WO2016152371A1

WO2016152371A1 - Substrate processing method and substrate processing device

Info

Publication number: WO2016152371A1
Application number: PCT/JP2016/055646
Authority: WO
Inventors: 佑介秋月
Original assignee: 株式会社Ｓｃｒｅｅｎホールディングス
Priority date: 2015-03-24
Filing date: 2016-02-25
Publication date: 2016-09-29

Abstract

In order to solve the problem of satisfactorily removing a resist from the surface of a substrate, the present invention is a substrate processing device (1) having a spin chuck (5) and an SPM feed unit (6) for feeding SPM to the substrate (W) held by the spin chuck (5), wherein the SPM feed unit (6) includes a mixing unit (30) for mixing an aqueous hydrogen peroxide solution and hydrofluoric acid and producing a liquid mixture of hydrogen peroxide water and hydrofluoric acid, and an HF-mixed SPM production unit (14) for mixing the liquid mixture and sulfuric acid and producing HF-mixed SPM.

Description

Substrate processing method and substrate processing apparatus

The present invention relates to a substrate processing apparatus and a substrate processing method for removing a resist from the surface of a substrate. Examples of substrates to be processed include semiconductor wafers, liquid crystal display substrates, plasma display substrates, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, photomask substrates, ceramic substrates, and solar cells. For example.

In order to remove the resist from the surface of the substrate, it is known to supply a mixed solution of sulfuric acid and hydrogen peroxide (SPM) to the surface of the substrate.

In a wafer subjected to high dose ion implantation, the surface layer of the resist is hardened due to carbonization and alteration of the resist, so that a hardened layer may be formed on the surface of the resist.

Patent Document 1 proposes a method of removing a resist from the surface of a substrate without ashing even a resist having a hardened layer on the surface. This document discloses a method of supplying high-temperature SPM to a substrate in order to remove the resist whose surface layer is cured by ion implantation from the substrate.

Japanese Patent Laid-Open No. 2008-4878

However, in the method of Patent Document 1, a high-temperature SPM droplet accelerated by nitrogen gas collides with the substrate, so that the device on the wafer may be damaged. Furthermore, since the SPM is supplied as droplets, it may be difficult to secure a sufficient amount of liquid for removing the resist.

Therefore, an object of the present invention is to provide a substrate processing method and a substrate processing apparatus that can satisfactorily remove the resist from the surface of the substrate.

One embodiment of the present invention is a substrate processing method for removing a resist from a surface of a substrate, wherein a mixing step of mixing a hydrogen peroxide solution and hydrofluoric acid to generate a mixed solution of the hydrogen peroxide solution and hydrofluoric acid. And, after the mixing step, a mixture step of mixing the hydrogen peroxide solution and hydrofluoric acid with sulfuric acid to generate an HF mixed SPM that is a mixture solution of sulfuric acid, hydrogen peroxide solution, and hydrofluoric acid. And a supply step of supplying the HF mixed SPM to the surface of the substrate.

The hydrogen peroxide solution and hydrofluoric acid mixed in the mixing step may both be at room temperature.

The generating step may be a step of mixing the hydrogen peroxide solution and hydrofluoric acid mixed solution with sulfuric acid at a position away from the substrate.

The generating step may be a step of mixing the hydrogen peroxide solution and hydrofluoric acid mixed solution and sulfuric acid on the surface of the substrate.

According to these methods, it is possible to remove the resist satisfactorily while suppressing damage to the device on the wafer.

Another embodiment of the present invention includes a substrate holding unit for holding a substrate whose surface is covered with a resist, and sulfuric acid, hydrogen peroxide solution, and hydrofluoric acid on the surface of the substrate held by the substrate holding unit. The SPM supply unit supplies an HF mixed SPM that is a mixed solution of the above, and the SPM supply unit mixes hydrogen peroxide solution and hydrofluoric acid to generate a mixture solution of hydrogen peroxide solution and hydrofluoric acid. And after the mixing unit mixes the hydrogen peroxide solution and hydrofluoric acid, the hydrogen peroxide solution and hydrofluoric acid mixed solution and sulfuric acid are mixed to generate an HF mixed SPM, and A substrate processing apparatus is provided. According to this configuration, it is possible to satisfactorily remove the resist while suppressing damage to devices on the wafer.

The mixing unit may include a mixing tank in which hydrogen peroxide solution and hydrofluoric acid are separately supplied, and the mixture solution of the hydrogen peroxide solution and hydrofluoric acid supplied to the HF mixed SPM generating unit is stored. . According to this configuration, the hydrogen peroxide solution and the hydrofluoric acid can be reliably mixed before the mixed solution of the hydrogen peroxide solution and the hydrofluoric acid is mixed with the sulfuric acid.

The mixing unit may further include a stirring unit for stirring the mixed solution in the mixing tank. According to this configuration, the hydrogen peroxide solution and hydrofluoric acid can be uniformly mixed. The stirring unit may be a rotor that rotates in the liquid mixture stored in the mixing tank, or may be a bubbling unit that generates bubbles in the liquid mixture stored in the mixing tank.

The stirring unit may include a bubbling unit that generates bubbles in the mixed solution by discharging gas from a gas discharge port disposed in the mixed solution stored in the mixing tank. According to this configuration, the hydrogen peroxide solution and hydrofluoric acid are uniformly mixed by the generation of bubbles.

The mixing unit may mix a hydrogen peroxide solution and a smaller amount of hydrofluoric acid than the hydrogen peroxide solution. In this case, the HF mixed SPM generating unit may mix sulfuric acid and the mixed liquid in a smaller amount than the sulfuric acid. According to this configuration, it is possible to generate an HF mixed SPM capable of peeling the resist while suppressing damage to the substrate, that is, an HF mixed SPM having a low HF concentration.

The above-described or other objects, features, and effects of the present invention will be clarified by the following description of embodiments with reference to the accompanying drawings.

1 is a schematic plan view showing a substrate processing apparatus according to an embodiment of the present invention. It is the schematic diagram which looked at the inside of the chamber with which the substrate processing apparatus shown in FIG. 1 was equipped horizontally. It is a block diagram which shows the control apparatus with which the substrate processing apparatus was equipped. It is a flowchart which shows an example of the resist removal process performed by the processing unit shown in FIG. It is a figure which shows the conditions and result of a resist removal test. It is a figure which shows a part of substrate processing apparatus which concerns on other embodiment of this invention. It is a figure which shows a part of substrate processing apparatus which concerns on other embodiment of this invention.

FIG. 1 is a schematic plan view showing a substrate processing apparatus 1 according to an embodiment of the present invention. FIG. 2 is a schematic view of the inside of the chamber 4 provided in the substrate processing apparatus 1 as viewed horizontally.

As shown in FIG. 1, the substrate processing apparatus 1 is a single-wafer type apparatus that processes a disk-shaped substrate W such as a semiconductor wafer one by one. The substrate processing apparatus 1 includes a plurality of load ports LP that hold a plurality of carriers C that accommodate a substrate W, and a plurality of processing units 2 that process the substrate W transferred from the plurality of load ports LP with a processing liquid or a processing gas. And substrate transfer robots IR and CR that transfer the substrate W between the plurality of load ports LP and the plurality of processing units 2, and the control device 3 that controls the substrate processing apparatus 1.

As shown in FIG. 2, each processing unit 2 is a single-wafer type unit. Each processing unit 2 holds a box-shaped chamber 4 having an internal space and a single substrate W in the chamber 4 in a horizontal posture, and the substrate W around a vertical rotation axis A1 passing through the center of the substrate W. SPM, H ₂ O ₂ and HF mixed SPM (hereinafter collectively referred to as SPM, etc.) are supplied to a spin chuck (substrate holding unit) 5 that rotates the substrate and a substrate W held on the spin chuck 5 An SPM supply unit 6, a rinse liquid supply unit 8, and a cylindrical cup 9 surrounding the spin chuck 5. HF mixed SPM means SPM to which HF is added.

The spin chuck 5 includes a disc-shaped spin base 10 held in a horizontal posture, a plurality of chuck pins 11 that hold the substrate W in a horizontal posture above the spin base 10, and a central portion of the spin base 10. A rotation shaft 12 extending downward, and a spin motor 13 that rotates the rotation shaft 12 to rotate the substrate W and the spin base 10 around the rotation axis A1. The spin chuck 5 is not limited to a clamping chuck in which a plurality of chuck pins 11 are brought into contact with the peripheral end surface of the substrate W, and the back surface (lower surface) of the substrate W, which is a non-device forming surface, is adsorbed to the upper surface of the spin base 10. Thus, a vacuum chuck that holds the substrate W horizontally may be used.

The cup 9 is disposed outward (in a direction away from the rotation axis A1) from the substrate W held by the spin chuck 5. The cup 9 surrounds the periphery of the spin base 10. When the processing liquid is supplied to the substrate W while the spin chuck 5 is rotating the substrate W, the processing liquid supplied to the substrate W is shaken off around the substrate W. When the processing liquid is supplied to the substrate W, the upper end portion 9 a of the cup 9 that opens upward is disposed above the spin base 10. Therefore, the processing liquid such as SPM and rinse liquid discharged around the substrate W is received by the cup 9. Then, the processing liquid received by the cup 9 is sent to a collecting device or a draining device (not shown).

The rinsing liquid supply unit 8 includes a rinsing liquid nozzle 35 that discharges the rinsing liquid toward the substrate W held by the spin chuck 5, a rinsing liquid pipe 36 that supplies the rinsing liquid to the rinsing liquid nozzle 35, and a rinsing liquid pipe. And a rinsing liquid valve 37 for switching supply and stop of the rinsing liquid from 36 to the rinsing liquid nozzle 35. The rinse liquid nozzle 35 is a fixed nozzle that discharges the rinse liquid in a state where the discharge port of the rinse liquid nozzle 35 is stationary. The rinsing liquid supply unit 8 may include a rinsing liquid nozzle moving unit that moves the rinsing liquid landing position relative to the upper surface of the substrate W by moving the rinsing liquid nozzle 35.

When the rinse liquid valve 37 is opened, the rinse liquid supplied from the rinse liquid pipe 36 to the rinse liquid nozzle 35 is discharged from the rinse liquid nozzle 35 toward the center of the upper surface of the substrate W. The rinse liquid is, for example, pure water (deionized water) at room temperature (about 23 ° C.). The temperature of pure water is not limited to room temperature, and may be higher than room temperature (for example, 70 to 90 ° C.). That is, the rinse liquid may be warm water (pure water having a temperature higher than normal temperature). The rinse liquid is not limited to pure water, but may be any of carbonated water, electrolytic ion water, hydrogen water, ozone water, and hydrochloric acid water having a diluted concentration (for example, about 10 to 100 ppm).

The SPM supply unit 6 includes an SPM nozzle 14 that selectively discharges SPM and the like toward the upper surface of the substrate W, a first nozzle arm 15 having the SPM nozzle 14 attached to the tip, and a first nozzle arm 15. And a first nozzle moving unit 16 that moves the SPM nozzle 14.

The SPM nozzle 14 is, for example, a straight nozzle that selectively discharges SPM or the like in a continuous flow state. For example, the SPM nozzle 14 is applied to the first nozzle arm 15 in a vertical posture that discharges the processing liquid in a direction perpendicular to the upper surface of the substrate W. It is attached. The first nozzle arm 15 extends in the horizontal direction and is provided to be rotatable around a first swing axis (not shown) extending in the vertical direction around the spin chuck 5.

The SPM nozzle 14 is an inward direction in which SPM or the like is discharged in a discharge direction inclined with respect to the upper surface of the substrate W so that the SPM or the like is deposited inward (rotation axis A1 side) from the discharge port. It may be held by the first nozzle arm 15 in a posture, or with respect to the upper surface of the substrate W so that SPM or the like is deposited outside the discharge port (on the opposite side to the rotation axis A1). You may hold | maintain at the 1st nozzle arm 15 in the outward attitude | position which discharges SPM etc. in the inclined discharge direction.

The first nozzle moving unit 16 rotates the first nozzle arm 15 around the first swing axis, thereby causing the SPM nozzle 14 to move horizontally along a trajectory passing through the center of the upper surface of the substrate W in plan view. Move. The first nozzle moving unit 16 includes a processing position where the SPM discharged from the SPM nozzle 14 is deposited on the upper surface of the substrate W and a home position where the SPM nozzle 14 is positioned around the spin chuck 5 in plan view. In the meantime, the SPM nozzle 14 is moved horizontally. The processing position includes a central position where the SPM discharged from the SPM nozzle 14 lands on the center of the upper surface of the substrate W, and a peripheral position where the SPM discharged from the SPM nozzle 14 lands on the periphery of the upper surface of the substrate W. Including.

The SPM supply unit 6 is connected to the SPM nozzle 14 and is connected to the sulfuric acid pipe 17 to which H ₂ SO ₄ is supplied from the sulfuric acid supply source. The SPM supply unit 6 is connected to the SPM nozzle 14 and is mixed with hydrogen peroxide and hydrofluoric acid. And a mixed liquid pipe 27 to which hydrogen oxide water is supplied. The upstream end of the mixed liquid pipe 27 is connected to the mixing unit 30, and the downstream end of the mixed liquid pipe 27 is connected to the SPM nozzle 14.

The mixing unit 30 is an example of a mixing unit that mixes H ₂ O ₂ and HF before being mixed with H ₂ SO ₄ . The mixing unit 30 is connected to a hydrogen peroxide water pipe 18 to which H ₂ O ₂ is supplied from a hydrogen peroxide supply source, and a hydrofluoric acid pipe 28 to which HF is supplied from a hydrofluoric acid supply source.

H ₂ SO ₄ supplied from the sulfuric acid supply source, H ₂ O ₂ supplied from the hydrogen peroxide supply source, and HF supplied from the hydrofluoric acid supply source are all aqueous solutions. The concentration of H ₂ SO ₄ is, for example, 90 to 98%, the concentration of H ₂ O ₂ is, for example, 30 to 50%, and the concentration of HF is, for example, 47 to 51%.

The sulfuric pipe 17, a sulfate valve 19 for opening and closing the sulfuric pipe _17, the sulfuric acid flow rate adjusting valve 20 to change the flow rate of H 2 SO _{_4,} a heater 21 for heating the H 2 SO ₄ is from SPM nozzle 14 side They are inserted in this order. Although not shown, the sulfuric acid flow rate adjusting valve 20 includes a valve body in which a valve seat is provided, a valve body that opens and closes the valve seat, and an actuator that moves the valve body between an open position and a closed position. Including. The same applies to the other valves. The actuator of each valve is controlled by the control device 3.

The heater 21 maintains H ₂ SO ₄ at a temperature higher than room temperature (a constant temperature within a range of 70 to 100 ° C., for example, 90 ° C.). Heater 21 for heating the H ₂ SO ₄ may be a heater of one-pass system as shown in FIG. 2, for heating the _H 2 SO ₄ by circulating _H 2 SO ₄ in a circulating path including a heater A circulating heater may be used. The one-pass method is a method in which the heated liquid passes through the heater only once, and the circulation method is a method in which the heated liquid passes through the heater a plurality of times.

The hydrogen peroxide solution pipe 18 includes a hydrogen peroxide solution valve 22 that opens and closes the hydrogen peroxide solution pipe 18 and a hydrogen peroxide solution flow rate adjustment valve 23 that changes the flow rate of H ₂ O _2. Are installed in this order. The mixing unit 30 is supplied with normal temperature (about 23 ° C.) H ₂ O ₂ whose temperature is not adjusted through the hydrogen peroxide pipe 18.

In the hydrofluoric acid pipe 28, a micropump 31 for supplying HF to the mixing unit 30 is interposed. The micropump 31 has a function of sending the liquid downstream and a function of blocking the flow of the liquid. When the micropump 31 is driven, HF at room temperature (about 23 ° C.) whose temperature is not adjusted is supplied to the mixing unit 30 through the hydrofluoric acid pipe 28. The flow rate of HF sent from the micropump 31 to the mixing unit 30 is controlled by the control device 3. The micropump 31 is an example of a hydrofluoric acid switching unit that switches between a supply state in which HF is supplied to the mixing unit 30 and a supply stop state in which the supply of HF to the mixing unit 30 is stopped. The hydrofluoric acid switching unit may be a hydrofluoric acid valve 32 (see FIG. 6) that opens and closes the hydrofluoric acid pipe 28.

The mixing unit 30 is a substantially cylindrical member, and H ₂ O ₂ and HF are stirred and mixed inside the mixing unit 30. The mixing unit 30 may be a mixing valve having the functions of the hydrogen peroxide solution valve 22 and the hydrofluoric acid switching unit. In this case, the hydrogen peroxide valve 22 and the hydrofluoric acid switching unit may be omitted.

The flow rates of H ₂ O ₂ and HF flowing into the mixing unit 30 are adjusted by the hydrogen peroxide flow rate adjusting valve 23 and the micropump 31. The flow rate of H ₂ O ₂ is 300 ml / min. In this case, the flow rate of HF is, for example, 90 μl / min. It is. Even when the flow rates are different from each other as in this example, H ₂ O ₂ and HF are uniformly mixed by being stirred in the mixing unit 30.

The SPM nozzle 14 has, for example, a substantially cylindrical casing. A mixing chamber is formed inside the casing. The sulfuric acid pipe 17 is connected to a sulfuric acid introduction port arranged on the side wall of the casing of the SPM nozzle 14. The mixed liquid pipe 27 is connected to a mixed liquid inlet disposed on the side wall of the casing of the SPM nozzle 14. The liquid mixture inlet is disposed above the sulfuric acid inlet.

When the micropump 31 is driven in a state where the sulfuric acid valve 19 (see FIG. 2) and the hydrogen peroxide water valve 22 (see FIG. 2) are opened, H ₂ SO ₄ from the sulfuric acid pipe 17 is supplied to the SPM nozzle 14. While being supplied from the sulfuric acid inlet to the mixing chamber, H ₂ O ₂ and HF from the mixed liquid pipe 27 are supplied from the mixed liquid inlet of the SPM nozzle 14 to the mixing chamber.

H ₂ SO ₄ , H ₂ O ₂ , and HF that have flowed into the mixing chamber of the SPM nozzle 14 are sufficiently stirred and mixed in the mixing chamber. This _mixture, H 2 SO ₄ and _H 2 _{O 2} and is mingled _evenly, a mixed solution of _H 2 SO ₄ and _H 2 _{O 2} by reaction of H 2 SO ₄ and _H _{2 O} 2 (SPM) is generated Is done. Thereby, SPM containing HF, that is, HF mixed SPM is generated.

SPM contains peroxymonosulfuric acid (H ₂ SO ₅ ) having a strong oxidizing power, and is higher than the temperature of H ₂ SO ₄ and H ₂ O ₂ before mixing (100 ° C. or higher, for example, 160 ° C.). Until heated. The high-temperature HF mixed SPM generated in the mixing chamber of the SPM nozzle 14 is discharged from a discharge port opened at the front end (lower end) of the casing.

Here, the order of generating the HF mixed SPM will be considered.

When SPM (mixture of H ₂ SO ₄ and H ₂ O ₂ ) is generated first, and then a very small amount of HF is mixed into the SPM, the HF comes into contact with the SPM at a high temperature (100 ° C. or higher). It will evaporate. Therefore, the HF mixed SPM in which HF is uniformly dispersed is not generated. However, as described above, it is possible to generate an HF mixed SPM in which a very small amount of HF component is uniformly dispersed by sufficiently mixing HF and H ₂ O ₂ in advance.

FIG. 3 is a block diagram showing the control device 3. FIG. 4 is a flowchart showing an example of the resist removal process performed by the processing unit 2.

As shown in FIG. 3, the control device 3 is constituted by, for example, a microcomputer. The control device 3 controls the operations of the spin motor 13, the nozzle moving unit 16, the heater 21 and the like according to a predetermined program. The control device 3 controls the opening and closing of the sulfuric acid valve 19, the hydrogen peroxide water valve 22, the micropump 31, the rinse liquid valve 37 and the like, and controls the actuators of the flow

rate adjusting valves

20, 23, 33 to The opening degree of the

flow regulating valves

20 and 23 is controlled.

The control device 3 includes a storage unit 3b that stores information such as a program and an arithmetic unit 3a that controls the substrate processing apparatus 1 according to the information stored in the storage unit 3b. A recipe indicating the processing procedure and processing steps of the substrate W is stored in the storage unit 3b. The control device 3 is programmed to cause the substrate processing apparatus 1 to execute each process described below by controlling the substrate processing apparatus 1 based on the recipe stored in the storage unit 3b.

Hereinafter, an example of the resist removal process will be described with reference to FIGS. 2 and 4. The substrate W to be processed is a substrate that has been subjected to ion implantation at a high dose. It is assumed that this substrate W has not undergone a process for ashing the resist.

When the processing unit 2 performs a resist removal process on the substrate W, a loading process for loading the substrate W into the chamber 4 is performed (step S1). Specifically, the control device 3 moves the hand of the substrate transport robot CR (see FIG. 1) holding the substrate W in the chamber 4 in a state where all the nozzles and the like are retracted from above the spin chuck 5. By entering the inside, the substrate W is placed on the spin chuck 5 with the surface thereof directed upward. Thereafter, the control device 3 starts the rotation of the substrate W by the spin motor 13 (step S2). The rotational speed of the substrate W is increased to a predetermined processing rotational speed (in the range of 100 to 500 rpm, for example, about 300 rpm), and is maintained at the processing rotational speed.

When the rotational speed of the substrate W reaches the processing rotational speed, the control device 3 then performs an SPM processing step (step S3) for supplying SPM to the substrate W. Specifically, the control device 3 moves the SPM nozzle 14 from the home position to the processing position by controlling the first nozzle moving unit 16. Thereby, the SPM nozzle 14 is disposed above the substrate W.

After the SPM nozzle 14 is disposed above the substrate W, the control device 3 opens the sulfuric acid valve 19 and the hydrogen peroxide water valve 22 and further drives the micropump 31. Thus, the _H 2 _{O 2} flowing hydrogen peroxide water pipe 18, and the HF flowing through the hydrofluoric acid pipe 28 flows into the mixing portion 30, a mixed solution (HF mixture _H 2 _{O 2)} is generated ( Mixing step). Further, the mixed solution that has passed through the mixing unit 30 and H ₂ SO ₄ that flows through the sulfuric acid pipe 17 are supplied to the SPM nozzle 14, and H ₂ SO ₄ , H ₂ O _2, and HF are mixed in the mixing chamber of the SPM nozzle 14. And HF mixed SPM at a high temperature (for example, 160 ° C.) is generated (generation process). The HF mixed SPM is discharged from the discharge port of the SPM nozzle 14 and is deposited on the upper surface of the substrate W (supply process). The control device 3 controls the first nozzle moving unit 16 to move the liquid deposition position of the HF mixed SPM with respect to the upper surface of the substrate W in this state between the central portion and the peripheral portion.

The HF mixed SPM discharged from the SPM nozzle 14 lands on the upper surface of the substrate W rotating at a processing rotation speed (for example, 300 rpm), and then flows outward along the upper surface of the substrate W by centrifugal force. Therefore, the HF mixed SPM is supplied to the entire upper surface of the substrate W, and a liquid film of the HF mixed SPM that covers the entire upper surface of the substrate W is formed on the substrate W.

Thereby, even a resist having a hardened layer on the surface can be effectively removed. The cured layer on the resist surface is obtained by curing an organic substance mainly composed of carbon by ion implantation. The reason why the resist is effectively removed is that HF has a function of dissolving a group 14 element oxide (such as SiO ₂ ), and HF contained in the HF mixed SPM effectively removes the organic oxide on the resist surface. This is probably because

In addition, HF that has penetrated into the non-hardened layer of the resist slightly etches Si and SiO ₂ constituting the surface of the substrate W at the boundary between the resist and the surface of the substrate W, thereby improving the resist peeling performance. It is also possible to do.

Furthermore, since the control device 3 moves the liquid deposition position of the HF mixed SPM with respect to the upper surface of the substrate W between the central portion and the peripheral edge while the substrate W is rotating, the liquid deposition position of the HF mixed SPM is Passes through the entire upper surface of the substrate W, and the entire upper surface of the substrate W is scanned. Therefore, the HF mixed SPM discharged from the SPM nozzle 14 is supplied to the entire upper surface of the substrate W, and the entire upper surface of the substrate W is processed uniformly.

When a predetermined HF mixing SPM processing time has elapsed from the start of discharging the HF mixing SPM, the SPM processing step (step S3) ends. Subsequent to the end of the SPM processing step (step S3), a hydrogen peroxide solution supplying step (step S4) for supplying H ₂ O ₂ to the substrate W is performed.

Specifically, the control device 3 controls the first nozzle moving unit 16 to dispose the SPM nozzle 14 above the center of the upper surface of the substrate W, and then opens the hydrogen peroxide solution valve 22. The sulfuric acid valve 19 is closed while maintaining the state. At the same time, the control device 3 stops the micropump 31. As a result, only H ₂ O ₂ flows through the hydrogen peroxide solution pipe 18 and the mixed solution pipe 27 and is supplied to the SPM nozzle 14. The hydrogen peroxide solution supplied to the SPM nozzle 14 passes through the inside of the SPM nozzle 14 and is discharged from the discharge port of the SPM nozzle 14. The H ₂ O ₂ is deposited on the center of the upper surface of the substrate W rotating at the processing rotation speed. That is, the processing liquid discharged from the SPM nozzle 14 is switched from the HF mixed SPM to H ₂ O ₂ .

The H ₂ O ₂ deposited on the center of the upper surface of the substrate W flows outward on the substrate W toward the peripheral edge of the substrate W. The SPM on the substrate W is replaced with H ₂ O ₂ , and eventually, the entire upper surface of the substrate W is covered with a liquid film of H ₂ O ₂ .

When a predetermined hydrogen peroxide supply time elapses from the start of the discharge of the hydrogen peroxide solution, the control device 3 closes the hydrogen peroxide solution valve 22 and stops the discharge of H ₂ O ₂ from the SPM nozzle 14. Further, the control device 3 controls the first nozzle moving unit 16 to move the SPM nozzle 14 from the processing position to the home position. As a result, the SPM nozzle 14 is retracted from above the substrate W.

Next, a rinsing liquid supply step (step S5) for supplying the rinsing liquid to the substrate W is performed. Specifically, the control device 3 opens the rinse liquid valve 37 and discharges the rinse liquid from the rinse liquid nozzle 35 toward the center of the upper surface of the substrate W. The rinse liquid discharged from the rinse liquid nozzle 35 is deposited on the center of the upper surface of the substrate W covered with H ₂ O ₂ . The rinse liquid deposited on the center of the upper surface of the substrate W flows outward on the substrate W toward the peripheral edge of the substrate W. As a result, H ₂ O ₂ on the substrate W is pushed outward by the rinse liquid and discharged around the substrate W. Therefore, the liquid film of H ₂ O ₂ on the substrate W is replaced with the liquid film of the rinsing liquid that covers the entire upper surface of the substrate W. As a result, H ₂ O ₂ is washed away in the entire upper surface of the substrate W. When the rinsing liquid supply time elapses after the rinsing liquid valve 37 is opened, the control device 3 closes the rinsing liquid valve 37 and stops the discharge of the rinsing liquid from the rinsing liquid nozzle 35.

Next, a drying process (step S6) for drying the substrate W is performed. Specifically, the control device 3 controls the spin motor 13 to accelerate the substrate W to a drying rotation speed (for example, several thousand rpm) and rotate the substrate W at the drying rotation speed. Thereby, a large centrifugal force is applied to the liquid on the substrate W, and the liquid adhering to the substrate W is shaken off around the substrate W. In this way, the liquid is removed from the substrate W, and the substrate W is dried. When a predetermined time elapses after the high-speed rotation of the substrate W is started, the control device 3 controls the spin motor 13 to stop the rotation of the substrate W by the spin chuck 5 (step S7).

Next, an unloading process for unloading the substrate W from the chamber 4 is performed (step S8). Specifically, the control device 3 causes the hand of the substrate transport robot CR to enter the chamber 4 in a state where all the nozzles and the like are retracted from above the spin chuck 5. Then, the control device 3 holds the substrate W on the spin chuck 5 by the hand of the substrate transport robot CR. Thereafter, the control device 3 retracts the hand of the substrate transport robot CR from the chamber 4. Thereby, the processed substrate W is unloaded from the chamber 4.

In the processing example of FIG. 4, the hydrogen peroxide solution supply step (step S4) is executed after the SPM treatment step (step S3), but the hydrogen peroxide solution supply step (step S4) can be omitted. .

In the processing example of FIG. 4, the case where the substrate W is rotated at the SPM processing speed (for example, about 300 rpm) in the SPM processing step (step S3) has been described. However, at least a part of the SPM processing step (step S3) is described. In the period, the substrate W may be in a paddle state. The paddle state means a state in which the upper surface of the substrate W is covered with a liquid film and the substrate is stationary in the rotation direction or rotating at a low rotation speed (50 rpm or less). In the paddle state, the discharge of SPM from the substrate W is suppressed, and the SPM liquid film is held on the upper surface of the substrate W. When the substrate W is in the paddle state, the supply of SPM (discharge of SPM) to the substrate W may be stopped.

Next, the resist removal test will be described.

FIG. 5 is a diagram showing conditions and results of a resist removal test. This resist removal test is for confirming the relationship between the concentration of HF in the SPM and the resist removal performance.

In the sample used in this test, a resist pattern for KrF (krypton fluoride) excimer laser was formed on the entire surface without gaps, and As (arsenic) was dosed at 1 × 10 ¹⁶ atoms / cm using this resist pattern as a mask. ^2. A silicon wafer W having a diameter of 300 mm and ion-implanted into the surface with a dose energy of 40 kev.

Using this substrate, the substrate processing apparatus 1 was used to carry out resist removal processing of Examples and Comparative Examples described below. Then, the presence or absence of the remaining resist after the resist removal treatment and the degree of damage to other than the resist were observed using an electron microscope. The mixing ratio (flow rate ratio) of H ₂ SO ₄ and H ₂ O ₂ in the SPM used in the SPM processing step of Step S3 is 2: 1, and the processing time of the SPM processing step of Step S3 is 1 minute. did. At this time, the concentration of HF was changed from 0 (comparative example) to 10000 ppm (data 3). When adding _HF, flow rate of H 2 _{O 2} means the flow rate of the mixed solution of HF and _H 2 _{O 2.}

<Example>
The same treatment was performed with HF mixed SPM having different HF concentrations. The HF concentration in the HF mixed SPM at this time is as follows.

Data 1 (100 ppm)
Data 2 (1000ppm)
Data 3 (10000 ppm)
<Comparative example>
In the above-described embodiment, the same processing was performed using an SPM that does not contain HF.

The results of this resist removal test are shown in FIG. In FIG. 5, “○” indicates that there is no resist residue and no damage to the substrate surface, and “Δ1” indicates that a small amount of resist residue is generated. The case where there is damage is indicated by “Δ2”, the case where a large amount of resist remains, or the case where the resist is not peeled off at all, is indicated by “X”.

As shown in FIG. 5, in the example, the resist stripping performance is improved as the HF concentration increases. However, depending on the pattern shape, damage to the substrate surface, that is, etching of the substrate surface was confirmed even when the HF concentration was 1000 ppm. Further, when the HF concentration was 10,000 ppm, damage to the substrate surface was confirmed in all pattern shapes. On the other hand, in the comparative example, almost no resist peeling was observed with respect to the silicon wafer W on which high-dose ion implantation was performed.

As described above, it can be seen that the resist stripping performance can be improved by mixing HF with SPM.

Although one embodiment of the present invention has been described above, the present invention can be implemented in other forms.

In the above-described embodiment, the SPM supply unit 6 includes the mixed solution pipe 27 that guides the mixed solution mixed by the mixing unit 30 to the SPM nozzle 14, but is not limited thereto. FIG. 6 is a diagram showing an SPM supply unit 6a according to another embodiment. In FIG. 6, the same devices as those in FIG.

A mixed liquid pipe 27 of the SPM supply unit 6 a shown in FIG. 6 is connected to the mixing tank 130 instead of the mixing unit 30. The mixed liquid pump 131 is interposed in the mixed liquid pipe 27. Connected to the mixing tank 130 are a hydrogen peroxide pipe 18 to which H ₂ O ₂ is supplied from a hydrogen peroxide supply source and a hydrofluoric acid pipe 28 to which HF is supplied from a hydrofluoric acid supply source.

The hydrofluoric acid pipe 28 is provided with a hydrofluoric acid valve 32 for opening and closing the hydrofluoric acid pipe 28 and a hydrofluoric acid flow rate adjusting valve 33 for changing the flow rate of HF in this order from the mixing tank 130 side. The mixing tank 130 is supplied with HF at room temperature (about 23 ° C.) whose temperature is not adjusted through the hydrofluoric acid pipe 28.

Prior to the SPM processing step (step S3), the control device 3 executes a blending step of blending the mixed solution (HF mixed H ₂ O ₂ ) in the mixing tank 130. Specifically, the control device 3 supplies 30 L of a predetermined concentration of H ₂ O ₂ to the mixing tank 130 by opening the hydrogen peroxide solution valve 22. Thereafter, the control device 3 opens the hydrofluoric acid valve 32 to supply 10 ml to 100 ml of HF having a predetermined concentration to the mixing tank 130. The supply of HF to the mixing tank 130 may be started before or after the supply of H ₂ O ₂ is started, or may be started simultaneously with the supply of H ₂ O ₂ .

H ₂ O ₂ and HF are mixed in the mixing tank 130. The SPM supply unit 6 a may further include a stirring unit that stirs the H ₂ O ₂ and HF in the mixing tank 130. The stirring unit is, for example, a bubbling unit 132 that generates bubbles in the liquid mixture by discharging a gas such as nitrogen gas from a gas discharge port 132a disposed in the liquid mixture in the mixing tank 130. When a stirring unit is provided, H ₂ O ₂ and HF in the mixing tank 130 are mixed more uniformly.

The concentration of HF mixed with H ₂ O ₂ in the mixing tank 130 may be lower than usual (for example, hydrogen fluoride: water = 1: 100). In this case, the amount of hydrogen fluoride contained in the HF mixed H ₂ O ₂ can be controlled with high accuracy.

The HF mixed H ₂ O ₂ generated in the mixing tank 130 is supplied to the SPM nozzle 14 by the mixed liquid pump 131. Similarly, H ₂ SO ₄ is supplied from the sulfuric acid pipe 17 to the SPM nozzle 14. The H ₂ SO ₄ , H ₂ O ₂ , and HF that have flowed into the mixing chamber of the SPM nozzle 14 are sufficiently stirred and mixed in the mixing chamber, thereby generating an HF mixed SPM. Thereafter, the HF mixed SPM is discharged from the SPM nozzle 14 and supplied onto the substrate W. In the SPM supply unit 6a according to this embodiment, it is possible to generate a H ₂ O ₂ / HF mixed liquid having a HF concentration lower than that in the above-described embodiment. The reason is that the ratio of H ₂ O ₂ and HF can be freely changed as compared with the case where H ₂ O ₂ and HF are mixed in a pipe or a valve.

In the above-described embodiment and other embodiments, H ₂ SO ₄ , H ₂ O ₂ , and HF are supplied to one SPM nozzle 14. However, the present invention is not limited to this. FIG. 7 is a diagram showing an SPM supply unit 6b according to another embodiment.

The SPM supply unit 6b includes a sulfuric acid nozzle 14a and an H ₂ O ₂ / HF nozzle 14b. The sulfuric acid nozzle 14 a discharges H ₂ SO ₄ toward the substrate W. The H ₂ O ₂ / HF nozzle 14 b discharges the H ₂ O ₂ / HF mixed solution supplied from the mixing unit 30 toward the substrate W. The H ₂ O ₂ / HF nozzle 14 b may discharge the H ₂ O ₂ / HF mixed solution supplied from the mixing tank 130 toward the substrate W.

The sulfuric acid from the sulfuric acid nozzle 14a and the H ₂ O ₂ / HF mixed solution from the H ₂ O ₂ / HF nozzle 14b are supplied to the rotating substrate W, whereby H ₂ SO ₄ , H ₂ O ₂ , And HF are stirred and mixed on the substrate W. Thereby, HF mixing SPM is produced | generated. In other words, the HF mixed SPM generating unit including the sulfuric acid nozzle 14 a and the H ₂ O ₂ / HF nozzle 14 b generates the HF mixed SPM on the substrate W. In the SPM supply unit 6b according to this embodiment, the HF mixed SPM is generated in a region closer to the substrate W than in the above-described embodiment. Therefore, it becomes possible to process the substrate W while maintaining the chemical activity of the SPM at a high level.

In each of the above-described embodiments, the case where the substrate processing apparatus 1 is an apparatus that processes the disk-shaped substrate W has been described. However, the substrate processing apparatus 1 is a polygonal substrate such as a substrate for a liquid crystal display device. An apparatus for processing W may be used.

This application was filed in Japanese Patent Application No. 2015-61287 filed with the Japan Patent Office on March 24, 2015, and Japanese Patent Application No. 2015-246629 filed with the Japan Patent Office on December 17, 2015. And the entire disclosure of this application is hereby incorporated by reference.

Although the embodiments of the present invention have been described in detail, these are merely specific examples used to clarify the technical contents of the present invention, and the present invention is construed to be limited to these specific examples. The spirit and scope of the present invention should not be limited only by the appended claims.

1 substrate processing device 3 control device 5 spin chuck (substrate holding unit)
6 SPM supply unit 14 SPM nozzle (HF mixed SPM generation unit)
14a Sulfuric acid nozzle (HF mixed SPM generation unit)
14b H ₂ O ₂ / HF nozzle (HF mixed SPM generating unit)
30 mixing section (mixing unit)
130 Mixing tank (mixing unit)
132 Bubbling unit (stirring unit)
132a Gas outlet W Substrate

Claims

A substrate processing method for removing a resist from a surface of a substrate,
A mixing step of mixing hydrogen peroxide water and hydrofluoric acid to produce a mixture of hydrogen peroxide water and hydrofluoric acid;
After the mixing step, the hydrogen peroxide solution and hydrofluoric acid mixed solution and sulfuric acid are mixed with each other to generate sulfuric acid, hydrogen peroxide solution, and hydrofluoric acid mixed solution SPM,
And a supply step of supplying the HF mixed SPM to the surface of the substrate.
The substrate processing method according to claim 1, wherein the hydrogen peroxide solution and hydrofluoric acid mixed in the mixing step are both at room temperature.
3. The substrate processing method according to claim 1, wherein the generating step is a step of mixing the hydrogen peroxide solution and hydrofluoric acid mixed solution and sulfuric acid at a position away from the substrate.
3. The substrate processing method according to claim 1, wherein the generating step is a step of mixing the hydrogen peroxide solution and hydrofluoric acid mixed solution and sulfuric acid on the surface of the substrate.
A substrate holding unit for holding a substrate whose surface is covered with a resist;
An SPM supply unit for supplying HF mixed SPM, which is a mixed solution of sulfuric acid, hydrogen peroxide solution, and hydrofluoric acid, to the surface of the substrate held by the substrate holding unit;
The SPM supply unit is
A mixing unit that mixes hydrogen peroxide and hydrofluoric acid to produce a mixture of hydrogen peroxide and hydrofluoric acid;
An HF mixed SPM generating unit that mixes the hydrogen peroxide solution and hydrofluoric acid and then mixes the hydrogen peroxide solution and hydrofluoric acid with sulfuric acid to generate an HF mixed SPM. Substrate processing equipment.
The mixing unit includes a mixing tank that is supplied with hydrogen peroxide solution and hydrofluoric acid separately and stores the mixed solution of the hydrogen peroxide solution and hydrofluoric acid supplied to the HF mixed SPM generating unit. 2. The substrate processing apparatus according to 1.
The substrate processing apparatus according to claim 6, wherein the mixing unit further includes an agitation unit for agitating the mixed liquid in the mixing tank.
The agitation unit includes a bubbling unit that generates bubbles in the mixed liquid by discharging gas from a gas discharge port arranged in the mixed liquid stored in the mixing tank. The substrate processing apparatus as described.
The mixing unit mixes a hydrogen peroxide solution and a smaller amount of hydrofluoric acid than the hydrogen peroxide solution,
The substrate processing apparatus according to any one of claims 5 to 8, wherein the HF mixed SPM generating unit mixes sulfuric acid with a smaller amount of the mixed liquid than the sulfuric acid.