, an exhaust port 52 for discharging the gas supplied from the FFU 21 to the outside of the processing unit 16 is formed at the bottom of the recovery cup 50.

[0056] The nozzle 40 is held by a nozzle arm (not shown). The nozzle arm enables the nozzle 40 to be located above any radial position of the wafer W, and further enables the nozzle 40 to be located at an original position (standby position) outside the recovery cup 50. A pseudo-distribution port (not shown) is provided at a position directly below the nozzle 40 in the original position or in the vicinity of the position. As is well known in the technical field, the pseudo-distribution port serves to receive the liquid ejected from the nozzle 40 (for example, the liquid retained in the liquid ejection path nearest to the nozzle 40) and guide it to a specified liquid discharge path.

[0057] The nozzles 40 and the nozzle arms are provided in the number required to supply the processing liquid used in the processing performed in the processing unit 16. Examples of the processing liquid include a chemical liquid such as SPM (a mixture of sulfuric acid and hydrogen peroxide) and SC1 liquid, and an organic solvent for drying such as DIW (pure water) and IPA (isopropyl alcohol) as a rinse liquid.

[0058] The treatment liquid is supplied from the treatment liquid supply source to the nozzle 40 via the treatment liquid supply mechanism 70. As is well known in the technical field of semiconductor manufacturing equipment, the treatment liquid supply mechanism 70 includes a pipeline (passage) for circulating the treatment liquid, and flow control devices such as a flow meter, a flow control valve, and a shut-off valve (opening and closing valve) arranged in the pipeline. The structure of the treatment liquid supply mechanism for supplying SPM will be described in detail later. As a supply mechanism for the treatment liquid other than SPM, a mechanism known in the technical field can be appropriately selected. In addition, a low-humidity and low-oxygen concentration gas, such as an inactive gas such as nitrogen, can also be supplied from the nozzle 40 to promote the drying of the wafer W.

[0059] Next, refer to Figure 3 The structure of the chemical liquid supply mechanism 100 for supplying SPM will be described. The chemical liquid supply mechanism 100 constitutes a part of the processing liquid supply mechanism 70.

[0060] SPM (mixed solution of sulfuric acid and hydrogen peroxide) is a mixed solution of hydrogen peroxide (first raw material solution) and sulfuric acid (second raw material solution).

[0061] The chemical solution supply mechanism 100 has a first raw material solution flow path 111 connected to a hydrogen peroxide solution supply source 110 at its upstream end. The first raw material solution flow path 111 is provided with a flow meter 112, a flow control valve 113, and a stop valve 114 as flow control devices in order from the upstream side.

[0062] The liquid medicine supply mechanism 100 has a second raw liquid flow path 121 connected to a sulfuric acid supply source 120 at its upstream end. A flow meter 122, a flow control valve 123, and a stop valve 124 are provided in the second raw liquid flow path 121 in order from the upstream side as flow control devices. Although the stop valve 124 provided in the second raw liquid flow path 121 is not shown in detail, it has the same structure as the stop valve 114 provided in the first raw liquid flow path 111.

[0063] The hydrogen peroxide supply source 110 and the sulfuric acid supply source 120 may be provided by, for example, factory-supplied energy, or may be a tank storing raw material liquids (hydrogen peroxide and sulfuric acid).

[0064] The first raw material liquid flow path 111 and the second raw material liquid flow path 121 merge at the confluence point 140 to form a drug liquid flow path 141. The downstream end of the drug liquid flow path 141 is connected to the nozzle 40. A line mixer 142 (shown by a dotted line) may be provided at the confluence point 140 or at a position slightly downstream of the confluence point 140 in the drug liquid flow path 141.

[0065] The stop valve 114 is constituted by a pneumatic valve and has an inlet port 1141, an outlet port 1142, and a pilot port 1143. An air cylinder 1145 is provided inside a valve box 1144 of the stop valve 114. A piston 1146 is provided inside the air cylinder 1145.

[0066] The piston 1146 is connected to a valve body 1148 via a rod 1147. A flow path 1149 is provided inside the valve box 1144 to connect the inlet port 1141 and the outlet port 1142. A valve seat 1150 is provided in the flow path 1149 to seat the valve body 1148. The valve body 1148 is urged to seat on the valve seat 1150 by a spring 1151 that urges the piston 1146. By supplying pressurized air to the pilot port 1143, the valve body 1148 is separated from the valve seat 1150 by overcoming the urging force of the spring 1151. That is, the stop valve 114 is a normally closed valve.

[0067] The pilot port 1143 is connected to an air passage 160. The upstream end of the air passage 160 is connected to a compressed air supply source 161. The air passage 160 is provided with an on-off valve (stop valve) 162, a speed controller 163, and a pressure gauge 164 in order from the upstream side.

[0068] The speed controller 163 is also referred to as a "speed controller" by those skilled in the art in the technical field of pneumatic circuits (Japanese: air pressure circuits), and is composed of a combination of a needle valve (a valve with adjustable opening) 166 and a check valve 167 arranged in parallel. In the present embodiment, the needle valve 166 is configured to be able to adjust the opening by an actuator 168, and the actuator 168 is operated according to a control signal from the outside (for example, the control device 4).

[0069] A branch exhaust path 170 branches from the air passage 160 at a branch point 169 provided between the on-off valve 162 and the speed controller 163. The branch exhaust path 170 is provided with an on-off valve (stop valve) 171 and an orifice 172. The orifice 172 may not be provided.

[0070] The operation of the stop valve 114 will be described.

[0071] When the stop valve 114 is changed from the closed state to the open state, the on-off valve 162 is opened while the on-off valve 171 is closed. Then, pressurized air is supplied from the compressed air supply source 161 to the cylinder chamber 1152 through the air passage 160 and the pilot port 1143, thereby overcoming the force of the spring 1151 to move the piston 1146 to the cylinder chamber 1152. Figure 3 The valve body 1148 moves upward in the valve seat 1150, thereby separating the valve body 1148 from the valve seat 1150. In addition, at this time, most of the compressed air passing through the speed controller 163 passes through the check valve 167 (and also passes through the needle valve 166 according to the opening degree of the needle valve 166). In other words, regardless of the opening degree of the needle valve 166, the stop valve 114 is always opened at a high speed.

[0072] When the stop valve 114 is changed from an open state to a closed state, the on-off valve 171 is opened while the on-off valve 162 is closed. As a result, the pressurized air in the cylinder chamber 1152 flows out to the air passage 160, and is discharged into the surrounding atmosphere through the branch point 169 and the branch exhaust passage 170. At this time, all the compressed air passing through the speed controller 163 passes through the needle valve 166 (cannot pass through the check valve 167). When the pressure in the cylinder chamber 1152 drops, the valve body 1148 sits on the valve seat 1150 due to the force of the spring 1151. When the opening of the needle valve 166 is small (large), the pressure drop speed in the cylinder chamber 1152 decreases (increases), and the valve closing speed decreases (increases).

[0073] When the valve closing speed is small (large), the amount of hydrogen peroxide passing through the stop valve 114 increases (decreases) during the period from the start time of the valve closing operation (the time when the valve body 1148 starts to move toward the valve seat 1150) to the completion time of the valve closing (the time when the valve body 1148 sits on the valve seat 1150). This situation is the same for the stop valve of the second raw liquid flow path 121 through which sulfuric acid flows. That is, based on the relationship between the valve closing speed of the stop valve 114 of the first raw liquid flow path 111 and the valve closing speed of the stop valve 124 of the second raw liquid flow path 121, the interval from the stop valve 114 to the nozzle 40 remaining in the first raw liquid flow path 111 and the interval from the stop valve 124 to the nozzle 40 remaining in the second raw liquid flow path 121 are determined (these intervals are in Figure 3 In the following description, for the sake of simplicity, the closing speed of the shutoff valve 124 of the second raw material liquid flow path 121 through which sulfuric acid flows is fixed to a certain specific value (the closing speed is not adjusted).

[0074] In the single-wafer processing unit 16 that performs etching processing on the wafer W using a mixture of sulfuric acid and hydrogen peroxide, dummy dispensing is performed with the nozzle 40 located at the original position immediately before the mixture of sulfuric acid and hydrogen peroxide is supplied to the wafer W so as not to supply the mixture of sulfuric acid and hydrogen peroxide that has been mixed with hydrogen peroxide for a long time to the wafer W. Depending on the change in the closing speed of the first stop valve 114 at the end of the dummy dispensing (since the closing speed of the second stop valve 124 is set to be fixed, the second stop valve 124 is not considered here), the residual hydrogen peroxide / sulfuric acid ratio changes.

[0075] When the wafer W is processed after the pseudo allocation, the nozzle 40 is positioned above the center of the rotating wafer W, and in this state, the mixed liquid of sulfuric acid and hydrogen peroxide is sprayed toward the center of the wafer W for 5 to 10 seconds, and the liquid film of the mixed liquid of sulfuric acid and hydrogen peroxide expanded by the centrifugal force covers the entire surface of the wafer W. Thereafter, the liquid film of the mixed liquid of sulfuric acid and hydrogen peroxide is maintained on the entire surface of the wafer W, and the mixed liquid of sulfuric acid and hydrogen peroxide is sprayed toward the wafer W for about 40 seconds while the nozzle 40 is moved between above the center of the wafer W and above the peripheral portion (this is only an example, but processing is generally performed in a similar sequence).

[0076] At this time, first, initially, a mixed liquid (a liquid obtained by mixing residual hydrogen peroxide and residual sulfuric acid) obtained by mixing the liquid remaining in the section from the first shutoff valve 114 to the nozzle 40 and the liquid remaining in the section from the second shutoff valve 124 to the nozzle 40 is ejected from the nozzle 40 toward the center of the wafer W. Thereafter, the hydrogen peroxide and sulfuric acid flow toward the nozzle 40 at controlled flow rates through the first raw material liquid flow path 111 and the second raw material liquid flow path 121, respectively, so that the mixing ratio of the hydrogen peroxide and sulfuric acid is substantially maintained constant until the ejection of the mixed liquid of sulfuric acid and hydrogen peroxide from the nozzle 40 is completed.

[0077] The composition of the mixed liquid initially sprayed from the nozzle 40 toward the center of the wafer (which depends on the above-mentioned residual hydrogen peroxide / sulfuric acid ratio) particularly affects the amount of etching near the center of the wafer W. Usually, when the residual hydrogen peroxide / sulfuric acid ratio is large, the temperature of the mixed liquid (a mixture of sulfuric acid and hydrogen peroxide) also becomes higher, and the etching active ingredients such as carboxylic acid increase, so the amount of etching near the center of the wafer W becomes larger. This situation can be used to control the radial etching profile of the wafer W (referring to the distribution of the etching amount in the radial direction. The same applies below.). In other words, if you want to make the etching amount near the center of the wafer W more (less) than the etching amount of the surrounding parts, you only need to make the residual hydrogen peroxide / sulfuric acid ratio higher (lower).

[0078] Next, the control of the etching profile in the radial direction of the wafer W by controlling the residual hydrogen peroxide / sulfuric acid ratio by controlling the opening degree of the needle valve 166 will be described.

[0079] First, the opening of the needle valve 166 associated with the first stop valve 114 is changed to various values ​​to perform pseudo allocation and processing of the wafer W, and the film thickness profiles in the radial direction of the wafer W before and after the processing are compared to obtain the relationship between the opening of the needle valve 166 and the etching profile in the radial direction of the wafer W. A function or table expressing the relationship between the opening of the needle valve 166 and the etching profile in the radial direction of the wafer W is created and stored in, for example, the storage unit 19 of the control device 4.

[0080] In one embodiment, when the wafer W is actually processed, the control device 4 acquires pre-processing film thickness profile data representing the film thickness distribution in the radial direction of the etching target film existing on the wafer W before the processing. The pre-processing film thickness profile data can be acquired by acquiring from a host computer using communication, by receiving inspection data from an independent film thickness inspection device, or by input by an operator via a user interface (not shown).

[0081] Next, the control device 4 obtains the processed target film thickness profile data representing the target value of the film thickness distribution in the radial direction of the etching target film present on the wafer W after the treatment. The processed target film thickness profile corresponds to, for example, a uniform film thickness distribution in the radial direction. The processed target film thickness profile data does not need to be newly obtained each time a wafer W is processed. For example, in the case where a uniform film thickness profile is generally desired, it is sufficient to input some data that enables the control device 4 to identify the desired uniform film thickness profile at the start of the operation of the substrate processing system 1 or at the start of processing a new batch of wafers W. Based on the existence of such some data inputs, the control device 4 is deemed to have obtained the processed target film thickness profile data. In the case where the film thickness distribution in the radial direction before the treatment is uneven, the control device 4 refers to the above-mentioned function or table to determine the opening of the needle valve 166, which is an opening that can obtain the distribution of the etching amount in the radial direction (etching profile) that eliminates the unevenness. Then, the control device 4 operates the actuator 168 to achieve the determined angle of the needle valve 166.

[0082] Below, refer to Figures 4 to 8 , to illustrate the experimental results obtained by finding the relationship between the opening of the needle valve 166 and the etching profile in the radial direction of the wafer W. The experiment was conducted using Figure 3 In addition, for the convenience of the experiment, the actuator 168 was not installed on the needle valve 166, but an operating knob was installed, and the opening degree was changed by rotating the operating knob. Figures 4 to 7 The graphs are based on data obtained from the same experiment.

[0083] exist Figures 4 to 7 In the graph, line graph (1) shows the test results when the opening of the needle valve 166 is set to the standard opening (hereinafter, for the sake of convenience, also referred to as "condition 1"), line graph (2) shows the test results when the operating knob is set to be turned 0.8 turns from the standard opening in the opening direction (hereinafter, for the sake of convenience, also referred to as "condition 2"), and line graph (3) shows the test results when the operating knob is set to be turned 1.6 turns from the standard opening in the opening direction (hereinafter, for the sake of convenience, also referred to as "condition 3").

[0084] Figure 4 1 is a graph showing the experimental results of investigating the relationship between the opening degree of the needle valve 166 and the pressure detected by the pressure gauge 164. Figure 4 The horizontal axis of the graph of is pseudo-allocated from about 4 seconds to about 9 seconds. Figure 4 At the time point of 9 seconds in the graph of , the on-off valve 162 is closed and the on-off valve 171 is opened to end the pseudo distribution. Figure 4 The pressure change detected by the pressure gauge 164 at this time is shown in FIG.

[0085] From Figure 4 the line graphs (1) to (3) of the diagrams, it can be seen that the greater (smaller) the opening degree of the needle valve 166, the steeper (gentler) the decrease in the detected pressure of the pressure gauge 164. At this time, the nozzle 40 where pseudo-distribution was taking place was photographed with a camera, and the time from the time point when the on-off valve 162 was closed and the on-off valve 171 was opened to the time point when the ejection of the liquid from the nozzle 40 completely stopped (hereinafter, also simply referred to as "liquid draining time (Japanese: 液切れ時間)") was investigated. The liquid draining time in the case of line graph (1) was 1.57 seconds, the liquid draining time in the case of line graph (2) was 1.13 seconds, and the liquid draining time in the case of line graph (3) was 0.85 seconds.

[0086] It is obvious that the difference in this liquid draining time depends on the valve closing speed of the first stop valve 114 (since the valve closing speed of the second stop valve is set to be fixed). It is obvious that the larger (the liquid draining time), the larger (smaller) the residual hydrogen peroxide / sulfuric acid ratio.

[0087] Figure 5 The graph shows the change over time of the temperature of the mixed liquid of sulfuric acid and hydrogen peroxide supplied to the wafer W immediately after the actual start of the processing of the wafer W. From Figure 5 the line graphs (1) to (3) of the diagrams, it can be seen that when the opening degree of the needle valve 166 is small (large) and thus the residual hydrogen peroxide / sulfuric acid ratio is large (small), the temperature of the mixed liquid medicine ejected from the nozzle 40 immediately after the actual start of the processing of the wafer W is high (low).

[0088] Figure 6 The graph shows the radial distribution (etching profile) of the etching amount after the actual processing of the wafer W when the wafer with a TiN film formed on its surface is subjected to SPM etching. In addition, Figure 6 in the diagrams, the actual experimental results themselves are not shown. The position of line graph (1) is fixed and line graphs (2) and (3) are appropriately shifted up and down so that the etching amounts at the periphery of the wafer W are the same. That is, Figure 6 the diagrams can also be said to be diagrams showing the difference between the etching amount at the peripheral part of the wafer W and the etching amount of other parts (especially the central part) under each condition. From Figure 6 the diagrams, it can be seen that the residual hydrogen peroxide / sulfuric acid ratio has a particularly large influence on the etching amount of the central part of the wafer W. From Figure 6 the line graphs (1) to (3) of the diagrams, it can be seen that when the opening degree of the needle valve 166 is small (large) and thus the residual hydrogen peroxide / sulfuric acid ratio is large (small), the etching amount of the central part of the wafer W becomes large (small).

[0089] Figure 7 The graph shows the above-mentioned "liquid draining time" and the etching amount at the center of the wafer W (which is from Figure 6 The relationship between Figure 7 As can be seen from the graph, there is a roughly linear relationship between the liquid draining time and the etching amount at the center of the wafer W. The longer (shorter) the liquid draining time is, the greater (smaller) the etching amount at the center of the wafer W is.

[0090] Figure 8 The relationship between the “decay rate” and the “liquid drain time” when the opening degree of the needle valve 166 is changed to various values ​​is shown.

[0091] Here, the "decay rate" refers to the value detected by the pressure gauge 164. Figure 4 The numerical value of the index of the pressure drop mode and drop speed as shown in the line graphs (1) to (3). Figure 4 , three attenuation curves (ie, pressure drop curves) corresponding to three different openings of the needle valve 166 are depicted, but fifteen attenuation curves (ie, pressure drop curves) corresponding to fifteen different openings of the needle valve 166 can be obtained through experiments, for example.

[0092] Here, it is assumed that the pressure drop with time detected by the pressure gauge 164 corresponds to an exponential decrease, and as a function showing the exponential decrease, for example, the following function is defined.

[0093]

Number 1

[0094] N(t))=bboexp(bt)

[0095] In the above formula, "t" is the time from the time when the pressure drop starts, N(t) is the pressure after time t, b0 is the intercept, and b1 is the decay rate [s- 1 ]. In addition, the intercept b0 is the pressure value at t=0 and is therefore common to all fifteen decay curves.

[0096] The above function is fitted to the 15 pressure drop curves (the time variation of the pressure detected by the pressure gauge 164) corresponding to the 15 different openings of the needle valve 166 to determine the parameters b0 and b1 in the above formula. The b1 thus obtained is Figure 8 The attenuation rate is shown on the horizontal axis. Various programs are known as programs for fitting a function, and many of the known programs use the least squares method for fitting.

[0097] The definition of "liquid drain time" is as described above. Since the valve closing condition (valve closing speed) of the second stop valve 124 is not changed, the "liquid drain time" changes only depending on the change of the valve closing speed of the first stop valve 114. When obtaining data related to the above-mentioned "attenuation rate", the "liquid drain time" corresponding to the fifteen different openings of the needle valve 166 is also obtained.

[0098] By mastering Figure 8 The relationship between the attenuation rate and the liquid draining time as shown in the graph of can be used to monitor the temporal change of the detection value of the pressure gauge 164 (or by monitoring the attenuation rate calculated based thereon), so as to confirm whether the liquid draining time is correctly managed when the pseudo-distribution is performed immediately before the actual processing of the wafer W. The control device 4 can, for example, terminate the processing of the wafer W that should be performed immediately after the pseudo-distribution when it is determined that the temporal change or attenuation rate of the detection value of the monitored pressure gauge 164 is inappropriate. In addition, in the case of termination, an alarm can be generated for the operator. Alternatively, the control device 4 can also change the opening of the needle valve 166 based on the data of the monitored pressure gauge 164 and perform the pseudo-distribution again.

[0099] If it is desired to manage the liquid drain time itself during normal operation of the substrate processing system (processing unit 16), it is necessary to provide a camera capable of photographing the nozzle 40 performing pseudo-dispensing, or to provide a liquid ejection sensor (such a structure can also be adopted). The camera or the liquid ejection sensor may need to be cleaned regularly. In contrast, it is considered that the method of monitoring the detection value of the pressure gauge 164 can save the work of device management.

[0100] According to the above description, the change of the detection value of the pressure gauge 164 over time, the attenuation rate, the liquid draining time and the etching profile accompanying the change of the opening of the needle valve 166 are obvious. Various controls can be performed using the relationship between these parameters. In addition, the etching profile can be simplified as the difference between the etching amount of the etching target film in the center of the wafer W and the etching amount of the etching target film in the peripheral portion of the wafer W. In other words, the pre-processing film thickness profile data related to the etching target film existing on the wafer W before processing can also be simplified as the difference between the film thickness of the etching target film in the center of the wafer W and the film thickness of the etching target film in the peripheral portion of the wafer W. If it is desired to make the film thickness distribution after processing uniform, it is also possible to determine a simplified etching profile (the difference in etching amount between the peripheral portion and the central portion) that eliminates the film thickness difference between the peripheral portion and the central portion based on the simplified pre-processing film thickness profile data (the difference in film thickness between the peripheral portion and the central portion), and determine the opening of the needle valve 166 based on the etching profile.

[0101] According to the above-mentioned embodiment, the etching profile can be changed by controlling the closing speed of the stop valve during pseudo-distribution. Therefore, the control performed when the chemical solution is actually supplied to the wafer W can be simplified. If you want to obtain the same effect as the opening adjustment of the needle valve 166 in the above-mentioned embodiment, you must perform precise opening control of the flow control valve 113 (or 123) when the chemical solution starts to be sprayed from the nozzle 40 or immediately after the chemical solution starts to be sprayed from the nozzle 40, but such an operation is not required in the above-mentioned embodiment. In addition, even if the opening of the needle valve 166 is changed, the composition of the chemical solution (a mixture of sulfuric acid and hydrogen peroxide) when it is sprayed from the nozzle 40 is not affected (except immediately before the spraying stops), so it is impossible to have an adverse effect on the processing of the wafer W when the wafer W is actually processed.

[0102] According to the above-mentioned embodiment, the etching profile is changed by controlling the valve closing speed of the stop valve (first stop valve 114) during pseudo-dispensing, but it is not limited to this. When a plurality of substrates are processed one after another in the processing unit 16, the etching profile of the wafer W (first substrate) to be processed next in the processing unit 16 can also be adjusted by controlling the valve closing speed of the stop valve 114 when the wafer W (second substrate) to be processed immediately before the substrate W to be processed is processed in the processing unit 16. That is, the residual hydrogen peroxide / sulfuric acid ratio after the processing of the second substrate (before the processing of the first substrate) can be adjusted by controlling the valve closing speed of the first stop valve 114 when the spraying of the liquid sprayed from the nozzle 40 for the processing of the second substrate is stopped. That is, the etching profile can be adjusted in the same way as the case of controlling the valve closing speed of the stop valve 114 during pseudo-dispensing. In this case, pseudo-dispensing can also be omitted.

[0103] In addition, in this case, the mixing ratio of hydrogen peroxide and sulfuric acid immediately before the end of spraying the mixed liquid from the nozzle 40 to the second substrate (wafer W) changes according to the closing speed of the first stop valve 114, but this hardly becomes a problem. This is because, at this point in time, the entire surface of the second substrate is covered with a liquid film of a mixed liquid (mixed liquid) of sulfuric acid and hydrogen peroxide at a temperature sufficiently high at a specified mixing ratio. In addition, if this is considered a problem, it can also be set to sweep the nozzle 40 out (move the nozzle 40 to a position outside the periphery of the wafer W when viewed from above) immediately before the end of spraying the liquid from the nozzle 40, so that the mixed liquid that does not have the specified mixing ratio does not fall on the second substrate. Instead of sweeping the nozzle 40 out, it is also possible to stop spraying the liquid from the nozzle 40 while the nozzle 40 is located directly above the edge removal area.

[0104] In the above-mentioned embodiment, the valve closing speed of the first stop valve 114 of the first raw liquid flow path 111 responsible for the supply of hydrogen peroxide is controlled, and the valve closing speed of the second stop valve 124 of the second raw liquid flow path 121 is set to be fixed, but the present invention is not limited to this. The valve closing speed of the second stop valve 124 of the second raw liquid flow path 121 responsible for the supply of sulfuric acid may be controlled, and the valve closing speed of the first stop valve 114 of the first raw liquid flow path 111 may be set to be fixed. It is also possible to control the valve closing speeds of both the first stop valve 114 and the second stop valve 124, but the control becomes complicated, so it is preferable to control the valve closing speed of only one side.

[0105] In the above-mentioned embodiment, hydrogen peroxide and sulfuric acid are used as examples of the first raw material liquid and the second raw material liquid, but the present invention is not limited thereto. In the above-mentioned embodiment, as the first raw material liquid and the second raw material liquid, it is beneficial to mix the first raw material liquid and the second raw material liquid just before being ejected from the nozzle toward the wafer W and the mixing ratio of the first raw material liquid and the second raw material liquid has a relatively large influence on the etching profile. The number of mixed raw material liquids is not limited to two, and three or more raw material liquids may be mixed just before being ejected from the nozzle toward the wafer W.

[0106] One of the multiple raw material liquids may also be water. Sometimes the dissociation degree changes according to the mixing ratio of the liquid and water, causing the etching rate to change. In addition, when the mixing of the liquid and water is an exothermic reaction, sometimes the temperature of the mixed liquid changes according to the mixing ratio, causing the etching rate to change. Therefore, when one of the multiple raw material liquids is water, it is also beneficial to adjust the ratio of the residual raw material liquid by the method shown in the above embodiment.

[0107] As a combination of two or more raw material solutions as the raw material of the chemical solution, in addition to the combination of hydrogen peroxide solution and sulfuric acid as the raw material solution of the mixed solution of sulfuric acid and hydrogen peroxide, the following combinations can be exemplified.

[0108] - HF (hydrofluoric acid) and DIW (pure water) as raw materials for DHF (dilute hydrofluoric acid)

[0109] -NH4OH (ammonia water), H2O2 (hydrogen peroxide) and DIW as raw materials of SC1

[0110] -HCl (hydrochloric acid), H2O2 (hydrogen peroxide) and DIW as raw materials of SC2

[0111] -HCl and DIW as raw materials for DHCl (dilute hydrochloric acid)

[0112] The substrate to be processed is not limited to a semiconductor wafer, but may be another type of substrate having a film to be etched formed on the surface, such as a ceramic substrate, a glass substrate, or the like.

[0113] The embodiments disclosed herein are illustrative in all respects and should not be construed as restrictive. The embodiments described above may be omitted, replaced, or modified in various ways without departing from the appended claims and the gist thereof.

[0114] Description of Reference Numerals

[0115] 4: control unit (control device); 40: nozzle; 111: first raw material liquid flow path; 121: second raw material liquid flow path; 141: drug liquid flow path; 114: stop valve (first stop valve); 160: air passage; 166: needle valve; 168: actuator.

Claims

1. A substrate processing device, comprising: a substrate holding and rotating portion that holds a substrate and rotates the substrate; a nozzle configured to eject a liquid obtained by mixing at least a first raw material liquid and a second raw material liquid toward the substrate held by the substrate holding portion; a nozzle arm that supports the nozzle and moves the nozzle; A liquid medicine supply mechanism supplies the liquid medicine to the nozzle, the liquid medicine supply mechanism comprising: a first raw material liquid flow path, which is used to supply the first raw material liquid; a second raw material liquid flow path, which is used to supply the second raw material liquid; a liquid medicine flow path connected to the first raw material liquid flow path and the second raw material liquid flow path, and connected to the nozzle; A first stop valve, which is provided in the first raw material liquid supply path and is constituted by a pneumatic valve; a second stop valve, which is provided in the second raw material liquid supply path; an air passage connected to the first stop valve and configured to allow at least the air exhausted from the stop valve to flow when the first stop valve is switched from an open valve state to a closed valve state; a needle valve disposed in the air passage and capable of adjusting a closing speed of the stop valve by adjusting an exhaust resistance of air exhausted from the stop valve; as well as an actuator, which is used to adjust the opening of the needle valve; as well as a control unit for controlling the operation of the substrate processing device, The control unit is configured to cause the substrate processing device to perform the following processing: acquiring pre-processing film thickness profile data representing a film thickness distribution in a radial direction of the substrate of an etching target film existing on the first substrate before processing; adjusting the opening of the needle valve to a first opening by means of the actuator based on a difference between post-processing target film thickness profile data representing a target value of film thickness distribution in the radial direction of the substrate of the etching target film present on the first substrate after processing and the pre-processing film thickness profile data; Before ejecting the chemical liquid from the nozzle toward the first substrate, ejecting the chemical liquid from the nozzle toward an ejection destination different from the first substrate, and stopping ejecting the chemical liquid from the nozzle in a state where the opening of the needle valve is adjusted to the first opening, thereby causing the first raw material liquid and the second raw material liquid to remain in the chemical liquid flow path and the first raw material liquid flow path between the first shut-off valve and the nozzle and in the chemical liquid flow path and the second raw material liquid flow path between the second shut-off valve and the nozzle at a ratio corresponding to the opening of the needle valve; and After stopping the spraying of the chemical liquid from the nozzle to the spraying destination different from the first substrate, the first stop valve and the second stop valve are opened while the substrate is rotated by the substrate holding rotating part and the nozzle is located above the center of the first substrate, thereby supplying a mixed solution of the first raw material liquid and the second raw material liquid remaining in the chemical liquid flow path and the first raw material liquid flow path between the first stop valve and the nozzle and in the chemical liquid flow path and the second raw material liquid flow path between the second stop valve and the nozzle to the center of the first substrate from the nozzle, thereby starting the etching process of the etching object film on the first substrate.

2. The substrate processing apparatus according to claim 1, wherein: The first raw material liquid is one of sulfuric acid and hydrogen peroxide, and the second raw material liquid is the other of sulfuric acid and hydrogen peroxide.

3. The substrate processing apparatus according to claim 1, wherein: A pressure sensor is further provided, the pressure sensor being provided in the air passage at a first position between the first stop valve and the needle valve and capable of detecting a pressure change at the first position of the air passage, The control unit monitors the detection value of the pressure sensor at least when closing the first stop valve to end the discharge of the chemical solution from the nozzle to the discharge destination different from the first substrate, and determines based on the monitoring result whether the closing action of the first stop valve is performed as intended.

4. The substrate processing apparatus according to claim 3, wherein: When the control unit determines based on the monitoring result that the valve closing operation of the first shutoff valve is not being performed as intended, the control unit generates an alarm in the substrate processing apparatus without causing the substrate processing apparatus to start etching the etching target film on the substrate.

5. The substrate processing apparatus according to claim 3, wherein: The discharge destination different from the first substrate is a dummy dispensing port, and the discharge of the chemical liquid from the nozzle to the dummy dispensing port is dummy dispensing. When the control unit determines based on the monitoring result that the valve closing operation of the first stop valve is not being performed as intended, the control unit changes the opening degree of the needle valve based on the monitoring result and causes the substrate processing apparatus to perform dummy allocation again.

6. The substrate processing apparatus according to claim 1, wherein: The device further comprises an imaging device capable of detecting a state of a dripping liquid hanging from the nozzle generated when the discharge of the chemical liquid from the nozzle to the discharge destination different from the first substrate is completed, The control unit monitors the state of the dripping liquid by the camera device at least when the first stop valve is closed to end the ejection of the mixed liquid from the nozzle to the ejection destination different from the first substrate, and determines whether the closing action of the first stop valve is performed as intended based on the monitoring result.

7. The substrate processing apparatus according to any one of claims 1 to 4 and 6, wherein: The ejection destination different from the first substrate is a dummy distribution port.

8. The substrate processing apparatus according to any one of claims 1 to 6, wherein: The ejection destination different from the first substrate is a second substrate which is held by the substrate holding and rotating portion immediately before the etching process of the first substrate and is subjected to the same etching process as the first substrate.

9. A substrate processing method, comprising: using a substrate processing apparatus to process a substrate having an etching target film formed on a surface thereof using a chemical solution, the substrate processing apparatus comprising: a substrate holding and rotating portion that holds a substrate and rotates the substrate; a nozzle configured to eject a liquid obtained by mixing at least a first raw material liquid and a second raw material liquid toward the substrate held by the substrate holding portion; a nozzle arm that supports and moves the nozzle; and A liquid medicine supply mechanism supplies the liquid medicine to the nozzle, the liquid medicine supply mechanism comprising: a first raw material liquid flow path, which is used to supply the first raw material liquid; a second raw material liquid flow path, which is used to supply the second raw material liquid; a liquid medicine flow path connected to the first raw material liquid flow path and the second raw material liquid flow path, and connected to the nozzle; A first stop valve, which is provided in the first raw material liquid supply path and is constituted by a pneumatic valve; a second stop valve, which is provided in the second raw material liquid supply path; an air passage connected to the first stop valve and configured to allow at least air exhausted from the stop valve to flow when the first stop valve is switched from an open state to a closed state; a needle valve disposed in the air passage and capable of adjusting a closing speed of the stop valve by adjusting an exhaust resistance of air exhausted from the stop valve; as well as an actuator for adjusting the opening of the needle valve, The substrate processing method comprises: acquiring pre-processing film thickness profile data representing a film thickness distribution in a radial direction of the substrate of an etching target film existing on the first substrate before processing; adjusting the opening of the needle valve to a first opening by means of the actuator based on a difference between post-processing target film thickness profile data representing a target value of film thickness distribution in the radial direction of the substrate of the etching target film present on the first substrate after processing and the pre-processing film thickness profile data; Before ejecting the chemical liquid from the nozzle toward the first substrate, ejecting the chemical liquid from the nozzle toward an ejection destination different from the first substrate, and stopping ejecting the chemical liquid from the nozzle in a state where the opening of the needle valve is adjusted to the first opening, thereby causing the first raw material liquid and the second raw material liquid to remain in the chemical liquid flow path and the first raw material liquid flow path between the first shut-off valve and the nozzle and in the chemical liquid flow path and the second raw material liquid flow path between the second shut-off valve and the nozzle at a ratio corresponding to the opening of the needle valve; and After stopping the spraying of the chemical liquid from the nozzle to the spraying destination different from the first substrate, the first stop valve and the second stop valve are opened while the first substrate is rotated by the substrate holding rotating part and the nozzle is located above the center of the first substrate, thereby supplying a mixed solution of the first raw material liquid and the second raw material liquid remaining in the chemical liquid flow path and the first raw material liquid flow path between the first stop valve and the nozzle and in the chemical liquid flow path and the second raw material liquid flow path between the second stop valve and the nozzle to the center of the substrate from the nozzle, thereby starting the etching process of the etching object film on the first substrate.

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