Substrate processing device and substrate processing method

Abstract

A substrate processing device comprises: a liquid processing section, which includes a substrate holding section for holding a substrate horizontally and a liquid supply section for supplying a processing liquid to the substrate from above the substrate held by the substrate holding section; a liquid preparation section for preparing a processing liquid used in the liquid processing section; and a control section for controlling the liquid supply section and the liquid preparation section, wherein the control section controls the liquid supply section to set a supply speed of the processing liquid such that a flow rate in a vertical direction of the processing liquid from the liquid supply section toward the substrate is faster than a flow rate in a horizontal direction of the processing liquid flowing along the upper surface of the substrate.

Description

Technical Field

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

[0002] For example, in the case of a process requiring a long processing time, a substrate processing device as described in Patent Document 1 is used. The substrate processing device has a processing liquid storage unit for storing a processing liquid for processing a substrate. The processing liquid storage unit has a processing tank for storing the processing liquid, and the substrate is immersed in the processing liquid stored in the processing tank for a predetermined time. The substrate is held vertically inside the processing tank, and the processing liquid flows vertically along the surface of the substrate.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-143684 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The present disclosure provides the following technology: without immersing the substrate in a processing liquid, the processing liquid is supplied to the upper surface of a horizontal substrate and the supplied processing liquid is allowed to flow along the upper surface of the substrate, thereby improving the replacement property of the processing liquid and reducing the concentration gradient of the eluted components from the substrate to the processing liquid.

[0008] Solutions for solving problems

[0009] A substrate processing apparatus according to one embodiment of the present disclosure includes:

[0010] a liquid processing unit including a substrate holding unit for holding a substrate horizontally, and a liquid supply unit for supplying a processing liquid to the substrate from above the substrate held by the substrate holding unit;

[0011] a liquid preparation section that prepares a treatment liquid used in the liquid treatment section; and

[0012] a control unit that controls the liquid supply unit and the liquid production unit,

[0013] The control unit controls the liquid supply unit to set the supply speed of the processing liquid so that a vertical flow speed of the processing liquid from the liquid supply unit toward the substrate is faster than a horizontal flow speed of the processing liquid flowing along the upper surface of the substrate.

[0014] Effects of the Invention

[0015] According to one embodiment of the present disclosure, the substrate is not immersed in the processing liquid. When the processing liquid is supplied to the upper surface of the horizontal substrate and the supplied processing liquid is made to flow along the upper surface of the substrate, the replaceability of the processing liquid can be improved, thereby reducing the concentration gradient of the eluted components from the substrate to the processing liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a diagram showing a substrate processing apparatus according to one embodiment.

[0017] Figure 2A This is a cross-sectional view showing a state immediately before processing of a substrate according to one embodiment is started.

[0018] Figure 2B This is a cross-sectional view showing a state immediately before processing of a substrate according to one embodiment is completed.

[0019] Figure 3 This is a diagram of a nozzle according to one embodiment when the nozzle is viewed from below.

[0020] Figure 4 This is a diagram of a nozzle according to a modification example as viewed from below.

[0021] Figure 5 1 is a flowchart showing a method for processing a substrate according to an embodiment.

[0022] Figure 6 This is a flowchart showing the concentration adjustment of the eluted component according to one embodiment.

[0023] Fig. 7A This is a cross-sectional view showing a state of the substrate according to Example 1 after being processed.

[0024] Figure 7B This is a cross-sectional view showing a state of a substrate according to Example 2 after being processed.

[0025] Figure 7C This is a cross-sectional view showing a state of the substrate according to Comparative Example 1 after being processed. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In addition, in each of the drawings, the same or corresponding structures are sometimes denoted by the same reference numerals, and the description thereof is omitted.

[0027] Figure 1 It is a diagram showing a substrate processing apparatus according to one embodiment. Figure 2A This is a cross-sectional view showing a state immediately before processing of a substrate according to one embodiment is started. Figure 2BThis is a cross-sectional view showing a state immediately before processing of a substrate according to one embodiment is completed.

[0028] The substrate processing apparatus 1 processes the substrate 2 using the processing liquid 3. For example Figure 2A As shown, the substrate 2 includes a silicon wafer 21, a silicon oxide film 22, and a silicon nitride film 23. The silicon oxide film 22 and the silicon nitride film 23 are repeatedly and alternately stacked to form a stacked film 24. A conductive film (not shown) and the like are formed between the stacked film 24 and the silicon wafer 21. The stacked film 24 includes an opening 25 that penetrates the stacked film 24 in the thickness direction.

[0029] The treatment liquid 3 is a solution containing phosphoric acid (e.g., a phosphoric acid aqueous solution), and the treatment liquid 3 enters the opening 25 of the laminated film 24 and Figure 2B As shown, the silicon nitride film 23 is selectively etched and removed from the silicon oxide film 22 and the silicon nitride film 23. The etching selectivity is determined by the silicon concentration in the processing liquid 3, etc. The higher the silicon concentration, the higher the selectivity. On the other hand, when the silicon concentration exceeds the saturation concentration, silicon dioxide is precipitated.

[0030] The processing liquid 3 enters the opening 25 of the stacked film 24 and etches the silicon nitride film 23 along the in-plane direction of the silicon nitride film 23. The in-plane direction is a direction orthogonal to the thickness direction. As the etching of the silicon nitride film 23 progresses, silicon is dissolved inside the stacked film 24. The dissolved silicon diffuses to the outside of the stacked film 24 through the opening 25 of the stacked film 24. The deeper the depth from the surface 26 of the stacked film 24 or the farther the distance to the opening 25, the longer the diffusion distance, and therefore the higher the silicon concentration.

[0031] As described above, the silicon concentration varies depending on the location, and the maximum value of the silicon concentration is determined by the pattern 27 of the substrate 2 processed by the processing liquid 3. The processed pattern 27 is a pattern to be removed, that is, a pattern of a path where the dissolved silicon diffuses. The pattern 27 is a three-dimensional pattern.

[0032] The pattern 27 of the substrate 2 includes the number of stacked films 24 (that is, the total number of silicon oxide films 22 and silicon nitride films 23). The greater the number of stacked films 24, the longer the diffusion distance is, and thus the higher the maximum value of the silicon concentration is.

[0033] The pattern 27 of the substrate 2 includes the film thickness T of each silicon nitride film 23 and the width W of the opening 25. The smaller the film thickness T of each silicon nitride film 23 or the narrower the width W of the opening 25, the narrower the width of the silicon diffusion path, and thus the higher the maximum value of the silicon concentration.

[0034] The substrate processing apparatus 1 is an apparatus that improves the replacement property of the processing liquid 3 to reduce the concentration gradient of the eluted component (such as silicon) in the processing liquid 3, thereby suppressing the precipitation of the eluted component. Figure 1 The structure of the substrate processing apparatus 1 will be described.

[0035] The substrate processing apparatus 1 includes a liquid processing unit 5, a liquid preparation unit 6, and a control unit 9. The liquid processing unit 5 processes the substrate 2 using the processing liquid 3. The liquid preparation unit 6 prepares the processing liquid 3 used in the liquid processing unit 5. The control unit 9 controls the liquid processing unit 5 and the liquid preparation unit 6.

[0036] The liquid processing unit 5 includes a substrate holding unit 51 for horizontally holding a single substrate 2 and a liquid supply unit 52 for supplying the processing liquid 3 to the substrate 2 from above the substrate 2 held by the substrate holding unit 51. The substrate holding unit 51 holds the substrate 2 horizontally with the surface of the substrate 2 on which the pattern 27 is formed facing upward. The substrate holding unit 51 is a mechanical chuck, a vacuum chuck, or an electrostatic chuck.

[0037] The liquid supply unit 52 includes a first nozzle 521 for ejecting the processing liquid 3. In addition, the liquid supply unit 52 includes a liquid delivery path 522 for delivering the processing liquid 3 produced by the liquid production unit 6 to the first nozzle 521, and also includes, for example, a first opening and closing valve 523, a flow meter 524, a flow controller 525, and a second opening and closing valve 526 in the middle of the liquid delivery path 522.

[0038] When the processing liquid 3 is to be ejected from the first nozzle 521, the control unit 9 opens the first opening and closing valve 523 and the second opening and closing valve 526, and controls the flow controller 525 so that the measured value of the flow meter 524 becomes the set value. The supply amount of the processing liquid 3 supplied from the first nozzle 521 to the substrate 2 is equal to the measured value of the flow meter 524. On the other hand, when the ejection of the processing liquid 3 from the first nozzle 521 is to be stopped, the control unit 9 closes the first opening and closing valve 523 and the second opening and closing valve 526.

[0039] like Figure 2B As shown, the control unit 9 controls the liquid supply unit 52 to set the supply speed of the processing liquid 3 such that the vertical flow speed V1 of the processing liquid 3 from the first nozzle 521 of the liquid supply unit 52 toward the substrate 2 is faster than the horizontal flow speed V2 of the processing liquid 3 flowing along the upper surface of the substrate 2. The vertical flow speed V1 and the horizontal flow speed V2 are measured in a coordinate system fixed to the substrate 2, for example, when the substrate 2 rotates, the measurement is performed in a coordinate system that rotates together with the substrate 2.

[0040] The vertical flow velocity V1 can be represented by the flow velocity directly below the ejection port of the first nozzle 521. 3 / sec) and the area of ​​the nozzle (m 2) etc. When there are a plurality of discharge ports, the flow rate of the treatment liquid 3 is the total flow rate, and the area of ​​the discharge ports is the total area.

[0041] The horizontal flow velocity V2 is measured, for example, by computer simulation analysis such as the VOF (Volume Of Fluid) method, or by image analysis of an image captured by a camera. The horizontal flow velocity V2 is determined by the flow rate of the processing liquid 3 ejected from the first nozzle 521, the rotation speed of the substrate 2, and the distance to the rotation center of the substrate 2.

[0042] The horizontal flow velocity V2 can be decomposed into a circumferential flow velocity V2A and a radial flow velocity V2B. When the substrate 2 rotates, the circumferential flow velocity V2A is dominant, so only the circumferential flow velocity V2A can be simply used as the horizontal flow velocity V2.

[0043] When the substrate 2 rotates, the circumferential flow velocity V2A depends on the distance from the rotation center of the substrate 2. The greater the distance from the rotation center of the substrate 2, the faster the circumferential flow velocity V2A. Therefore, if the vertical flow velocity V1 is made faster than the circumferential flow velocity V2A at the periphery of the substrate 2, the overall vertical flow velocity V1 of the substrate 2 is also faster than the circumferential flow velocity V2A.

[0044] Therefore, it is sufficient that the vertical flow velocity V1 is faster than the horizontal flow velocity V2 at the periphery of the area where the pattern 27 is formed on the upper surface of the substrate 2. In addition, it is sufficient that V1 is faster than V2 at the area where the pattern 27 needs to be etched, and it is not necessary to make V1 faster than V2 at the periphery of the upper surface of the substrate 2 where the pattern 27 is not formed.

[0045] According to this embodiment, the vertical flow velocity V1 is faster than the horizontal flow velocity V2. Therefore, for example, when the processing liquid 3 is supplied from directly above the opening 25 of the stacked membrane 24, the flow rate of the processing liquid 3 flowing into the interior of the opening 25 is greater than the flow rate of the processing liquid 3 that does not flow into the interior of the opening 25 but flows along the surface 26 of the stacked membrane 24.

[0046] In addition, according to Patent Document 1, as described above, the substrate 2 is held vertically inside the processing tank, and the processing liquid 3 flows vertically along the surface of the substrate 2. In this case, even if the vertical flow velocity V1 is increased, since the opening 25 extends in the horizontal direction, the amount of the processing liquid 3 flowing into the opening 25 remains almost unchanged.

[0047] In contrast, according to the present embodiment, as described above, the substrate 2 is held horizontally, and the vertical flow velocity V1 is faster than the horizontal flow velocity V2, so the flow rate of the processing liquid 3 flowing into the opening 25 extending in the vertical direction is large. As a result, the replacement of the processing liquid 3 inside the pattern 27 of the substrate 2 can be improved, thereby reducing the excessive rise of the eluted component eluted from the substrate 2 to the processing liquid 3. Therefore, the maximum value of the eluted component can be reduced, thereby suppressing the precipitation of the eluted component.

[0048] Figure 3 FIG. 2 is a diagram showing a nozzle according to an embodiment of the present invention as viewed from below. Figure 3 As shown, the first nozzle 521 may be a shower head nozzle in which the ejection ports 521 a of the processing liquid 3 are two-dimensionally dispersed. The shower head nozzle ejects the processing liquid 3 in a shower form from the plurality of ejection ports 521 a toward the substrate 2 .

[0049] The shower head nozzle supplies the processing liquid 3 to multiple points on the upper surface of the substrate 2, so that the replaceability of the processing liquid 3 inside the pattern 27 of the substrate 2 can be improved at multiple points on the upper surface of the substrate 2, thereby reducing the excessive concentration increase of the dissolved components dissolved from the substrate 2 to the processing liquid 3. Therefore, the maximum value of the dissolved components can be reduced at multiple points on the upper surface of the substrate 2, thereby suppressing the precipitation of the dissolved components.

[0050] A plurality of ejection ports 521a are two-dimensionally dispersed in a circular region A on the lower surface of the shower head nozzle. If the diameter of the region A is smaller than the diameter of the substrate 2, it is possible to prevent the processing liquid 3 from flowing outside the substrate 2 without hitting the substrate 2, thereby wasting the processing liquid 3, and to reduce the amount of processing liquid 3 used. The diameter of the region A is, for example, greater than 90% of the diameter of the substrate 2 and less than 100% of the diameter.

[0051] Figure 4 This is a view of a nozzle according to a modified example when the nozzle is viewed from below. Figure 4 As shown, the first nozzle 521 may be a strip-shaped nozzle in which the ejection outlets 521a of the processing liquid 3 are arranged in a row. The strip-shaped nozzle is arranged along the diameter of the substrate 2, and the supply points of the processing liquid 3 are arranged along the diameter of the substrate 2. In addition, the number of rows of the ejection outlets 521a formed in the strip-shaped nozzle is not limited to one row, and may be a plurality of rows.

[0052] The strip nozzle supplies the processing liquid 3 to multiple points on the upper surface of the rotating substrate 2, so that the replaceability of the processing liquid 3 inside the pattern 27 of the substrate 2 can be improved at multiple points on the upper surface of the substrate 2, thereby reducing the excessive concentration increase of the eluted components eluted from the substrate 2 to the processing liquid 3. Therefore, the maximum value of the eluted components can be reduced at multiple points on the upper surface of the substrate 2, thereby suppressing the precipitation of the eluted components.

[0053] The plurality of ejection ports 521a are arranged in one or more rows in the rod-shaped region A on the lower surface of the strip-shaped nozzle. If the length of the region A is smaller than the diameter of the substrate 2, it is possible to prevent the processing liquid 3 from flowing outside the substrate 2 without hitting the substrate 2, thereby wasting the processing liquid 3, and to reduce the amount of processing liquid 3 used. The length of the region A is, for example, greater than 90% of the diameter of the substrate 2 and less than 100% of the diameter.

[0054] like Figure 1 As shown, the liquid supply unit 52 may also have a second nozzle 527 for ejecting a rinsing liquid such as DIW (Deionized Water) separately from the first nozzle 521. The second nozzle 527 may be a shower head nozzle similar to the first nozzle 521, or may be a common nozzle, that is, it may be a nozzle for supplying a rinsing liquid to a point on the upper surface of the substrate 2. While the first nozzle 521 is supplying the processing liquid 3 to the substrate 2, the second nozzle 527 is on standby at a radially outer standby position of the substrate 2. Thereafter, when the first nozzle 521 is at the radially outer standby position of the substrate 2, the second nozzle 527 moves to a position directly above the center of the substrate 2, and supplies a rinsing liquid to the substrate 2 to flush away the processing liquid 3 remaining on the substrate 2. Unlike the case where the first nozzle 521 ejects both the processing liquid 3 and the rinsing liquid, there is no need to perform liquid replacement inside the first nozzle 521, and there is no need for the waiting time spent on the liquid replacement.

[0055] In addition, the liquid supply unit 52 may also have a third nozzle 528 for spraying a liquid other than the processing liquid 3, which is separate from the first nozzle 521. The third nozzle 528 may be a shower head nozzle similar to the first nozzle 521, or may be a common nozzle similar to the second nozzle 527, that is, it may be a nozzle for supplying a liquid to a point on the upper surface of the substrate 2. When the processing liquid 3 is an aqueous phosphoric acid solution, as the liquid other than the processing liquid 3, for example, one or more liquids selected from DHF (dilute hydrofluoric acid), SC1 (aqueous solution containing hydrogen peroxide and ammonium hydroxide), and SC2 (aqueous solution containing hydrogen peroxide and hydrochloric acid) are used. When a plurality of liquids are used, a third nozzle 528 may be prepared for each solution.

[0056] The liquid processing unit 5 further includes a driving unit 53 that performs at least one of rotation and movement of the substrate holding unit 51 and rotation and movement of the liquid supply unit 52 in such a manner that the supply point of the processing liquid 3 on the upper surface of the substrate 2 is displaced over time. The supply point is the intersection of an extension line of the ejection port 521a in the ejection direction thereof and the upper surface of the substrate 2.

[0057] The driving unit 53 is a motor, for example, and only rotates the substrate holding unit 51. The rotation center of the substrate holding unit 51 is arranged to pass through the center of the substrate 2. Since the substrate 2 rotates together with the substrate holding unit 51, the supply point of the processing liquid 3 on the upper surface of the substrate 2 shifts over time.

[0058] In the present embodiment, the driving unit 53 only rotates the substrate holding unit 51, but as described above, it is sufficient to perform at least one of the rotation and movement of the substrate holding unit 51 and the rotation and movement of the liquid supply unit 52. It is sufficient that the supply point of the processing liquid 3 on the upper surface of the substrate 2 is shifted over time.

[0059] As long as the supply point of the processing liquid 3 on the upper surface of the substrate 2 is shifted over time, the replaceability of the processing liquid 3 inside the pattern 27 of the substrate 2 can be improved at more points on the upper surface of the substrate 2, thereby reducing the excessive concentration increase of the eluted components eluted from the substrate 2 to the processing liquid 3. Therefore, the maximum value of the eluted components can be reduced at more points on the upper surface of the substrate 2, thereby suppressing the precipitation of the eluted components.

[0060] In addition, when the driving unit 53 rotates the substrate holding unit 51, the substrate 2 rotates together with the substrate holding unit 51, so that centrifugal force acts on the liquid film of the processing liquid 3 formed on the upper surface of the substrate 2. The centrifugal force increases the horizontal flow velocity V2. In this way, the horizontal flow velocity V2 may be increased due to the action performed by the driving unit 53.

[0061] Therefore, the control unit 9 controls the liquid supply unit 52 and the driving unit 53 to set the supply speed of the processing liquid 3 and the speed of the action so that the vertical flow velocity V1 is faster than the horizontal flow velocity V2. As described above, the action is at least one of the rotation and movement of the substrate holding unit 51 and the rotation and movement of the liquid supply unit 52. For example, the control unit 9 can slow down the horizontal flow velocity V2 by reducing the rotation speed of the substrate holding unit 51.

[0062] Alternatively, the driving unit 53 may perform at least one of the rotation and movement of the liquid supply unit 52 in a state where the substrate holding unit 51 is stopped, so as to suppress the increase in the horizontal flow velocity V2. The rotation and movement of the liquid supply unit 52 in the operation performed by the driving unit 53 hardly increase the horizontal flow velocity V2 compared with the rotation and movement of the substrate holding unit 51. This is because, for example, even if the liquid supply unit 52 is rotated, centrifugal force will not act on the liquid film of the processing liquid 3 formed on the upper surface of the substrate 2 unless the substrate holding unit 51 is rotated.

[0063] Furthermore, during the period when the substrate 2 is processed by the processing liquid 3, neither the rotation and movement of the substrate holding portion 51 nor the rotation and movement of the liquid supply portion 52 is performed. In this case, the supply point of the processing liquid 3 on the upper surface of the substrate 2 does not shift with time, and on the contrary, the vertical flow velocity V1 can be made faster than the horizontal flow velocity V2 more reliably.

[0064] Furthermore, while the substrate 2 is being processed by the processing liquid 3, the processing liquid 3 flows along the upper surface of the substrate 2 and falls from the periphery of the substrate 2 even if neither the rotation or movement of the substrate holding portion 51 nor the rotation or movement of the liquid supply portion 52 is performed. This is because when new processing liquid 3 is supplied to the upper surface of the substrate 2, the processing liquid 3 originally present on the upper surface of the substrate 2 is squeezed out.

[0065] The liquid processing unit 5 further includes a recovery unit 54 that recovers the processing liquid 3 supplied from the liquid supply unit 52 to the substrate 2. The recovery unit 54 includes, for example, a cup 541 that receives the substrate 2 held by the substrate holding unit 51. The cup 541 recovers the processing liquid 3 spilled from the substrate 2 into the cup 541.

[0066] The cup 541 includes a cylindrical portion 542, a bottom cover portion 543, and an inclined portion 544. The cylindrical portion 542 is arranged vertically and has an inner diameter larger than the diameter of the substrate 2. The bottom cover portion 543 blocks the opening at the lower end of the cylindrical portion 542. The inclined portion 544 is formed over the entire circumference of the upper end of the cylindrical portion 542 and is inclined upward as it goes to the radial inner side of the cylindrical portion 542.

[0067] The recovery unit 54 has a drain pipe 545 and an exhaust pipe 546 at the bottom cover 543 of the cup 541. The drain pipe 545 is used to discharge the processing liquid 3 from the inside of the cup 541 to the outside of the liquid processing unit 5. In addition, the exhaust pipe 546 is used to discharge gas from the inside of the cup 541 to the outside of the liquid processing unit 5.

[0068] As described above, the liquid preparation section 6 prepares the treatment liquid 3 used in the liquid processing section 5. The liquid preparation section 6 includes, for example, a supply tank 61, a first supply device 62, a circulation path 63, and a liquid delivery path 64. The supply tank 61 is used to store the treatment liquid 3. The first supply device 62 supplies the treatment liquid 3 to the supply tank 61. The circulation path 63 is used to return the treatment liquid 3 taken out from the supply tank 61 to the supply tank 61. The liquid delivery path 64 branches off from the middle of the circulation path 63 and is connected to the liquid delivery path 522 of the liquid processing section 5, and is used to deliver the treatment liquid 3 to the liquid delivery path 522.

[0069] In addition, the liquid processing unit 5 Figure 1In this case, the liquid preparation unit 6 prepares the processing liquid 3 used in the plurality of liquid processing units 5. Compared with the case where a supply tank 61 is provided for each liquid processing unit 5, the number of supply tanks 61 can be reduced, and the substrate processing apparatus 1 can be miniaturized.

[0070] The first supplier 62 includes a supply source 621 of the treatment liquid 3 and a pipe 622 extending from the supply source 621 to the supply tank 61. The first supplier 62 also includes a flow meter 623, a flow controller 624, and an on-off valve 625 in the pipe 622, for example.

[0071] When the processing liquid 3 is to be supplied from the supply source 621 to the supply tank 61, the control unit 9 opens the on-off valve 625 and controls the flow controller 624 so that the measured value of the flow meter 623 becomes the set value. The supply amount of the processing liquid 3 supplied from the supply source 621 to the supply tank 61 is equal to the measured value of the flow meter 623. On the other hand, when the supply of the processing liquid 3 from the supply source 621 to the supply tank 61 is to be stopped, the control unit 9 closes the on-off valve 625.

[0072] In addition, the liquid preparation unit 6 includes, for example, a pump 65, a filter 66, and a heater 67 in the middle of the circulation path 63. The pump 65 pressurizes and delivers the treatment liquid 3 along the circulation path 63, and the pump 65 pressurizes and delivers the treatment liquid 3 from the middle of the circulation path 63 to the liquid processing unit 5. The filter 66 collects particles contained in the treatment liquid 3. The heater 67 heats the treatment liquid 3 to a desired temperature.

[0073] When the treatment liquid 3 is a phosphoric acid aqueous solution, the heater 67 heats the phosphoric acid aqueous solution to a boiling point or a temperature slightly lower than the boiling point. After the treatment liquid 3 is heated to a desired temperature by the heater 67 , the treatment liquid 3 is supplied to the liquid processing unit 5 .

[0074] The liquid preparation unit 6 further includes a first concentration meter 68 in the middle of the circulation path 63. The first concentration meter 68 measures the concentration of a first component in the processing liquid 3. The first component is a component eluted from the substrate 2 into the processing liquid 3, for example, silicon. The first concentration meter 68 is provided in the middle of the circulation path 63, so that the silicon concentration of the processing liquid 3 immediately before being supplied to the liquid processing unit 5 can be measured.

[0075] The liquid preparation unit 6 further includes a second concentration meter 69 in the middle of the circulation path 63. The second concentration meter 69 measures the concentration of the second component in the processing liquid 3. The second component is an etching component for etching the substrate 2, for example, phosphoric acid. The second concentration meter 69 is provided in the middle of the circulation path 63, so that the phosphoric acid concentration of the processing liquid 3 immediately before being supplied to the liquid processing unit 5 can be measured.

[0076] In addition, the treatment liquid 3 contains a third component having a lower boiling point than the second component. The third component is, for example, water. The boiling point of water is lower than that of phosphoric acid. The treatment liquid 3 is heated by the heater 67, so that as time passes, the water concentration in the treatment liquid 3 decreases and the phosphoric acid concentration in the treatment liquid 3 increases.

[0077] Therefore, the liquid preparation unit 6 includes a second supplier 71 in addition to the first supplier 62. The second supplier 71 supplies water as a third component to the supply tank 61 to maintain the concentration of phosphoric acid as a second component in the treatment liquid 3 at a desired value. The control unit 9 supplies water from the second supplier 71 to the supply tank 61 so that the measured value of the phosphoric acid concentration becomes a set value.

[0078] The second supplier 71 includes a water supply source 711 and a pipe 712 extending from the supply source 711 to the supply tank 61. The second supplier 71 includes a flow meter 713, a flow controller 714, and an on-off valve 715 in the middle of the pipe 712, for example.

[0079] When water is to be supplied from the supply source 711 to the supply tank 61, the control unit 9 opens the on-off valve 715 and controls the flow controller 714 so that the measured value of the flow meter 713 becomes the set value. The amount of water supplied from the supply source 711 to the supply tank 61 is equal to the measured value of the flow meter 713. On the other hand, when the supply of water from the supply source 711 to the supply tank 61 is to be stopped, the control unit 9 closes the on-off valve 715.

[0080] The liquid preparation unit 6 includes a recovery tank 72 for storing the processing liquid 3 sent from the recovery unit 54 of the liquid processing unit 5. The recovery tank 72 is connected to the cup 541 via a drain pipe 545, for example, to store the processing liquid 3 sent from the cup 541.

[0081] The liquid preparation unit 6 includes a return path 73 for returning the processing liquid 3 stored in the recovery tank 72 to the supply tank 61. The processing liquid 3 stored in the recovery tank 72 can be returned to the supply tank 61 via the return path 73, thereby reducing the amount of waste processing liquid 3.

[0082] The liquid preparation unit 6 includes, for example, an on-off valve 74 and a pump 75 in the middle of the return path 73. When the processing liquid 3 is to be refluxed from the recovery tank 72 to the supply tank 61, the control unit 9 opens the on-off valve 74 and operates the pump 75 to pressurize and transport the processing liquid 3. On the other hand, when the processing liquid 3 is to be stopped from flowing back from the recovery tank 72 to the supply tank 61, the control unit 9 closes the on-off valve 74 and stops the pump 75.

[0083] In addition, the processing liquid 3 is supplied from the supply tank 61 to the liquid processing unit 5, and is supplied to the substrate 2 in the liquid processing unit 5. The processing liquid 3 increases the concentration of the eluted components from the substrate 2, is recovered in the recovery tank 72, and is returned to the supply tank 61 again. Therefore, as the number of substrates 2 to be processed increases, the eluted components from the substrates 2 accumulate in the processing liquid 3, and the concentration of the eluted components in the processing liquid 3 increases.

[0084] Therefore, the liquid preparation unit 6 includes a discharge path 76 for discharging the processing liquid 3 stored in the recovery tank 72 to the outside of the substrate processing apparatus 1. The processing liquid 3 having an excessively high concentration of eluted components can be discharged from the recovery tank 72 through the discharge path 76 to the outside of the substrate processing apparatus 1.

[0085] The liquid preparation unit 6 includes, for example, an on-off valve 77 and a discharge source 78 in the middle of the discharge path 76. The discharge source 78 is an ejector or a pump. When the processing liquid 3 is to be discharged from the recovery tank 72 to the outside of the substrate processing device 1, the control unit 9 opens the on-off valve 77 and operates the discharge source 78 to pressurize and transport the processing liquid. On the other hand, when the processing liquid 3 is to be stopped from being discharged from the recovery tank 72 to the outside of the substrate processing device 1, the control unit 9 closes the on-off valve 77 and stops the discharge source 78.

[0086] The control unit 9 is, for example, a computer, and includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory. The storage medium 92 stores a program for controlling various processes executed in the substrate processing apparatus 1. The control unit 9 controls the operation of the substrate processing apparatus 1 by causing the CPU 91 to execute the program stored in the storage medium 92. In addition, the control unit 9 includes an input interface 93 and an output interface 94. The control unit 9 receives a signal from the outside using the input interface 93, and sends a signal to the outside using the output interface 94.

[0087] The above-mentioned program is stored in, for example, a computer-readable storage medium, and is installed from the storage medium to the storage medium 92 of the control unit 9. Examples of computer-readable storage media include a hard disk (HD), a floppy disk (FD), a compact disk (CD), a magneto-optical disk (MO), a memory card, etc. In addition, the program may be downloaded from a server via the Internet and installed in the storage medium 92 of the control unit 9.

[0088] Figure 5 1 is a flowchart showing a method for processing a substrate according to an embodiment. Figure 5The process shown is performed under the control of the control unit 9. First, the transport device (not shown) transports the substrate 2 into the liquid processing unit 5 (S101). Then, the substrate holding unit 51 receives the substrate 2 from the transport device and holds the substrate 2 horizontally. Thereafter, the transport device is withdrawn to the outside of the liquid processing unit 5.

[0089] Next, the liquid supply unit 52 supplies DHF to the substrate 2 held by the substrate holding unit 51, and processes the substrate 2 with DHF (S102). DHF is ejected from the third nozzle 528 and supplied to the center of the substrate 2 rotating together with the substrate holding unit 51, and spreads by centrifugal force to wet the entire substrate 2. Thereafter, the liquid supply unit 52 stops supplying DHF to the substrate 2.

[0090] Next, the liquid supply unit 52 supplies a rinse liquid to the substrate 2 held by the substrate holding unit 51, and uses the rinse liquid to wash away the DHF remaining on the substrate 2 (S103). The rinse liquid is ejected from the second nozzle 527 and supplied to the center of the substrate 2 rotating together with the substrate holding unit 51, and spreads by centrifugal force to wet the entire substrate 2, thereby replacing the DHF. Thereafter, the liquid supply unit 52 stops supplying the rinse liquid to the substrate 2.

[0091] Next, the liquid supply unit 52 supplies the processing liquid 3 to the substrate 2 held by the substrate holding unit 51, and processes the substrate 2 using phosphoric acid contained in the processing liquid 3 (S104). The processing liquid 3 is ejected from the first nozzle 521 and supplied to the entire substrate 2 rotating at a low speed together with the substrate holding unit 51. The processing liquid 3 enters the opening 25 of the stacked film 24 and etches the silicon nitride film 23 in the in-plane direction of the silicon nitride film 23.

[0092] During the supply of the processing liquid 3 to the substrate 2, the control unit 9 controls the liquid supply unit 52 and the driving unit 53 to set the supply speed of the processing liquid 3 and the rotation speed of the substrate holding unit 51 so that the vertical flow speed V1 is faster than the horizontal flow speed V2. If the rotation speed of the substrate holding unit 51 is reduced, the centrifugal force can be reduced, thereby slowing down the horizontal flow speed V2. Thereafter, the liquid supply unit 52 stops supplying the processing liquid 3 to the substrate 2.

[0093] Next, the liquid supply unit 52 supplies a rinse liquid to the substrate 2 held by the substrate holding unit 51, and uses the rinse liquid to wash away the processing liquid 3 remaining on the substrate 2 (S105). The rinse liquid is sprayed from the second nozzle 527 and supplied to the center of the substrate 2 rotating together with the substrate holding unit 51, and spreads by centrifugal force to wet the entire substrate 2, thereby replacing the processing liquid 3. Thereafter, the liquid supply unit 52 stops supplying the rinse liquid to the substrate 2.

[0094] Next, the liquid supply unit 52 supplies SC1 to the substrate 2 held by the substrate holding unit 51, and processes the substrate 2 using SC1 (S106). SC1 is ejected from the third nozzle 528 and supplied to the center of the substrate 2 rotating together with the substrate holding unit 51, and spreads by centrifugal force to wet the entire substrate 2. Thereafter, the liquid supply unit 52 stops supplying SC1 to the substrate 2.

[0095] Next, the liquid supply unit 52 supplies a rinse liquid to the substrate 2 held by the substrate holding unit 51, and uses the rinse liquid to wash away the SC1 remaining on the substrate 2 (S107). The rinse liquid is ejected from the second nozzle 527 and supplied to the center of the substrate 2 rotating together with the substrate holding unit 51, and spreads by centrifugal force to wet the entire substrate 2, thereby replacing the SC1. Thereafter, the liquid supply unit 52 stops supplying the rinse liquid to the substrate 2.

[0096] Next, the liquid supply unit 52 rotates the substrate 2 together with the substrate holding unit 51 at high speed, and blows off the rinse liquid remaining on the substrate 2 by centrifugal force, thereby drying the substrate 2 ( S108 ). Thereafter, the liquid supply unit 52 stops the rotation of the substrate holding unit 51 .

[0097] Finally, the transport device receives substrate 2 from substrate holding portion 51 and carries substrate 2 out of liquid processing unit 5 ( S109 ).

[0098] In addition, the drying (S108) of the substrate 2 is performed by spin drying in the present embodiment, but it may be performed by IPA drying or supercritical drying, etc. In addition, the drying (S108) of the substrate 2 may be performed after the substrate 2 is unloaded (S109).

[0099] In addition, as described above, the processing liquid 3 is supplied from the supply tank 61 to the liquid processing unit 5, and is supplied to the substrate 2 in the liquid processing unit 5. The processing liquid 3 increases the concentration of the eluted component from the substrate 2, is recovered in the recovery tank 72, and is returned to the supply tank 61 again. Therefore, as the number of processed substrates 2 increases, the eluted component from the substrate 2 accumulates in the processing liquid 3, and the concentration of the eluted component in the processing liquid 3 increases. Therefore, the control unit 9 adjusts the concentration of the eluted component in the processing liquid 3.

[0100] Figure 6 This is a flowchart showing the concentration adjustment of the eluted component according to one embodiment. Figure 6 The operation shown is performed periodically under the control of the control unit 9, for example. First, the first concentration meter 68 measures the concentration of the eluted component in the processing liquid 3 (S201). The eluted component is, for example, silicon.

[0101] Next, the control unit 9 checks whether the measured value C1 of the eluted component concentration exceeds the set value C1. 0 (S202) Regarding the setting value C10 The setting value C1 is set in advance by experiments, etc., so that the eluted component will not precipitate when the substrate 2 is treated with the treatment liquid 3. 0 . Set value C1 0 The value can be set for each pattern 27 of the substrate 2 .

[0102] When the measured value C1 is the set value C1 0 In the following case (S202: "No"), since the concentration of the eluted component is so low that the eluted component will not be precipitated when the substrate 2 is processed by the processing liquid 3, the control unit 9 ends the current processing. In addition, before ending the current processing, the control unit 9 may measure the liquid level in the recovery tank 72 using the liquid level gauge 721, and when the measured value exceeds the upper limit, the liquid preparation unit 6 may be controlled to make the processing liquid 3 flow back from the recovery tank 72 to the supply tank 61. The amount of the reflux may be all of the processing liquid in the recovery tank 72, or a portion of the processing liquid in the recovery tank 72.

[0103] On the other hand, when the measured value C1 exceeds the set value C1 0 In the case of (S202: "Yes"), since the concentration of the eluted component is too high, the control unit 9 controls the liquid preparation unit 6 to discharge the processing liquid 3 from the recovery tank 72 to the outside of the substrate processing apparatus 1 (S203). The amount discharged may be all of the processing liquid in the recovery tank 72, or a portion of the processing liquid in the recovery tank 72.

[0104] The processing liquid 3 in the recovery tank 72 has a higher concentration of eluted components than the concentration of eluted components in the processing liquid 3 in the supply tank 61. This is because, as described above, the processing liquid 3 is supplied from the supply tank 61 to the liquid processing unit 5, supplied to the substrate 2 in the liquid processing unit 5, and the processing liquid 3 is recovered in the recovery tank 72 after increasing the concentration of eluted components from the substrate 2.

[0105] According to this embodiment, the control unit 9 controls the liquid preparation unit 6 to 0 In the case of (S202: Yes), the processing liquid 3 in the recovery tank 72 is discharged to the outside of the substrate processing apparatus 1, and the processing liquid 3 in the supply tank 61 is not discharged. By discharging the processing liquid 3 with a high concentration of the eluted component, the waste amount of the processing liquid 3 used to adjust the concentration of the eluted component can be reduced.

[0106] As described above, the amount discharged may be all of the processing liquid in the recovery tank 72 or a portion of the processing liquid in the recovery tank 72. In the latter case, at least a portion of the remaining portion in the recovery tank 72 may be returned to the supply tank 61.

[0107] Next, the control unit 9 controls the liquid preparation unit 6 to supply the processing liquid 3 from the first supply device 62 to the supply tank 61 (S204). As long as the concentration of the eluted component in the supplied processing liquid 3 is higher than the set value C1 0 The measured value C1 can be lower than the set value C1, for example, 0. By replenishing the processing liquid 3 (S204), the measured value C1 becomes the set value C1 again. 0 Therefore, it is possible to suppress the precipitation of eluted components when the substrate 2 is processed by the processing liquid 3 .

[0108] Furthermore, the control of the concentration adjustment of the output component is not limited to Figure 6 Controls shown.

[0109] For example, the control unit 9 may also perform feedback control on the discharge of the processing liquid 3 from the recovery tank 72 to the outside of the substrate processing apparatus 1 and the replenishment of the processing liquid 3 from the first supply device 62 to the supply tank 61 so that the measured value C1 is equal to the set value C1. 0 The deviation becomes 0. In this case, too, when the measured value C1 exceeds the set value C1 0 In the case of (S202: Yes), the control unit 9 controls the liquid preparation unit 6 to discharge the processing liquid 3 (S203) and replenish the processing liquid 3 (S204).

[0110] Alternatively, the control unit 9 may perform the following control instead of using the first concentration meter 68 to measure the concentration of the eluted component: the number of processed substrates 2 is counted, and when the number of processed substrates exceeds a set number, the processing liquid 3 is discharged (S203) and the processing liquid 3 is replenished (S204). When the number of processed substrates exceeds the set number, the measured value C1 exceeds the set value C1. 0 The number of sheets can be set in the same way.

[0111] Table 1 shows the processing conditions of Examples 1 and 2 and Comparative Example 1.

[0112] [Table 1]

[0113]

[0114] In Examples 1 and 2 and Comparative Example 1, the substrate 2 was processed under the same processing conditions except that the rotation speed of the substrate 2 was changed. Specifically, the substrate 2 with a radius of 25 mm was rotated, and the phosphoric acid aqueous solution was supplied from a nozzle arranged just above the center of the substrate 2. As the substrate 2, a substrate in which a silicon oxide film 22 and a silicon nitride film 23 were repeatedly and alternately stacked on a silicon wafer 21 and an opening 25 was formed to penetrate the stacked film 24 in the thickness direction was used. The supply amount of the phosphoric acid aqueous solution was 1 L / min, and the processing time was 40 minutes. The circumferential flow velocity V2A and the radial flow velocity V2B were obtained by the VOF method at a position 15 mm from the rotation center of the substrate 2. The vertical direction flow velocity V1 was obtained as a value obtained by dividing the flow rate of the phosphoric acid aqueous solution ejected from the nozzle by the area of ​​the nozzle.

[0115] It is clear from Table 1 that the circumferential flow velocity V2A is dominant in the horizontal flow velocity V2 in Examples 1 and 2 and Comparative Example 1. In addition, in Examples 1 and 2, the vertical flow velocity V1 is faster than the horizontal flow velocity V2, whereas in Comparative Example 1, the vertical flow velocity V1 is slower than the horizontal flow velocity V2.

[0116] Fig. 7A This is a cross-sectional view showing a state of the substrate according to Example 1 after being processed. Figure 7B This is a cross-sectional view showing a state of a substrate according to Example 2 after being processed. Figure 7C 2 is a cross-sectional view showing the processed state of the substrate involved in Comparative Example 1. In Examples 1 and 2, unlike Comparative Example 1, the vertical flow velocity V1 is faster than the horizontal flow velocity V2, so that compared with Comparative Example 1, less precipitate 28 precipitated from the phosphoric acid aqueous solution is produced, and less clogging of the pattern 27 caused by the precipitate 28 is produced.

[0117] The above describes the embodiments of the substrate processing device and the substrate processing method involved in the present disclosure, but the present disclosure is not limited to the above embodiments, etc. Various changes, corrections, substitutions, additions, deletions and combinations can be made within the scope of the patent claims. These also belong to the technical scope of the present disclosure.

[0118] For example Figure 1 The first nozzle 521 shown in the figure sprays the processing liquid 3 vertically downward, but the processing liquid 3 may also be sprayed obliquely. If the horizontal component of the spraying direction of the processing liquid 3 is directed toward the rotation direction of the substrate 2, the horizontal flow velocity V2 (especially the circumferential flow velocity V2A) of the processing liquid 3 on the substrate 2 can be slowed down.

[0119] The processing liquid 3 in the above embodiment is a phosphoric acid aqueous solution, the first component is silicon, the second component is phosphoric acid, and the third component is water, but the technology disclosed in the present invention can also be applied to processing liquids other than phosphoric acid aqueous solution. The processing liquid 3 can be any processing liquid as long as it etches the substrate 2, for example, it can also be ammonia water. In addition, an organic solvent can also be used instead of water.

[0120] The substrate 2 in the above embodiment includes a silicon wafer 21, a silicon oxide film 22, and a silicon nitride film 23, but the structure of the substrate 2 is not particularly limited. For example, the substrate 2 may include a silicon carbide substrate, a gallium oxide substrate, a gallium nitride substrate, a sapphire substrate, or a glass substrate instead of the silicon wafer 21.

[0121] This application claims priority based on Japanese Patent Application No. 2019-137214 filed with the Japan Patent Office on July 25, 2019, and the entire contents of Japanese Patent Application No. 2019-137214 are cited in this application.

[0122] Description of Reference Numerals

[0123] 1: substrate processing device; 2: substrate; 3: processing liquid; 5: liquid processing unit; 51: substrate holding unit; 52: liquid supply unit; 6: liquid preparation unit; 9: control unit.

Claims

1. A substrate processing device, comprising: a liquid processing unit including a substrate holding unit for holding a substrate horizontally, and a liquid supply unit for supplying a processing liquid to the substrate from above the substrate held by the substrate holding unit; a liquid preparation section that prepares a treatment liquid used in the liquid treatment section; and a control unit that controls the liquid supply unit and the liquid production unit, in, The control unit controls the liquid supply unit to set the supply speed of the processing liquid so that the vertical flow speed of the processing liquid from the liquid supply unit toward the substrate is faster than the horizontal flow speed of the processing liquid flowing along the upper surface of the substrate. The horizontal flow velocity can be decomposed into a circumferential flow velocity and a radial flow velocity, and the circumferential flow velocity and the radial flow velocity depend on the distance from the rotation center of the substrate.

2. The substrate processing device according to claim 1, characterized in that: The liquid processing unit further includes a driving unit that performs at least one of rotation and movement of the substrate holding unit and rotation and movement of the nozzle of the liquid supply unit in such a manner that a supply point of the processing liquid on the upper surface of the substrate is displaced over time. The control unit controls the liquid supply unit and the driving unit to set the supply speed of the processing liquid and the speed of the action so that the vertical flow velocity of the processing liquid from the liquid supply unit toward the substrate is faster than the horizontal flow velocity of the processing liquid flowing along the upper surface of the substrate.

3. The substrate processing device according to claim 1, characterized in that: The liquid preparation section includes: a supply tank for storing the treatment liquid; a supplier for supplying the treatment liquid to the supply tank; a circulation path for returning the treatment liquid taken out from the supply tank to the supply tank; and a liquid delivery path for transporting the treatment liquid to the liquid supply section of the liquid processing section from the middle of the circulation path.

4. The substrate processing device according to claim 3, characterized in that: The liquid processing unit further includes a recovery unit configured to recover the processing liquid supplied to the substrate. The liquid preparation section also includes: a recovery tank for storing the processing liquid transported from the recovery section; a return path for returning the processing liquid stored in the recovery tank to the supply tank; and a discharge path for discharging the processing liquid stored in the recovery tank to the outside of the substrate processing device.

5. The substrate processing device according to claim 4, characterized in that: The liquid preparation unit includes a concentration meter in the circulation path for measuring the concentration of a component eluted from the substrate into the processing liquid. When the measured value of the concentration of the eluted component exceeds a set value, the control unit controls the liquid preparation unit to discharge the processing liquid stored in the recovery tank to the outside of the substrate processing apparatus.

6. The substrate processing device according to claim 5, characterized in that: When the measured value of the concentration of the eluted component exceeds the set value, the control unit controls the liquid preparation unit to supply the processing liquid having a concentration of the eluted component lower than the set value from the supplier to the supply tank.

7. The substrate processing apparatus according to any one of claims 1 to 6, characterized in that: The liquid supply unit includes a shower head nozzle in which discharge ports of the processing liquid are two-dimensionally dispersed.

8. The substrate processing apparatus according to any one of claims 1 to 6, characterized in that: The liquid supply unit includes a stripe-shaped nozzle having ejection outlets of the processing liquid arranged in one or more rows.

9. The substrate processing apparatus according to any one of claims 1 to 6, characterized in that: There are multiple liquid processing parts. The liquid preparation section supplies the processing liquid to the liquid supply section of each of the plurality of liquid processing sections.

10. A substrate processing method, comprising: Keep the substrate horizontal; as well as supplying a processing liquid to the substrate from above the horizontal substrate to process the substrate, In the substrate processing method, the substrate is processed by supplying the processing liquid at a supply speed such that a vertical flow rate of the processing liquid from above the substrate toward the substrate is faster than a horizontal flow rate of the processing liquid flowing along the upper surface of the substrate. The horizontal flow velocity can be decomposed into a circumferential flow velocity and a radial flow velocity, and the circumferential flow velocity and the radial flow velocity depend on the distance from the rotation center of the substrate.

11. The substrate processing method according to claim 10, characterized in that: The method further includes rotating and moving the substrate so that a supply point of the processing liquid on the upper surface of the substrate is displaced over time, and rotating and moving a nozzle that sprays the processing liquid onto the substrate. In the substrate processing method, the substrate is processed at a supply amount of the processing liquid and a speed of the operation such that the flow velocity in the vertical direction is faster than the flow velocity in the horizontal direction.

12. The substrate processing method according to claim 10, characterized in that: Also includes: delivering the processing liquid from a supply tank to a nozzle that sprays the processing liquid onto the substrate; allowing the treatment liquid sprayed from the nozzle to be stored in a recovery tank before returning to the supply tank; measuring the concentration of a component eluted from the substrate into the processing liquid in the middle of a flow path of the processing liquid from the supply tank to the nozzle; as well as When the measured value of the concentration of the eluted component exceeds a set value, the treated liquid stored in the recovery tank is discharged to the outside.

13. The substrate processing method according to claim 12, characterized in that: Also includes: When the measured value of the concentration of the eluted component exceeds the set value, the processing liquid having a concentration of the eluted component lower than the set value is supplied to the supply tank.

14. The substrate processing method according to any one of claims 10 to 13, characterized in that: The substrate includes a stacked film, the stacked film alternately including a silicon oxide film and a silicon nitride film, The laminate film has an opening that penetrates the laminate film in a thickness direction. The processing liquid selectively etches the silicon nitride film among the silicon oxide film and the silicon nitride film.

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