Substrate processing method and substrate processing apparatus

Abstract

The present invention provides a substrate processing method that can increase the etching rate of an etching target while improving the etching uniformity of the etching target, which is at least one of silicon and polysilicon. [Solution] The substrate processing method includes preparing a substrate W containing a silicon layer 100, which is an example of an etching target and is at least one of silicon and polysilicon, and etching the silicon layer 100 by supplying hot AOM, which is an example of high-temperature ammonia water with a dissolved oxygen concentration increased at a temperature higher than room temperature, to the substrate W.

Description

Technical Field

[0001] The present invention relates to a substrate processing method and a substrate processing apparatus for processing a substrate. The substrate includes, for example, a semiconductor wafer, a substrate for a FPD (Flat Panel Display) such as a liquid crystal display device or an organic EL (electroluminescence) display device, a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, a substrate for a solar cell, and the like.

Background Art

[0002] Patent Document 1 discloses a cleaning method for cleaning the surface of a semiconductor substrate. In this cleaning method, ozone water is supplied to a cleaning tank in which the semiconductor substrate is housed to oxidize the surface, and then a cleaning liquid in which an ammonia solution is mixed into the ozone water is generated, and the cleaning liquid is supplied so as to be applied to the surface of the semiconductor substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, Patent Document 1 does not disclose the temperature of the cleaning liquid in which an ammonia solution is mixed into ozone water.

[0005] At least one embodiment of the present invention provides a substrate processing method and a substrate processing apparatus capable of increasing the etching rate (etching amount per unit time) of an etching target while enhancing the uniformity of etching of the etching target which is at least one of silicon and polysilicon.

Means for Solving the Problems

[0006] One embodiment of the present invention provides a substrate processing method comprising: preparing a substrate containing an etching target which is at least one of silicon and polysilicon; and etching the etching target by supplying high-temperature ammonia water with a dissolved oxygen concentration increased at a temperature higher than room temperature to the substrate.

[0007] In the above embodiment, at least one of the following features may be added to the substrate processing method.

[0008] The substrate processing method further includes generating high-temperature ammonia water by mixing ammonia water, ozonated water, and hot water at a temperature higher than room temperature.

[0009] Etching the object to be etched includes discharging the high-temperature ammonia water from the etching solution nozzle, and generating the high-temperature ammonia water includes mixing the ammonia water, the ozonated water, and the hot water in the path to the etching solution nozzle, excluding the tank for storing the ammonia water.

[0010] Etching the target to be etched includes exposing the etching stop layer covered by the target to be etched, and the high-temperature ammonia water is a liquid that etches the etching stop layer at an etching rate lower than the etching rate of the target to be etched.

[0011] The thickness of the etching stop layer is smaller than the thickness to which the high-temperature ammonia water etches the target material.

[0012] The substrate comprises a plate-shaped substrate made of a silicon single crystal having a front surface and a back surface, and a thin film in contact with the front surface of the substrate. Etching the target to be etched includes removing the entire substrate by etching the substrate corresponding to the target to be etched from the back surface of the substrate.

[0013] The substrate processing method further includes removing the native oxide film to be etched by supplying a native oxide film removal solution to the substrate before supplying the high-temperature ammonia water to the substrate.

[0014] Etching the target to be etched includes supplying the high-temperature ammonia water to the upper surface of the substrate, and the substrate processing method further includes supplying a heating solution at a temperature higher than room temperature to the lower surface of the substrate while the high-temperature ammonia water is in contact with the upper surface of the substrate.

[0015] Etching the target to be etched includes supplying the high-temperature ammonia water to the substrate, thereby etching the target to be etched in the thickness direction of the substrate over the entire area from the center of the substrate to the outer periphery of the substrate, and thinning the entire substrate.

[0016] Another embodiment of the present invention provides a substrate processing apparatus that includes a substrate holder for holding a substrate to be etched, which is at least one of silicon and polysilicon, and an etching solution nozzle for etching the substrate to be etched by supplying high-temperature ammonia water, which has a higher dissolved oxygen concentration at a temperature higher than room temperature, to the substrate held in the substrate holder. At least one of the features of the substrate processing method described above may be added to the substrate processing apparatus. [Brief explanation of the drawing]

[0017] [Figure 1A-D] This is a schematic diagram showing an example of a manufacturing process for a semiconductor device to which a substrate processing method according to one embodiment is applied. [Figure 2] This is a schematic diagram showing the inside of a processing unit provided in a substrate processing apparatus according to one embodiment, viewed horizontally. [Figure 3] This is a schematic diagram showing the AOM supply system installed in the substrate processing equipment. [Figure 4] This is a process diagram illustrating an example of substrate processing performed by a substrate processing device. [Figure 5A-D]It is a schematic diagram for explaining an example of the process shown in FIG. 4 and a phenomenon that is assumed to occur on the substrate when the process shown in FIG. 4 is being performed.

Embodiments for Carrying Out the Invention

[0018] Hereinafter, embodiments of this invention will be described in detail with reference to the accompanying drawings.

[0019] FIGS. 1A, 1B, 1C, and 1D are schematic diagrams showing an example of a manufacturing process of a semiconductor device to which a substrate processing method according to an embodiment is applied. FIG. 1A is a perspective view of a first silicon wafer W1 and a second silicon wafer W2 before being bonded together. FIGS. 1B, 1C, and 1D are cross-sectional views of the bonded first silicon wafer W1 and second silicon wafer W2.

[0020] The bonded substrate W includes disk-shaped first silicon wafer W1 and second silicon wafer W2 whose diameters are equal to or approximately equal to each other. The first silicon wafer W1 and the second silicon wafer W2 are bonded such that the surface of the first silicon wafer W1 faces the surface of the second silicon wafer W2. FIGS. 1A to 1D show a state where the surface of the first silicon wafer W1 is directed downward and the surface of the second silicon wafer W2 is directed upward.

[0021] As shown in FIG. 1B, the first silicon wafer W1 includes a silicon layer 100, an etching stop layer 101, and a silicon active layer 102. The silicon layer 100 is an example of a plate-shaped base material made of a single crystal of silicon having a front surface and a back surface. The silicon layer 100 is also an example of an object to be etched. The etching stop layer 101 is an example of a thin film in contact with the surface of the base material.

[0022] The etching stop layer 101 is formed on the surface of the silicon layer 100. The etching stop layer 101 is, for example, a silicon germanium (SiGe) layer. The etching stop layer 101 may be a thin film of a material other than silicon germanium such as silicon dioxide (SiO2). The silicon active layer 102 is formed on the surface of the etching stop layer 101. The silicon active layer 102 is, for example, a silicon epitaxial growth layer epitaxially grown from the etching stop layer 101. Transistors and other semiconductor devices (not shown) are formed in the silicon active layer 102.

[0023] A multilayer wiring layer 103 is formed on the silicon active layer 102. The multilayer wiring layer 103 is formed by laminating wiring layers and interlayer insulating layers (both not shown). A buried power rail 104 (BPR: Berried Power Rail) is disposed across the silicon active layer 102 and the multilayer wiring layer 103. The surface of the multilayer wiring layer 103 (the lower surface in FIG. 1B) corresponds to the surface of the first silicon wafer W1.

[0024] The surface of the first silicon wafer W1 (the lower surface of the multilayer wiring layer 103 in FIG. 1B) is bonded to the surface of the second silicon wafer W2 (the upper surface in FIG. 1B) via an adhesive layer 300. Thereby, a bonded substrate W is fabricated. The adhesive layer 300 may include, for example, a SiCN layer. In the example shown in FIGS. 1B to 1D, the second silicon wafer W2 includes a silicon substrate 200 and an insulating layer 201 formed on the surface of the silicon substrate 200. In this example, the surface of the insulating layer 201 is bonded to the surface of the multilayer wiring layer 103 of the first silicon wafer W1 via the adhesive layer 300. Therefore, the surface of the insulating layer 201 and the surface of the multilayer wiring layer 103 correspond to two bonding surfaces.

[0025] The first silicon wafer W1 and the second silicon wafer W2 may be directly bonded together without an adhesive layer 300 (so-called direct bonding). The second silicon wafer W2 may be a wafer on which no semiconductor devices are formed (so-called carrier wafer), or it may be a wafer on which semiconductor devices are formed. In the latter case, the semiconductor device formed on the first silicon wafer W1 may be a logic semiconductor device, and the semiconductor device formed on the second silicon wafer W2 may be a memory semiconductor device.

[0026] Hereinafter, the bonded substrate W, that is, the bonded first silicon wafer W1 and second silicon wafer W2, will also be simply referred to as the substrate W. The back surface of the substrate W (the top surface in Figures 1A to 1D) is the processing surface where a thinning process for thinning the substrate W is performed. The thinning process is a process of removing the silicon layer 100 of the first silicon wafer W1 to expose the etching stop layer 101. In other words, the target of the thinning process is the silicon layer 100. After the silicon layer 100 is removed, a backside power delivery network (BSPDN) is constructed to supply power to the semiconductor devices in the silicon active layer 102 via the power rail 104.

[0027] The thinning process includes a grinding process in which the silicon layer 100 is removed by friction between abrasive grains and the silicon layer 100, and a wet treatment process in which a treatment solution such as an etching solution is supplied to the back surface (top surface in Figures 1B to 1C) of the silicon layer 100 after the grinding process. Figure 1B shows a cross-section of the substrate W before the grinding process. Figure 1C shows a cross-section of the substrate W after the grinding process but before the wet treatment process. Figure 1D shows a cross-section of the substrate W after the wet treatment process. The thickness of the etching stop layer 101 may be equal to the thickness of the silicon layer 100 immediately before the etching solution is supplied to the silicon layer 100, or it may be greater or less than that thickness.

[0028] The thinning process may include, in addition to the grinding process and the wet treatment process, at least one of a polishing process and a dry etching process. The polishing process is performed after the grinding process and before the wet treatment process, in which the silicon layer 100 is abraded by friction between abrasive grains and the silicon layer 100, and the back surface of the silicon layer 100 is smoothed. The dry etching process is performed after the grinding or polishing process and before the wet treatment process, in which the silicon layer 100 is etched while the substrate W remains dry by bringing an etching gas (containing at least one of ions and radicals generated from the etching gas) into contact with the back surface of the silicon layer 100. The polishing process may be CMP (Chemical Mechanical Polishing).

[0029] The wet processing step includes an AOM supply step in which an Ammonia Ozone Mixture (AOM), which is a mixture of ammonia water and ozonated water, is supplied to the back surface of the silicon layer 100. As will be described later, in the AOM supply step, hot AOM, which is hotter than room temperature (for example, 20-30°C), is supplied. The AOM supply step is a step in which the silicon layer 100 is removed to expose the etching stop layer 101. Even after the AOM supply step is performed, that is, after the AOM is removed from the substrate W, the etching stop layer 101 remains on the substrate W.

[0030] The wet treatment process may include multiple etching solution supply steps for individually supplying multiple types of etching solutions to the back surface of the silicon layer 100, and at least one rinse solution supply step for supplying a rinse solution to the back surface of the silicon layer 100 before changing the type of etching solution. The AOM supply step is one of the multiple etching solution supply steps.

[0031] The multiple etching solution supply steps may include at least one of the following: a hydrofluoric acid supply step, which supplies hydrofluoric acid (a mixture of hydrofluoric acid and nitric acid) to the back surface of the silicon layer 100 before supplying hot AOM; and a TMAH supply step, which supplies TMAH (Tetramethylammonium hydroxide) to the back surface of the silicon layer 100 before supplying hot AOM. If the multiple etching solution supply steps include an AOM supply step, a hydrofluoric acid supply step, and a TMAH supply step, hydrofluoric acid, TMAH, and hot AOM may be supplied to the back surface of the silicon layer 100 in this order. Hydrofluoric acid, TMAH, and hot AOM are all examples of etching solutions.

[0032] The rate at which the thickness of the substrate W decreases during the wet processing step is less than the rate at which the thickness of the substrate W decreases during the grinding step. Therefore, the rate at which the thickness of the substrate W decreases when supplied with hydrofluoric acid, TMAH, or hot AOM is less than the rate at which the thickness of the substrate W decreases during the grinding step. The rate at which hot AOM etches the silicon layer 100 (etching rate per unit time) is less than the rate at which hydrofluoric acid etches the silicon layer 100, and less than the rate at which TMAH etches the silicon layer 100.

[0033] When the hot AOM etches the silicon layer 100, the etching stop layer 101 is exposed from the silicon layer 100, and the hot AOM comes into contact with the etching stop layer 101. The hot AOM is a liquid that selectively etches the silicon layer 100 without etching or with little etching of the etching stop layer 101. The rate at which the hot AOM etches the silicon layer 100 is greater than the rate at which the hot AOM etches the etching stop layer 101. The ratio of the rate at which the silicon layer 100 is etched to the rate at which the etching stop layer 101 is etched is defined as the selectivity ratio. The selectivity ratio when the hot AOM is supplied is greater than the selectivity ratio when the hydrofluoric acid is supplied, and is greater than the selectivity ratio when the TMAH is supplied.

[0034] Next, we will describe the substrate processing apparatus 1 that performs the aforementioned wet processing step.

[0035] Figure 2 is a schematic diagram showing the interior of a processing unit 2 in a substrate processing apparatus 1 according to one embodiment, viewed horizontally. The substrate processing apparatus 1 is a single-wafer type apparatus that processes disc-shaped substrates W one at a time. The substrate processing apparatus 1 includes a load port that holds a carrier that accommodates multiple substrates W, such as a FOUP (Front-Opening Unified Pod), a plurality of processing units 2 that process the substrates W transported from the carrier on the load port with a processing fluid such as a processing liquid or processing gas, a transport system that transports the substrates W between the carrier on the load port and the plurality of processing units 2, and a control device 3 that controls the substrate processing apparatus 1.

[0036] The control device 3 controls the electrical and electronic equipment provided in the substrate processing device 1. The control device 3 includes at least one computer that can communicate with each other. The computer includes a memory 3b for storing information such as programs, and a CPU 3a (central processing unit) that controls the substrate processing device 1 according to the programs stored in the memory 3b. By controlling the substrate processing device 1, the control device 3 performs processing on the substrate W, which will be described later. In other words, the control device 3 is programmed to perform processing on the substrate W, which will be described later.

[0037] Figure 2 shows one of several processing units 2. Each processing unit 2 is a wet processing unit that performs at least the wet processing steps described above. The processing unit 2 includes a chamber 4 for housing the substrate W and a spin chuck 10 that holds one substrate W horizontally within the chamber 4 and rotates it around a vertical axis of rotation A1 passing through the center of the substrate W.

[0038] Chamber 4 includes a box-shaped partition wall 5 with a passage 5b through which the substrate W passes, and a door 6 that opens and closes the passage 5b. The FFU 7 (Fan Filter Unit 7) is positioned above an air outlet 5a located at the top of the partition wall 5. The FFU 7 constantly supplies clean air (air filtered by the filter) into Chamber 4 from the air outlet 5a. The gas inside Chamber 4 is discharged from Chamber 4 through an exhaust duct 8 connected to the bottom of a processing cup 21, which will be described later. This constantly creates a downflow of clean air inside Chamber 4. The flow rate of the exhaust discharged into the exhaust duct 8 is changed according to the opening degree of the exhaust valve 9 located inside the exhaust duct 8.

[0039] The spin chuck 10 includes a horizontally held disc-shaped spin base 12, a plurality of chuck pins 11 that horizontally hold the substrate W above the spin base 12, and a spin motor 13 that rotates the spin base 12 and the plurality of chuck pins 11 around a rotation axis A1. The spin chuck 10 is not limited to a mechanical chuck in which the plurality of chuck pins 11 contact the end face of the substrate W, but may also be a vacuum chuck that holds the substrate W horizontally by adhering the lower surface of the substrate W to the upper surface 12u of the spin base 12. If the spin chuck 10 is a mechanical chuck, the plurality of chuck pins 11 correspond to a substrate holder. If the spin chuck 10 is a vacuum chuck, the spin base 12 corresponds to a substrate holder.

[0040] The processing unit 2 includes a cylindrical processing cup 21 that receives processing liquid splashed from the substrate W. The processing cup 21 includes a plurality of guards 24 that receive processing liquid discharged outward from the substrate W held by the spin chuck 10, a plurality of cups 23 that receive processing liquid guided downward by the plurality of guards 24, and a cylindrical outer wall 22 that surrounds the plurality of guards 24 and the plurality of cups 23. Figure 2 shows an example in which four guards 24 and three cups 23 are provided, and the outermost cup 23 is integrated with the third guard 24 from the top.

[0041] The guard 24 includes a cylindrical portion 25 surrounding the spin chuck 10 and an annular ceiling portion 26 extending diagonally upward toward the rotation axis A1 from the upper end of the cylindrical portion 25. Multiple ceiling portions 26 are stacked vertically, and multiple cylindrical portions 25 are arranged concentrically. The annular upper end of the ceiling portion 26 corresponds to the upper end 24u of the guard 24 surrounding the substrate W and spin base 12 in a plan view. Multiple cups 23 are each located below the multiple cylindrical portions 25. The cups 23 form annular grooves that receive the processing liquid guided downward by the guard 24.

[0042] The processing unit 2 includes a lifting actuator 27 that individually raises and lowers multiple guards 24. The lifting actuator 27 holds the guards 24 stationary at any position within the range from the upper position to the lower position. Figure 2 shows a state where two guards 24 are positioned in the upper position and the remaining two guards 24 are positioned in the lower position. The upper position is a position where the upper end 24u of the guard 24 is positioned above the holding position where the substrate W held by the spin chuck 10 is placed. The lower position is a position where the upper end 24u of the guard 24 is positioned below the holding position.

[0043] An actuator is a device that converts driving energy, represented by electricity, fluid, magnetic, thermal, or chemical energy, into mechanical work, i.e., the motion of a tangible object. Actuators include electric motors (rotary motors), linear motors, air cylinders, and other devices. When the motion of the actuator differs from the motion of the object, a motion converter may be provided to convert the actuator's motion into linear motion or rotation. For example, if the actuator is an electric motor and the object is to move in a linear motion, a motion converter such as a ball screw and ball nut may be used to convert the rotation of the electric motor into linear motion.

[0044] The processing unit 2 includes a plurality of nozzles that discharge processing fluids such as processing liquid and processing gas toward the substrate W held by the spin chuck 10. The plurality of nozzles include chemical nozzles 31a, rinse nozzles 31b, and etching nozzles 31c, etc.

[0045] The chemical nozzle 31a is a nozzle that discharges the chemical solution toward the upper surface of the substrate W. The rinsing solution nozzle 31b is a nozzle that discharges the rinsing solution toward the upper surface of the substrate W. The etching solution nozzle 31c is a nozzle that discharges the etching solution toward the upper surface of the substrate W. Figure 2 shows an example in which the chemical solution is DHF (Dilute Hydrogen Fluoride), the rinsing solution is DIW (Pure Water), and the etching solution is HotAOM (Ammonia Water, Ozone Water, and Hot Water).

[0046] The chemical nozzle 31a may be a scanning nozzle that moves the impact position of the chemical on the substrate W within the upper surface of the substrate W, or it may be a fixed nozzle that cannot move the impact position of the chemical on the substrate W. The same applies to the other nozzles. Figure 2 shows an example in which the chemical nozzle 31a, rinse nozzle 31b, and etching nozzle 31c are scanning nozzles.

[0047] The chemical nozzle 31a is connected to a first nozzle actuator 35a that moves the chemical nozzle 31a in at least one of the vertical and horizontal directions. The chemical nozzle 31a extends downward from a first nozzle arm 34a that extends horizontally within the chamber 4. The first nozzle actuator 35a moves the chemical nozzle 31a by moving the first nozzle arm 34a.

[0048] The rinse liquid nozzle 31b is connected to a second nozzle actuator 35b that moves the rinse liquid nozzle 31b in at least one of the vertical and horizontal directions. The rinse liquid nozzle 31b extends downward from a second nozzle arm 34b that extends horizontally within the chamber 4. The second nozzle actuator 35b moves the rinse liquid nozzle 31b by moving the second nozzle arm 34b.

[0049] The etching nozzle 31c is connected to a third nozzle actuator 35c that moves the etching nozzle 31c in at least one of the vertical and horizontal directions. The etching nozzle 31c extends downward from a third nozzle arm 34c that extends horizontally within the chamber 4. The third nozzle actuator 35c moves the etching nozzle 31c by moving the third nozzle arm 34c.

[0050] The first nozzle actuator 35a moves the chemical solution nozzle 31a horizontally between a processing position in which the chemical solution discharged from the chemical solution nozzle 31a is supplied to the upper surface of the substrate W, and a standby position in which the chemical solution nozzle 31a is positioned around the processing cup 21 in a plan view. The same applies to the second nozzle actuator 35b and the third nozzle actuator 35c. Figure 2 shows the state in which the chemical solution nozzle 31a and the rinse solution nozzle 31b are positioned in the standby position, and the etching solution nozzle 31c is positioned in the processing position.

[0051] The chemical nozzle 31a is connected to a chemical pipe 32a that guides the chemical solution. When the chemical valve 33a attached to the chemical pipe 32a is opened, the discharge port of the chemical nozzle 31a continuously discharges the chemical solution downwards. The chemical solution may be a liquid containing at least one of sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, acetic acid, ammonia water, hydrogen peroxide, organic acids (e.g., citric acid, oxalic acid, etc.), organic alkalis (e.g., TMAH (Tetramethylammonium hydroxide)), surfactants, and corrosion inhibitors, or it may be any other liquid.

[0052] Although not shown in the diagram, the chemical solution valve 33a includes a valve body provided with an annular valve seat through which the chemical solution passes, a valve element movable relative to the valve seat, and an actuator that moves the valve element between a closed position where the valve element is in contact with the valve seat and an open position where the valve element is away from the valve seat. The same applies to other valves. The actuator may be a pneumatic actuator or an electric actuator, or any other type of actuator. The control device 3 opens and closes the chemical solution valve 33a, etc., by controlling the actuator.

[0053] The rinse liquid nozzle 31b is connected to the rinse liquid piping 32b that guides the rinse liquid. When the rinse liquid valve 33b attached to the rinse liquid piping 32b is opened, the outlet of the rinse liquid nozzle 31b continuously discharges the rinse liquid downwards. The rinse liquid may be any of the following: pure water (deionized water: DIW), carbonated water, electrolyzed ionized water, hydrogen water, ozonated water, hydrochloric acid water at a dilution concentration (e.g., about 1 to 100 ppm), or ammonia water at a dilution concentration (e.g., about 1 to 100 ppm), or any other liquid.

[0054] The etching solution nozzle 31c is connected to the etching solution piping 32c that guides the etching solution. When the etching solution valve 33c attached to the etching solution piping 32c is opened, the discharge port of the etching solution nozzle 31c continuously discharges the etching solution downwards. The etching solution is a hot AOM (a mixture of ammonia water, ozonated water, and hot water) at a temperature higher than room temperature.

[0055] The multiple nozzles include a chemical nozzle 31a and the like, as well as a bottom nozzle 31h that discharges the processing liquid toward the center of the lower surface of the substrate W. The bottom nozzle 31h includes a disc portion positioned between the upper surface 12u of the spin base 12 and the lower surface of the substrate W, and a cylindrical portion extending downward from the disc portion. The discharge port of the bottom nozzle 31h opens at the center of the upper surface of the disc portion. When the substrate W is held in the spin chuck 10, the discharge port of the bottom nozzle 31h faces the center of the lower surface of the substrate W, both vertically and horizontally.

[0056] The lower nozzle 31h is connected to a rinse fluid pipe 32h that guides the rinse fluid. Figure 2 shows an example where the rinse fluid is pure water. When the rinse fluid valve 33h attached to the rinse fluid pipe 32h is opened, the rinse fluid is continuously discharged upward from the outlet of the lower nozzle 31h. Figure 2 shows an example in which a heater 36h is provided to heat the pure water supplied from the rinse fluid pipe 32h to the lower nozzle 31h. In this example, hot water (pure water at a temperature higher than room temperature), which is an example of a heated liquid, is supplied from the lower nozzle 31h to the substrate W.

[0057] Next, we will describe the AOM supply system that supplies hot AOM to the substrate W.

[0058] Figure 3 is a schematic diagram showing the AOM supply system provided in the substrate processing apparatus 1. The substrate processing apparatus 1 includes an AOM supply system for supplying hot AOM to the substrate W. The AOM supply system includes an etching solution nozzle 31c, an etching solution piping 32c, and an etching solution valve 33c. The AOM supply system further includes a tank 41e for storing ammonia water, an ozone water generator 42c for generating ozonated water by dissolving ozone gas in pure water, and a hot water heater 43c for generating hot water by heating pure water. The tank 41e, the ozone water generator 42c, and the hot water heater 43c are located outside the chamber 4.

[0059] The etching nozzle 31c includes a discharge port 31p for discharging hot AOM toward the upper surface of the substrate W. The discharge port 31p is open on the surface of the etching nozzle 31c and is spaced apart from the upper surface of the substrate W, facing it vertically. Figure 3 shows an example in which ozonated water and hot water are mixed with ammonia water in the path to the discharge port 31p of the etching nozzle 31c, excluding the tank 41e. In this example, ammonia water piping 41b, ozonated water piping 42b, and hot water piping 43b are connected to the etching pipe 32c, and the ammonia water, ozonated water, and hot water are mixed in the etching pipe 32c. The ozonated water and hot water may also be mixed with ammonia water in the tank 41e.

[0060] In the example shown in Figure 3, ammonia water is sent from tank 41e to ammonia water piping 41b by pump 41d. Foreign matter contained in the ammonia water is removed by filter 41c attached to ammonia water piping 41b. When the ammonia water valve 41a attached to ammonia water piping 41b is opened, ammonia water from tank 41e is supplied to etching solution piping 32c via ammonia water piping 41b. When the ozone water valve 42a attached to ozone water piping 42b is opened, ozone water generated by ozone water generator 42c is supplied to etching solution piping 32c via ozone water piping 42b. When the hot water valve 43a attached to hot water piping 43b is opened, hot water generated by hot water heater 43c is supplied to etching solution piping 32c via hot water piping 43b.

[0061] Figure 3 shows an example in which the ammonia water valve 41a, ozone water valve 42a, and hot water valve 43a are part of the mixing valve MV. The ammonia water valve 41a is a valve that serves as both an on / off valve that switches between an open state that allows liquid such as ammonia water to pass through and a closed state that stops the liquid, and a flow control valve that stabilizes the flow rate of the liquid passing through at any value within a certain range. The ozone water valve 42a and hot water valve 43a are similar. Instead of the ammonia water valve 41a, separate on / off valves and flow control valves may be installed in the etching solution piping 32c. The same applies to the other piping.

[0062] When the ammonia water valve 41a, ozone water valve 42a, and hot water valve 43a are opened, the ammonia water, ozone water, and hot water mix in the etching solution piping 32c at a mixing ratio corresponding to the opening of the ammonia water valve 41a, ozone water valve 42a, and hot water valve 43a. As a result, an etching solution equivalent to the mixture of ammonia water, ozone water, and hot water is supplied from the etching solution piping 32c to the etching solution nozzle 31c and discharged from the discharge port 31p of the etching solution nozzle 31c.

[0063] Ammonia water is also called ammonium hydroxide (NH4OH). A mixture of ammonia water, ozonated water, and hot water is a liquid obtained by mixing ozonated water with diluted ammonia water (dNH4OH) diluted with hot water. AOM (Ammonia Ozone Mixture) is a mixture of ammonia water and ozonated water. A mixture of ammonia water, ozonated water, and hot water is included in AOM. A mixture of ammonia water, ozonated water, and hot water is hot AOM, which is at a temperature higher than room temperature.

[0064] As long as the temperature of the hot AOM is higher than room temperature, the temperatures of the ammonia water, ozonated water, and hot water may be any. The temperature of the hot water is higher than the temperature of the ammonia water. The temperature of the hot water is higher than the temperature of the ozonated water. The temperature of the ammonia water may be equal to or different from the temperature of the ozonated water. The temperature of the ammonia water may be room temperature or a different value from room temperature. The same applies to the ozonated water.

[0065] The concentration of ozone gas in ozonated water is higher than the concentration of ozone gas in ammonia water. The concentration of ozone gas in ozonated water is higher than the concentration of ozone gas in hot water. Multiple ozone molecules in ozonated water are converted into multiple oxygen molecules. This increases the dissolved oxygen concentration in ozonated water. The dissolved oxygen concentration in ozonated water is higher than the dissolved oxygen concentration in ammonia water. The dissolved oxygen concentration in ozonated water is higher than the dissolved oxygen concentration in hot water. The dissolved oxygen concentration in ammonia water may be equal to or different from that of hot water. Ammonia water may be a liquid with an unadjusted dissolved oxygen concentration, or a liquid with an increased or decreased dissolved oxygen concentration. The same applies to hot water.

[0066] The concentration of ozone gas in a hot AOM may be the saturation concentration of ozone gas at the temperature of the hot AOM, or it may be less than the saturation concentration. Under the same conditions, such as temperature, the solubility of ozone gas in water is higher than that of oxygen gas. Therefore, mixing ozonated water (water in which ozone gas is dissolved) with ammonia water can increase the dissolved oxygen concentration of the hot AOM to a higher value than when mixing oxygenated water (water in which oxygen gas is dissolved) with ammonia water.

[0067] If the diameter of the disc-shaped substrate W is 300 mm, the flow rate of the hot AOM supplied to the top surface of the substrate W may be 2000 ml / min or less. The concentration of ammonia in the hot AOM is, for example, 0.5 to 5.0 wt% or vol%, and the concentration of ozonated water is, for example, 10 to 50 ppm. For example, 30 ppm ozonated water is mixed at a rate of 50 ml / min with ammonia water flowing at 2000 ml / min. The temperature of the hot AOM may be above room temperature and below 90°C. The concentration of ammonia in the ammonia water may be 0.5 to 5.0 wt% or vol%. The concentration of ozone gas in the ozonated water may be 5 to 80 ppm. The temperature of the hot water may be 40 to 89.9°C.

[0068] The following describes an example in which room temperature ammonia water with an ammonia concentration of 0.5-5.0 wt% or vol%, room temperature ozonated water with an ozone gas concentration of 5-80 ppm, and hot water at 40-89.9°C are mixed so that hot AOM is supplied to the substrate W at a rate of approximately 2000 ml / min. In this example, the flow rate of the ammonia water is 95 ml / min, the flow rate of the ozonated water is 33.3-400 ml / min, and the flow rate of the hot water is 1505-1871.7 ml / min.

[0069] When hot water, which is an example of a heating liquid, is discharged from the lower nozzle 31h toward the lower surface of the substrate W, the temperature of the hot water may be equal to or different from the temperature of the hot AOM. In this case, the temperature of the hot water discharged from the lower nozzle 31h may be equal to or different from the temperature of the hot water used to generate the hot AOM. The temperature of the hot water discharged from the lower nozzle 31h may be between room temperature and 90°C. The flow rate of the hot water discharged from the lower nozzle 31h may be greater than 0 and less than or equal to 2000 ml / min. In other words, the flow rate of the heating liquid discharged toward the lower surface of the substrate W may be equal to or different from the flow rate of the hot AOM discharged toward the upper surface of the substrate W.

[0070] Next, we will describe an example of the processing of substrate W.

[0071] Figure 4 is a process diagram illustrating an example of substrate W processing performed by the substrate processing apparatus 1. Figure 5A is a schematic diagram illustrating the same example. The following references are to Figures 2, 4, and 5A. In Figure 5A, DIW represents pure water.

[0072] When processing the substrate W with the substrate processing apparatus 1, a loading process (step S1 in Figure 4) is performed in which the substrate W is loaded into the chamber 4.

[0073] Specifically, with all guards 24 in the lower position and all scan nozzles in the standby position, the transport system (not shown) places the substrate W on the hand (not shown) onto the multiple chuck pins 11 with the silicon layer 100 (see Figure 1C) facing upward, and then retracts the hand from inside the chamber 4. Once the substrate W is placed on the multiple chuck pins 11, all the chuck pins 11 are pressed against the end face of the substrate W, and the substrate W is held in the spin chuck 10. Then the spin motor 13 is driven and the rotation of the substrate W begins (step S2 in Figure 4).

[0074] Next, a chemical solution supply step (step S3 in Figure 4) is performed in which DHF, an example of a chemical solution, is supplied to the upper surface of the substrate W to form a liquid film of DHF that covers the entire upper surface of the substrate W.

[0075] Specifically, with at least one guard 24 in the upper position, the first nozzle actuator 35a moves the chemical nozzle 31a from the standby position to the processing position. Then, the chemical valve 33a opens, and the chemical nozzle 31a starts discharging DHF. After a predetermined time has elapsed since the chemical valve 33a was opened, the chemical valve 33a is closed, and the discharge of DHF stops. Then, the first nozzle actuator 35a moves the chemical nozzle 31a back to the standby position.

[0076] As shown on the left edge of Figure 5A, the DHF discharged from the chemical nozzle 31a collides with the upper surface of the substrate W, which is rotating at the chemical supply speed, and then flows outward along the upper surface of the substrate W. As a result, the DHF is supplied to the entire upper surface of the substrate W, and a liquid film of DHF is formed that covers the entire upper surface of the substrate W. When the chemical nozzle 31a is discharging DHF, the first nozzle actuator 35a may move the collision position of the DHF with respect to the upper surface of the substrate W so that the collision position passes through the center and the outer periphery, or it may keep the collision position stationary in the center. The same applies to the processing liquid supplied to the upper surface of the substrate W after the DHF in terms of whether or not to move the collision position.

[0077] Next, a first rinsing solution supply step (step S4 in Figure 4) is performed, in which pure water, which is an example of a rinsing solution, is supplied to the upper surface of the substrate W to wash away the DHF on the substrate W.

[0078] Specifically, with at least one guard 24 in the upper position, the second nozzle actuator 35b moves the rinse liquid nozzle 31b from the standby position to the processing position. Then, the rinse liquid valve 33b opens, and the rinse liquid nozzle 31b begins to discharge pure water. Before the discharge of pure water begins, the lifting actuator 27 may move at least one guard 24 vertically to switch the guard 24 that receives the liquid discharged from the substrate W. The same applies to the processing liquid supplied to the upper surface of the substrate W after the pure water, regarding whether or not to switch the guard 24 that receives the liquid discharged from the substrate W.

[0079] As shown second from the left in Figure 5A, the pure water discharged from the rinse liquid nozzle 31b collides with the upper surface of the substrate W, which is rotating at the rinse liquid supply speed, and then flows outward along the upper surface of the substrate W. The DHF on the substrate W is replaced by the pure water discharged from the rinse liquid nozzle 31b. This forms a liquid film of pure water that covers the entire upper surface of the substrate W. After a predetermined time has elapsed since the rinse liquid valve 33b was opened, the rinse liquid valve 33b is closed and the discharge of pure water stops. Subsequently, the second nozzle actuator 35b moves the rinse liquid nozzle 31b to the standby position.

[0080] Next, an AOM supply step (step S5 in Figure 4) is performed, in which a hot AOM, which is an example of an etching solution, is supplied to the upper surface of the substrate W to form a liquid film of hot AOM that covers the entire upper surface of the substrate W.

[0081] Specifically, with at least one guard 24 in the upper position, the third nozzle actuator 35c moves the etching solution nozzle 31c from the standby position to the processing position. Then, the etching solution valve 33c is opened, and the etching solution nozzle 31c begins dispensing hot AOM.

[0082] As shown in the third image from the left in Figure 5A, the hot AOM discharged from the etching solution nozzle 31c collides with the upper surface of the substrate W, which is rotating at the etching solution supply speed, and then flows outward along the upper surface of the substrate W. The pure water on the substrate W is replaced by the hot AOM discharged from the etching solution nozzle 31c. This forms a liquid film of hot AOM that covers the entire upper surface of the substrate W. After a predetermined time has elapsed since the etching solution valve 33c was opened, the etching solution valve 33c is closed and the discharge of hot AOM stops. Subsequently, the third nozzle actuator 35c moves the etching solution nozzle 31c to the standby position.

[0083] When the etching nozzle 31c is discharging hot AOM toward the upper surface of the substrate W, the lower nozzle 31h may or may not discharge a heating liquid at a temperature higher than room temperature, such as hot water, toward the lower surface of the substrate W. Figures 4 and 5A show an example in which hot water is discharged from the lower nozzle 31h while hot AOM is being discharged from the etching nozzle 31c. The discharge of hot water from the lower nozzle 31h may start at the same time that the etching nozzle 31c starts discharging hot AOM, or it may start before or after the etching nozzle 31c starts discharging hot AOM. The discharge of hot water from the lower nozzle 31h may stop at the same time that the etching nozzle 31c stops discharging hot AOM, or it may stop before or after the etching nozzle 31c starts discharging hot AOM.

[0084] Next, a second rinse solution supply step (step S6 in Figure 4) is performed, in which pure water, which is an example of a rinse solution, is supplied to the upper surface of the substrate W to wash away the hot AOM on the substrate W.

[0085] Specifically, with at least one guard 24 in the upper position, the second nozzle actuator 35b moves the rinse liquid nozzle 31b from the standby position to the processing position. Then, the rinse liquid valve 33b opens, and the rinse liquid nozzle 31b begins to discharge pure water. As shown in the fourth position from the left in Figure 5A, this forms a liquid film of pure water that covers the entire upper surface of the substrate W. After a predetermined time has elapsed since the rinse liquid valve 33b was opened, the rinse liquid valve 33b is closed, and the discharge of pure water stops. Then, the second nozzle actuator 35b moves the rinse liquid nozzle 31b back to the standby position.

[0086] Next, a drying process (step S7 in Figure 4) is performed to dry the substrate W by rotating it.

[0087] Specifically, the spin motor 13 accelerates the substrate W in the rotational direction, rotating the substrate W at the highest drying speed (e.g., several thousand rpm) in the example of substrate W processing shown in Figure 4. As shown on the far right of Figure 5A, when the spin motor 13 starts high-speed rotation of the substrate W, the liquid is scattered outward from the substrate W and removed from the substrate W. This dries the substrate W. After a predetermined time has elapsed since the high-speed rotation of the substrate W began, the spin motor 13 stops rotating. This stops the rotation of the substrate W (step S8 in Figure 4).

[0088] Next, an unloading process (step S9 in Figure 4) is performed to unload the substrate W from the chamber 4.

[0089] Specifically, the lifting actuator 27 lowers all the guards 24 to their lowest position. Then, a transport system (not shown) moves a hand (not shown) into the chamber 4. After the multiple chuck pins 11 release the substrate W from gripping it, the transport system supports the substrate W on the spin chuck 10 with the hand. Then, while supporting the substrate W with the hand, the transport system retracts the hand from inside the chamber 4. As a result, the processed substrate W is discharged from the chamber 4.

[0090] Next, we will explain the phenomena that are expected to occur on the substrate W when the process shown in Figure 4 is being performed.

[0091] Figures 5B, 5C, and 5D are schematic cross-sectional views of the substrate W to illustrate the phenomenon. When the silicon layer 100 is exposed to air, the surface layer of the silicon layer 100 changes into a native silicon oxide film 105, that is, a thin film of silicon dioxide. Figure 5B shows a state in which DHF, an example of a native oxide film removal solution, is in contact with the native oxide film 105.

[0092] As shown in Figures 5B and 5C, when DHF is supplied to the substrate W, the native oxide film 105 dissolves in the DHF and is removed from the silicon layer 100. This exposes the silicon single crystal that makes up the back surface (top surface in Figures 5B and 5C) of the silicon layer 100. If the dry etching process is included in the thinning process, the particles generated on the back surface of the silicon layer 100 during the dry etching process are removed from the silicon layer 100 along with the native oxide film 105.

[0093] After replacing the DHF on the substrate W with pure water, when hot AOM is supplied to the substrate W, the hot AOM comes into contact with the back surface of the silicon layer 100, i.e., the silicon single crystal, as shown in Figure 5C. Si in Figures 5B and 5C represents the silicon single crystal. The silicon single crystal dissolves in the hot AOM. Therefore, as shown in Figure 5D, the silicon layer 100 is etched in the thickness direction of the substrate W over the entire area from the center to the outer periphery of the substrate W, and the etching stop layer 101 is exposed over the entire back surface of the substrate W (see also Figure 5A).

[0094] As shown in Figure 5C, multiple ozone molecules transform into multiple oxygen molecules. Therefore, when ozonated water is dissolved in ammonia water, the ammonia water is diluted with the ozonated water, and the dissolved oxygen concentration in the ammonia water increases. The oxygen molecules in the hot AOM oxidize the back surface of the silicon layer 100. The ozone molecules in the hot AOM also oxidize the back surface of the silicon layer 100. As a result, excessive etching of the silicon layer 100 by the ammonia water is suppressed, and the uniformity of etching of the silicon layer 100 is expected to increase.

[0095] On the other hand, since ozonated water and hot water are mixed with ammonia water, the ammonia water is diluted with ozonated water and hot water, and the ammonia water and ozonated water are heated by the hot water. This generates hot AOM, which is hotter than room temperature. This increases the etching rate of the silicon layer 100, that is, the etching speed of the silicon layer 100 (amount of etching per unit time). Therefore, it is possible to shorten the time required to etch the silicon layer 100 while improving the uniformity of etching the silicon layer 100.

[0096] Generally, scanning the nozzle while rotating the substrate W (moving the impact position of the processing liquid within the upper surface of the substrate W while rotating the substrate W) improves processing uniformity compared to when the impact position of the processing liquid is stationary in the center of the upper surface of the substrate W. When hot AOM is supplied to the upper surface of the substrate W while rotating the substrate W, it was confirmed that uniformity equivalent to or better than when the impact position of the hot AOM is moved within the upper surface of the substrate W can be obtained even if the impact position of the hot AOM is stationary in the center of the upper surface of the substrate W.

[0097] Next, the effects of this embodiment will be described.

[0098] In this embodiment, the hot AOM corresponds to high-temperature ammonia water with a higher dissolved oxygen concentration at a temperature higher than room temperature. This hot AOM is supplied to the substrate W. As a result, the hot AOM comes into contact with the silicon layer 100, which is an example of an etching target, and etches the silicon layer 100. Since the dissolved oxygen concentration of the hot AOM is increased, the uniformity of etching the silicon layer 100 can be improved. Furthermore, since the temperature of the hot AOM is increased, the etching rate of the silicon layer 100 can be increased while improving the uniformity of etching the silicon layer 100.

[0099] In this embodiment, a hot AOM (a mixture of ammonia water, ozonated water, and hot water) is produced by mixing these together. The ammonia water and ozonated water are heated by the hot water. This allows the temperature of the hot AOM to be raised to a value higher than room temperature. Multiple ozone molecules in the hot AOM are converted into multiple oxygen molecules. This increases the dissolved oxygen concentration of the hot AOM. The oxygen molecules in the hot AOM oxidize the back surface of the silicon layer 100. The ozone molecules in the hot AOM also oxidize the back surface of the silicon layer 100. This is expected to suppress excessive etching of the silicon layer 100 by the ammonia water and improve the uniformity of the etching of the silicon layer 100.

[0100] When etching materials such as silicon and polysilicon with ammonia water, oxygen from the air can dissolve into the ammonia water, potentially reducing the uniformity of the etching process. Dispersing ozone gas, an example of an oxidizing agent, into the ammonia water can mitigate or prevent the reduction in uniformity caused by oxygen in the air. Furthermore, it was confirmed that adding ozonated water to ammonia water significantly improved the etching uniformity of the etching material while hardly changing the etching rate. Therefore, it is possible to improve the etching uniformity of the etching material with minimal impact on the etching rate.

[0101] In this embodiment, the ammonia water, ozonated water, and hot water are mixed in the path to the etching solution nozzle 31c, rather than in the tank 41e where the ammonia water is stored. Therefore, compared to the case where the ammonia water, ozonated water, and hot water are mixed in the tank 41e, the time from when they are mixed until they are supplied to the substrate W can be shortened. The rate at which ozone molecules in a liquid decompose increases with increasing temperature of the liquid. This rate also increases with increasing pH (hydrogen ion concentration) of the liquid. Hot AOM is a liquid with a temperature higher than room temperature and a pH greater than 7. Therefore, ozone molecules in hot AOM decompose in a short time. By shortening the time from when the ammonia water, ozonated water, and hot water are mixed until they are supplied to the substrate W, the amount of ozone molecules that decompose before the hot AOM is supplied to the substrate W can be reduced.

[0102] In this embodiment, the silicon layer 100 is etched with hot AOM until the etching stop layer 101 is exposed. Hot AOM is a liquid that etches the etching stop layer 101 at an etching rate lower than the etching rate of the silicon layer 100. When the etching stop layer 101 is exposed, the hot AOM comes into contact with the etching stop layer 101, and etching of the etching stop layer 101 begins. If the etching of the silicon layer 100 is uneven, only a part of the etching stop layer 101 will be exposed, and then the entire etching stop layer 101 will be exposed. In this case, the etching stop layer 101 will also be etched unevenly. By improving the uniformity of the etching of the silicon layer 100, uneven etching of the etching stop layer 101 can be reduced.

[0103] In this embodiment, the thickness of the etching stop layer 101 is less than the thickness to which the hot AOM etches the silicon layer 100. If the etching of the silicon layer 100 is uneven, the etching stop layer 101 will also be etched unevenly by the hot AOM. In this case, if the etching stop layer 101 is thin, there is a possibility that a part of the etching stop layer 101 will penetrate. By improving the uniformity of the etching of the silicon layer 100, uneven etching of the etching stop layer 101 can be reduced. This makes it possible to make the etching stop layer 101 thinner, and thus the material and time required to manufacture the etching stop layer 101 can be reduced.

[0104] In this embodiment, by supplying hot AOM to the substrate W, the silicon layer 100, which corresponds to a plate-shaped substrate made of a single crystal of silicon, is etched from the back side of the silicon layer 100. As a result, the entire silicon layer 100 is removed from the substrate W. The etching stop layer 101 corresponds to a thin film in contact with the surface of the substrate. Once the entire silicon layer 100 is removed from the substrate W, the hot AOM comes into contact with the etching stop layer 101. Since the uniformity of etching of the silicon layer 100 is increased when the hot AOM is supplied, even if the etching stop layer 101 is etched by the hot AOM, it is possible to reduce the uneven etching of the etching stop layer 101. Furthermore, since the entire silicon layer 100 is removed, although a large amount needs to be etched by the hot AOM, the etching rate of the silicon layer 100 is increased, so the increase in the time required to remove the silicon layer 100 can be reduced.

[0105] In this embodiment, before supplying high-temperature ammonia water to the substrate W, a treatment solution containing hydrofluoric acid such as DHF is supplied to the substrate W as a native oxide film removal solution. This removes the native oxide film 105 of the silicon layer 100. Therefore, compared to not removing the native oxide film 105, the hot AOM can be brought into contact with the silicon layer 100 more efficiently, and the silicon layer 100 can be etched more efficiently. Furthermore, if foreign matter such as particles is attached to the native oxide film 105, the foreign matter can be removed along with the native oxide film 105, thereby improving the cleanliness of the substrate W.

[0106] In this embodiment, with the hot AOM in contact with the upper surface of the substrate W, hot water, which is an example of a heating liquid, is supplied to the lower surface of the substrate W. If the temperature of the hot water is higher than the temperature of the hot AOM, the temperature of the hot AOM can be increased. If the temperature of the hot water is lower than or equal to the temperature of the hot AOM, the rate at which the temperature of the hot AOM decreases can be reduced. In either case, the time required to remove the silicon layer 100 can be shortened compared to when hot water is not supplied to the lower surface of the substrate W.

[0107] In this embodiment, thinning of the substrate W is performed by supplying high-temperature ammonia water to the substrate W. That is, the silicon layer 100 is etched in the thickness direction of the substrate W over the entire area from the center to the outer edge of the substrate W, thereby reducing the overall thickness of the substrate W. As a result, the entire substrate W becomes thinner. Since the uniformity of etching the silicon layer 100 by hot AOM is increased, the entire substrate W can be thinned uniformly. In addition, since the etching rate when etching the silicon layer 100 by hot AOM is increased, the time required for thinning the substrate W can be shortened.

[0108] Next, other embodiments will be described.

[0109] The etching target may not be a single silicon crystal such as silicon layer 100, but rather polysilicon, which is an aggregate of silicon single crystals. Alternatively, both silicon single crystals and polysilicon may be the etching targets.

[0110] Instead of mixing ozonated water and ammonia water, ozone gas may be dissolved in ammonia water at room temperature or higher. The dissolved oxygen concentration of the ammonia water may be increased by dissolving a gas other than ozone gas, such as oxygen gas, in ammonia water at room temperature or higher. Alternatively, the dissolved oxygen concentration of the ammonia water may be increased by mixing water containing a gas other than ozone gas with ammonia water at room temperature or higher. In other words, if the temperature of the high-temperature ammonia water is higher than room temperature and the dissolved oxygen concentration of the high-temperature ammonia water is increased, ozone gas-free high-temperature ammonia water may be supplied to the substrate W.

[0111] The substrate W to which the hot AOM should be supplied may be a substrate W other than a bonded substrate W that includes a bonded first silicon wafer W1 and a second silicon wafer W2.

[0112] Hot AOM may be supplied to the substrate W in processes other than the thinning process.

[0113] Instead of etching the entire silicon layer 100 with hot AOM and then removing the hot AOM from the substrate W, the hot AOM may be removed from the substrate W while a portion of the silicon layer 100 remains on the substrate W. In this case, the etching target may be etched in the plane direction of the substrate W, which is perpendicular to the thickness direction of the substrate W, in addition to or instead of the thickness direction of the substrate W. The etching target may be covered by a thin film other than the etching target, such as a resist pattern.

[0114] Ammonia water, ozonated water, and hot water may be mixed at a location other than the etching solution piping 32c. For example, ammonia water, ozonated water, and hot water may be mixed in the etching solution nozzle 31c. If two of the ammonia water, ozonated water, and hot water are mixed at a first mixing location such as the tank 41e or the etching solution piping 32c, the remaining one of the ammonia water, ozonated water, and hot water may be mixed with the other two at a second mixing location different from the first mixing location.

[0115] After supplying DHF but before supplying hot AOM, a processing solution other than DHF and hot AOM, such as hydrofluoric acid, may be supplied to the substrate W. Alternatively, after supplying hot AOM but before drying the substrate W, a processing solution other than DHF and hot AOM may be supplied to the substrate W.

[0116] Processing unit 2 may perform processes included in the thinning process other than the wet processing process, in addition to the wet processing process. Multiple processing units 2 may include processing units 2 that perform processes included in the thinning process other than the wet processing process, in addition to a wet processing unit that performs at least the wet processing process. In this case, the substrate W can be transported between the multiple processing units 2.

[0117] Instead of dispensing the chemical solution, rinse solution, and first etching solution from separate nozzles, two or more of these may be dispensed from a single nozzle.

[0118] The substrate processing apparatus 1 is not limited to an apparatus for processing a disc-shaped substrate W, but may also be an apparatus for processing a polygonal substrate W.

[0119] If the back surface of the substrate W (the upper surface of the silicon layer 100 in Figure 1C) is etched with hot AOM or similar high-temperature ammonia water, and the front surface of the substrate W (the lower surface of the silicon substrate 200 in Figure 1C) is not etched or is hardly etched by the high-temperature ammonia water, then the substrate processing apparatus 1 may be a batch-type apparatus that processes multiple substrates W at once.

[0120] You may combine two or more of the aforementioned configurations. You may also combine two or more of the aforementioned processes.

[0121] Although embodiments of the present invention have been described in detail, these are merely specific examples used to clarify the technical content of the present invention, and the present invention should not be construed as being limited to these specific examples. The spirit and scope of the present invention are limited only by the appended claims. [Explanation of Symbols]

[0122] 1: Substrate processing device, 10: Spin chuck, 11: Chuck pin, 12: Spin base, 13: Spin motor, 31a: Chemical nozzle, 31b: Rinse solution nozzle, 31c: Etching solution nozzle, 31h: Bottom nozzle, 31p: Discharge port, 41a: Ammonia water valve, 41b: Ammonia water piping, 41c: Filter, 41d: Pump, 41e: Tank, 42a: Ozone water valve, 42b: Ozone water piping 42c: Ozone water generator, 43a: Hot water valve, 43b: Hot water piping, 43c: Hot water heater, 100: Silicon layer, 101: Etching stop layer, 102: Silicon active layer, 103: Multilayer wiring layer, 104: Power rail, 105: Native oxide film, 200: Silicon substrate, 201: Insulating layer, 300: Adhesive layer, MV: Mixing valve, W: Substrate, W1: First silicon wafer, W2: Second silicon wafer

Claims

1. Prepare a substrate containing an etching target which is at least one of silicon and polysilicon, A substrate processing method comprising: etching the target to be etched by supplying high-temperature ammonia water, in which the dissolved oxygen concentration is increased at a temperature higher than room temperature, to the substrate.

2. The substrate processing method according to claim 1, further comprising generating high-temperature ammonia water by mixing ammonia water, ozonated water, and hot water at a temperature higher than room temperature.

3. Etching the object to be etched includes discharging the high-temperature ammonia water from the etching solution nozzle, The substrate processing method according to claim 2, wherein generating the high-temperature ammonia water includes mixing the ammonia water, the ozonated water, and the hot water in a path from the ammonia water storage tank to the etching solution nozzle.

4. Etching the etching target includes exposing the etching stop layer covered by the etching target by etching the etching target, The substrate processing method according to any one of claims 1 to 3, wherein the high-temperature ammonia water is a liquid that etches the etching stop layer at an etching rate lower than the etching rate of the object to be etched.

5. The substrate processing method according to claim 4, wherein the thickness of the etching stop layer is smaller than the thickness to which the high-temperature ammonia water etches the target to be etched.

6. The substrate comprises a plate-shaped substrate made of a single crystal of silicon having a front surface and a back surface, and a thin film in contact with the front surface of the substrate. The substrate processing method according to any one of claims 1 to 3, wherein etching the target to be etched includes removing the entirety of the substrate by etching the substrate corresponding to the target to be etched from the back side of the substrate.

7. The substrate processing method according to any one of claims 1 to 3, further comprising removing the native oxide film to be etched by supplying a native oxide film removal solution to the substrate before supplying the high-temperature ammonia water to the substrate.

8. Etching the object to be etched includes supplying the high-temperature ammonia water to the upper surface of the substrate, The substrate processing method according to any one of claims 1 to 3, further comprising supplying a heating liquid at a temperature higher than room temperature to the lower surface of the substrate while the high-temperature ammonia water is in contact with the upper surface of the substrate.

9. The substrate processing method according to any one of claims 1 to 3, wherein etching the target to be etched includes supplying the high-temperature ammonia water to the substrate to etch the target to be etched in the thickness direction of the substrate over the entire area from the center of the substrate to the outer periphery of the substrate, thereby thinning the entire substrate.

10. A substrate holder for holding a substrate to be etched, which is at least one of silicon and polysilicon, A substrate processing apparatus comprising: an etching solution nozzle for etching the target to be etched by supplying high-temperature ammonia water, which has a higher dissolved oxygen concentration at a temperature higher than room temperature, to the substrate held in the substrate holder.

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