Substrate processing method and substrate processing apparatus

Abstract

This disclosure describes a substrate processing method and a substrate processing apparatus capable of suppressing the corrosion of polysilicon. [Solution] The substrate processing method includes a first step of supplying a hydrogen-dissolved chemical solution, in which hydrogen is dissolved in a chemical solution, to a substrate including a laminated film comprising a polysilicon film and a metal film laminated adjacent to the polysilicon film, wherein the energy level of the hydrogen-dissolved chemical solution is higher than the energy level of the metal film, and a second step of supplying hydrogen water to the substrate after the first step.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a method for cleaning a substrate on which a circuit is formed. In this method, the pH of pure water or ultrapure water is adjusted to 8.5 or more and less than 9.5, and the circuit-formed substrate is cleaned using alkaline hydrogen water in which hydrogen gas is dissolved while applying a physical action.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure describes a substrate processing method and a substrate processing apparatus capable of suppressing the corrosion of polysilicon.

Means for Solving the Problems

[0005] An example of the substrate processing method includes a first step of supplying a hydrogen-dissolved chemical solution in which hydrogen is dissolved in a chemical solution to a substrate including a stacked film including a polysilicon film and a metal film stacked adjacent to the polysilicon film, wherein the energy level of the hydrogen-dissolved chemical solution is higher than the energy level of the metal film, and a second step of supplying hydrogen water to the substrate after the first step.

Effects of the Invention

[0006] According to the substrate processing method and the substrate processing apparatus according to the present disclosure, it is possible to suppress the corrosion of polysilicon.

Brief Description of the Drawings

[0007] [Figure 1] Figure 1 is a schematic plan view showing an example of a substrate processing system. [Figure 2] Figure 2 is a cross-sectional view showing an example of a substrate. [Figure 3] Figure 3 is a schematic diagram showing an example of a liquid processing unit. [Figure 4] Figure 4 is a block diagram showing an example of the main components of a substrate processing system. [Figure 5] Figure 5 is a schematic diagram showing an example of the controller's hardware configuration. [Figure 6] Figure 6 is a flowchart illustrating an example of substrate processing. [Figure 7] Figure 7 is a diagram illustrating an example of substrate processing. [Figure 8] Figure 8 is a cross-sectional view showing an example of a substrate to illustrate how polysilicon corrodes. [Figure 9] Figure 9 is a diagram illustrating the movement of electrons when a single chemical solution is supplied to a substrate. [Figure 10] Figure 10 is a diagram illustrating the movement of electrons when a hydrogen-dissolved chemical solution is supplied to a substrate. [Modes for carrying out the invention]

[0008] In the following descriptions, the same reference numeral will be used for identical elements or elements with the same function, and redundant explanations will be omitted. Furthermore, in this specification, when referring to the top, bottom, right, and left of a figure, the direction of the reference numeral in the figure will be used as the reference.

[0009] [Circuit board processing system] First, with reference to Figure 1, a substrate processing system 1 (substrate processing apparatus) configured to process a substrate W will be described. The substrate processing system 1 comprises an input / output station 2, a processing station 3, and a controller Ctr (control unit). The input / output station 2 and the processing station 3 may be arranged in a single line horizontally, for example.

[0010] The substrate W may be disc-shaped, or it may be a plate shape other than circular, such as a polygon. The substrate W may have a notch in which a part is cut out. The notch may be, for example, a notch (groove such as U-shaped or V-shaped), or a straight section extending in a straight line (a so-called orientation flat). The substrate W may be, for example, a semiconductor substrate (silicon wafer), a glass substrate, a mask substrate, an FPD (Flat Panel Display) substrate, or various other types of substrates. The diameter of the substrate W may be, for example, about 200 mm to 450 mm.

[0011] As illustrated in Figure 2, the substrate W includes a base body 100 and a multilayer film 110. The base body 100 may be, for example, a silicon wafer, or a silicon wafer with at least one film formed on its upper surface.

[0012] The laminated film 110 may have a pattern exhibiting a predetermined shape. The laminated film 110 includes at least a polysilicon film 111 and a metal film 112 laminated adjacent to the polysilicon film 111. In the example of Figure 2, the laminated film 110 includes, in order from the substrate 100 side, a polysilicon film 111, a metal film 112, and an insulating film 113. The metal film 112 may be composed of one metal film or of multiple metal films. In the example of Figure 2, the metal film 112 may be composed of two metal films 112a and 112b, in order from the substrate 100 side.

[0013] The metal film 112 may be composed of, for example, titanium nitride (TiN), titanium silicon nitride (TiSiN), tungsten (W), molybdenum (Mo), etc. That is, the metal film 112 in direct contact with the polysilicon film 111 may be composed of titanium nitride, titanium silicon nitride, tungsten, molybdenum, etc. In the example of FIG. 2, the metal film 112a may be composed of titanium nitride, and the metal film 112b may be composed of tungsten. In this document, the energy level of the metal film 112 is defined by the work function (the minimum energy required to extract one electron from the surface of a substance to infinity). The insulating film 113 may be composed of, for example, silicon nitride (SiN).

[0014] In this specification, the upper surface Wa of the substrate W refers to the upper surface of the element located at the uppermost part among all the elements constituting the substrate W. That is, as illustrated in FIG. 2, when the substrate W is composed of, for example, the base body W1, the metal film 112, and the insulating film 113, the upper surface Wa of the substrate W refers to the upper surface of the insulating film 113. When the substrate W is composed of, for example, the base body W1 and the metal film 112, the upper surface Wa of the substrate W refers to the upper surface of the metal film 112.

[0015] Returning to FIG. 1, the loading / unloading station 2 includes a placement unit 4, a loading / unloading unit 5, and a shelf unit 6. The placement unit 4 includes a plurality of placement tables (not shown) arranged in the width direction (the vertical direction in FIG. 1). Each placement table is configured to be able to place the carrier 7. The carrier 7 is configured to accommodate at least one substrate W in a sealed state. The carrier 7 includes an opening / closing door (not shown) for taking in and out the substrate W. [[ID=​​

[0017] The loading / unloading unit 5 incorporates a transfer arm A1 and a shelf unit 6. The transfer arm A1 is configured to be capable of horizontal movement in the width direction of the loading / unloading unit 5, vertical movement in the vertical direction, and turning movement around the vertical axis based on a signal from the controller Ctr. The transfer arm A1 is configured to take out the substrate W from the carrier 7 and deliver it to the shelf unit 6, and also to receive the substrate W from the shelf unit 6 and return it into the carrier 7. The shelf unit 6 is located near the processing station 3 and is configured to accommodate the substrate W.

[0018] The processing station 3 includes a transfer unit 8 and a plurality of liquid processing units U. The transfer unit 8 extends horizontally, for example, in the direction (left - right direction in FIG. 1) in which the loading / unloading station 2 and the processing station 3 are arranged. The transfer unit 8 incorporates a transfer arm A2 (transfer unit). The transfer arm A2 is configured to be capable of horizontal movement in the longitudinal direction of the transfer unit 8, vertical movement in the vertical direction, and turning movement around the vertical axis based on a signal from the controller Ctr. The transfer arm A2 is configured to take out the substrate W from the shelf unit 6 and deliver it to the liquid processing unit U, and also to receive the substrate W from the liquid processing unit U and return it into the shelf unit

[0018] 6.

[0019] The plurality of liquid processing units U are arranged in a row along the longitudinal direction (left - right direction in FIG. 1) of the transfer unit 8 on each of both sides of the transfer unit 8. The configuration of the liquid processing unit U will be described later.

[0020] The controller Ctr, which will be described in detail later, is configured to control the substrate processing system 1 partially or entirely.

[0021] [Liquid Processing Unit] Next, the liquid treatment unit U will be described in detail with reference to Figure 3. The liquid treatment unit U is configured to perform a predetermined liquid treatment (for example, a treatment to remove dirt and foreign matter) on the substrate W. The liquid treatment unit U may be, for example, a single-wafer cleaning device that cleans the substrate W one by one by spin cleaning.

[0022] The liquid processing unit U includes a housing 10, a blower 20, a rotating and holding unit 30, a supply unit 40 (first supply unit), a supply unit 50 (second supply unit), a supply unit 60 (third supply unit), a cup unit 70, and a liquid receiving unit 80.

[0023] The housing 10 houses the rotating holding unit 30 inside. The housing 10 is configured to allow the substrate W to be loaded into and unloaded from its interior. An loading / unloading port (not shown) is formed in the side wall of the housing 10. The substrate W is transported into the housing 10 and unloaded from the housing 10 through this loading / unloading port by the transport arm A2.

[0024] The air blower 20 is mounted on the top wall of the housing 10. The air blower 20 is configured to create a downward flow within the housing 10 based on a signal from the controller Ctr. The downward flow created by the air blower 20 flows toward the upper surface Wa of the substrate W held by the rotating holding unit 30.

[0025] The rotating and holding unit 30 includes a drive unit 31, a shaft 32, and a holding unit 33. The drive unit 31 is configured to operate based on a control signal from the controller Ctr and to rotate the shaft 32. The drive unit 31 may be a power source such as an electric motor.

[0026] The holding portion 33 is provided at the tip of the shaft 32. The holding portion 33 is configured to hold the back surface Wb of the substrate W, for example, by suction. That is, the rotating holding portion 30 may be configured to rotate the substrate W around a rotation center axis Ax perpendicular to the upper surface Wa of the substrate W, while the substrate W is in a substantially horizontal position. Alternatively, the holding portion 33 may be configured to hold the substrate W by a plurality of movable members that grip the peripheral edge of the substrate W, instead of suction.

[0027] The supply unit 40 includes supply units 41 and 42, valves V1 and V2, a mixing unit MX, a drive unit 43, and a nozzle N1. Supply unit 41 functions as a source of chemical solution. That is, supply unit 41 is configured to deliver the chemical solution to nozzle N1 through piping D1.

[0028] The chemical solution may be, for example, an acidic solution or an alkaline solution. Acidic solutions may include, for example, SC-2 solution (a mixture of hydrochloric acid, hydrogen peroxide, and pure water), SPM (a mixture of sulfuric acid and hydrogen peroxide solution), HF solution (hydrofluoric acid), DHF solution (dilute hydrofluoric acid), HNO3+HF solution (a mixture of nitric acid and hydrofluoric acid), etc. Alkaline solutions may include, for example, SC-1 solution (a mixture of ammonia, hydrogen peroxide, and pure water), hydrogen peroxide solution, etc.

[0029] The supply unit 42 functions as a source of hydrogen water L2 (see Figure 7). That is, the supply unit 42 is configured to supply hydrogen water L2 to pipe D1 through pipe D2. The downstream end of pipe D2 is connected to the middle of pipe D1. Hydrogen water L2 may be produced, for example, by mixing water with hydrogen gas obtained by electrolysis of water using a gas-liquid mixer. The water to which the hydrogen gas is mixed may be the same as the cleaning solution L3 described later. The hydrogen concentration in hydrogen water L2 may be, for example, 1 ppm or more, or it may be the saturation concentration (about 1.6 ppm).

[0030] Valve V1 is located upstream of the connection point between pipes D1 and D2 in piping D1. Valve V2 is located in piping D2. Valves V1 and V2 are configured to open and close based on control signals from controller Ctr. The opening degree of valves V1 and V2 may change in steps, for example, or it may change continuously to any desired size.

[0031] The mixing unit MX is located downstream of the connection point between pipes D1 and D2 in the piping D1. The mixing unit MX is configured to mix the chemical solution supplied from supply unit 41 with hydrogen water L2 supplied from supply unit 42 to produce hydrogen-dissolved chemical solution L1 (see Figure 7). The energy level of the hydrogen-dissolved chemical solution L1 is higher than the energy level of the metal film 112. In this document, the energy level of the hydrogen-dissolved chemical solution L1 is defined by the oxidation-reduction potential (ORP). The hydrogen concentration of the hydrogen-dissolved chemical solution L1 may be, for example, 1 ppm or more, or it may be the saturation concentration (approximately 1.6 ppm).

[0032] When the chemical solution and hydrogen water L2 are supplied from supply unit 41 and supply unit 42, respectively, the hydrogen-dissolved chemical solution L1 generated in the mixing unit MX reaches nozzle N1 through piping D1 and is discharged from nozzle N1. On the other hand, when the chemical solution is supplied from supply unit 41, the chemical solution reaches nozzle N1 through piping D1 and is discharged from nozzle N1.

[0033] The drive unit 43 operates based on a control signal from the controller Ctr and is configured to move the nozzle N1 horizontally or vertically. The drive unit 43 may be configured to move the nozzle N1 between, for example, above the substrate W held by the rotating holding unit 30 and outside the substrate W held by the rotating holding unit 30 (for example, outside the cup portion 70).

[0034] The supply unit 50 includes a supply unit 51, a valve V3, a drive unit 52, and a nozzle N2. The supply unit 51 functions as a source of hydrogen water L2, similar to the supply unit 42. That is, the supply unit 51 is configured to deliver hydrogen water L2 to the nozzle N2 through the piping D3. The hydrogen concentration of the hydrogen water L2 supplied from the supply unit 51 may be approximately equal to the hydrogen concentration of the hydrogen water L2 supplied from the supply unit 42. Alternatively, hydrogen water L2 from the supply unit 42 may be supplied to the piping D3 instead of the supply unit 51.

[0035] Valve V3 is installed in piping D3. Valve V3 is configured to open and close based on a control signal from controller Ctr. The opening degree of valve V3 may change in steps, for example, or it may change continuously to any desired size.

[0036] The drive unit 52 operates based on a control signal from the controller Ctr and is configured to move the nozzle N2 horizontally or vertically. The drive unit 52 may be configured to move the nozzle N2 between, for example, above the substrate W held by the rotating holding unit 30 and outside the substrate W held by the rotating holding unit 30 (for example, outside the cup portion 70).

[0037] The supply unit 60 includes a supply unit 61, a valve V4, a drive unit 62, and a nozzle N3. The supply unit 61 functions as a source of cleaning liquid L3. That is, the supply unit 61 is configured to deliver the cleaning liquid L3 to the nozzle N3 through the piping D4. The cleaning liquid L3 delivered by the supply unit 61 is supplied from the nozzle N3 to the upper surface Wa of the substrate W. The cleaning liquid L3 may include, for example, pure water (DIW), ozonated water, carbonated water (CO2 water), ammonia water, etc. In this document, the hydrogen-dissolved chemical solution L1, hydrogen water L2, and cleaning liquid L3 are sometimes collectively referred to as the "processing liquid".

[0038] Valve V4 is installed in piping D4. Valve V4 is configured to open and close based on a control signal from controller Ctr. The opening degree of valve V4 may change in steps, for example, or it may change continuously to any desired size.

[0039] The drive unit 62 operates based on a control signal from the controller Ctr and is configured to move the nozzle N3 horizontally or vertically. The drive unit 62 may be configured to move the nozzle N3 between, for example, above the substrate W held by the rotating holding unit 30 and outside the substrate W held by the rotating holding unit 30 (for example, outside the cup portion 70).

[0040] The cup portion 70 is provided so as to surround the periphery of the holding portion 33 and the periphery of the substrate W held by the holding portion 33 from the outside. The cup portion 70 is configured to collect the processing liquid that is swept away from the outer edge of the substrate W when the processing liquid is supplied to the upper surface Wa of the substrate W while it is rotating by the rotating holding portion 30.

[0041] The cup portion 70 includes a side wall portion 70a, a top wall portion 70b, and a bottom wall portion 70c. The side wall portion 70a is cylindrical in shape as a whole, surrounding the holding portion 33 from the outside. The top wall portion 70b is annular in shape and extends inward from the upper end of the side wall portion 70a. In the example shown in Figure 3, the top wall portion 70b extends diagonally upward from the upper end of the side wall portion 70a inward. The bottom wall portion 70c is provided at the lower end of the side wall portion 70a so as to close the lower end of the side wall portion 70a.

[0042] The bottom wall portion 70c of the cup portion 70 is provided with a drain port 71 and an exhaust port 72. The drain port 71 is configured to discharge the processed liquid collected by the cup portion 70 to the outside of the liquid processing unit U. The exhaust port 72 is configured to discharge the downward flow formed around the substrate W by the blower portion 20 to the outside of the liquid processing unit U. This downward flow is accompanied by gas generated around the substrate W as the substrate W is processed by the processing liquid.

[0043] The liquid receiving section 80 is located outside the cup section 70. The liquid receiving section 80 includes an opening 81 that is open upward to receive the processing liquid discharged from the nozzles N1 and N2.

[0044] [controller] As shown in Figure 4, the controller Ctr has a reading unit M1, a storage unit M2, a processing unit M3, and an instruction unit M4 as functional modules. These functional modules are merely a convenient division of the controller Ctr's functions into multiple modules, and do not necessarily mean that the hardware constituting the controller Ctr is divided into such modules. Each functional module is not limited to being implemented by program execution, but may also be implemented by a dedicated electrical circuit (e.g., a logic circuit) or an integrated circuit (ASIC: Application Specific Integrated Circuit) that integrates these.

[0045] The reading unit M1 is configured to read a program from a computer-readable recording medium RM (device). The recording medium RM stores programs for operating each part of the substrate processing system 1 (transport arms A1, A2, blower unit 20, rotation holding unit 30, drive units 43, 52, 62, valves V1~V4, etc.). The recording medium RM may be, for example, a semiconductor memory, an optical recording disk, a magnetic recording disk, or a magneto-optical recording disk. The recording medium RM may be built into the substrate processing system 1 or may be a separate unit from the substrate processing system 1.

[0046] The storage unit M2 is configured to store various types of data. For example, the storage unit M2 may store programs read from the recording medium RM by the reading unit M1, setting data input from the operator via an external input device (not shown), and so on.

[0047] The processing unit M3 is configured to process various types of data. For example, the processing unit M3 may be configured to generate operation signals for operating each part of the substrate processing system 1 based on various types of data stored in the storage unit M2.

[0048] The instruction unit M4 is configured to transmit the operation signals generated in the processing unit M3 to each part of the substrate processing system 1.

[0049] The hardware of the controller Ctr may consist of, for example, one or more control computers. The controller Ctr may include, for example, the circuit C1 shown in Figure 5 as a hardware configuration. Circuit C1 may consist of electrical circuit elements. Circuit C1 may include, for example, a processor C2, a memory C3 (storage unit), a storage C4 (storage unit), a driver C5, and an input / output port C6. The processor C2 executes a program in cooperation with at least one of the memory C3 and the storage C4, and performs signal input and output via the input / output port C6, thereby configuring each of the above-mentioned functional modules. The memory C3 and the storage C4 function as storage unit M2. The driver C5 is a circuit that drives each part of the board processing system 1. The input / output port C6 performs signal input and output between the driver C5 and each part of the board processing system 1.

[0050] The substrate processing system 1 may have one controller Ctr, or it may have a controller group (control unit) composed of multiple controllers Ctr. In the latter case, each of the above functional modules may be implemented by one controller Ctr, or by a combination of two or more controllers Ctr. If the controller Ctr is composed of multiple computers (circuit C1), each of the above functional modules may be implemented by one computer (circuit C1), or by a combination of two or more computers (circuit C1). The controller Ctr may include multiple processors C2. In this case, each of the above functional modules may be implemented by one processor C2, or by a combination of two or more processors C2.

[0051] [Substrate Processing Method] Next, the processing of the substrate W will be explained with reference to Figures 6 and 7. The initial state will be described as the substrate W being held by the rotating holding unit 30 and the valves V1 to V4 being closed.

[0052] First, the controller Ctr instructs the rotation holding unit 30 to rotate the substrate W. Next, the controller Ctr instructs the drive unit 43 to position the nozzle N1 above the substrate W (for example, above the center of the substrate W). Then, while the substrate W continues to rotate, the controller Ctr instructs the valves V1 and V2 to open them. As a result, the hydrogen-dissolved chemical solution L1 is discharged from the nozzle N1 onto the upper surface Wa of the substrate W, and liquid treatment of the substrate W (for example, removal of dirt and foreign matter) is performed (see step S10 in Figure 6 and Figure 7(a)).

[0053] Next, after a predetermined time t1 has elapsed since the start of discharge of the hydrogen-dissolved chemical solution L1 from the nozzle N1, the controller Ctr instructs valves V1 and V2 to close them. This stops the discharge of the hydrogen-dissolved chemical solution L1 from the nozzle N1. The predetermined time t1 may be, for example, 10 to 300 seconds. Next, the controller Ctr instructs the drive unit 43 to move the nozzle N1 to the outside of the substrate W (for example, to the outside of the cup portion 70).

[0054] Next, the controller Ctr instructs the drive unit 52 to position the nozzle N2 above the substrate W (for example, above the center of the substrate W). Then, while the substrate W continues to rotate, the controller Ctr instructs the valve V3 to open the valve V3. As a result, hydrogen water L2 is discharged from the nozzle N2 onto the upper surface Wa of the substrate W (see step S11 in Figure 6 and Figure 7(b)). Therefore, the hydrogen-dissolved chemical solution L1 on the upper surface Wa of the substrate W is pushed away from the upper surface Wa of the substrate W by the hydrogen water L2.

[0055] Next, after a predetermined time t2 has elapsed since the start of hydrogen water L2 discharge from nozzle N2, controller Ctr instructs valve V3 to close valve V3. This stops the discharge of hydrogen water L2 from nozzle N2. At this time, all or almost all of the hydrogen-dissolved chemical solution L1 is washed away from the upper surface Wa of the substrate W by the hydrogen water L2. Therefore, mainly hydrogen water L2 is present on the upper surface Wa of the substrate W (see Figure 7(c)). The predetermined time t2 may be, for example, a time sufficient for the hydrogen water L2 to wash away all or almost all of the hydrogen-dissolved chemical solution L1 on the upper surface Wa of the substrate W. The predetermined time t2 may be, for example, about 30 to 120 seconds. Next, controller Ctr instructs drive unit 52 to move nozzle N2 to the outside of the substrate W (for example, outside the cup portion 70).

[0056] Next, the controller Ctr instructs the drive unit 62 to position the nozzle N3 above the substrate W (for example, above the center of the substrate W). Then, while the substrate W continues to rotate, the controller Ctr instructs the valve V4 to open the valve V4. As a result, the cleaning liquid L3 is discharged from the nozzle N3 onto the upper surface Wa of the substrate W (see step S12 in Figure 6 and Figure 7(d)). Therefore, the hydrogen water L2 on the upper surface Wa of the substrate W is pushed away from the upper surface Wa of the substrate W by the cleaning liquid L3.

[0057] Next, after a predetermined time t3 has elapsed since the start of discharge of the cleaning liquid L3 from the nozzle N3, the controller Ctr instructs the valve V4 to close. This stops the discharge of the cleaning liquid L3 from the nozzle N3. At this time, all or almost all of the hydrogen water L2 is washed away from the upper surface Wa of the substrate W by the cleaning liquid L3. The predetermined time t3 may be, for example, a time sufficient for the cleaning liquid L3 to wash away all or almost all of the hydrogen water L2 on the upper surface Wa of the substrate W. The predetermined time t3 may be, for example, about 60 to 180 seconds. Next, the controller Ctr instructs the drive unit 62 to move the nozzle N3 to the outside of the substrate W (for example, outside the cup portion 70). After supplying the cleaning liquid L3 to the substrate W, an organic solvent (for example, isopropyl alcohol (IPA)) may be supplied to the substrate W.

[0058] Next, the controller Ctr instructs the rotation holding unit 30 to continue rotating the substrate W for a predetermined time t4 after the discharge of the cleaning liquid L3 from the nozzle N3 stops. This causes the cleaning liquid L3 on the upper surface Wa of the substrate W to be swept outwards from the outer edge of the substrate W, and the substrate W is dried (see step S13 in Figure 6). With this, the processing of the substrate W is completed.

[0059] [Effect] Incidentally, when a pattern is formed on the substrate W containing the polysilicon film 111 by dry etching, polymer residue adheres to the substrate W. Therefore, in order to remove this residue, the substrate W is treated with a chemical solution.

[0060] However, the inventors have found that when a chemical solution is supplied alone to a substrate W containing a laminated film 110 comprising a polysilicon film 111 and a metal film 112 laminated adjacent to the polysilicon film 111, corrosion may occur in the portion 111a of the polysilicon film 111 near the bonding surface of the metal film 112, as illustrated in Figure 8. When corrosion occurs, the corroded portion 111a of the polysilicon film 111 becomes thinner, which may affect the electrical properties, and when the substrate W containing the polysilicon film 111 becomes an electronic device as a final product, there is a concern that current leakage or poor contact may occur in the corroded portion 111a.

[0061] Further research by the inventors revealed that the corrosion of the polysilicon film 111 occurs because the energy level of the chemical solution is lower than the energy level of the metal film 112. This will be explained with reference to Figure 9. The band gap of silicon is relatively small (approximately 1.1 eV), and electrons in the valence band are easily excited by heat at approximately room temperature or by light such as visible light, and transition to the conduction band (see arrow Ar1 in Figure 9). On the other hand, the energy level of the metal film 112a (titanium nitride) bonded to the polysilicon film is lower than the energy level of the conduction band, so electrons that have transitioned to the conduction band move to the metal film 112a (see arrow Ar2 in Figure 9). Furthermore, the energy level of the metal film 112b (tungsten) bonded to the metal film 112a is lower than that of the metal film 112a, so electrons from the metal film 112a can move to the metal film 112b (see arrow Ar3 in Figure 9).

[0062] Furthermore, since the energy level of the chemical solution (e.g., dilute hydrofluoric acid) is lower than the energy levels of the metal films 112a and 112b, electrons from the metal films 112a and 112b move to the chemical solution (see arrow Ar4 in Figure 9). The electrons that move to the chemical solution are then transferred to the hydrogen ions (H) of the water (H2O) solvent in the chemical solution. +The electrons are consumed in the reduction of (see arrow Ar5 in Figure 9), producing hydrogen (H2). In this way, electrons are removed from silicon as they move through the metal film 112 to the chemical solution. In the portion 111a of silicon from which electrons have been removed, the silicon becomes an oxide and is etched by the chemical solution (see Figure 8). Corrosion of the polysilicon film 111 occurs through the mechanism described above.

[0063] However, in the above example, a hydrogen-dissolved chemical solution L1 having a higher energy level than the metal film 112 is supplied to the substrate W. Therefore, electrons that have moved from the conduction band of silicon to the metal film 112 are less likely to move to the hydrogen-dissolved chemical solution L1. Consequently, as illustrated in Figure 10, electrons that were not consumed in the reduction of hydrogen ions return to the valence band of silicon (see arrow Ar6 in Figure 10). As a result, silicon becomes less susceptible to oxidation.

[0064] In addition, according to the above example, hydrogen-dissolved chemical solution L1 is supplied to the substrate W, and then hydrogen water L2 is supplied to the substrate W. Therefore, since hydrogen water L2 is supplied to the hydrogen-dissolved chemical solution L1 that is retained on the upper surface Wa of the substrate W, the hydrogen concentration of the mixture does not decrease easily when the hydrogen-dissolved chemical solution L1 and hydrogen water L2 are mixed on the upper surface Wa of the substrate W. Consequently, the energy level of the mixture does not easily become lower than the energy level of the metal film 112. As a result, the hydrogen-dissolved chemical solution L1 retained on the upper surface Wa of the substrate W is washed away by hydrogen water L2 while the oxidation of silicon by the mixture is suppressed.

[0065] Therefore, it is possible to suppress the corrosion of the polysilicon film 111.

[0066] As shown in the above example, the hydrogen concentration of the hydrogen-dissolved chemical solution L1 may be 1 ppm or higher. In this case, the energy level of the hydrogen-dissolved chemical solution L1 tends to be higher than the energy level of the metal film 112. Therefore, it becomes possible to further suppress the corrosion of the polysilicon film 111.

[0067] As shown in the above example, the hydrogen concentration of the hydrogen-dissolved chemical solution L1 may be the saturation concentration. In this case, the energy level of the hydrogen-dissolved chemical solution L1 tends to be even higher than the energy level of the metal film 112. Therefore, it becomes possible to further suppress the corrosion of the polysilicon film 111.

[0068] In the above example, hydrogen water L2 is supplied to the substrate W, and then cleaning solution L3 is supplied to the substrate W. Therefore, the hydrogen-dissolved chemical solution L1 is washed away by the hydrogen water L2 before the cleaning solution L3 is supplied to the substrate W. Consequently, since the cleaning solution L3 is supplied to the upper surface Wa of the substrate W when there is almost no hydrogen-dissolved chemical solution L1 present on the upper surface Wa of the substrate W, even if the hydrogen concentration of the mixture decreases as the cleaning solution L3 mixes with the hydrogen water L2 on the upper surface Wa of the substrate W, oxidation of silicon is extremely unlikely to occur. As a result, it is possible to suppress corrosion of the polysilicon film 111 due to the supply of cleaning solution L3 to the substrate W. In addition, since the substrate W is cleaned by the cleaning solution L3, in the process of supplying hydrogen water L2 to the substrate W, the amount of hydrogen water L2 supplied can be set to an amount sufficient to wash away the hydrogen-dissolved chemical solution L1 remaining on the upper surface Wa of the substrate W. Therefore, the amount of hydrogen water L2 used is reduced, making it possible to reduce the cost of substrate processing.

[0069] In the above example, the chemical solution and hydrogen water L2 are supplied from supply units 41 and 42, respectively, and are mixed in the mixing unit MX to produce a hydrogen-dissolved chemical solution L1. This hydrogen-dissolved chemical solution L1 is then supplied to the upper surface Wa of the substrate W. In this case, the hydrogen water L2 is mixed with the chemical solution immediately before the hydrogen-dissolved chemical solution L1 is supplied. Therefore, the hydrogen concentration of the hydrogen-dissolved chemical solution L1 does not decrease significantly before it is supplied to the substrate W. Consequently, corrosion of the polysilicon film 111 can be further suppressed.

[0070] [Differentiation] The disclosures herein should be considered in all respects to be illustrative and not restrictive. Various omissions, substitutions, and modifications may be made to the above examples without departing from the claims and the gist thereof.

[0071] Before supplying the hydrogen-dissolved chemical solution L1 to the upper surface Wa of the substrate W in step S10, the controller Ctr may acquire information about the substrate W. Information about the substrate W may be acquired, for example, by reading ID information (e.g., a string of characters, a two-dimensional code, etc.) formed on the upper surface Wa of the substrate W using an imaging unit or the like. Information about the substrate W may also be acquired, for example, by storing the ID information of the substrate W in the storage unit of the carrier 7 that houses the substrate W and reading the ID information from the storage unit. The ID information may be information indicating, for example, whether or not the substrate W contains a laminated film 110 comprising a polysilicon film 111 and a metal film 112 laminated adjacent to the polysilicon film 111.

[0072] If the controller Ctr determines, by acquiring information about the substrate W, that the substrate W contains a multilayer film 110, it may execute the processes in steps S10 to S13. In this case, by acquiring information about the substrate W in advance, it is determined whether or not to supply the hydrogen-dissolved chemical solution L1 and hydrogen water L2 to the substrate W. Therefore, the hydrogen-dissolved chemical solution L1 and hydrogen water L2 are supplied only to the substrates W that require them. Consequently, the waste of hydrogen water L2 is reduced, making it possible to suppress the cost of substrate processing.

[0073] If the controller Ctr determines, by acquiring information about the substrate W, that the substrate W does not contain the laminated film 110, it may instruct valve V1 to open valve V1 while the substrate W is still rotating and valve V2 is closed. This allows the chemical solution to be supplied from supply unit 41 to the upper surface Wa of the substrate W, and the substrate W is treated with the chemical solution. Next, while the substrate W is still rotating, the controller Ctr instructs valve V4 to open valve V4. This allows the cleaning solution L3 to be supplied from supply unit 61 to the upper surface Wa of the substrate W, and the substrate W is cleaned. Next, the controller Ctr instructs the rotation holding unit 30 to continue rotating the substrate W for a predetermined time. This dries the substrate W. In this way, if it is determined that the substrate W does not contain the laminated film 110, the substrate W may be treated with the chemical solution and cleaning solution L3 without using the hydrogen-dissolved chemical solution L1 and hydrogen water L2.

[0074] If the controller Ctr determines, by acquiring information about the substrate W, that the substrate W contains a laminated film 110, it may dummy-dispense the hydrogen-dissolved chemical solution L1 before executing step S10. Specifically, the controller Ctr instructs the drive unit 43 to position the nozzle N1 above the liquid receiving unit 80. Next, the controller Ctr instructs the valves V1 and V2 to open them. As a result, the hydrogen-dissolved chemical solution L1 is discharged (dummy-dispensed) into the liquid receiving unit 80 before being supplied to the upper surface Wa of the substrate W. In this case, the dummy dispensing preemptively discharges the hydrogen-dissolved chemical solution L1 that has accumulated in the piping D1 and whose hydrogen concentration has decreased. Therefore, the hydrogen-dissolved chemical solution L1, which has a higher energy level than the metal film 112, is appropriately supplied to the substrate W. Thus, it becomes possible to further suppress the corrosion of the polysilicon film 111.

[0075] If the controller Ctr determines, by acquiring information about the substrate W, that the substrate W contains a laminated film 110, it may dummy-dispense hydrogen water L2 before executing step S11. Specifically, the controller Ctr instructs the drive unit 52 to position the nozzle N2 above the liquid receiving unit 80. Next, the controller Ctr instructs the valve V3 to open the valve V3. As a result, the hydrogen water L2 is discharged (dummy-dispensed) into the liquid receiving unit 80 before being supplied to the upper surface Wa of the substrate W. In this case, the dummy dispensing preemptively discharges the hydrogen water L2 that has accumulated in the piping D3 and whose hydrogen concentration has decreased. Therefore, if hydrogen water L2 is supplied to the hydrogen-dissolved chemical solution L1 accumulated on the upper surface Wa of the substrate W in step S11, the hydrogen concentration of the mixture will not decrease significantly when the hydrogen-dissolved chemical solution L1 and the hydrogen water L2 are mixed on the upper surface Wa of the substrate W. Therefore, the energy level of the mixture is unlikely to become lower than the energy level of the metal film 112. As a result, with the oxidation of silicon by the mixture suppressed, the hydrogen-dissolved chemical solution L1 remaining on the upper surface Wa of the substrate W is washed away by the hydrogen water L2. Thus, it becomes possible to further suppress the corrosion of the polysilicon film 111.

[0076] In the above example, the hydrogen-dissolved chemical solution L1 was produced by mixing the chemical solution supplied from supply unit 41 with hydrogen water L2 supplied from supply unit 42. However, the hydrogen-dissolved chemical solution L1 may also be produced by directly mixing hydrogen gas with the chemical solution. Methods for directly mixing hydrogen gas with the chemical solution include, for example, bubbling hydrogen gas into the chemical solution or injecting hydrogen gas into the chemical solution.

[0077] [Example of experiment] The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0078] (Examples) A substrate with a multilayer film pattern composed of polysilicon film, titanium nitride, tungsten, and titanium nitride formed on a silicon wafer was prepared by cutting it into 20mm x 20mm chips. Next, the chips were immersed for 12 seconds in a hydrogen-dissolved chemical solution obtained by mixing hydrofluoric acid and hydrogen water (hydrogen dissolved concentration of 1.6 ppm) in a ratio of 1:360 (dilute hydrofluoric acid with dissolved hydrogen is obtained by mixing hydrofluoric acid and hydrogen water). Next, the chips were immersed for 15 seconds in hydrogen water (hydrogen dissolved concentration of 1.6 ppm). Next, the chips were immersed for 20 seconds in isopropyl alcohol (IPA). Finally, the chips were dried by blowing air onto them.

[0079] Next, the line width of the polysilicon film on the silicon wafer side (bottom) and the line width on the titanium nitride side (top) were measured for the chip, and the difference between these line widths (top / bottom difference) was calculated.

[0080] (Comparative example) A substrate with a multilayer film pattern composed of polysilicon film, titanium nitride, tungsten, and titanium nitride formed on a silicon wafer was prepared by cutting it into 20cm x 20cm chips. Next, the chips were immersed for 12 seconds in dilute hydrofluoric acid obtained by mixing hydrofluoric acid and pure water (DIW) in a ratio of 1:360. Next, the chips were immersed for 15 seconds in pure water (DIW). Next, the chips were immersed for 20 seconds in isopropyl alcohol (IPA). Finally, the chips were dried by blowing air onto them.

[0081] Next, the line width of the polysilicon film on the silicon wafer side (bottom) and the line width on the titanium nitride side (top) were measured for the chip, and the difference between these line widths (top / bottom difference) was calculated.

[0082] (result) In the examples, the top / bottom difference was at least 0.8, and in most patterns, the top / bottom difference significantly exceeded 0.8. On the other hand, in the comparative examples, the top / bottom difference was approximately 0.7. Therefore, it was confirmed that the corrosion of the polysilicon film can be suppressed according to the examples.

[0083] [Other examples] Example 1. An example of a substrate processing method includes a first step of supplying a hydrogen-dissolved chemical solution, in which hydrogen is dissolved in a chemical solution, to a substrate containing a laminated film comprising a polysilicon film and a metal film laminated adjacent to the polysilicon film, wherein the energy level of the hydrogen-dissolved chemical solution is higher than the energy level of the metal film, and a second step of supplying hydrogen water to the substrate after the first step.

[0084] According to the method in Example 1, a hydrogen-dissolved chemical solution, in which hydrogen is dissolved in the chemical solution and which has a higher energy level than the metal film, is supplied to the substrate. In this case, electrons that have moved from the conduction band of silicon to the metal film are less likely to move to the hydrogen-dissolved chemical solution. Therefore, electrons that were not consumed in the reduction of hydrogen ions return to the valence band of silicon. Consequently, silicon becomes less susceptible to oxidation.

[0085] In addition, according to the method in Example 1, hydrogen water is supplied to the substrate after the first step. In this case, since hydrogen water is supplied to the hydrogen-dissolved chemical solution that remains on the upper surface of the substrate, the hydrogen concentration of the mixture does not decrease easily when the hydrogen-dissolved chemical solution and hydrogen water mix on the upper surface of the substrate. Therefore, the energy level of the mixture does not easily become lower than the energy level of the metal film. Consequently, the hydrogen-dissolved chemical solution remaining on the upper surface of the substrate is washed away by the hydrogen water while the oxidation of silicon by the mixture is suppressed.

[0086] Therefore, it is possible to suppress the corrosion of the polysilicon film.

[0087] Example 2. In the method of Example 1, the hydrogen concentration of the hydrogen-dissolved chemical solution may be 1 ppm or higher. In this case, the energy level of the hydrogen-dissolved chemical solution tends to be higher than the energy level of the metal film. Therefore, it becomes possible to further suppress the corrosion of the polysilicon film.

[0088] Example 3. In the method of Example 1 or Example 2, the hydrogen concentration of the hydrogen-dissolved chemical solution may be the saturation concentration. In this case, the energy level of the hydrogen-dissolved chemical solution tends to be even higher than the energy level of the metal film. Therefore, it becomes possible to further suppress the corrosion of the polysilicon film.

[0089] Example 4. Any of the methods in Examples 1 to 3 may further include a third step after the second step, in which a cleaning solution is supplied to the substrate. In this case, the cleaning solution is supplied to the substrate after the hydrogen-dissolved chemical solution has been washed away by hydrogen water. Therefore, since the cleaning solution is supplied to the top surface of the substrate when there is almost no hydrogen-dissolved chemical solution present on the top surface of the substrate, even if the cleaning solution is mixed with hydrogen water on the top surface of the substrate and the hydrogen concentration of these mixtures decreases, oxidation of silicon is extremely unlikely to occur. Thus, it is possible to suppress corrosion of the polysilicon film due to the supply of cleaning solution to the substrate. In addition, since the substrate is cleaned by the cleaning solution, the amount of hydrogen water supplied in the second step can be set to an amount sufficient to wash away the hydrogen-dissolved chemical solution remaining on the top surface of the substrate. Therefore, the amount of hydrogen water used is reduced, and the cost of substrate processing can be reduced.

[0090] Example 5. Any of the methods in Examples 1 to 4 may further include a fourth step before the first step in which information about the substrate is obtained to determine whether or not the substrate contains a multilayer film, and if it is determined in the fourth step that the substrate contains a multilayer film, the first and second steps may be executed. In this case, by obtaining information about the substrate in advance, it is possible to determine whether or not it is necessary to supply hydrogen-dissolved chemical solution and hydrogen water to the substrate. Therefore, hydrogen-dissolved chemical solution and hydrogen water are supplied only to the substrates that require it. Consequently, the waste of hydrogen water is reduced, and the cost of substrate processing can be suppressed.

[0091] Example 6. In the method of Example 5, if it is determined in the fourth step that the substrate contains a multilayer film, the first step may include supplying and mixing hydrogen water and a chemical solution from a hydrogen water source and a chemical solution source, respectively, to produce a hydrogen-dissolved chemical solution, and then supplying the hydrogen-dissolved chemical solution to the substrate. In this case, hydrogen water is mixed with the chemical solution immediately before the hydrogen-dissolved chemical solution is supplied to the substrate requiring the hydrogen-dissolved chemical solution. Therefore, the hydrogen concentration of the hydrogen-dissolved chemical solution is unlikely to decrease significantly by the time it is supplied to the substrate. Consequently, corrosion of the polysilicon film can be further suppressed.

[0092] Example 7. The method of Example 5 or Example 6 may further include a fifth step of dummy dispensing of hydrogen-dissolved chemical solution before the first step if it is determined in the fourth step that the substrate contains a multilayer film. In this case, the dummy dispensing discharges the hydrogen-dissolved chemical solution that has accumulated in the piping and whose hydrogen concentration has decreased. As a result, the hydrogen-dissolved chemical solution, which has a higher energy level than the metal film, is appropriately supplied to the substrate. Therefore, it becomes possible to further suppress the corrosion of the polysilicon film.

[0093] Example 8. An example of a substrate processing apparatus comprises a rotating holding unit configured to rotate a substrate including a laminated film comprising a polysilicon film and a metal film laminated adjacent to the polysilicon film; a first supply unit configured to supply a hydrogen-dissolved chemical solution in which hydrogen is dissolved in a chemical solution to the upper surface of the substrate held by the rotating holding unit; a second supply unit configured to supply hydrogen water to the upper surface of the substrate held by the rotating holding unit; and a control unit. The control unit is configured to perform a first process in which the first supply unit is controlled to supply the hydrogen-dissolved chemical solution to the upper surface of the substrate held by the rotating holding unit, and a second process in which, after the first process, the second supply unit is controlled to supply hydrogen water to the upper surface of the substrate held by the rotating holding unit. In this case, the same effects and advantages as in Example 1 can be obtained.

[0094] Example 9. In the apparatus of Example 8, the hydrogen concentration of the hydrogen-dissolved chemical solution may be 1 ppm or higher. In this case, the same effects as those of the method in Example 2 can be obtained.

[0095] Example 10. In the apparatus of Example 8 or Example 9, the hydrogen concentration of the hydrogen-dissolved chemical solution may be the saturation concentration. In this case, the same effects as those of the method in Example 3 can be obtained.

[0096] Example 11. Any apparatus of Examples 8 to 10 may further include a third supply unit configured to supply cleaning fluid to the upper surface of a substrate held by a rotating holding unit, and the control unit may be configured to perform a third process after the second process by controlling the third supply unit to supply cleaning fluid to the upper surface of the substrate held by the rotating holding unit. In this case, the same effects as the method of Example 4 can be obtained.

[0097] Example 12. In any of the devices in Examples 8 to 11, the control unit may be configured to perform a fourth process before the first process, which involves acquiring information about the substrate to determine whether or not the substrate contains a multilayer film. If the fourth process determines that the substrate contains a multilayer film, the control unit may be configured to perform the first and second processes. In this case, the same effects and advantages as the method in Example 5 can be obtained.

[0098] Example 13. In the apparatus of Example 12, the first supply unit includes a hydrogen water supply source and a chemical solution supply source, and if it is determined in the fourth process that the substrate contains a laminated film, the first process may include controlling the first supply unit to supply and mix hydrogen water and chemical solution from the hydrogen water supply source and the chemical solution supply source, respectively, to produce a hydrogen-dissolved chemical solution, and then supplying the hydrogen-dissolved chemical solution to the substrate. In this case, the same effects as the method of Example 6 can be obtained.

[0099] Example 14. In the apparatus of Example 12 or Example 13, the control unit may be configured to perform a fifth process before the first process by controlling the first supply unit to dummy-dispense the hydrogen-dissolved chemical solution if it determines in the fourth process that the substrate contains a laminated film. In this case, the same effects as the method of Example 7 can be obtained. [Explanation of Symbols]

[0100] 1...Substrate processing system (substrate processing device), 30...Rotation holding unit, 40...Supply unit (first supply unit), 50...Supply unit (second supply unit), 60...Supply unit (third supply unit), 80...Liquid receiving unit, 110...Laminated film, 111...Polysilicon film, 112...Metal film, Ctr...Controller (control unit), L1...Hydrogen-dissolved chemical solution, L2...Hydrogen water, L3...Cleaning solution, U...Liquid processing unit, W...Substrate.

Claims

1. A first step of supplying a hydrogen-dissolved chemical solution, in which hydrogen is dissolved in a chemical solution, to a substrate comprising a laminated film comprising a polysilicon film and a metal film laminated adjacent to the polysilicon film, wherein the energy level of the hydrogen-dissolved chemical solution is higher than the energy level of the metal film. A substrate processing method comprising a second step of supplying hydrogen water to the substrate after the first step.

2. The method according to claim 1, wherein the hydrogen concentration of the hydrogen-dissolved chemical solution is 1 ppm or more.

3. The method according to claim 1, wherein the hydrogen concentration of the hydrogen-dissolved chemical solution is the saturation concentration.

4. The method according to claim 1, further comprising a third step of supplying a cleaning solution to the substrate after the second step.

5. Prior to the first step, the process further includes a fourth step of determining whether or not the substrate contains the laminated film by acquiring information about the substrate, The method according to any one of claims 1 to 4, wherein if it is determined in the fourth step that the substrate contains the laminated film, the first step and the second step are performed.

6. The method according to claim 5, wherein, in the fourth step, it is determined that the substrate contains the laminated film, the first step includes supplying and mixing the hydrogen water and the chemical solution from the hydrogen water supply source and the chemical solution supply source, respectively, to produce the hydrogen-dissolved chemical solution, and then supplying the hydrogen-dissolved chemical solution to the substrate.

7. The method according to claim 5, further comprising a fifth step of dummy dispensing the hydrogen-dissolved chemical solution before the first step, if it is determined in the fourth step that the substrate contains the laminated film.

8. A rotating holding unit configured to hold and rotate a substrate including a laminated film comprising a polysilicon film and a metal film laminated adjacent to the polysilicon film, A first supply unit is configured to supply a hydrogen-dissolved chemical solution in which hydrogen is dissolved in a chemical solution to the upper surface of the substrate held by the rotating holding unit, A second supply unit configured to supply hydrogen water to the upper surface of the substrate held by the rotating holding unit, It includes a control unit, The control unit, A first process involves controlling the first supply unit to supply the hydrogen-dissolved chemical solution to the upper surface of the substrate held by the rotating holding unit, A substrate processing apparatus configured to perform a second process after the first process, which involves controlling the second supply unit to supply the hydrogen water to the upper surface of the substrate held by the rotating holding unit.

9. The apparatus according to claim 8, wherein the hydrogen concentration of the hydrogen-dissolved chemical solution is 1 ppm or more.

10. The apparatus according to claim 8, wherein the hydrogen concentration of the hydrogen-dissolved chemical solution is the saturation concentration.

11. The rotating holding unit further comprises a third supply unit configured to supply cleaning fluid to the upper surface of the substrate held by the rotating holding unit, The apparatus according to claim 8, wherein the control unit is configured to perform a third process after the second process, which involves controlling the third supply unit to supply cleaning fluid to the upper surface of the substrate held by the rotating holding unit.

12. The control unit, The system is configured to perform a fourth process before the first process by acquiring information about the substrate to determine whether or not the substrate contains the laminated film. The apparatus according to any one of claims 8 to 11, wherein if it is determined in the fourth process that the substrate contains the laminated film, the first process and the second process are executed.

13. The first supply unit includes the hydrogen water supply source and the chemical solution supply source, The apparatus according to claim 12, wherein, in the fourth process, it is determined that the substrate contains the laminated film, the first process includes controlling the first supply unit to supply and mix the hydrogen water and the chemical solution from the hydrogen water supply source and the chemical solution supply source, respectively, to produce the hydrogen-dissolved chemical solution, and then supplying the hydrogen-dissolved chemical solution to the substrate.

14. The apparatus according to claim 12, wherein the control unit is configured to perform a fifth process, before the first process, by controlling the first supply unit to dummy dispense the hydrogen-dissolved chemical solution, if it determines in the fourth process that the substrate contains the laminated film.

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