JP2012064893A - Liquid processing method, recording medium storing program for executing the same, and liquid processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid processing method capable of removing a titanium element remaining on the back of a substrate in a shorter time than the conventional time when removing a titanium-containing film from the back of the substrate on which the titanium-containing film was formed on the surface and back of the substrate.SOLUTION: A liquid processing method for processing the back of the substrate with a processing liquid includes a first step S11 of supporting a substrate on which the titanium-containing film is formed on the surface and back of the substrate by the support part which is provided rotatably and supports the substrate, rotating the substrate supported by the support part together with the support part, supplying a first processing liquid including ammonia hyperhydration to the back of a rotating substrate, and processing the back of the substrate with the supplied first processing liquid.

Description

  The present invention relates to a liquid processing method for processing using a processing liquid, a recording medium on which a program for executing the liquid processing method is recorded, and a liquid processing apparatus.

  In a semiconductor device manufacturing process and a flat panel display (FPD) manufacturing process, a liquid processing process is often used in which a processing liquid is supplied to a semiconductor wafer or glass substrate, which is a substrate to be processed, to perform liquid processing.

  As one of such liquid processing processes, there is a liquid processing process in which a processing liquid is supplied to the back surface of the substrate and the liquid processing is performed on the back surface of the substrate with the supplied processing liquid.

  For example, in a manufacturing process of a semiconductor device or the like, a film forming process may be performed to form various thin films on the surface of the substrate. In the film forming process, a thin film may be formed not only on the surface of the substrate but also on the back surface of the substrate. It is preferable to remove the thin film formed on the back surface of the substrate because it may cause warpage of the substrate during the subsequent manufacturing process, for example, during heat treatment. Therefore, a liquid processing process may be performed in which a processing liquid is supplied to the back surface of the substrate, and the back surface of the substrate is etched by the supplied processing liquid.

  As a liquid processing apparatus that performs such a liquid processing process, a substrate processing apparatus that performs liquid processing on a lower surface of a substrate by supplying a processing liquid to the lower surface of the substrate is known (see, for example, Patent Document 1). .) In the example shown in Patent Document 1, the substrate processing apparatus includes a substrate holding unit (supporting unit), a first driving unit (rotating unit), and an etching liquid supply unit (processing liquid supply unit). The substrate holding means holds the substrate in a state where it is supported in a horizontal posture. The first driving unit rotates the substrate held by the substrate holding unit around the axis in the vertical direction. The etching solution supply unit supplies the processing solution to the lower surface of the substrate held by the substrate holding unit and rotated by the first driving unit.

  Further, it is known that an etching solution containing hydrofluoric acid is used as a processing solution for etching and removing a titanium-containing film from a substrate having a titanium-containing film containing titanium formed on the front and back surfaces of the substrate. (For example, see Patent Document 2).

JP 2000-235948 A JP-A-2005-97715

  However, in the liquid processing method and the liquid processing apparatus for removing the titanium-containing film from the back surface of the substrate in which the etching liquid containing hydrofluoric acid is used as the processing liquid and the titanium-containing film is formed on the front surface and the back surface, There's a problem.

  Even when the thickness of the titanium-containing film on the back surface of the substrate becomes substantially equal to 0 when the titanium-containing film is removed from the back surface of the substrate by supplying the treatment liquid containing hydrofluoric acid to the back surface of the rotating substrate, The detected value of the titanium element detected by analysis does not decrease below an allowable predetermined value. Therefore, in order to make the detection value of the titanium element equal to or less than a predetermined value, the titanium-containing film on the back surface of the substrate must be treated with a treatment solution for a longer time after the thickness of the titanium-containing film becomes substantially zero. That is, the inventor cannot remove the titanium element remaining on the back surface of the substrate in a short time when removing the titanium-containing film from the back surface of the substrate on which the titanium-containing film is formed on the front surface and the back surface of the substrate. discovered.

  The present invention has been made in view of the above points, and when removing the titanium-containing film from the back surface of the substrate on which the titanium-containing film is formed on the front surface and the back surface, the titanium element remaining on the back surface of the substrate is conventionally reduced. A liquid processing method and a liquid processing apparatus that can be removed in a short time are provided.

  In order to solve the above-described problems, the present invention is characterized by the following measures.

  According to one embodiment of the present invention, in the liquid processing method for processing the back surface of the substrate with the processing liquid, the titanium-containing film is formed on the front surface and the back surface by the support portion that rotatably supports the substrate. The substrate supported by the support unit is rotated together with the support unit, and the first treatment liquid containing ammonia-hydrogen peroxide is supplied to the back surface of the rotating substrate, and the supplied substrate is supplied. There is provided a liquid processing method including a first step of processing the back surface of the substrate with a first processing liquid.

  According to one embodiment of the present invention, in the liquid processing apparatus for processing the back surface of the substrate with the processing liquid, the support unit that rotatably supports the substrate, and the rotation unit that rotates the support unit, A substrate having a titanium-containing film formed on the front surface and the back surface thereof by the processing liquid supply unit for supplying a first processing liquid containing ammonia perwater to the back surface of the substrate supported by the support unit; The substrate supported by the support unit is rotated together with the support unit by the rotating unit, and the first processing solution is supplied to the back surface of the rotating substrate by the processing solution supplying unit. And a control unit that processes the back surface of the substrate with the supplied first processing liquid.

  According to the present invention, when the titanium-containing film is removed from the back surface of the substrate on which the titanium-containing film is formed on the front surface and the back surface, the titanium element remaining on the back surface of the substrate can be removed in a shorter time than before.

It is a schematic sectional drawing which shows the structure of the liquid processing apparatus which concerns on embodiment. It is the schematic sectional drawing which expanded the rotation cup vicinity of the liquid processing apparatus which concerns on embodiment. It is a perspective view of the rotation cup of the liquid processing apparatus which concerns on embodiment. It is a flowchart for demonstrating the procedure of the liquid processing method which concerns on embodiment. It is sectional drawing which shows typically the state of the wafer in the liquid processing method which concerns on embodiment. It is sectional drawing which shows typically the state of the wafer in the liquid processing method which concerns on a comparative example. It is a graph which shows the time change of the film thickness of a titanium content film typically comparing between an embodiment and a comparative example. It is a figure which shows the photograph of the surface of the wafer after performing the liquid processing method which concerns on embodiment compared with the photograph of the surface of the wafer after performing the liquid processing method which concerns on a comparative example. It is a figure which shows a mode that a titanium containing film is etched in the liquid processing method which concerns on embodiment compared with a mode that a titanium containing film is etched in the liquid processing method which concerns on a comparative example. It is a schematic sectional drawing which shows the structure of the liquid processing apparatus which concerns on the modification of embodiment. It is a flowchart for demonstrating the procedure of the liquid processing method which concerns on the modification of embodiment. It is sectional drawing which shows typically the state of the wafer in the liquid processing method which concerns on the modification of embodiment.

Next, a mode for carrying out the present invention will be described with reference to the drawings. Here, a case where the present invention is applied to a liquid processing apparatus that performs backside processing of a semiconductor wafer (hereinafter simply referred to as “wafer”) will be described.
(Embodiment)
First, the liquid processing apparatus according to the embodiment will be described with reference to FIGS. 1 to 3. The liquid processing apparatus according to the present embodiment processes the lower surface of the wafer W by supplying a processing liquid to the lower surface of a semiconductor wafer W (hereinafter referred to as a wafer W) that is an object to be processed.

  FIG. 1 is a schematic cross-sectional view showing a configuration of a liquid processing apparatus 100 according to the present embodiment. FIG. 2 is an enlarged schematic cross-sectional view of the vicinity of the rotating cup 30 of the liquid processing apparatus 100 according to the present embodiment. FIG. 3 is a perspective view of the rotating cup 30 of the liquid processing apparatus 100 according to the present embodiment.

  As shown in FIG. 1, the liquid processing apparatus 100 includes a processing liquid supply mechanism 10, a discharge mechanism 20, a rotating cup 30, a support pin 35, a top plate 40, a base plate (base) 50, a rotation driving unit 60, and a control unit 70. have.

  The processing liquid supply mechanism 10 and the rotation driving unit 60 correspond to the processing liquid supply unit and the rotation unit in the present invention. Further, the rotary cup 30 and the support pin 35 correspond to a support portion in the present invention.

  The processing liquid supply mechanism 10 supplies a processing liquid to the lower surface of the wafer W. The discharge mechanism 20 discharges the processing liquid that has processed the wafer W. The rotating cup 30 is provided outside the periphery of the wafer W, and guides the processing liquid that has processed the wafer W to the discharge mechanism 20.

  As illustrated in FIG. 1, the processing liquid supply mechanism 10 includes a processing liquid supply unit 11 a, a pure water supply unit 11 b, an opening / closing mechanism 11 c, and a processing liquid supply pipe 12. The processing liquid supply unit 11a supplies the first processing liquid E1, and the pure water supply unit 11b supplies pure water (DIW). The opening / closing mechanism 11c connects the processing liquid supply unit 11a and the pure water supply unit 11b to the processing liquid supply pipe 12 so as to be switchable. The processing liquid supply pipe 12 supplies the first processing liquid E1 supplied in a switchable manner from the processing liquid supply portion 11a and the pure water (DIW) supplied in a switchable manner from the pure water supply portion 11b to the lower surface side of the wafer W. Lead. The upper surface of the processing liquid supply pipe 12 constitutes a processing liquid supply port 12a.

  In the present embodiment, for example, the processing liquid supply mechanism 10 first supplies the first processing liquid E1 containing ammonia overwater (SC1) from the processing liquid supply unit 11a, and then the pure water supply unit 11b supplies the pure water. It can be configured to supply water (DIW).

  The discharge mechanism 20 has a drain cup 21 and a drain pipe 22 as shown in FIG. The drainage cup 21 receives the processing liquid guided by the rotating cup 30. The drainage pipe 22 discharges the processing liquid received by the drainage cup 21. An exhaust cup 23 is provided around the drain cup 21, and an exhaust pipe 24 that sucks and discharges a gas such as nitrogen gas in the exhaust cup 23 is provided in the exhaust cup 23. The exhaust pipe 24 is connected to a discharge / suction part (not shown) for applying a suction force.

  As shown in FIGS. 1 to 3, a plurality of support pins 35 are provided at the lower end of the rotary cup 30 so as to protrude inward from the periphery. The support pins (support portions) 35 support the lower surface of the peripheral portion of the wafer W.

  As shown in FIG. 1, the top plate 40 is provided on the upper surface side of the wafer W supported by the support pins 35 so as to cover the wafer W. An inert gas supply pipe 47 connected to an inert gas supply unit 46 that supplies an inert gas (nitrogen gas in the present embodiment) such as nitrogen gas or argon gas extends inside the top plate 40. ing. The inert gas supply pipe 47 is an end at the center of the top plate 40, and the end constitutes an inert gas supply port 47a. As shown in FIG. 1, the top plate 40 is connected to a top plate driving unit 49 that moves the top plate 40 in the vertical direction.

  As shown in FIG. 1, the base plate (base) 50 is provided on the lower side of the rotary cup 30. The base plate (base) 50 has a hollow shape and is provided with a hollow rotating shaft 51 extending downward.

  The rotation drive unit 60 rotates the rotation shaft 51. The rotation drive unit 60 is connected to the rotation shaft 51. By rotating the rotation shaft 51 by the rotation drive unit 60, the base plate 50 and the rotation cup 30 can be rotated, and the wafer W on the support pins 35 provided on the rotation cup 30 can be rotated.

  As shown in FIG. 1, the rotation drive unit 60 includes a motor 61, a pulley 62, and a drive belt 63. The pulley 62 is disposed outside the periphery of the rotation shaft 51. The drive belt 63 is wound around the pulley 62. The motor 61 rotates the rotating shaft 51 via the pulley 62 by applying a driving force to the driving belt 63. A bearing 52 is disposed on the outer periphery of the rotating shaft 51.

  Further, as shown in FIG. 1, a lift pin 55a is provided in the hollow of the rotary cup 30 and the rotary shaft 51. The lift pin plate 55 is formed in a hollow shape, and extends downward from the lift pin plate 55 to form a hollow shape. A lift shaft 56 is arranged. Further, as shown in FIG. 1, the processing liquid supply pipe 12 extends in the vertical direction inside the lift pin plate 55 and the lift shaft 56 (in the hollow space). The lift shaft 56 is connected to a lift shaft drive unit (not shown) that moves the lift shaft 56 in the vertical direction.

  Further, as shown in FIG. 2, a spacer 31 is disposed between the base plate 50 and the rotating cup 30, and a fastening member such as a screw for fastening the rotating cup 30 and the base plate 50 in the spacer 31. 32 is provided. As shown in FIG. 3, the rotary cup 30 is provided with a hole 30 a for allowing the fastening member 32 to pass therethrough.

  In the present embodiment, the support pin 35 and the rotary cup 30 are integrally formed. Further, the spacer 31 and the rotary cup 30 are also integrally formed.

  The control unit 70 includes, for example, an arithmetic processing unit, a storage unit, and a display unit (not shown). The arithmetic processing unit is, for example, a computer having a CPU (Central Processing Unit). The storage unit is a computer-readable recording medium configured with, for example, a hard disk, in which a program for causing the arithmetic processing unit to execute various processes is recorded. A display part consists of a screen of a computer, for example. The arithmetic processing unit reads a program recorded in the storage unit and executes a liquid processing method described later.

  Next, the operation of the liquid processing apparatus 100 according to the present embodiment will be described.

  First, a lift pin of a lift pin plate 55 in which a wafer W taken out from a carrier (not shown) by a transfer robot (not shown) is positioned at a delivery position (upper position) by a lift shaft driving unit (not shown). 55a. At this time, the top plate 40 is positioned above the delivery position of the wafer W by the top plate driving unit 49.

  Next, the lift pin plate 55 is moved downward by the lift shaft driving unit (not shown) and positioned at the wafer processing position (see FIG. 1). Thus, while the lift pin plate 55 is moved downward, the peripheral portion of the wafer W is supported by the support pins 35 provided on the rotary cup 30. Thereafter, the top plate drive unit 49 positions the top plate 40 in the lower position.

  In the present embodiment, the inner peripheral surface 30f of the rotary cup 30 is inclined downward (see FIG. 2). For this reason, the wafer W can be slid downward to a predetermined position, and the wafer W can be reliably supported by the support pins 35.

  Next, the rotation shaft 51 is driven to rotate by the rotation drive unit 60, whereby the base plate 50 and the rotation cup 30 are rotated. As a result, the wafer W on the support pins 35 provided on the rotation cup 30 is rotated. (See FIG. 1). Here, the rotating shaft 51 is rotationally driven by applying a driving force from the motor 61 to the pulley 62 via the driving belt 63.

  At this time, the first processing liquid E1 is supplied to the lower surface of the wafer W by the processing liquid supply mechanism 10 (see FIG. 1). Then, the first processing liquid E1 supplied to the lower surface of the wafer W is moved toward the outer periphery by the centrifugal force generated by the rotation of the wafer W.

On the other hand, nitrogen (N ₂ ) gas is supplied from an inert gas supply port 47a provided at the center of the top plate 40 (see FIG. 1). The nitrogen gas flows through the outer surface of the wafer W after passing through the upper surface of the wafer W.

  Next, with reference to FIG.4 and FIG.5, the liquid processing method performed by the control part 70 using the liquid processing apparatus 100 is demonstrated. FIG. 4 is a flowchart for explaining the procedure of the liquid processing method according to the present embodiment. FIG. 5 is a cross-sectional view schematically showing the state of the wafer W in the liquid processing method according to the present embodiment. In FIG. 5, only the wafer W and the processing liquid supply mechanism 10 are shown for ease of illustration (the same applies to FIG. 7 described later).

  In the liquid processing method according to the present embodiment, a wafer W having a titanium-containing film TF formed on an upper surface (front surface) TS and a lower surface (back surface) BS is rotated, and ammonia is applied to the lower surface (back surface) BS of the rotating wafer W. The first treatment liquid E1 containing excess water is supplied to remove the titanium-containing film TF from the lower surface (back surface) BS.

  In the liquid processing method according to the present embodiment, an example in which the wafer W is supported so that the front surface is the upper surface TS and the back surface is the lower surface BS will be described. However, a liquid processing apparatus configured to supply the first processing liquid E1 to the upper surface TS of the wafer W may be used. In this case, the back surface of the wafer W is the upper surface TS, and the front surface is the lower surface BS. The wafer W may be supported as described above.

  As shown in FIG. 4, the liquid processing method according to the present embodiment includes a first step (step S11), a rinsing step (step S12), and a drying step (step S13).

  In the first step (step S11), the first processing liquid E1 containing ammonia overwater is supplied to the lower surface (back surface) BS of the rotating wafer W.

  First, the wafer W having the titanium-containing film TF formed on the upper surface (front surface) TS and the lower surface (back surface) BS is taken out from the carrier. Then, the wafer W taken out from the carrier is placed on the lift pins 55 a of the lift pin plate 55. Furthermore, by moving the lift pin plate 55 downward to the wafer processing position, the peripheral portion of the wafer W is supported by the support pins 35 that are rotatably provided to support the wafer W. Thereafter, the top plate 40 is lowered to the lower position by the top plate driving unit 49.

  Next, the wafer W supported by the support pins 35 of the rotary cup 30 is rotated together with the rotary cup 30. Then, in the state where the wafer W is rotated, the opening / closing mechanism 11c is switched, and the lower surface (back surface) BS of the rotating wafer W is subjected to a first process including ammonia overwater by the process liquid supply unit 11a of the process liquid supply mechanism 10. Supply liquid E1. FIGS. 5A and 5B show the state of the wafer W immediately after the supply of the first processing liquid E1 is started and immediately before the supply of the first processing liquid E1 is stopped.

  As shown in FIG. 5A, the first processing liquid E1 supplied to the lower surface (rear surface) BS of the wafer W is the lower surface (rear surface) BS of the wafer W due to the centrifugal force generated by the rotation of the wafer W. Move toward the outside of the periphery. As a result, the lower surface (back surface) BS of the wafer W is processed with the first processing liquid E1.

  Further, as shown in FIG. 5A, a part of the first processing liquid E1 that has moved the lower surface (back surface) BS of the wafer W toward the outer periphery is partially upper surface from the lower surface (back surface) BS of the wafer W. (Surface) Wrap around TS. As a result, the first processing liquid E1 is also supplied to the peripheral portion of the upper surface (front surface) TS of the wafer W, and the peripheral portion of the upper surface (front surface) TS of the wafer W is also processed by the first processing liquid E1.

  The amount of the first processing liquid E1 that wraps around the periphery of the wafer W from the lower surface (back surface) BS to the upper surface (front surface) TS is adjusted by adjusting the number of rotations of the rotating cup 30 and the flow rate of nitrogen gas. be able to.

  Further, as will be described using a modification of the embodiment, the second processing liquid may be supplied to the peripheral portion (bevel) of the wafer W by the second processing liquid supply mechanism.

  Thereafter, when the supply of the first treatment liquid E1 is continued, the titanium-containing film TF is removed from the lower surface (back surface) BS of the wafer W as shown in FIG. Further, the titanium-containing film TF is also removed from the side surface of the wafer W and the peripheral portion of the upper surface (front surface) TS.

The titanium-containing film TF may be a film containing titanium, and for example, titanium oxide (TiO _x ) can be used. Further, the thickness of the titanium-containing film TF is not particularly limited, but can be set to 40 nm, for example.

  It is preferable that the rotation speed of the wafer W is 1000 rpm or more and 2000 rpm or less. This is because when the rotational speed of the wafer W is less than 1000 rpm, the first processing liquid E1 cannot be uniformly supplied to the lower surface (back surface) BS of the wafer W. When the rotation speed of the wafer W exceeds 2000 rpm, the first processing liquid E1 hits the rotary cup 30 and a large amount of liquid splash occurs, and the upper surface (front surface) TS of the wafer W is contaminated by the first processing liquid E1. Because it will do.

As the first treatment liquid E1, ammonia overwater (SC1) made of ammonia water (NH ₄ OH) and hydrogen peroxide water (H ₂ O ₂ ) can be used. That is, ammonia and hydrogen peroxide are included as the first treatment liquid E1.

  As the concentration of ammonia and hydrogen peroxide in the first treatment liquid E1, it is preferable that the concentration of ammonia is 3 wt% or more by weight and the concentration of hydrogen peroxide is 30 wt% by weight. This is because if the concentration of ammonia is less than 3 wt% by weight or the concentration of hydrogen peroxide is less than 30 wt% by weight, the etching rate for etching the titanium-containing film TF decreases.

  The supply amount of the first treatment liquid E1 is preferably 500 sccm or more and 1500 sccm or less. This is because when the supply amount of the first processing liquid E1 is less than 500 sccm, the first processing liquid E1 cannot be uniformly supplied to the lower surface (back surface) BS of the wafer W. Further, when the supply amount of the first processing liquid E1 exceeds 1500 sccm, the first processing liquid E1 hits the rotating cup 30 and a large amount of liquid splash occurs, and the upper surface (surface) of the wafer W is generated by the first processing liquid E1. This is because TS is contaminated.

  The temperature of the first processing liquid E1 to be supplied is preferably 60 ° C. or higher and 80 ° C. or lower. This is because when the temperature is lower than 60 ° C., the etching rate becomes small and is not practical. Moreover, when temperature exceeds 80 degreeC, it is necessary to improve the heat resistance of each member of a liquid processing apparatus, and it is because manufacturing cost increases.

  After the first step (step S11), in the rinsing step (step S12), pure water (DIW) is supplied to the lower surface (back surface) BS of the rotating wafer W.

  In a state where the wafer W supported by the support pin 35 of the rotary cup 30 is rotated together with the rotary cup 30, the opening / closing mechanism 11c is switched, and the supply of the first processing liquid E1 by the processing liquid supply unit 11a is stopped, Supply of pure water (DIW) by the pure water supply part 11b is started. Then, pure water (DIW) is supplied to the lower surface (back surface) BS of the rotating wafer W by the pure water supply unit 11b.

  After the rinsing process (step S12), the wafer W is dried in the drying process (step S13).

  In a state where the wafer W supported by the support pins 35 of the rotary cup 30 is rotated together with the rotary cup 30, the opening / closing mechanism 11c is switched, and the supply of pure water (DIW) by the pure water supply unit 11b is stopped. As a result, pure water (DIW) remaining on the lower surface (back surface) BS of the wafer W is shaken off outward by the centrifugal force, and the wafer W is shaken off and dried.

  After the drying process (step S13), the rotation of the rotary cup 30 is stopped, the rotation of the wafer W supported by the support pins 35 is also stopped, and the liquid processing is finished.

  Next, as compared with the comparative example, the liquid processing method according to the present embodiment can remove the titanium element remaining on the lower surface (back surface) BS of the wafer W in a shorter time, and the upper surface ( (Surface) The fact that it is possible to prevent flaking in TS will be described.

  FIG. 6 is a cross-sectional view schematically showing the state of the wafer W in the liquid processing method according to the comparative example.

  In the liquid processing method according to the comparative example, the wafer W having the titanium-containing film TF formed on the upper surface (front surface) TS and the lower surface (back surface) BS is rotated, and hydrofluoric acid is applied to the lower surface (back surface) BS of the rotating wafer W. The treatment liquid E0 is supplied, and the titanium-containing film TF is removed from the lower surface (back surface) BS. Moreover, it is the same as that of the liquid processing method which concerns on this Embodiment except the kind of processing liquid.

  The wafer W, which is supported by the support pins 35 of the rotating cup 30 and on which the titanium-containing film TF is formed on the upper surface (front surface) TS and the lower surface (back surface) BS, is rotated together with the rotating cup 30, and the lower surface of the rotating wafer W is rotated. (Back side) The processing liquid E0 containing hydrofluoric acid is supplied to the BS by the processing liquid supply mechanism 10. FIGS. 6A and 6B show the state of the wafer W immediately after the supply of the processing liquid E0 is started and immediately before the supply of the processing liquid E0 is stopped.

  As shown in FIG. 6A, the processing liquid E0 supplied to the lower surface (back surface) BS of the wafer W moves the lower surface (back surface) BS of the wafer W out of the periphery by the centrifugal force generated by the rotation of the wafer W. Move towards. Further, as shown in FIG. 6A, a part of the processing liquid E0 that has moved the lower surface (back surface) BS of the wafer W toward the periphery outward is partially from the lower surface (back surface) BS of the wafer W to the upper surface (front surface). Go around TS. As a result, the processing liquid E0 is also supplied to the peripheral portion of the upper surface (front surface) TS of the wafer W, and the peripheral portion of the upper surface (front surface) TS of the wafer W is also processed by the processing liquid E0.

  Thereafter, when the supply of the processing liquid E0 is continued, the titanium-containing film TF is removed from the lower surface (back surface) BS of the wafer W as shown in FIG. Further, the titanium-containing film TF is also removed from the side surface of the wafer W. Then, the titanium-containing film TF is also removed from the peripheral portion of the upper surface (front surface) TS of the wafer W.

  FIG. 7 is a graph schematically showing the change over time of the film thickness of the titanium-containing film TF between the embodiment and the comparative example. FIG. 7A and FIG. 7B show temporal changes in the embodiment and the comparative example, respectively. The film thickness of the titanium-containing film TF can be measured by, for example, the X-ray reflectivity method.

  Usually, when the treatment liquid E0 containing hydrofluoric acid is used, the etching rate is faster than when the first treatment liquid E1 containing ammonia perwater is used. Therefore, after the processing is started, the time t1 when the thickness of the titanium-containing film TF becomes 0 is earlier in the comparative example shown in FIG. 7B than in the embodiment shown in FIG.

  However, as will be described later with reference to FIG. 9, when the treatment liquid E0 containing hydrofluoric acid is used, after the film thickness of the titanium-containing film TF on the lower surface (back surface) BS of the wafer W becomes substantially equal to zero, In order to make the detected value of the element below the reference value, it must be processed for a longer time. Depending on the conditions, for example, the time from time t1 to time t2 may reach several hundred percent with respect to the time up to time t1 after starting the processing.

  On the other hand, when the first treatment liquid E1 containing ammonia overwater is used, after the thickness of the titanium-containing film TF on the lower surface (back surface) BS of the wafer W becomes substantially equal to 0, the detected value of the titanium element is used as a reference. It is not necessary to process for a longer time in order to make it below the value. Although depending on the conditions, for example, about 10% of the time from the time t1 to the time t2 with respect to the time from the start of processing to the time t1 is sufficient.

  Therefore, at the time t2 when the detected value of the titanium element is equal to or lower than the reference value, the embodiment shown in FIG. 7A is earlier than the comparative example shown in FIG. 7B. Therefore, according to the present embodiment, the titanium element remaining on the lower surface (back surface) BS of the wafer W can be removed in a shorter time.

  Next, after performing the liquid processing method, the wafer W near the boundary between the portion (peripheral portion) where the titanium-containing film TF is removed on the upper surface (surface) TS and the portion (center portion) where the titanium-containing film TF is not removed. The upper surface (surface) TS of was observed with an electron microscope (Scanning Electron Microscope; SEM). The results in the embodiment and the comparative example are shown in FIG. 8 (a) and FIG. 8 (b), respectively. FIG. 8 is a view showing a photograph of the surface of the wafer W after the liquid processing method according to the present embodiment is compared with a photograph of the surface of the wafer W after the liquid processing method according to the comparative example. It is.

  As shown in FIG. 8A, in the liquid processing method according to the embodiment, it can be seen that the upper surface (surface) TS is flat in the vicinity of the boundary between the peripheral edge portion and the central portion. On the other hand, as shown in FIG. 8B, in the liquid processing method according to the comparative example, fine irregularities are observed on the upper surface (surface) TS near the boundary between the peripheral portion and the central portion, and a large number of titanium-containing films TF are present. It turns out that it has peeled in the location of.

  That is, according to the comparative example using the treatment liquid E0 containing hydrofluoric acid, the titanium-containing film TF is peeled off in a flake shape on the upper surface (surface) TS of the wafer W, but the first treatment liquid E1 containing ammonia overwater is removed. According to this embodiment to be used, it is possible to prevent the titanium-containing film TF from peeling off in a flake form on the upper surface (surface) TS of the wafer W.

  As described above, the titanium element remaining on the lower surface (back surface) BS of the wafer W can be removed in a shorter time, and the upper surface (front surface) TS of the wafer W can be prevented from peeling off in a flake shape. 9 can be used for explanation. FIG. 9 is a diagram illustrating a state in which the titanium-containing film TF is etched in the liquid processing method according to the present embodiment in comparison with a state in which the titanium-containing film TF is etched in the liquid processing method according to the comparative example. .

  Each of FIG. 9A and FIG. 9C stops the supply of the first treatment liquid E1 immediately after the supply of the first treatment liquid E1 is started in the liquid treatment method according to the present embodiment. The state of the lower surface (back surface) BS of the immediately preceding wafer W is shown. FIG. 9B shows the wafer W in the vicinity of the boundary between the portion where the titanium-containing film TF immediately before the supply of the first treatment liquid E1 is removed and the portion where the titanium-containing film TF is not removed. The state of the upper surface (surface) TS of is shown.

  On the other hand, each of FIG. 9D and FIG. 9F shows the lower surface of the wafer W immediately after the supply of the processing liquid E0 is started and immediately after the supply of the processing liquid E0 is stopped in the liquid processing method according to the comparative example. (Back side) Shows the state of BS. FIG. 9E shows the upper surface (surface) of the wafer W at the boundary between the portion where the titanium-containing film TF is removed and the portion where the titanium-containing film TF is not removed immediately before the supply of the processing liquid E0 is stopped. ) Indicates the status of TS. FIG. 9E also shows a state in the middle of processing with the processing liquid E0 on the lower surface (back surface) BS of the wafer W.

  For example, as shown in FIGS. 9A and 9D, the titanium-containing film TF includes, for example, crystal grains G and grain boundaries GB, or crystallized portions G and non-crystallized portions GB. It is thought that. And when using the process liquid E0 containing a hydrofluoric acid, it is thought that an etching rate differs in each part. Therefore, in the liquid processing method according to the comparative example, with the supply of the processing liquid E0, for example, as shown in FIG. Removed. Since the titanium-containing film TF is not uniformly etched over the entire surface, even when the film thickness is measured to be 0 by the film thickness measurement, as shown in FIG. The crystallized portion G remains. For this reason, it is thought that the detection value of the titanium element detected by elemental analysis becomes larger than the reference value.

  On the other hand, when using the 1st process liquid E1 containing ammonia overwater, in each part of the crystal grain G and the grain boundary GB, or each part of the crystallized part G and the non-crystallized part GB, the etching rate is It is considered to be approximately equal. That is, in the liquid processing method according to the embodiment, for example, the grain boundary GB and the non-crystallized portion GB are not removed first with the supply of the first processing liquid E1. Therefore, as shown in FIG. 9C, the titanium-containing film TF is uniformly etched over the entire surface. For this reason, when the film thickness is measured to be 0 by the film thickness measurement, the detection value of the titanium element detected by the elemental analysis is considered to be equal to or less than the reference value.

  Furthermore, the supply amount of the first processing liquid E1 gradually decreases from the peripheral side toward the central side at the peripheral portion of the upper surface (front surface) TS of the wafer W. For this reason, as shown in FIG. 9B, in the vicinity of the boundary between the portion where the titanium-containing film TF is removed and the portion where the titanium-containing film TF is not removed, the film thickness gradually increases from the peripheral side toward the center side. Conceivable.

In other words, the thickness of the titanium-containing film TF decreases uniformly from the portion (center portion) where the titanium-containing film TF is not removed on the upper surface (surface) TS to the portion (peripheral portion) where the titanium-containing film TF is removed. Thus, the titanium-containing film TF can be etched. Then, in the vicinity of the boundary between the portion (peripheral portion) where the titanium-containing film TF is removed on the upper surface (surface) TS and the portion (center portion) where the titanium-containing film TF is not removed (the center portion), the titanium-containing film TF becomes brittle and flakes. Can be prevented from peeling off.
(Modification of the embodiment)
Next, a liquid processing apparatus according to a modification of the embodiment will be described with reference to FIG. The liquid processing apparatus according to this modification is different from the liquid processing apparatus according to the embodiment in that the processing liquid is also supplied to the peripheral portion of the wafer W. That is, the liquid processing apparatus according to this modification supplies the processing liquid to the peripheral portions of the lower surface and the upper surface of the wafer W, and processes the peripheral portions of the lower surface and the upper surface of the wafer W.

  FIG. 10 is a schematic cross-sectional view showing the configuration of the liquid processing apparatus 100a according to this modification.

  As shown in FIG. 10, the liquid processing apparatus 100a includes a processing liquid supply mechanism 10, a discharge mechanism 20, a rotating cup 30, a support pin 35, a top plate 40, a base plate (base) 50, a rotation driving unit 60, a control unit 70, And a second processing liquid supply mechanism 80. Portions other than the second processing liquid supply mechanism 80 are the same as those of the liquid processing apparatus according to the embodiment described with reference to FIG. 1, and the same reference numerals as those in FIG. The second processing liquid supply mechanism 80 corresponds to the second processing liquid supply unit in the present invention.

  As shown in FIG. 10, the second processing liquid supply mechanism 80 has a second processing liquid supply unit 81a, a second pure water supply unit 81b, an opening / closing mechanism 81c, and a second processing liquid supply pipe 82. ing. The second processing liquid supply unit 81a supplies the second processing liquid E2, and the second pure water supply unit 81b supplies pure water (DIW). The opening / closing mechanism 81c connects the second processing liquid supply unit 81a and the second pure water supply unit 81b to the second processing liquid supply pipe 82 so as to be switchable. The second processing liquid supply pipe 82 is supplied with the second processing liquid E2 that is switchably supplied from the second processing liquid supply part 81a and the pure water (switchable from the second pure water supply part 81b). DIW) is guided to the peripheral edge of the wafer W. The lower surface of the second processing liquid supply pipe 82 constitutes a second processing liquid supply port 82a.

  In the present modification, the second processing liquid supply mechanism 80 is also, for example, similar to the processing liquid supply mechanism 10. For example, first, the second processing liquid supply unit 81 a includes the second processing liquid containing ammonia overwater (SC1). It is possible to supply E2 and then supply pure water (DIW) by the second pure water supply unit 81b.

  The operation of the liquid processing apparatus 100a according to this modification is also substantially the same as the operation of the liquid processing apparatus 100 according to the embodiment. However, the liquid processing apparatus 100a according to the present modification includes a second processing liquid supply mechanism 80. Accordingly, the processing liquid is supplied from the second processing liquid supply mechanism 80 to the peripheral edge of the upper surface of the wafer W that is rotationally driven.

  Next, with reference to FIG.11 and FIG.12, the liquid processing method performed by the control part 70 using the liquid processing apparatus 100a is demonstrated. FIG. 11 is a flowchart for explaining the procedure of the liquid processing method according to the present modification. FIG. 12 is a cross-sectional view schematically showing the state of the wafer W in the liquid processing method according to this modification. In FIG. 12, only the wafer W, the processing liquid supply mechanism 10, and the second processing liquid supply mechanism 80 are shown for ease of illustration.

  In the liquid processing method according to this modification, the wafer W having the titanium-containing film TF formed on the upper surface (front surface) TS and the lower surface (back surface) BS is rotated, and ammonia is applied to the lower surface (back surface) BS of the rotating wafer W. The first processing liquid E1 containing water is supplied, the second processing liquid E2 containing ammonia perhydration is supplied to the peripheral portion of the upper surface (front surface) TS of the rotating wafer W, the lower surface (back surface) BS and the upper surface ( Surface) The titanium-containing film TF is removed from the peripheral portion of TS.

  In the liquid processing method according to this modification, an example in which the wafer W is supported so that the front surface is the upper surface TS and the back surface is the lower surface BS will be described. However, a liquid processing apparatus configured to supply the first processing liquid E1 to the upper surface TS of the wafer W may be used. In this case, the back surface of the wafer W is the upper surface TS, and the front surface is the lower surface BS. The wafer W may be supported as described above.

  As shown in FIG. 11, the liquid processing method according to this modification includes a first step (step S21), a second step (step S22), a rinsing step (step S23), and a drying step (step S24). .

  In the first step (step S21), the first processing liquid E1 containing ammonia overwater is supplied to the lower surface (back surface) BS of the rotating wafer W. The first step (step S21) can be the same as the first step (step S11) in the embodiment.

  However, in this modification, the second processing liquid E2 is supplied to the peripheral portion of the wafer W in the second step (step S22). For this reason, in the first step (step S21), a part of the supplied first processing liquid E1 does not have to go from the lower surface (back surface) BS of the wafer W to the upper surface (front surface) TS.

  In the second step (step S22), the second processing liquid E2 containing ammonia overwater is supplied to the peripheral portion of the upper surface (front surface) TS of the rotating wafer W. With the wafer W rotated, the open / close mechanism 81c is switched, and the second processing liquid supply unit 81a of the second processing liquid supply mechanism 80 is placed on the periphery of the upper surface (front surface) TS of the rotating wafer W. A second treatment liquid E2 containing water is supplied. The second step (step S22) may be performed simultaneously with the first step (step S21) or may not be performed simultaneously. Hereinafter, an example in which the second step (step S22) is performed simultaneously with the first step (step S21) will be described.

  The state of the wafer W immediately after the supply of the first treatment liquid E1 and the supply of the second treatment liquid E2 is started and immediately before the supply of the first treatment liquid E1 and the supply of the second treatment liquid E2 is stopped. These are shown in FIGS. 12 (a) and 12 (b), respectively.

  As shown in FIG. 12A, the first processing liquid E1 supplied to the lower surface (back surface) BS of the wafer W is the lower surface (back surface) BS of the wafer W due to the centrifugal force generated by the rotation of the wafer W. Move toward the outside of the periphery. Further, as shown in FIG. 12A, the second processing liquid E2 supplied to the peripheral portion of the upper surface (front surface) TS of the wafer W is also affected by the centrifugal force generated by the rotation of the wafer W. The upper surface (front surface) TS is moved outward from the periphery. As a result, the lower surface (back surface) BS, the side surface, and the peripheral portion of the upper surface (front surface) TS of the wafer W are processed by the first processing liquid E1 and the second processing liquid E2.

  Thereafter, when the supply of the first processing liquid E1 and the second processing liquid E2 is continued, the titanium-containing film TF is removed from the lower surface (back surface) BS of the wafer W as shown in FIG. Further, the titanium-containing film TF is also removed from the side surface of the wafer W. Then, the titanium-containing film TF is also removed from the peripheral portion of the upper surface (front surface) TS of the wafer W.

  At this time, in the vicinity of the boundary between the portion (peripheral portion) where the titanium-containing film TF is removed on the upper surface (surface) TS and the portion where the titanium-containing film TF is not removed (center portion), the titanium-containing film TF becomes brittle and flakes. Will not peel off. Therefore, the film thickness of the titanium-containing film TF is uniformly reduced from the portion (center portion) where the titanium-containing film TF is removed on the upper surface (surface) TS to the portion (peripheral portion) where the titanium-containing film TF is removed. In addition, the titanium-containing film TF can be etched.

  Further, similarly to the liquid processing method according to the embodiment, the titanium element remaining on the lower surface (back surface) BS of the wafer W can be removed in a shorter time compared to the case where the processing liquid E0 containing hydrofluoric acid is used. .

As the second treatment liquid E2, similarly to the first treatment liquid E1, ammonia overwater (SC1) composed of ammonia water (NH ₄ OH) and hydrogen peroxide water (H ₂ O ₂ ) may be used. it can. That is, the second treatment liquid E2 contains ammonia and hydrogen peroxide.

  Concentrations of ammonia and hydrogen peroxide in the second treatment liquid E2 are similar to those in the first treatment liquid E1, and the ammonia concentration is 3 wt% or more by weight and the hydrogen peroxide concentration is weight. The ratio is preferably 30 wt%. Further, the second treatment liquid E2 may have a concentration of ammonia and hydrogen peroxide equal to the concentration of ammonia and hydrogen peroxide in the first treatment liquid E1, or the ammonia and hydrogen peroxide in the first treatment liquid E1. It may be different from the concentration of hydrogen peroxide.

  In addition, after the second step (step S22), in the rinse step (step S23), pure water (DIW) is supplied to the lower surface (back surface) BS of the rotating wafer W.

  In a state where the wafer W supported by the support pin 35 of the rotary cup 30 is rotated together with the rotary cup 30, the opening / closing mechanism 11c is switched, and the supply of the first processing liquid E1 by the processing liquid supply unit 11a is stopped, Supply of pure water (DIW) by the pure water supply part 11b is started. Then, pure water (DIW) is supplied to the lower surface (back surface) BS of the rotating wafer W by the pure water supply unit 11b.

  In this modification, the opening / closing mechanism 81c is switched, the supply of the second processing liquid E2 by the second processing liquid supply unit 81a is stopped, and the pure water (DIW) is supplied by the second pure water supply unit 81b. To start. Then, pure water (DIW) is supplied to the peripheral portion of the upper surface (front surface) TS of the rotating wafer W by the second pure water supply unit 81b.

  After the rinsing process (step S23), the wafer W is dried in the drying process (step S24).

  In a state where the wafer W supported by the support pin 35 of the rotating cup 30 is rotated together with the rotating cup 30, the opening / closing mechanism 11c and the opening / closing mechanism 81c are switched to switch the pure water supply unit 11b and the second pure water supply unit 81b. The supply of pure water (DIW) is stopped. As a result, pure water (DIW) remaining on the lower surface (back surface) BS of the wafer W and pure water (DIW) remaining on the peripheral portion of the upper surface (front surface) TS of the wafer W are spun off outward by the centrifugal force, The wafer W is shaken and dried.

  After the drying process (step S24), the rotation of the rotary cup 30 is stopped, the rotation of the wafer W supported by the support pins 35 is also stopped, and the liquid processing is finished.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be modified or changed.

DESCRIPTION OF SYMBOLS 10 Treatment liquid supply mechanism 30 Rotating cup 35 Support pin 60 Rotation drive part 70 Control part 100 Liquid processing apparatus

The concentrations of ammonia and hydrogen peroxide in the first treatment liquid E1 are preferably such that the ammonia concentration is 3 wt% or more by weight and the hydrogen peroxide concentration is 30 wt% or more by weight. . This is because if the concentration of ammonia is less than 3 wt% by weight or the concentration of hydrogen peroxide is less than 30 wt% by weight, the etching rate for etching the titanium-containing film TF decreases.

Concentrations of ammonia and hydrogen peroxide in the second treatment liquid E2 are similar to those in the first treatment liquid E1, and the ammonia concentration is 3 wt% or more by weight and the hydrogen peroxide concentration is weight. The ratio is preferably 30 wt% or more . Further, the second treatment liquid E2 may have a concentration of ammonia and hydrogen peroxide equal to the concentration of ammonia and hydrogen peroxide in the first treatment liquid E1, or the ammonia and hydrogen peroxide in the first treatment liquid E1. It may be different from the concentration of hydrogen peroxide.

Claims (11)

In the liquid processing method of processing the back surface of the substrate with the processing liquid,
A support part that rotatably supports the substrate supports the substrate on which the titanium-containing film is formed on the front and back surfaces, and rotates the substrate supported by the support part together with the support part. A liquid processing method comprising: a first step of supplying a first processing liquid containing ammonia perwater to the back surface of the rotating substrate, and processing the back surface of the substrate with the supplied first processing liquid. .   In the first step, the titanium-containing film is removed from the back surface of the substrate by treating the back surface of the substrate with the supplied first treatment liquid, and the titanium-containing film is removed. The liquid processing method according to claim 1, wherein the titanium element remaining on the back surface of the substrate is removed.   The liquid processing method according to claim 1, wherein the back surface is a lower surface, and the front surface is an upper surface.   In the first step, the first processing liquid supplied to the lower surface is circulated from the lower surface to the upper surface, and the peripheral portion of the upper surface is processed by the wrapped first processing liquid. The liquid processing method according to claim 3.   4. The method according to claim 3, further comprising a second step of supplying a second treatment liquid containing ammonia perwater to the peripheral portion of the rotating substrate and treating the peripheral portion of the upper surface with the supplied second treatment liquid. The liquid processing method as described.   A computer-readable recording medium having recorded thereon a program for causing a computer to execute the liquid processing method according to any one of claims 1 to 5. In the liquid processing apparatus that processes the back surface of the substrate with the processing liquid,
A support portion that is rotatably provided to support the substrate;
A rotating part for rotating the support part;
A treatment liquid supply part for supplying a first treatment liquid containing ammonia perwater to the back surface of the substrate supported by the support part;
The substrate having a titanium-containing film formed on the front surface and the back surface is supported by the support unit, the substrate supported by the support unit is rotated together with the support unit by the rotating unit, and the rotating substrate is rotated. A liquid processing apparatus, comprising: a control unit configured to supply the first processing liquid to the back surface by the processing liquid supply unit, and to process the back surface of the substrate with the supplied first processing liquid.   The control unit removes the titanium-containing film from the back surface of the substrate by processing the back surface of the substrate with the supplied first processing liquid, and the substrate containing the titanium-containing film is removed. The liquid processing apparatus of Claim 7 which removes the titanium element which remains on the said back surface.   The liquid processing apparatus according to claim 7, wherein the back surface is a lower surface and the front surface is an upper surface.   The said control part makes the said 1st process liquid supplied to the said lower surface wrap around to the said upper surface from the said lower surface, and processes the peripheral part of the said upper surface with the said 1st process liquid made to wrap around. 9. The liquid processing apparatus according to 9. A second treatment liquid supply part for supplying a second treatment liquid containing ammonia perwater to the peripheral edge of the substrate supported by the support part;
The control unit supplies the second processing liquid to the peripheral portion of the rotating substrate by the second processing liquid supply unit, and processes the peripheral portion of the upper surface with the supplied second processing liquid. The liquid processing apparatus of Claim 9 which is a thing.