SUBSTRATE PROCESSING APPARATUS AND SUBSTRATE PROCESSING METHOD

Abstract

To improve uniformity of etching processing in a technique to collectively etch a plurality of substrates.SOLUTION: A substrate processing apparatus according to the present disclosure comprises a processing tank, a gas supply unit, a changing unit, and a control unit. The processing tank performs etching processing on a plurality of substrates having a plurality of types of metal layers by immersing the substrates in processing liquid. The gas supply unit is arranged below the plurality of substrates inside the processing tank, and discharges a gas to an inside of the processing tank. The changing unit changes a flow rate of the gas discharged from the gas supply unit. The control unit controls the changing unit to cause the gas to be discharged from the gas supply unit at a first flow rate during a first period from when the etching processing is started, and subsequently change the flow rate of the gas supplied from the gas supply unit to a second flow rate smaller than the first flow rate.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present disclosure relates to a substrate processing apparatus and a substrate processing method. [Background technology]

[0002] Patent Document 1 discloses a technique for etching a plurality of substrates at once by immersing the substrates in a processing tank that stores a processing liquid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-14470 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique for simultaneously etching a plurality of substrates, which can improve the uniformity of the etching process. [Means for solving the problem]

[0005] A substrate processing apparatus according to an embodiment of the present disclosure includes a processing tank, a gas supply unit, a change unit, and a control unit. The processing tank performs an etching process by immersing a plurality of substrates having a plurality of types of metal layers in a processing liquid. The gas supply unit is disposed inside the processing tank below the plurality of substrates and discharges gas into the processing tank. The change unit changes a flow rate of the gas discharged from the gas supply unit. The control unit controls the change unit to discharge gas from the gas supply unit at a first flow rate during a first period after the start of the etching process, and then changes the flow rate of the gas supplied from the gas supply unit to a second flow rate that is less than the first flow rate. Effect of the Invention

[0006] According to the present disclosure, in a technique for simultaneously etching a plurality of substrates, it is possible to improve the uniformity of the etching process. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of substrate processing. [Diagram 2] FIG. 2 is a diagram showing the configuration of the substrate processing apparatus according to the first embodiment. [Diagram 3] FIG. 3 is a diagram showing the configuration of a processing liquid supply unit according to the first embodiment. [Figure 4] FIG. 4 is a flowchart showing a procedure of the process executed by the substrate processing apparatus according to the first embodiment. [Diagram 5] FIG. 5 is an explanatory diagram of the flow rate changing process according to the first embodiment. [Figure 6] FIG. 6 is a diagram showing how the position where stagnation of the liquid flow occurs changes due to the flow rate changing process. [Figure 7] FIG. 7 is a diagram showing how the position where stagnation of the liquid flow occurs changes due to the flow rate changing process. [Figure 8] FIG. 8 is a diagram showing a configuration of a substrate processing apparatus according to a modified example of the first embodiment. [Figure 9] FIG. 9 is an explanatory diagram of a flow rate changing process according to a modified example of the first embodiment. [Figure 10] FIG. 10 is a diagram showing the configuration of a substrate processing apparatus according to the second embodiment. [Figure 11] FIG. 11 is a view of the gas supply unit according to the second embodiment as viewed from above. [Figure 12] FIG. 12 is an explanatory diagram of the flow rate changing process according to the second embodiment. [Figure 13] FIG. 13 is a graph showing the change in the in-plane temperature difference over time during etching processing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a detailed description will be given of a substrate processing apparatus and a substrate processing method according to the present disclosure (hereinafter, referred to as an "embodiment") with reference to the drawings. Note that the present disclosure is not limited to the embodiment. In addition, each embodiment can be appropriately combined as long as the processing contents are not contradictory. In addition, the same parts in each of the following embodiments are given the same reference numerals, and duplicated descriptions are omitted.

[0009] In addition, in the embodiments described below, expressions such as "constant", "orthogonal", "vertical" and "parallel" may be used, but these expressions do not necessarily mean "constant", "orthogonal", "vertical" and "parallel" strictly. In other words, each of the above expressions allows for deviations due to, for example, manufacturing accuracy and installation accuracy.

[0010] In addition, in the drawings referred to below, for ease of understanding, an orthogonal coordinate system may be shown in which the X-axis, Y-axis, and Z-axis directions are defined as being orthogonal to each other, and the Z-axis positive direction is the vertically upward direction. Also, the direction of rotation about the vertical axis may be referred to as the θ direction.

[0011] <Substrate processing> First, an example of a substrate processing method according to the present disclosure will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of a substrate processing method.

[0012] As shown in Fig. 1, the substrate processing according to the present disclosure involves etching a wafer W having a tungsten film 101, a titanium nitride film 102, and a silicon oxide film 103 formed on a polysilicon film 100, for example. Specifically, the silicon oxide films 103 are formed in multiple layers on the polysilicon film 100 at intervals from each other, and the titanium nitride films 102 are formed around each silicon oxide film 103 so as to cover the silicon oxide films 103. The tungsten film 101 is formed so as to cover the titanium nitride film 102 and the silicon oxide film 103. Therefore, before the etching process, the titanium nitride film 102 and the silicon oxide film 103 are covered with the tungsten film 101.

[0013] The substrate processing according to the present disclosure etches back the tungsten film 101 and the titanium nitride film 102 to form recesses on the wafer W. As a processing liquid for etching the tungsten film 101 and the titanium nitride film 102, for example, a processing liquid containing phosphoric acid (H3PO4), acetic acid (CH3COOH), nitric acid (HNO3), and water (H2O) as components is used.

[0014] Specifically, first, only the tungsten film 101 exposed on the surface is etched, thereby exposing the titanium nitride film 102 that was covered by the tungsten film 101 (first etching process). After that, the tungsten film 101 and the titanium nitride film 102 are simultaneously etched (second etching process).

[0015] Patent Document 1 discloses a technology for improving the uniformity of the etching process by supplying a gas such as nitrogen gas from a gas nozzle provided at the bottom of the processing tank to form a liquid flow of the processing liquid within the processing tank.

[0016] However, the above-mentioned technique has a risk of forming a region (hereinafter, referred to as a "different region") in which the amount of etching is extremely small within the surface of the wafer.

[0017] One of the causes of this is stagnation of the liquid flow. That is, if there is a place where the processing liquid does not flow and stagnates, it is thought that the replacement ability of the processing liquid at that place is reduced, and the amount of etching at that place is reduced.

[0018] Therefore, in the first embodiment, the liquid flow in the processing tank is intentionally disturbed to prevent the liquid flow from stagnating in a certain location. This makes it difficult for a differentiated region to be formed, thereby improving the uniformity of the etching process.

[0019] Another possible cause is galvanic corrosion that occurs during the second etching process. Galvanic corrosion is a phenomenon in which, when different metals are brought into contact with each other in an aqueous solution, the metal with the lower potential (standard electrode potential) corrodes rapidly. Galvanic corrosion occurs more significantly as the flow rate of the gas supplied to the processing tank increases.

[0020] Therefore, in the second embodiment, the supply of gas into the processing tank is restricted after a certain period of time has elapsed since the start of the etching process, which makes it possible to suppress the occurrence of galvanic corrosion in the second etching process in which the tungsten film 101 and the titanium nitride film 102 are simultaneously etched.

[0021] (First embodiment) <Configuration of the substrate processing apparatus> First, the configuration of the substrate processing apparatus according to the first embodiment will be described with reference to Fig. 2. Fig. 2 is a diagram showing the configuration of the substrate processing apparatus according to the first embodiment.

[0022] 2 immerses the multiple wafers W held in a vertical position in a processing liquid, thereby simultaneously performing an etching process on the multiple wafers W. As described above, a processing liquid containing phosphoric acid, acetic acid, nitric acid, and water is used in the etching process, and the tungsten film 101 and the titanium nitride film 102 are etched by the etching process.

[0023] As shown in FIG. 2, the substrate processing apparatus 1 according to the first embodiment includes an inner bath 11, an outer bath 12, a substrate holding unit 20, processing liquid supply units 30_1 to 30_3, a circulation flow path 50, flow rate change units 60_1 to 60_3, and a control device 70.

[0024] In the following, when the processing liquid supply units 30_1 to 30_3 are not distinguished from each other, they may be simply referred to as processing liquid supply units 30. When the flow rate change units 60_1 to 60_3 are not distinguished from each other, they may be simply referred to as flow rate change units 60.

[0025] (Inner tank 11 and outer tank 12) The inner tank 11 is a box-shaped tank with an open top, and stores a processing liquid therein. A lot formed of a plurality of wafers W is immersed in the inner tank 11. In this manner, the inner tank 11 corresponds to an example of a processing tank in which a plurality of substrates are immersed in the processing liquid to perform an etching process.

[0026] The outer tank 12 is disposed around the upper portion of the inner tank 11. The outer tank 12 is open at the top and stores the processing liquid that has overflowed from the inner tank 11. In this manner, the outer tank 12 corresponds to an example of an overflow tank that stores the processing liquid that has overflowed from the processing tank.

[0027] A new liquid supply unit for supplying new processing liquid may be connected to the outer bath 12. Also, individual supply units for individually supplying phosphoric acid, acetic acid, nitric acid, and water, which are components of the processing liquid, may be connected to the outer bath 12.

[0028] (Substrate holding part 20) The substrate holding unit 20 holds the multiple wafers W in a vertical position (vertical orientation). The substrate holding unit 20 also holds the multiple wafers W arranged at regular intervals in the horizontal direction (here, the Y-axis direction). The substrate holding unit 20 is connected to a lifting mechanism (not shown), and can move the multiple wafers W between a processing position inside the inner tank 11 and a standby position above the inner tank 11.

[0029] (Processing liquid supply unit 30) The processing liquid supply unit 30 is disposed inside the inner tank 11 below the plurality of wafers W, and discharges the processing liquid into the inner tank 11.

[0030] Here, the configuration of the processing liquid supply unit 30 will be described with reference to Fig. 3. Fig. 3 is a diagram showing the configuration of the processing liquid supply unit 30 according to the first embodiment.

[0031] As shown in FIG. 3, the processing liquid supply units 30_1 to 30_3 include nozzles 31_1 to 31_3. The nozzles 31_1 to 31_3 are, for example, cylindrical members and extend along the arrangement direction (Y-axis direction) of the multiple wafers W. A multiple number of discharge ports 32_1 to 32_3 are provided on the upper portions of the nozzles 31_1 to 31_3 along the extension direction of the nozzles 31_1 to 31_3. The discharge ports 32_1 to 32_3 are, for example, circular, and have an opening diameter of, for example, about 0.5 mm to 1.0 mm. The discharge ports 32_1 to 32_3 discharge the processing liquid, for example, vertically upward (positive direction of the Z axis).

[0032] The nozzles 31_1 to 31_3 are connected to supply paths 52_1 to 52_3, which will be described later, and eject the processing liquid supplied from the supply paths 52_1 to 52_3 from the plurality of ejection openings 32_1 to 32_3.

[0033] (Circulation flow path 50) Returning to Fig. 2, the circulation flow path 50 connects the outer bath 12 and the treatment liquid supply units 30_1 to 30_3. Specifically, the circulation flow path 50 includes a discharge path 51, a plurality of supply paths 52_1 to 52_3, and a plurality of bypass paths 53_1 to 53_3. The discharge path 51 is connected to the bottom of the outer bath 12.

[0034] The discharge path 51 is provided with a pump 55, a heater 56, and a filter 57. The pump 55 sends the processing liquid in the outer bath 12 to the discharge path 51. The heater 56 heats the processing liquid flowing through the discharge path 51 to a temperature suitable for etching. The filter 57 removes impurities from the processing liquid flowing through the discharge path 51. The pump 55 and the heater 56 are electrically connected to and controlled by the control device 70.

[0035] A plurality of supply paths 52_1 to 52_3 branch off from the discharge path 51. Of these, the supply path 52_1 is connected to the processing liquid supply unit 30_1, the supply path 52_2 is connected to the processing liquid supply unit 30_2, and the supply path 52_3 is connected to the processing liquid supply unit 30_3.

[0036] The multiple bypass paths 53_1 to 53_3 connect the multiple supply paths 52_1 to 52_3 and the outer tank 12. Specifically, the bypass path 53_1 branches off from the supply path 52_1 and is connected to the outer tank 12, the bypass path 53_2 branches off from the supply path 52_2 and is connected to the outer tank 12, and the bypass path 53_3 branches off from the supply path 52_3 and is connected to the outer tank 12.

[0037] (Flow rate changing unit 60) The flow rate changing units 60_1-60_3 are, for example, liquid flow controllers (LFCs) and change the flow rates of the processing liquids supplied to the processing liquid supply units 30_1-30_3. That is, the flow rate changing units 60_1-60_3 change the flow rates of the processing liquids discharged from the multiple discharge ports 32_1-32_3 provided in the processing liquid supply units 30_1-30_3.

[0038] Specifically, the flow rate changer 60_1 is provided in the bypass path 53_1 and changes the flow rate of the treatment liquid supplied from the supply path 52_1 to the treatment liquid supply unit 30_1 by changing the flow rate of the treatment liquid flowing through the bypass path 53_1. The flow rate changer 60_2 is provided in the bypass path 53_2 and changes the flow rate of the treatment liquid supplied from the supply path 52_2 to the treatment liquid supply unit 30_2 by changing the flow rate of the treatment liquid flowing through the bypass path 53_2. The flow rate changer 60_3 is provided in the bypass path 53_3 and changes the flow rate of the treatment liquid supplied from the supply path 52_3 to the treatment liquid supply unit 30_3 by changing the flow rate of the treatment liquid flowing through the bypass path 53_3.

[0039] The flow rate changing units 60_1 to 60_3 are electrically connected to the control device 70 and are controlled by the control device 70.

[0040] (Control device 70) The control device 70 is, for example, a computer, and includes a control unit 71 and a storage unit 72. The storage unit 72 is realized by, for example, a semiconductor memory element such as a RAM or a flash memory, or a storage device such as a hard disk or an optical disk, and stores programs that control various processes executed in the substrate processing apparatus 1. The control unit 71 includes a microcomputer having a central processing unit (CPU), read only memory (ROM), random access memory (RAM), input / output ports, etc., and various circuits, and controls the operation of the substrate processing apparatus 1 by reading and executing the programs stored in the storage unit 72.

[0041] Such a program may be recorded in a computer-readable storage medium and installed from the storage medium into the storage unit 72 of the control device 70. Examples of computer-readable storage media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical disk (MO), and a memory card.

[0042] (Specific Operation of Substrate Processing Apparatus 1) Next, a specific operation of the substrate processing apparatus 1 according to the first embodiment will be described with reference to Fig. 3 and Fig. 4. Fig. 4 is a flow chart showing the procedure of the process executed by the substrate processing apparatus 1 according to the first embodiment. Each process shown in Fig. 4 is executed under the control of the control unit 71.

[0043] 4, in the substrate processing apparatus 1, first, a load process is performed in which a plurality of wafers W are immersed in the inner bath 11 (step S101). In the load process, the control unit 71 controls a lifting mechanism (not shown) of the substrate holding unit 20 to lower the substrate holding unit 20, thereby immersing the plurality of wafers W in the processing liquid stored in the inner bath 11.

[0044] Note that, before the start of the loading process, the control unit 71 controls the pump 55 to start supplying the processing liquid from the outer bath 12 to the processing liquid supply units 30_1-30_3. Also, before the start of the loading process, the control unit 71 controls the flow rate change units 60_1-60_3 to close the bypass paths 53_1-53_3. That is, before the start of the loading process, all of the processing liquid flowing through the circulation flow path 50 is supplied to the processing liquid supply units 30_1-30_3.

[0045] Next, an etching process is performed in the substrate processing apparatus 1 (step S102). In the etching process, a state in which the multiple wafers W are immersed in the processing liquid in the inner tank 11 is continued for a predetermined time. As a result, first, the tungsten film 101 exposed on the surface is etched to expose the titanium nitride film 102, and then the tungsten film 101 and the titanium nitride film 102 are etched simultaneously.

[0046] Thereafter, an unloading process is performed in the substrate processing apparatus 1 (step S103). In the unloading process, the control unit 71 controls a lifting mechanism (not shown) of the substrate holding unit 20 to raise the substrate holding unit 20, thereby lifting the multiple wafers W from the inner bath 11. After the unloading process is completed, the control unit 71 ends the series of substrate processing operations in the substrate processing apparatus 1.

[0047] During the etching process, the control unit 71 performs a flow rate changing process for changing the flow rates of the processing liquids supplied from the processing liquid supply units 30_1 to 30_3. The contents of the flow rate changing process will be described with reference to FIGS.

[0048] Fig. 5 is an explanatory diagram of the flow rate changing process according to the first embodiment, and Fig. 6 and Fig. 7 are diagrams showing how the position where stagnation of the liquid flow occurs changes due to the flow rate changing process.

[0049] 5 shows the time changes of the "circulation flow rate", "discharge flow rate", "bypass flow rate" and "valve opening" during the etching process. The "circulation flow rate" refers to the flow rate of the processing liquid flowing through the circulation flow path 50, and the "discharge flow rate" refers to the flow rate of the processing liquid discharged from the processing liquid supply units 30_1-30_3. The "bypass flow rate" refers to the flow rate of the processing liquid supplied to the outer bath 12 from the bypass paths 53_1-53_3, and the "valve opening" refers to the opening of the on-off valves (solenoid valves) of the flow rate change units 60_1-60_3.

[0050] In Fig. 5, the flow rate or the aperture corresponding to the processing liquid supply unit 30_1 is indicated by a solid line, the flow rate or the aperture corresponding to the processing liquid supply unit 30_2 is indicated by a dashed line, and the flow rate or the aperture corresponding to the processing liquid supply unit 30_3 is indicated by a dashed line. In Fig. 5, the circulation flow rate is indicated by a two-dot chain line.

[0051] 6 and 7, the processing liquid discharged from the processing liquid supply units 30_1 to 30_3 is indicated by a solid arrow, and the discharge flow rate of the processing liquid is indicated by the length of the solid arrow. Also, in Fig. 6 and 7, the liquid flow of the processing liquid formed in the inner tank 11 is indicated by a hatched arrow.

[0052] As shown in FIG. 5, the control unit 71 changes the discharge flow rates of the processing liquid supply units 30_1 to 30_3 by changing the valve openings of the flow rate changing units 60_1 to 60_3 to change the bypass flow rates.

[0053] The control unit 71 increases and decreases the flow rate of the processing liquid discharged from the processing liquid supply unit 30_1, the flow rate of the processing liquid discharged from the processing liquid supply unit 30_2, and the flow rate of the processing liquid discharged from the processing liquid supply unit 30_3 in different manners.

[0054] For example, in the example shown in FIG. 5, the control unit 71 alternately changes the valve opening degrees of the flow rate changing units 60_1 to 60_3 between a first opening degree V1 and a second opening degree V2 (<V1), thereby alternately changing the bypass flow rate between a third flow rate F3 and a fourth flow rate F4 (<F3). Thereby, the control unit 71 can alternately change the discharge flow rates of the processing liquid supply units 30_1 to 30_3 between a first flow rate F1 and a second flow rate F2 (<F1).

[0055] In the above process, the control unit 71 may make the change directions of the discharge flow rates different among the processing liquid supply units 30_1 to 30_3. For example, the control unit 71 increases the discharge flow rate of the processing liquid supply unit 30_2 from the second flow rate F2 to the first flow rate F1 at the timing when the discharge flow rate of the processing liquid supply unit 30_1 decreases from the first flow rate F1 to the second flow rate F2. Also, the control unit 71 decreases the discharge flow rate of the processing liquid supply unit 30_2 from the first flow rate F1 to the second flow rate F2 at the timing when the discharge flow rate of the processing liquid supply unit 30_1 increases from the second flow rate F2 to the first flow rate F1. By thus making the change directions of the discharge flow rates different among the processing liquid supply units 30_1 to 30_3, the liquid flow of the processing liquid in the inner tank 11 can be disturbed.

[0056] Also, the control unit 71 may make the timings for changing the discharge flow rates different among the processing liquid supply units 30_1 to 30_3. For example, the control unit 71 decreases the discharge flow rate of the processing liquid supply unit 30_3 from the first flow rate F1 to the second flow rate F2 after decreasing the discharge flow rate of the processing liquid supply unit 30_1 from the first flow rate F1 to the second flow rate F2 and before increasing it from the second flow rate F2 to the first flow rate F1. By thus making the timings for changing the discharge flow rates different among the processing liquid supply units 30_1 to 30_3, the liquid flow of the processing liquid in the inner tank 11 can also be disturbed.

[0057] According to the substrate processing apparatus 1 of the first embodiment, even if stagnation SA occurs in the liquid flow in the inner tank 11 as shown in Fig. 6, the liquid flow of the processing liquid is disturbed, so that the location where the stagnation SA occurs can be changed as shown in Fig. 7. This makes it possible to prevent a differentiated region where the amount of etching is extremely small from being formed on the wafer W. In other words, the uniformity of the etching process can be improved.

[0058] In the substrate processing apparatus 1 according to the first embodiment, among the processing liquids flowing through the circulation flow path 50, the processing liquids that are not supplied to the processing liquid supply units 30_1 to 30_3 are discharged to the outer bath 12 connected to the circulation flow path 50. As a result, as shown in FIG. 5, the discharge flow rates of the processing liquid supply units 30_1 to 30_3 can be changed while maintaining the circulation flow rate at a constant flow rate F0. In this manner, by keeping the circulation flow rate constant, the load of the pump 55 can be kept constant. If the load of the pump 55 fluctuates, the pressure applied to the filter 57 may change, causing foreign matter to be discharged from the filter 57. In the substrate processing apparatus 1 according to the first embodiment, the load of the pump 55 can be kept constant by controlling the flow rate change units 60_1 to 60_3 so that the circulation flow rate is constant. Therefore, according to the substrate processing apparatus 1, the discharge of foreign matter from the filter 57 can be suppressed.

[0059] 5, the control unit 71 may perform the above-mentioned flow rate changing process, i.e., the process of increasing and decreasing the discharge flow rates of the processing liquid supply units 30_1 to 30_3, multiple times during the etching process. The flow rate changing process may be performed continuously or intermittently. By performing the flow rate changing process multiple times in this manner, the effect of disturbing the liquid flow of the processing liquid can be enhanced.

[0060] Furthermore, the control unit 71 may repeat the flow rate change process from the start to the end of the etching process. In this way, by continuing the flow rate change process throughout the entire period of the etching process, the effect of disturbing the flow of the processing liquid can be further enhanced.

[0061] 5, the discharge flow rates before and after the change (for example, the first flow rate F1) are the same among the treatment liquid supply units 30_1 to 30_3. However, the control unit 71 may make at least one of the discharge flow rates before and after the change different among the treatment liquid supply units 30_1 to 30_3. This can enhance the effect of disturbing the flow of the treatment liquid.

[0062] 5, the change period of the discharge flow rate (the time from when the discharge flow rate is changed until when the discharge flow rate is returned to the original discharge flow rate) is the same among the treatment liquid supply units 30_1 to 30_3, but the control unit 71 may change the change period of the discharge flow rate differently among the treatment liquid supply units 30_1 to 30_3. This can enhance the effect of disturbing the flow of the treatment liquid.

[0063] 5, the discharge flow rates of the processing liquid supply parts 30_1 to 30_3 are changed between the first flow rate F1 and the second flow rate F2, but the control part 71 may increase or decrease the discharge flow rates of the processing liquid supply parts 30_1 to 30_3 in multiple stages. For example, the control part 71 may decrease (increase) the discharge flow rates of the processing liquid supply parts 30_1 to 30_3, maintain the decreased (increased) discharge flow rates for a certain period of time, and then further decrease (increase) the discharge flow rates. This can enhance the effect of disturbing the flow of the processing liquid.

[0064] <Modification of the Substrate Processing Apparatus 1 according to the First Embodiment> Next, a modified example of the substrate processing apparatus 1 according to the above-mentioned first embodiment will be described with reference to Fig. 8. Fig. 8 is a diagram showing the configuration of a substrate processing apparatus according to a modified example of the first embodiment.

[0065] 8, a substrate processing apparatus 1A according to a modified example includes a circulation path 50A. The circulation path 50A includes a discharge path 51, a plurality of supply paths 52_1 to 52_3, and one bypass path 53A. The bypass path 53A branches off from the discharge path 51 and is connected to the outer bath 12.

[0066] In the substrate processing apparatus 1A according to the modified example, the flow rate changers 60_1-60_3 are provided in the supply paths 52_1-52_3, respectively. Specifically, the flow rate changer 60_1 is provided in the supply path 52_1, the flow rate changer 60_2 is provided in the supply path 52_2, and the flow rate changer 60_3 is provided in the supply path 52_3.

[0067] Next, the contents of the flow rate changing process according to the modified example will be described with reference to Fig. 9. Fig. 9 is an explanatory diagram of the flow rate changing process according to the modified example of the first embodiment. In Fig. 9, the bypass flow rate is indicated by a dashed line.

[0068] 9, the control unit 71 changes the valve openings of the flow rate changing units 60_1-60_3 between a first opening V1 and a second opening V2, thereby changing the discharge flow rates of the treatment liquid supply units 30_1-30_3 between a first flow rate F1 and a second flow rate F2. This makes it possible to prevent the flow of the treatment liquid in the inner tank 11 from being disturbed, thereby preventing the formation of a unique region.

[0069] In the modified example, the bypass flow rate varies depending on the total amount of the discharge flow rate of the processing liquid supply parts 30_1-30_3. That is, when the total amount of the discharge flow rate of the processing liquid supply parts 30_1-30_3 increases, the bypass flow rate decreases, and when the total amount of the discharge flow rate of the processing liquid supply parts 30_1-30_3 decreases, the bypass flow rate increases. This allows the circulation flow rate to be maintained at the flow rate F0.

[0070] Second embodiment Fig. 10 is a diagram showing the configuration of a substrate processing apparatus according to a second embodiment. As shown in Fig. 10, a substrate processing apparatus 1B according to the second embodiment includes a circulation path 50B.

[0071] The circulation flow path 50B has the same configuration as the above-mentioned circulation flow paths 50 and 50A, except that it does not have a bypass path. That is, the circulation flow path 50B includes a discharge path 51 connected to the outer bath 12, and supply paths 52_1-52_3 branched from the discharge path 51 and connected to the treatment liquid supply units 30_1-30_3. In addition, a pump 55, a heater 56, and a filter 57 are provided in the discharge path 51.

[0072] The substrate processing apparatus 1B further includes a gas supply unit 80. The gas supply unit 80 is disposed below the plurality of wafers W and the plurality of processing liquid supply units 30_1 to 30_3 inside the inner tank 11. The gas supply unit 80 includes a plurality of nozzles 81, and ejects gas from the nozzles 81 into the inner tank 11 to generate a flow of the processing liquid inside the inner tank 11.

[0073] The configuration of the gas supply unit 80 will be described with reference to Fig. 11. Fig. 11 is a diagram showing the gas supply unit 80 according to the second embodiment as viewed from above.

[0074] 11, the multiple nozzles 81 included in the gas supply unit 80 are, for example, cylindrical members and extend along the arrangement direction (Y-axis direction) of the multiple wafers W. A multiple discharge ports 82 are provided in the upper part of the nozzle 81 along the extension direction of the nozzle 81. Note that the multiple discharge ports 82 do not necessarily need to be provided in the upper part of the nozzle 81. For example, the multiple discharge ports 82 may be provided in the lower part of the nozzle 81 and configured to discharge gas obliquely downward.

[0075] The multiple nozzles 81 are connected to a gas supply source 84 via a supply path 83. The gas supply source 84 supplies gas to the multiple nozzles 81. Here, it is assumed that nitrogen gas is supplied from the gas supply source 84 to the multiple nozzles 81, but the gas supplied from the gas supply source 84 to the multiple nozzles 81 may be an inert gas other than nitrogen gas, such as argon gas.

[0076] A flow rate changer 85 is provided in the supply path 83. The flow rate changer 85 is configured, for example, with an LFC or an on-off valve that fully closes or fully opens the supply path 83, and changes the flow rate of the nitrogen gas supplied from the gas supply source 84 to the multiple nozzles 81.

[0077] Next, the contents of the flow rate changing process according to the second embodiment will be described with reference to Fig. 12. Fig. 12 is an explanatory diagram of the flow rate changing process according to the second embodiment.

[0078] The control unit 71 controls the flow rate change unit 85 to discharge nitrogen gas from the gas supply unit 80 at a first flow rate F11 during the period T1. The control unit 71 also controls the flow rate change unit 85 to change the discharge flow rate of the nitrogen gas during the period T2 following the period T1 to a second flow rate less than the first flow rate F1, here 0. The period T2 continues at least until the etching process is completed.

[0079] The start timing of the period T2 is preferably, for example, a timing prior to the timing at which the titanium nitride film 102 covered with the tungsten film 101 is exposed in the etching process.

[0080] In this manner, by reducing the discharge flow rate of the nitrogen gas in the latter etching process in which the tungsten film 101 and the titanium nitride film 102 are simultaneously etched, the occurrence of galvanic corrosion can be suppressed.

[0081] Furthermore, by discharging nitrogen gas into the inner bath 11 in the first half of the etching process immediately after the plurality of wafers W are immersed in the inner bath 11, the uniformity of the etching process can be effectively improved.

[0082] This point will be described with reference to Fig. 13. Fig. 13 is a graph showing the change in in-plane temperature difference over time during etching processing. The in-plane temperature difference is the difference between the maximum temperature and the minimum temperature within the surface of the wafer W. In Fig. 13, the solid line shows the change in in-plane temperature difference over time when etching processing is performed while discharging nitrogen gas from the gas supply unit, and the dashed line shows the change in in-plane temperature difference over time when etching processing is performed without discharging nitrogen gas from the gas supply unit.

[0083] 13, when the etching process is performed while discharging nitrogen gas, the temperature difference within the surface of the wafer W can be reduced at an earlier stage than when the etching process is performed without discharging nitrogen gas. This effect is particularly significant at the beginning of the etching process.

[0084] The lower the in-plane temperature of the wafer W, the smaller the in-plane variation in the amount of etching. Therefore, by performing the etching process while discharging nitrogen gas from the gas supply unit 80 during the initial period T1 of the etching process, the uniformity of the etching process can be improved.

[0085] In this way, in the substrate processing apparatus 1B according to the second embodiment, nitrogen gas is discharged from the gas supply unit 80 in the early stage of the etching process, while the amount of nitrogen gas discharged is limited, more preferably, the discharge of nitrogen gas is stopped, in the latter stage of the etching process. As a result, in the first stage of the etching process, the in-plane temperature difference of the wafer W is reduced early, thereby improving the in-plane uniformity of the etching process. Also, in the latter stage of the etching process, the occurrence of galvanic corrosion is suppressed, thereby suppressing the decrease in the in-plane uniformity of the etching process.

[0086] Therefore, the substrate processing apparatus 1B according to the second embodiment can improve the uniformity of the etching process in a technique for simultaneously etching a plurality of wafers W having a plurality of types of metal layers formed thereon.

[0087] 12, the period T1 includes the loading process before the start of the etching process, but it is sufficient that the period T1 includes at least the period after the start of the etching process. The start timing of the period T1 may be, for example, the timing immediately before the multiple wafers W start to be immersed in the processing liquid in the inner tank 11, or the timing immediately after the multiple wafers W finish being immersed in the processing liquid in the inner tank 11. The start timing of the period T1 may also be the timing between when the multiple wafers W start to be immersed in the processing liquid in the inner tank 11 and when they finish being immersed.

[0088] (Other variations) In the first embodiment, the substrate processing apparatus 1, 1A is provided with the three nozzles 31_1 to 31_3. However, the substrate processing apparatus 1, 1A may be provided with at least two nozzles.

[0089] In the first embodiment, the substrate processing apparatus 1, 1A includes a plurality of nozzles 31_1-31_3, and a plurality of outlets 32_1-32_3 are provided in each of the nozzles 31_1-31_3. However, the present invention is not limited to this. The substrate processing apparatus 1, 1A may include a processing liquid supply unit in which a plurality of outlet groups (including a first outlet group and a second outlet group) having different supply paths are provided in a single flat plate member.

[0090] As described above, the substrate processing apparatus according to the embodiment (for example, the substrate processing apparatus 1, 1A) includes a processing tank (for example, the inner tank 11), a first outlet group (for example, any of the plurality of outlets 32_1-32_2 provided in the processing liquid supply units 30_1-30_3), a second outlet group (for example, any other of the plurality of outlets 32_1-32_2 provided in the processing liquid supply units 30_1-30_3), a first changer (for example, any of the plurality of flow rate changers 60_1-60_3), a second changer (for example, any other of the plurality of flow rate changers 60_1-60_3), and a controller (for example, the controller 71). The processing tank performs an etching process by immersing a plurality of substrates (for example, wafers W) in the processing liquid. The first outlet group and the second outlet group are disposed below the plurality of substrates in the processing tank, and discharge the processing liquid into the processing tank. The first changer changes the flow rate of the processing liquid discharged from the first outlet group. The second changer changes the flow rate of the processing liquid discharged from the second outlet group. The controller controls the first changer and the second changer during the etching process to perform a flow rate change process that increases and decreases the flow rates of the processing liquid discharged from the first outlet group and the second outlet group in different ways. Thus, according to the substrate processing apparatus of the embodiment, the uniformity of the etching process can be improved in the technique for etching a plurality of substrates at once.

[0091] The control unit may perform the flow rate change process multiple times, thereby increasing the effect of disturbing the flow of the treatment liquid.

[0092] The control unit may repeat the flow rate change process from the start to the end of the etching process, thereby further increasing the effect of disturbing the flow of the processing liquid.

[0093] In the flow rate changing process, the control unit may change the flow rate of the processing liquid discharged from the first discharge port group and the flow rate of the processing liquid discharged from the second discharge port group at different timings. In this way, by changing the timings of changing the discharge flow rates of the first discharge port group and the second discharge port group, it is possible to disturb the flow of the processing liquid in the processing tank.

[0094] In the flow rate change process, the control unit may decrease the flow rate of the treatment liquid discharged from the second discharge port group at the same time as increasing the flow rate of the treatment liquid discharged from the first discharge port group. In this way, by changing the discharge flow rate in different directions between the first discharge port group and the second discharge port group, the flow of the treatment liquid in the treatment tank can be disturbed.

[0095] The substrate processing apparatus according to the embodiment (for example, the substrate processing apparatus 1) may include an overflow tank (for example, the outer tank 12) and a circulation flow path (for example, the circulation flow path 50). The overflow tank stores the processing liquid overflowed from the processing tank. The circulation flow path connects the overflow tank to the first discharge port group and the second discharge port group. The circulation flow path may include a discharge path (for example, the discharge path 51), a first supply path (for example, any one of the plurality of supply paths 52_1 to 52_3), a second supply path (for example, any other one of the plurality of supply paths 52_1 to 52_3), a first bypass path (for example, any one of the plurality of bypass paths 53_1 to 53_3), and a second bypass path (for example, any other one of the plurality of bypass paths 53_1 to 53_3). The discharge path is connected to the overflow tank. The first supply path branches off from the discharge path and is connected to the first outlet group. The second supply path branches off from the discharge path and is connected to the second outlet group. The first bypass path branches off from the first supply path and is connected to the overflow tank. The second bypass path branches off from the second supply path and is connected to the overflow tank. In this case, the first changer may be provided in the first bypass path. Also, the second changer may be provided in the second bypass path. With this configuration, the discharge flow rates of the first outlet group and the second outlet group can be changed while keeping the circulation flow rate constant. Therefore, for example, the load on the pump is kept constant, thereby suppressing the discharge of foreign matter from the filter.

[0096] The substrate processing apparatus according to the embodiment (for example, the substrate processing apparatus 1A) may include an overflow tank (for example, the outer tank 12) and a circulation flow path (for example, the circulation flow path 50A). The overflow tank stores the processing liquid overflowed from the processing tank. The circulation flow path connects the overflow tank to the first discharge port group and the second discharge port group. The circulation flow path may also include a discharge path (for example, the discharge path 51), a first supply path (for example, any one of the plurality of supply paths 52_1 to 52_3), a second supply path (for example, any other one of the plurality of supply paths 52_1 to 52_3), and a bypass path (for example, the bypass path 53A). The discharge path is connected to the overflow tank. The first supply path branches off from the discharge path and is connected to the first discharge port group. The second supply path branches off from the discharge path and is connected to the second discharge port group. The bypass path branches off from the discharge path and is connected to the overflow tank. In this case, the first changer may be provided in the first supply path. Also, the second changer may be provided in the second supply path. With this configuration, the discharge flow rates of the first outlet group and the second outlet group can be changed while keeping the circulation flow rate constant. Therefore, for example, the load of the pump can be kept constant, thereby suppressing discharge of foreign matter from the filter.

[0097] The control unit may control the first and second change units to perform the flow rate change process so that the flow rate of the treatment liquid flowing through the circulation flow path is constant, thereby, for example, keeping the load on the pump constant and suppressing discharge of foreign matter from the filter.

[0098] Moreover, the substrate processing apparatus according to the embodiment (for example, the substrate processing apparatus 1B) includes a processing tank (for example, the inner tank 11), a gas supply unit (for example, the gas supply unit 80), a change unit (for example, the flow rate change unit 85), and a control unit (for example, the control unit 71). The processing tank performs an etching process by immersing a plurality of substrates (for example, the wafers W) having a plurality of types of metal layers in a processing liquid. The gas supply unit is disposed below the plurality of substrates in the processing tank, and discharges a gas (for example, nitrogen gas) into the processing tank. The change unit changes the flow rate of the gas discharged from the gas supply unit. The control unit controls the change unit to discharge gas from the gas supply unit at a first flow rate (for example, the first flow rate F11) during a first period (for example, the period T1) after the etching process is started, and then changes the flow rate of the gas supplied from the gas supply unit to a second flow rate (for example, 0) that is less than the first flow rate. Therefore, according to the substrate processing apparatus of the embodiment, it is possible to improve the uniformity of the etching process in a technique for simultaneously etching a plurality of substrates on which a plurality of types of metal layers are formed.

[0099] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0100] 1: Substrate processing equipment 11: Inner tank 12: Outer tank 20: Board holding part 30: Processing liquid supply unit 30_1 to 30_3: Processing liquid supply section 31_1~31_3: Nozzle 32_1~32_3:Discharge port 50: Circulation flow path 51 :Exhaust channel 52_1~52_3: Supply route 53_1: Bypass road 55: Pump 56: Heater 57: Filter 60_1~60_3: ​​Flow rate change section 70: Control device 71: Control section 72: Storage section 80: Gas supply section 81: Nozzle 82:Discharge port 83: Supply route 84: Gas supply source 85: Flow rate change section 100: Polysilicon film 101: Tungsten film 102: Titanium nitride film 103: Silicon oxide film W: Wafer

Claims

1. a processing tank for performing an etching process by immersing a plurality of substrates having a plurality of types of metal layers in a processing solution; a gas supply unit disposed inside the processing tank below the plurality of substrates and configured to discharge a gas into the processing tank; A change unit that changes a flow rate of the gas discharged from the gas supply unit; a control unit that controls the change unit to discharge the gas from the gas supply unit at a first flow rate during a first period after the etching process is started, and then changes the flow rate of the gas supplied from the gas supply unit to a second flow rate that is lower than the first flow rate; Equipped with the substrate has a first metal layer and a second metal layer covering the first metal layer; the processing liquid has a property capable of etching both the first metal layer and the second metal layer; The control unit switches the flow rate of the gas from the first flow rate to the second flow rate at a timing before the first metal layer covered with the second metal layer is exposed. Substrate processing equipment.

2. The second flow rate is 0. The substrate processing apparatus according to claim 1 .

3. the first metal layer is a titanium nitride film; The second metal layer is a tungsten film. The substrate processing apparatus according to claim 1 .

4. Etching a plurality of substrates having a plurality of types of metal layers using a treatment tank in which the substrates are immersed in a treatment solution; In the etching step, a gas is discharged into the processing tank from a gas supply unit disposed below the plurality of substrates in the processing tank; a step of discharging the gas from the gas supply unit at a first flow rate during a first period from the start of the etching step, and then changing the flow rate of the gas supplied from the gas supply unit to a second flow rate that is lower than the first flow rate; Including, the substrate has a first metal layer and a second metal layer covering the first metal layer; the processing liquid has a property capable of etching both the first metal layer and the second metal layer; The changing step switches the flow rate of the gas from the first flow rate to the second flow rate at a timing before the first metal layer covered with the second metal layer is exposed. A method for processing a substrate.

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