JP2014022558A - Substrate processing apparatus and substrate processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate processing apparatus including means for obtaining the interval between a top plate and a rotating substrate with certainty.SOLUTION: In order to obtain the interval of a top plate (50) and a substrate (W), a range-finding sensor (80) is provided. The range-finding sensor is configured to be able to measure the distance to a range-finding object. The range-finding sensor is attached to the top plate, or a member (e.g., a cup 60) having a fixed position in the vertical direction for a substrate holding part (20). The range-finding sensor is disposed so that a member (e.g., the substrate W or the cup 60), the vertical direction of which from the range-finding sensor changes corresponding to a change in the vertical direction between the substrate held by the substrate holding part and the top plate, becomes the range-finding object.

Description

  The present invention relates to a substrate processing apparatus and a substrate processing method for processing a substrate by supplying a processing fluid to the substrate while rotating the substrate.

  As one of various processes for manufacturing a semiconductor device, a substrate to be processed, for example, a semiconductor wafer (hereinafter simply referred to as “wafer”) is rotated about a vertical axis, and a processing liquid is supplied to the rotating wafer. There is a liquid processing step for processing the wafer.

  Some liquid processing apparatuses for performing such a liquid processing step supply a processing liquid to a processing target surface while rotating the processing target surface of the wafer downward (see, for example, Patent Document 1). . In this type of liquid processing apparatus, when the processing liquid reaches the upper surface opposite to the processing target surface, the upper surface is contaminated with particles. In order to prevent this, a top plate (also called a top plate, a top cover, etc.) is disposed at a processing position close to the upper surface of the wafer when wafer processing is executed. A gas is supplied to the central portion of the space formed between the top plate and the wafer, and this gas flows toward the peripheral edge of the wafer and blows out from between the top plate and the wafer at the peripheral edge of the wafer. By blowing out the gas, the processing liquid or its mist is prevented from approaching and coming into contact with the upper surface of the wafer.

  The top plate is disposed at the processing position only when processing is performed, and is disposed at the retracted position at other times. The retreat position is set to a position directly above the processing position or a position above the processing position and moved in the horizontal direction by a predetermined amount. The top plate moves up and down when moving between the processing position and the retracted position. Control of the vertical position of the top plate is usually performed based on the output of an encoder attached to the motor of the drive mechanism for raising and lowering the top plate.

  If any trouble occurs in the driving mechanism for raising and lowering the top plate, the size of the gap between the top plate at the processing position and the wafer may be out of the proper range. In addition, even when some trouble occurs in holding the wafer during processing, the size of the gap between the top plate and the wafer may be out of the proper range. If the distance is out of the proper range, the particle may be contaminated and the wafer may have to be discarded.

JP 2012-84607 A

  The present invention provides a substrate processing apparatus including means capable of grasping a distance between a top plate (top plate) and a substrate.

  The present invention includes a substrate holding unit that holds a substrate in a horizontal posture, a rotation drive mechanism that rotates the substrate holding unit around a vertical axis, a top plate for covering the substrate held by the substrate holding unit, A top plate that moves the top plate up and down between a first position that covers the substrate close to the upper surface of the substrate held by the substrate holding portion and a second position that is above the processing position. A lifting mechanism; a processing liquid supply nozzle that supplies a processing liquid to the lower surface of the substrate held by the substrate holding unit; and a distance measuring sensor that measures a distance to a distance measuring object, The vertical plate is attached to the top plate or a member whose position in the vertical direction relative to the substrate holding unit is unchanged, and corresponds to a change in vertical distance between the substrate held by the substrate holding unit and the top plate. Member whose vertical distance from the distance measuring sensor changes To provide a substrate processing apparatus according to the measuring object.

  Further, in the present invention, the substrate is held horizontally by the substrate holding unit, and a top plate is positioned at a predetermined position close to the upper surface of the substrate held by the substrate holding unit, and the substrate is moved by the top plate. Covering the substrate, rotating the substrate held by the substrate holding portion around a vertical axis, supplying a treatment liquid to the substrate, processing the substrate, and covering the substrate with the top plate Later, the board and the top board held by the board holding part from the distance measuring sensor by the distance measuring sensor attached to the top board or a member whose vertical position relative to the board holding part is unchanged. A substrate processing method comprising: measuring a distance from the distance measuring sensor to a member whose vertical distance changes in response to a change in a vertical distance between the first and second sensors.

  In a preferred embodiment, the distance measuring sensor is attached to the top plate. In this case, the distance measuring sensor can be arranged such that a cup body or a member fixed to the cup body is a distance measuring object. Alternatively, the distance measuring sensor can be provided such that the substrate itself held by the substrate holding part becomes a distance measuring object. In another embodiment, the distance measuring sensor may be attached to a cup body. In this case, the distance measuring sensor uses the top plate or a member attached to the top plate as a distance measuring object. Can do.

  According to the present invention, the distance between the top plate and the substrate can be grasped. For this reason, it is possible to grasp at an earlier stage that the processing failure of the substrate has occurred or its possibility.

It is a longitudinal cross-sectional view which shows the structure of one Embodiment of the substrate processing apparatus by this invention. It is a figure for demonstrating the airflow around the peripheral part of a board | substrate. It is a figure explaining other arrangement | positioning of a ranging sensor. It is a figure explaining other arrangement | positioning of a ranging sensor. It is a figure explaining other arrangement | positioning of a ranging sensor.

  Embodiments of a substrate processing apparatus according to the present invention will be described below with reference to the accompanying drawings. In this substrate processing apparatus, an unnecessary film such as SiN adhering to the back surface and side peripheral surface of a semiconductor wafer as a substrate to be processed on which a semiconductor device is formed is referred to as a hydrofluoric acid solution (hereinafter referred to as “HF solution”). ) To remove the liquid.

  The substrate processing apparatus includes a housing 10, a substrate holder 20 that holds the wafer W in a horizontal posture in the housing 10, and a rotation drive mechanism 30 that rotates the substrate holder 20 around a vertical axis. Yes.

  A fan filter unit (FFU) 11 is attached to the ceiling portion of the housing 10, and the FFU 11 forms a downflow of clean air from the top to the bottom in the internal space of the housing 10. A wafer entrance / exit 12 is provided on one side wall of the housing 10, and the entrance / exit 12 can be opened and closed by a shutter 13. An exhaust passage 14 for exhausting the atmosphere in the housing 10 is provided on the bottom wall of the housing 10.

  The substrate holding part 20 has a generally disc-shaped base plate 21. The upper surface of the base plate 21 faces the lower surface of the wafer W when the wafer W is held by the substrate holding unit 20. The distance between the upper surface of the base plate 21 and the lower surface of the wafer W at this time is due to the negative pressure generated by the airflow (toward the wafer peripheral edge) formed between the base plate 21 and the wafer W as it rotates. The force with which the wafer W is pressed against the substrate support piece 22B, which will be described later, becomes an appropriate magnitude, and the processing liquid supplied to the center of the lower surface of the wafer W is not prevented from flowing to the peripheral edge of the wafer W. An appropriate value such as 1 to 5 mm is set. Above the base plate 21, a generally annular ring member 22 is provided at a distance from the base plate 21 in the vertical direction. The base plate 21 and the ring member 22 are coupled so as not to move relative to each other by a plurality of (for example, twelve) coupling members 23 (for example, screws).

  The ring member 22 includes an annular guide portion 22A, and a plurality (for example, twelve) of substrate support pieces 22B projecting from the inner peripheral edge of the lower surface of the guide portion 22A toward the center of the annular ring. Yes. The upper surface of the substrate support piece 22 </ b> B supports the peripheral edge of the lower surface of the wafer W, whereby the wafer W is held on the substrate holding unit 20 in a horizontal posture. The substrate support piece 22B is provided at a position where the circumference is equally divided. In FIG. 1, only two substrate support pieces 22B are displayed. When the wafer W is placed on the substrate support piece 22B, the guide portion 22A surrounds the periphery of the wafer W, and at this time, a slight gap is formed between the inner periphery of the guide portion 22A and the outer periphery of the wafer W. Is done. The guide portion 22A guides the fluid flowing near the periphery of the wafer W when liquid processing is being performed on the wafer W (details will be described later).

  A cylindrical rotation shaft 31 extends downward from the center of the lower surface of the base plate 21 in the vertical direction. The rotating shaft 31 is rotatably supported by a bearing portion 32 having a built-in bearing. A pulley 33 is provided below the rotary shaft 31 outside the housing 10. A drive belt 36 is wound around the pulley 33 and a pulley 35 provided on the rotation shaft of the rotary motor 34. Therefore, by driving the rotation motor 34, the wafer W held on the substrate holding unit 20 can be rotated via the rotation shaft 31. The above-described components 31 to 36 constitute a rotation drive mechanism 30 that rotates the substrate holding unit 20 around the vertical axis.

  A cylindrical internal space extending in the vertical direction over the entire length of the rotary shaft 31 is provided in the rotary shaft 31. Further, an opening continuous with the cylindrical internal space passes through the central portion of the base plate 21. A cylindrical substrate lifter 40 is inserted into these internal spaces and openings. A plurality (for example, three) of substrate support pins 41 are provided on the upper end portion of the substrate lifter 40. The substrate lifter 40 can rotate relative to the rotating shaft 31 so that it does not rotate with the rotating shaft 31 even if the rotating shaft 31 rotates, and can rotate relative to the rotating shaft 31. It is supported in the shaft 31. A cylinder motor 43 is connected to the lower end portion of the substrate lifter 40 via an elevating plate 42. Accordingly, by driving the cylinder motor 43, the substrate lifter 40 can be moved up and down between the raised position and the lowered position, whereby the wafer W is supported by the tips of the substrate support pins 41 and moved up and down. Can do.

In the substrate lifter 40, an internal space extending in the axial direction of the substrate lifter 40, that is, in the vertical direction is provided. In this internal space, a processing liquid supply path 44 and a gas supply path 45 for supplying a processing liquid to the lower surface of the wafer W held by the substrate holding unit 20 are provided. The upper end opening 44 a of the processing liquid supply path 44 serves as a discharge port of a processing liquid nozzle that discharges the processing liquid toward the lower surface of the wafer W. The upper end opening 45 a of the gas supply path 45 serves as a discharge port of a dry gas nozzle that supplies a dry gas toward the lower surface of the wafer W. An HF solution supply mechanism 46 and a DIW (DeIonized Water) supply mechanism 47 are connected to the processing liquid supply path 44. By switching the switching valve 48, either the HF solution or DIW is supplied to the supply path 44. Either one can be supplied. The gas supply path 45 is connected with a supply mechanism 49 for N ₂ gas (nitrogen gas) as a dry gas. Each of the processing fluid supply mechanisms (46, 47, 49 (also described below as a supply mechanism 52)) is configured by components such as a processing fluid supply source, an on-off valve, and a flow rate adjustment valve.

  The substrate processing apparatus further includes a top plate (top plate) 50. The top plate 50 is close to the wafer W held by the substrate holding unit 20 and covers a processing position (position shown in FIG. 1) covering almost the entire upper surface of the wafer W, and a retraction position (not shown) retreated from the processing position. For example, it is possible to move between a position directly above the processing position and a position higher than the carry-in / out entrance 12. In the present embodiment, the top plate 50 is supported by a support arm 51, and the support arm 51 is moved up and down by a cylinder motor 52 provided as a top plate lifting mechanism. That is, the top plate 50 moves between the processing position and the retracted position only by raising and lowering. The top plate 50 may be swiveled around the vertical axis as well as lifted and moved between the processing position and the retracted position by a combination of horizontal movement and lifting movement.

  The vertical position (height position) of the top plate 50 is controlled by the top plate movement (lifting) control unit 57. Specifically, the top plate movement control unit 57 detects the vertical position of the top plate 50 based on an output pulse from a position encoder (not shown) such as a rotary encoder attached to the cylinder motor 52. The cylinder motor 52 is driven so that the detected vertical position matches the target vertical position (for example, the height position at the processing position).

A gas supply port 53 for supplying an inert gas such as nitrogen gas into a space formed between the wafer W held by the substrate holding unit 20 and the top plate 50 is provided at the center of the top plate 50. Is provided. An N ₂ gas supply mechanism 54 is connected to the gas supply port 53.

  On the other hand, an annular protrusion 55 protruding downward is formed on the lower surface of the top plate 50 along the peripheral edge. When the top plate 50 is in the processing position, the lower surface 55 a of the protrusion 55 is close to the upper surface of the wafer W held by the substrate holding unit 20. At this time, the size (vertical width) of the narrow gap 56 formed between the lower surface 55a of the protrusion 55 and the upper surface of the wafer W, that is, the distance between the wafer W and the top plate at the peripheral edge of the wafer is, for example, 0.5 to 1.5 mm. The distance between the central portion 57 on the lower surface of the top plate 50 and the upper surface of the wafer W is relatively large, for example, about 10 to 20 mm. The central portion 57 on the lower surface of the top plate 50 and the lower surface 55a of the protrusion 55 are connected via an inclined surface 55b.

  A cup body 60 is provided so as to surround the substrate holder 20 and the periphery of the top plate 50 at the processing position. The cup body 60 receives a processing fluid such as a chemical liquid scattered from the wafer W when the wafer W is being processed. A discharge path 61 is connected to the bottom of the cup 60. The discharge path 61 is connected to the factory exhaust system / waste liquid system via a mist separator, an ejector and the like (not shown). As shown in FIGS. 1 and 2, when the top plate 50 is in the processing position, the top plate 50 is accommodated in an upper opening formed in the ceiling portion of the cup body 60. A small gap is formed between the inner peripheral surface of the upper opening formed on the outer periphery and the outer peripheral surface of the top plate 50.

FIG. 2 shows the gas flow in the vicinity of the periphery of the wafer W when the wafer W is rotated while N ₂ gas is being discharged from the gas supply port 53. As the wafer W rotates, a gas flow toward the periphery of the wafer W is generated in the vicinity of the upper and lower surfaces of the wafer W. In other words, cause space towards the periphery of the wafer W N ₂ gas flow F _N between the top plate 50 and the wafer W, the N ₂ gas flow F _N flows out increasing the speed from narrow gap 56. Since the inclined surface 55 b is provided on the top plate 50, the N ₂ gas smoothly flows into the narrow gap 56. The gas flowing out of the narrow gap 56 flows toward the discharge path 61 through the space between the upper surface of the guide portion 22A of the ring member 22 and the lower surface of the ceiling portion of the cup body 60. Further, in the space between the lower surface of the wafer and the base plate 21, a gas flow F _L (air or N ₂ gas flow) directed toward the peripheral edge of the wafer W is generated, and this gas flow F _L is guided by the ring member 22. It flows toward the discharge path 61 through the space between the lower surface of the portion 22A and the base plate 21. Since the inside of the cup body 60 is exhausted through the discharge path 61, the clean air from the FFU is reduced from the gap between the inner peripheral surface of the upper opening of the cup body 60 and the outer peripheral surface of the top plate 50. The flow is drawn into the cup body 60. The drawn clean air merges with the N ₂ gas flow F _N, and then passes through the space between the upper surface of the guide portion 22A of the ring member 22 and the lower surface of the ceiling portion of the cup body 60 to the discharge path 61. It flows toward.

The space between the wafer W on the lower surface and the base plate 21 and the lower surface space from the wafer by the gas flow F _L flowing outward between the base plate 21 becomes vacuum state, thereby the wafer W is a substrate support piece 22B The wafer W is firmly held by the substrate holder 20. Note that since the N ₂ gas is supplied to the space on the upper surface side of the wafer W, the pressure becomes higher than the space on the lower side of the wafer W, so that the wafer W hardly rises.

The N ₂ gas flow F _N flowing out from the narrow gap 56 at a relatively high speed prevents the processing liquid flowing out of the wafer W together with the gas flow F _L or its mist from entering the upper surface side of the wafer W. In order to achieve this effect, it is necessary that the size (vertical width) of the narrow gap 56 be an appropriate value. The size is larger than the proper range of the narrow clearance 56, N ₂ gas flow F _N is the speed of outflow is slower from the narrow gap 56, the treatment liquid or a mist flows out from the lower surface side of the wafer W is, the upper surface of the wafer W It can wrap around and cause particles. On the other hand, when the size of the narrow gap 56 is smaller than an appropriate value, the wafer W and the top plate 50 may collide and be damaged when the rotating wafer W is lifted or vibrated up and down. .

  The substrate processing apparatus further includes at least one (preferably a plurality of) mechanical stoppers 70 for preventing the wafer W held by the substrate holding unit 20 and the top plate 50 from colliding with each other. In the present embodiment, the mechanical stopper 70 is screwed into the support portion 71 provided on the peripheral edge portion of the upper surface of the top plate 50, the screw shaft 72 screwed into the female screw hole formed in the support portion 71, and the screw shaft 72. And a receiving portion 74 provided around the opening on the upper surface of the cup body 60. The screw shaft 72 can be moved up and down by rotating the screw shaft 72, and the screw shaft 72 can be fixed by tightening the nut 73. The mechanical stopper 70 is adjusted so that the lower end of the screw shaft 72 and the receiving portion 74 collide with each other when the narrow gap 56 becomes 0.4 mm, for example, just before the wafer W and the top plate 50 collide. In the present embodiment, a plurality (specifically, three) mechanical stoppers 70 are provided at equal intervals along the circumferential direction of the top plate 50.

  The substrate processing apparatus further performs distance measurement for the purpose of measuring the distance between the wafer W held by the substrate holding unit 20 and the top plate 50, specifically, the size (vertical width) of the narrow gap 56. At least one (preferably a plurality) of distance measuring sensors 80 are provided. In the present embodiment, a plurality (specifically, three) of distance measuring sensors 80 are provided at positions where the circumference of the top plate 50 is equally divided. It is preferable that the mechanical stoppers 70 and the distance measuring sensors 80 are alternately provided along the circumferential direction. Although only one distance measuring sensor 80 may be provided, it is preferable to provide three or more distance measuring sensors because the inclination of the top plate 50 can be grasped.

  The distance measuring sensor 80 is preferably an optical sensor, and may be, for example, a laser-type reflective displacement sensor (position sensor). In the present embodiment, the distance measuring sensor 80 is attached to the upper surface of the top plate 50, and measures the distance from the distance measuring sensor 80 to the measurement point 81 set around the opening on the upper surface of the cup body 60. can do. The position where the measurement point 81 is set is not limited to the cup body 60 itself, and may be provided on another member fixed to the cup body 60. In the present embodiment, since the substrate holder 20 does not move up and down, the positional relationship in the vertical direction between the wafer W properly held by the substrate holder 20 and the cup body 60 is unchanged. Accordingly, the vertical distance from the distance measuring sensor 80 to the measurement point 81 on the cup body 60 is “X”, and the vertical distance between the top plate 50 and the wafer W (ie, the size of the narrow gap 56 (up and down) When the direction width)) is “Y”, the relationship “Y = X + K (K is a constant)” is established. Therefore, measuring the vertical distance from the distance measuring sensor 80 to the measurement point 81 on the cup body 60 is equivalent to measuring the size of the narrow gap 56.

  The constant “K” can be calculated based on the measurement value of the distance measuring sensor 80 and the distance between the upper surface of the top plate 50 and the upper surface of the wafer W. The distance between the top surface of the top plate 50 and the top surface of the wafer W is measured by a contact-type precision measuring instrument such as a dial gauge installed on the top surface of the top plate 50 in the vicinity of the distance measuring sensor 80. A through hole (closed by a plug) through which the probe of the dial gauge is passed is provided in the top plate 50, but it is not shown. The constant “K” is desirably measured for each distance measuring sensor 80, that is, measured at each angular position where each distance measuring sensor 80 is provided.

  The substrate processing apparatus further includes a wafer holding state detecting device 90 for detecting whether or not the wafer W is appropriately held by the substrate holding unit 20. In the present embodiment, the wafer holding state detection device 90 includes a reflective laser type displacement sensor 91 that is an optical sensor. The displacement sensor 91 is provided so as to irradiate laser light from a window provided on the side wall of the housing 10 toward the upper surface of the wafer W (an appropriate position other than the center of the upper surface). The laser beam reflected by the upper surface of the wafer W is reflected by the mirror 92 attached to the ceiling of the housing 10, enters the upper surface of the wafer W again, and returns to the displacement sensor 91. The optical path of the laser beam in this case is indicated by a one-dot chain line denoted by reference numeral 93. If the wafer W is rotated and stopped at three or more different angular positions, and the positions of the laser beams returned to the displacement sensor 91 at the respective angular positions are the same or the deviation amount is within a predetermined range, It can be seen that the wafer W is held by the substrate holding unit 20 in an appropriate state in a horizontal posture. Various detection devices for detecting the holding state of the wafer W are known, and the wafer holding state detection device 90 shown in the figure can be replaced with another type.

  The substrate processing apparatus has a controller (control unit) 200 that controls the overall operation of the substrate processing apparatus. The controller 200 includes all functional components of the substrate processing apparatus 100 (for example, a cylinder motor 43 for the substrate lifter 40, a cylinder motor 52 for the top plate 50, a rotation motor 33 for the rotation drive mechanism 30, a supply mechanism for various processing fluids, etc. ) Control the operation. The controller 200 can be realized by, for example, a general-purpose computer as hardware and a program (such as an apparatus control program and a processing recipe) for operating the computer as software. The software is stored in a storage medium such as a hard disk drive that is fixedly provided in the computer, or is stored in a storage medium that is detachably set in the computer such as a CD-ROM, DVD, or flash memory. Such a storage medium is indicated by reference numeral 201 in FIG. The processor 202 calls and executes a predetermined processing recipe from the storage medium 201 based on an instruction from a user interface (not shown) or the like as necessary, whereby each functional component of the substrate processing apparatus operates under the control of the controller 200. Then, a predetermined process is performed. The above-described top plate movement control unit 57 is configured as a part of the controller 200. An abnormality notification unit 203 is connected to the controller 200. The abnormality notification unit 203 includes an image display, an alarm sound generator, and the like, and notifies an operator of the substrate processing apparatus by an image, sound, or the like when an abnormality occurs in the measurement result of the distance measuring sensor 80.

  Next, liquid processing for removing unnecessary films such as SiN adhering to the back surface and side peripheral surface of the wafer W on which the semiconductor device is formed on the front surface by using the substrate processing apparatus described above will be described. .

  With the top plate 50 positioned at the retracted position and the shutter 13 opened, a transfer arm (not shown) holding the wafer W with the back side facing downward enters the housing 10 through the transfer port 12 and enters the wafer W. Is positioned directly above the substrate holder 20. Next, the substrate lifter 40 is raised, the wafer W held by the transfer arm (not shown) is lifted by the substrate support pins 41, and the wafer is received from the transfer arm. Next, a transfer arm (not shown) is withdrawn from the housing 10. Next, the substrate lifter 40 supporting the wafer W is lowered to the height position shown in FIG. In the lowering process, as shown in FIG. 1, the wafer W is placed on the substrate support piece 22 </ b> B of the substrate holding unit 20, and the wafer W moves away from the substrate lifter 40. Thus, the loading of the wafer W is completed.

  Thereafter, using the wafer holding state detection device 90, it is confirmed whether or not the wafer W is appropriately held by the substrate holding unit 20. If the wafer W is not properly held, the loading operation of the wafer W is retried. If the problem is not resolved even after retrying, the cause is investigated, and the substrate processing apparatus is adjusted or repaired as necessary. The abnormality detected by the wafer holding state detection device 90 is notified to the operator of the substrate processing apparatus by the abnormality notification unit 203.

  When it is confirmed that the wafer W is properly held by the substrate holder 20, the top plate 50 is lowered to the processing position (position shown in FIG. 1). At this time, the distance from each distance measuring sensor 80 to the corresponding measurement point 81 on the cup body 60 is measured. Based on the measurement value of each distance measuring sensor 80, the size (vertical width) of the narrow gap 56 at the angular position where each distance measuring sensor 80 is disposed is within an allowable range (for example, 0.5 to 1.5 mm). If it is confirmed, a series of processing for the wafer W is started. When the size of the narrow gap 56 is outside the allowable range at any angular position, the top plate 50 is once raised and then retried to move to the processing position. If the size of the narrow gap 56 does not fall within the allowable range even after retrying, the cause is investigated and the substrate processing apparatus is adjusted or repaired as necessary.

After confirming that the position of the top plate 50 is appropriate, a chemical treatment is performed. First, the wafer W is rotated by the rotation drive mechanism 30, and the HF solution is supplied to the lower surface of the wafer W from the upper end opening 44 a of the processing liquid supply path 44 provided in the substrate lifter 40. Unnecessary films such as SiN are removed by the HF solution flowing toward the peripheral edge on the lower surface of the wafer W by centrifugal force. At this time, as described earlier with reference to FIG. 2, HF solution is flowing outside of the wafer W with a gas flow F _L, the N ₂ gas flow F _N flowing at high speed from the narrow gap 56 It is possible to prevent the HF solution or its mist from entering the upper surface side of the wafer W.

  After the chemical solution treatment with the HF solution for a predetermined time, the discharge of the HF solution from the upper end opening 44a is stopped while the rotation of the wafer W is continued, and DIW is supplied from the upper end opening 44a to the back surface of the wafer W. Thereby, the rinsing process of the wafer W is performed.

After performing the rinse process by DIW for a predetermined time, the discharge of DIW from the upper end opening 44 a is stopped while the rotation of the wafer W is continued, and the N ₂ gas is discharged from the upper opening 45 a of the gas supply path 45. Thereby, the spin drying process of the wafer W is performed. Thus, a series of processes for the wafer W is completed.

  It is preferable that the distance measurement by the distance measuring sensor 80 is continuously performed during the chemical treatment, the rinse treatment, and the spin drying treatment. This is because when the position of the top plate 50 is shifted and the size of the narrow gap 56 is changed, the above-described problems occur. If it is determined that the size (width in the vertical direction) of the narrow gap 56 obtained based on the distance measurement by the distance measuring sensor 80 is outside the allowable range (0.5 to 1.5 mm), the wafer W is not loaded. The fact that the wafer W has been processed in an appropriate state is recorded in a memory (not shown) of the controller 200, and the controller 200 notifies the operator that the wafer W has been processed in an inappropriate state by the abnormality notification unit 203. In response to this, the operator responds as follows, for example. When the narrow gap 56 is slightly larger than the upper limit value of the allowable range (for example, 1.5 to 2.0 mm), that is, in the case of the first level abnormality, the number of particles increases, but a certain yield can be maintained. The process is completed as it is. However, for example, measures such as performing a particle check of the wafer W immediately after the wafer W is unloaded from the substrate processing apparatus are taken. When the narrow gap 56 is further increased (for example, more than 2.0 mm), that is, in the case of the second level abnormality, unacceptable levels of particles are generated in many areas on the surface of the wafer W, and the wafer W is discarded. . Moreover, since it is also considered that the lower surface of the top plate 50 is contaminated, the top plate 50 is cleaned as necessary. When the narrow gap 56 is considerably smaller than the lower limit value of the allowable range (for example, less than 0.4 mm), the wafer W is lifted from the substrate support piece 22B even before the mechanical stopper 70 acts. In such a case, the wafer W and the top plate 50 may collide with each other, so that the rotation of the wafer W is emergency stopped. The reference value for the response and determination when it is determined that the above-described allowable range is exceeded is merely an example, and may be changed due to the device configuration, or may be changed based on the user's risk management policy. The abnormality is notified to the operator of the substrate processing apparatus by the abnormality notification unit 203.

  When the processing of the wafer W is finished, the top plate 50 is raised to the retracted position, the wafer W is lifted by the substrate lifter 40, and the shutter 13 is opened. An empty transfer arm (not shown) enters the housing 10 through the carry-in / out opening 12 and is positioned directly below the wafer W. Thereafter, the substrate lifter 40 is lowered to transfer the wafer W to the transfer arm, and then the transfer arm is withdrawn from the housing 10.

  As described above, according to the present embodiment, the distance between the top plate 50 and the wafer W can be grasped and can be managed more reliably. For this reason, it is possible to grasp at an early stage that the processing failure of the wafer W has occurred or its possibility. Further, it is possible to prevent the substrate processing apparatus from being damaged due to the collision between the wafer W and the top plate 50.

  In the above embodiment, the distance sensor 80 is provided on the top plate 50 and the distance from the distance sensor 80 to the measurement point 81 set on the cup body 60 is measured. However, the present invention is not limited to this. For example, as shown in FIG. 3, a distance measuring sensor 80 may be provided on the cup body 60 to measure the distance to the measurement point 81 ′ set on the top plate 50 or a member fixed to the top plate 50. The measurement point 81 ′ can be provided by a member that protrudes radially outward from the peripheral edge of the top surface of the top plate 50. Also in this case, it is desirable to provide a plurality of distance measuring sensors 80, preferably three or more. Further, as shown in FIG. 4, the distance sensor 80 provided on the top plate 50 measures the distance from the distance sensor 80 to the measurement point 81 ″ set on the upper surface of the guide portion 22A of the ring member 22. The change in the vertical distance from the distance measuring sensor 80 provided on the top plate 50 to the ring member 22 corresponds to the change in the vertical distance between the wafer W and the top plate 50.

  Further, the distance from the distance measuring sensor 80 to the upper surface of the wafer W may be directly measured by the distance measuring sensor 80 provided on the top plate 50. A specific configuration example in this case is shown in FIG. According to this modified embodiment, in addition to the same effect as the above-described embodiment, when the holding state of the wafer W in the substrate holding unit 20 is bad or deteriorated, it can be reliably detected. The effect is achieved. Specifically, an inappropriate placement state of the wafer W on the substrate support piece 22B that cannot be detected by the wafer holding state detection device 90 can be detected. In addition, even if the wafer is lifted during processing while rotating the wafer W, it can be detected reliably in real time, so that the rotation of the wafer is stopped according to the situation. Thus, the substrate processing apparatus can be prevented from being greatly damaged. Further, according to this modified embodiment, if the wafer W breaks during processing, the distance from the distance measuring sensor 80 to the wafer W cannot be detected, or the distance detected by the distance measuring sensor 80 Changes significantly (for example, the distance to the base plate 21 is detected). When such an abnormality occurs in the detection value of the distance measuring sensor 80, it is possible to prevent the substrate treatment apparatus from causing a great deal of damage by immediately stopping the rotation of the substrate holding unit 20 immediately. Also in this case, it is desirable to provide a plurality of distance measuring sensors 80, preferably three or more.

  In each of the above-described embodiments, the distance measurement result obtained by the distance measurement sensor 80 is used exclusively for determination of abnormality and warning. However, the present invention is not limited to this, and the distance measurement result obtained by the distance measurement sensor 80. May be used as a feedback signal for controlling the vertical position of the top plate 50.

  In each of the above embodiments, the laser-type reflective displacement sensor is used as the distance measuring sensor 80. However, the present invention is not limited to this, and any method capable of measuring the distance to the distance measuring object. The distance measuring sensor can be used. Specifically, for example, a proximity sensor, specifically, an eddy current displacement sensor can be used. In this case, when the distance measuring object is not made of metal (for example, when it is a resin cup), a metal piece is attached to the distance measuring object so that detection by eddy current is possible. Further, when the object to be measured is not a substrate (wafer W), a contact-type displacement sensor can be used.

  The substrate to be processed by the substrate processing apparatus is not limited to a semiconductor wafer, and may be a glass substrate, a liquid crystal substrate, or the like. The processing liquid used for the substrate processing is not limited to the above-described processing liquid, and may be other processing liquid such as SC-1 liquid and SC-2 liquid. Further, the dry gas is not limited to that described above, and may be, for example, clean air or dry air. In addition, the substrate processing apparatus is not limited to the one configured to process the lower surface of the substrate as described above, and any processing that needs to grasp the distance between the top plate and the substrate, for example, the peripheral edge of the substrate Further, a bevel cleaning process for removing unnecessary films on the front surface and back surface (upper surface and lower surface) of the substrate in the vicinity thereof may be used.

W substrate (semiconductor wafer)
20 Substrate holder 30 Rotation drive mechanism 44a Treatment liquid supply nozzle
50 Top plate
60 Cup body 52 Top plate lifting mechanism 80 Distance sensor 90 Wafer holding state detecting means (wafer holding state detecting device)
200 Control means (controller)

Claims (16)

A substrate holder for holding the substrate in a horizontal position;
A rotation drive mechanism for rotating the substrate holding unit around a vertical axis;
A top plate for covering the substrate held by the substrate holding unit;
A ceiling that moves the top plate up and down between a first position that covers the substrate close to the upper surface of the substrate held by the substrate holding portion and a second position that is above the processing position. A plate lifting mechanism;
A processing liquid supply nozzle for supplying a processing liquid to the lower surface of the substrate held by the substrate holding unit;
A distance measuring sensor for measuring the distance to the object to be measured;
With
The distance measuring sensor is attached to the top plate or a member whose vertical position relative to the substrate holding unit is unchanged, and the vertical distance between the substrate held by the substrate holding unit and the top plate A substrate processing apparatus in which a member whose vertical distance from the distance measuring sensor changes corresponding to the change in the distance measuring object is the distance measuring object. The substrate processing apparatus further includes a cup body surrounding the periphery of the substrate held by the substrate holding unit,
The distance measuring sensor is attached to the top plate,
The distance measuring object is the cup body or a member fixed to the cup body,
The substrate processing apparatus according to claim 1. The distance measuring sensor is attached to the top plate,
The distance measuring object is a substrate held by the substrate holding unit,
The substrate processing apparatus according to claim 1. The substrate processing apparatus further includes a cup body surrounding the periphery of the substrate held by the substrate holding unit,
The distance measuring sensor is attached to the cup body,
The distance measuring object is the top plate or a member fixed to the top plate,
The substrate processing apparatus according to claim 1.   5. The distance measuring sensor according to claim 1, wherein at least three distance measuring sensors are provided, and the distance measuring sensors are arranged at different angular positions on a circumference around the vertical axis. Substrate processing equipment.   The said substrate processing apparatus is provided with the control means which determines whether the said top plate is appropriately located in the said 1st position by comparing the distance measured with the said ranging sensor with a reference value. The substrate processing apparatus as described in any one of 1-5.   When the distance measured by the distance measuring sensor is outside the allowable range after the top plate is positioned at the first position and before the substrate starts to rotate, the control means The substrate processing apparatus according to claim 6, wherein the top plate elevating mechanism is operated so as to be once raised and then lowered to be positioned again at the first position.   If the distance measured by the distance measuring sensor is outside the allowable range when the substrate is rotated and the substrate is being processed, the control means stops the substrate processing or the substrate is inappropriate. The substrate processing apparatus according to claim 6, wherein the processing is recorded or notified that processing has been performed in a stable state.   The substrate processing apparatus according to claim 1, further comprising a holding state detection unit that detects a holding state of the substrate by the substrate holding unit.   The substrate processing apparatus according to claim 1, wherein the distance measuring sensor includes a laser-type reflective displacement sensor. Holding the substrate horizontally by the substrate holder,
Positioning the top plate at a predetermined position close to the upper surface of the substrate held by the substrate holding unit, and covering the substrate with the top plate;
Rotating the substrate held by the substrate holding unit around a vertical axis and supplying a processing liquid to the substrate to process the substrate;
After the substrate is covered with the top plate, the distance measuring sensor attached to the top plate or a member whose vertical position relative to the substrate holding unit is unchanged, from the distance measuring sensor to the substrate holding unit. Measuring a distance from the distance measuring sensor to a member whose vertical distance changes in response to a change in vertical distance between the held substrate and the top plate;
A substrate processing method comprising:   The distance measurement by the distance measuring sensor is performed after the substrate is covered with the top plate and before the substrate is rotated, and when the distance is out of an allowable range, the top plate is temporarily removed. The substrate processing method according to claim 10, wherein the substrate is lowered to the predetermined position after being raised and the substrate is again covered with the top plate.   The measurement of the distance by the distance measuring sensor is performed when the substrate is rotated in a state where the substrate is covered by the top plate. When the distance is outside the allowable range, the processing of the substrate is performed. The substrate processing method according to claim 10, wherein the substrate processing method is stopped or recorded or notified that the substrate has been processed in an inappropriate state. The distance measuring sensor is attached to the top plate,
The distance measuring sensor measures a distance to a cup body surrounding the periphery of the substrate held by the substrate holding unit or a member fixed to the cup body,
The substrate processing method as described in any one of Claims 11-13. The distance measuring sensor is attached to the top plate,
The distance measuring sensor measures a distance to the substrate held by the substrate holding unit;
The substrate processing method as described in any one of Claims 11-13. The distance measuring sensor is attached to a cup body that surrounds the periphery of the substrate held by the substrate holding unit,
The distance measuring sensor measures the distance to the top plate or a member fixed to the top plate,
The substrate processing method as described in any one of Claims 11-13.

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