JP6529798B2 - Substrate processing apparatus and substrate processing method - Google Patents

Description

  The present invention relates to a substrate processing apparatus and a substrate processing method for processing a peripheral portion of a substrate by irradiating a peripheral portion of various substrates such as a semiconductor wafer with laser light.

  In the process of manufacturing an electronic device such as a semiconductor device or a liquid crystal display device, it may be necessary to remove a film formed on the peripheral portion of a substrate used for device formation. For example, the substrate may be warped due to the difference in thermal expansion coefficient between the substrate and the film formed thereon, and in order to prevent this, the unnecessary film is removed from the substrate before being subjected to the treatment. Need to be As a technique suitable for partial processing of such a substrate, there is one that applies a laser beam, such as a femtosecond laser, to a processing target region of the substrate. For example, in the technique described in Patent Document 1, the thin film formed on the irradiation site is peeled from the substrate by irradiating the peripheral portion of the substrate with the ultrashort pulse laser beam.

  In the film removal technology using laser light, there is a risk that the subsequent device manufacturing process may be adversely affected if machining debris such as fragments of the peeled film adhere to the substrate. On the other hand, as a technique in which this problem is taken into consideration, there is, for example, one described in Patent Document 2. In this technique, a liquid is supplied to the upper surface of a substrate supported in a horizontal posture to form a liquid film so as to cover a processing target site, and the liquid is suctioned to collect processing waste together with the liquid.

JP, 2013-021263, A JP 2007-144494 A

  When the above-mentioned prior art is applied for the purpose of processing the peripheral portion of the substrate, there may be a problem that the substrate surface is in contact with the liquid. For example, when a device having a fine pattern is formed on one main surface of a substrate, the surface tension of the liquid may cause the fine pattern in contact with the liquid to collapse. In addition, when a film is formed on the surface of the substrate, the film may be degraded by touching the liquid.

  From these things, the technique which can process the peripheral part of a board | substrate, without making a liquid contact a substrate surface, especially a device formation surface, is calculated | required. However, in the prior art described in Patent Document 2 described above, it is difficult to form a liquid film whose spread is appropriately managed in the peripheral portion of the substrate, and the liquid adheres to the substrate surface around the processing target portion Can not meet such needs because it is inevitable.

  The present invention has been made in view of the above problems, and in the technology in which the peripheral portion of the substrate is treated by irradiating the peripheral portion of the substrate with laser light, adhesion of the liquid to the substrate surface is suppressed while the substrate peripheral portion is The object is to provide a technology that can be processed well.

In one aspect of the substrate processing apparatus according to the present invention, in order to achieve the above object, a liquid holding means for holding liquid in a state in which the upper part of the liquid surface is open, and a substantially disk-shaped substrate A substrate holding means for holding a portion including the lowermost portion in the vertical direction of the peripheral portion of the substrate from the liquid surface and holding the substrate in a state of being inclined from a horizontal surface, and the peripheral portion of the substrate A laser irradiation means for processing the peripheral portion by causing a laser beam to enter the liquid immersion site immersed in the liquid via the liquid to move the liquid held by the liquid holding means to generate a liquid flow And the substrate holding unit rotates the substrate about a rotation axis perpendicular to the main surface through the center of the main surface during the processing by the laser light. In the circumference of the substrate Parts moves the said liquid flow generating means, the peripheral portion of the substrate to produce the liquid flow direction opposite to the direction of moving in said liquid.

In one aspect of the substrate processing method according to the present invention, in order to achieve the above object, a step of holding a liquid in a state in which the upper part of the liquid surface is opened, and a substantially disk-shaped substrate And immersing a portion of the peripheral portion of the substrate including the lowermost portion in the vertical direction from the liquid surface in the liquid, and the liquid in the peripheral portion of the substrate through the liquid to the soaked immersion region by the incidence of the laser beam and a step of processing the peripheral portion in the of the substrate in Rutotomoni said liquid by flowing the liquid in a predetermined direction The laser beam is made to enter the substrate while moving the peripheral portion, and the flow direction of the liquid is opposite to the direction in which the peripheral portion of the substrate moves in the liquid.

  In the invention configured as described above, the lowermost portion of the inclined substrate is immersed in the liquid surface formed by the liquid held by the liquid holding means. Then, laser light is irradiated to the liquid immersion site in the liquid among the substrates, and the substrate peripheral portion is processed in the liquid. As a result, the cuttings generated by the treatment are trapped in the liquid and prevented from scattering around. And about the range which touches a liquid among the substrate surfaces, it can control by the height of a liquid level. Also, gravity acts in a direction to move the liquid away from the substrate. Therefore, the probability of the liquid coming around and adhering to the substrate surface inside the peripheral portion is greatly reduced.

  As described above, according to the present invention, the laser light is made to enter the substrate in the liquid and the peripheral portion is treated to prevent scattering of the processing chips, and the lower portion of the inclined substrate is immersed in the liquid. It prevents liquid from flowing around the center of the substrate. Therefore, the substrate peripheral portion can be favorably processed while suppressing the adhesion of the liquid to the substrate surface.

It is a figure which shows one Embodiment of the substrate processing apparatus concerning this invention. It is a figure which shows operation | movement of a tilting stage part. It is a figure which shows in more detail the incident position of the laser beam on a board | substrate. It is a figure explaining the advantage at the time of hold | maintaining a board | substrate diagonally. It is a figure explaining the effect | action of a gas nozzle. It is a flowchart which shows operation | movement of a substrate processing apparatus. It is a figure which shows the modification of a substrate processing apparatus.

  FIG. 1 is a view showing an embodiment of a substrate processing apparatus according to the present invention. The substrate processing apparatus 1 has, for example, a function as a film removing apparatus for removing a film formed on the peripheral portion Wp of the substrate W by laser irradiation. As the substrate W, for example, a semiconductor wafer, a glass substrate for various display devices, a substrate for a photomask, a substrate for a magneto-optical disk, etc. can be applied. Further, as a film to be removed, for example, an insulating film such as oxide or nitride, a resist film, a metal film, a film in which these are laminated in multiple layers, etc. may be mentioned, but the types of substrate and film are limited to these. It is not something to be done.

  In the following, it is assumed that the substrate W is a semiconductor wafer and a device is formed on the one main surface Wf. In the following description, the device forming surface Wf of the main surface of the substrate W is referred to as the “front surface” of the substrate, and the main surface Wb opposite to this is referred to as the “back surface” of the substrate.

  In the present specification, the “peripheral edge” of the substrate includes not only the side surface connecting the two main surfaces of the flat substrate but also the peripheral edge closer to the side surface of the two main surfaces. It is a concept. In addition, a so-called beveled portion in which the connection portion between the main surface and the side surface of the substrate is chamfered or rounded corresponds to the “peripheral portion” mentioned here.

  The substrate processing apparatus 1 includes a spin chuck 2 for holding a substrate W, an inclined stage 3 for supporting the spin chuck 2, a laser irradiation unit 4 for causing a laser beam to be incident on the substrate W, and a chamber 6 for housing the spin chuck 2. And a control unit 8 which controls each part of the apparatus to execute a predetermined processing operation. In order to uniformly show the directions in the space in the chamber 6 in the following drawings, XYZ orthogonal coordinate axes are set as shown in FIG. Here, the XY plane represents a horizontal plane, and the Z axis represents a vertical axis. More specifically, the (−Z) direction represents the vertically downward direction.

  The spin chuck 2 includes a spin base 21 that holds a substantially circular substrate W. More specifically, the spin base 21 is a disk-like member having a diameter smaller than the diameter of the substrate W, and the upper surface thereof is a flat substrate mounting surface. A suction groove or suction hole connected to the chuck control unit 83 of the control unit 8 is provided on the substrate mounting surface, and the lower surface of the substrate W is held by the spin base 21 by negative pressure supplied from the chuck control unit 83. It is held. Since the spin base 21 is smaller than the substrate W, the substrate W is held in a state where the peripheral portion Wp of the substrate W is open to the space in the chamber without being in contact with the spin base 21.

  The spin base 21 is rotatable about a rotation axis AX by a chuck rotation mechanism 22. That is, the spin base 21 is connected to a rotation shaft 23 extending from a chuck rotation mechanism 22 incorporating a suitable rotation drive mechanism. Then, when the chuck rotation mechanism 22 operates in response to a control command from the chuck control unit 83 provided in the control unit 8 and the rotation shaft 23 rotates, the spin base 21 rotates around the rotation axis AX. The spin base 21 holds the substrate W such that the rotation axis AX coincides with the center Cw of the substrate W.

  The spin chuck 2 is mounted on the inclined stage 3. The inclined stage 3 includes a stage 31 on which the spin chuck 2 is mounted, a base 32 fixed to the bottom of the chamber 6, and support legs 33 and 34 which are erected from the base 32 and support the stage 31. ing. The support legs 33 and 34 expand and contract in response to a control command from the stage control unit 84 provided in the control unit 8, and change the inclination angle of the spin chuck 2 mounted on the stage 31 as described below. .

  FIG. 2 shows the operation of the tilting stage. The support legs 33 and 34 supporting the stage 31 expand and contract in accordance with a control command from the stage control unit 84, whereby the tilt of the stage 31 changes. Along with this, the tilt of the spin chuck 2 on the stage 31 changes, and the posture of the substrate W held by the spin chuck 2 changes. Specifically, as shown in FIG. 2A, the horizontal posture in which the surface (device forming surface) Wf of the substrate W is upward, and as shown in FIG. 2B, the substrate surface Wf is inclined from the horizontal surface The attitude of the substrate W changes between the inclined attitudes.

  The inclination angle θ of the substrate surface Wf from the horizontal plane is 0 degrees to 90 degrees. That is, when the inclination angle θ is 0 degree, the substrate W is in the horizontal posture as shown in FIG. 2 (a). When the tilt angle θ is larger than 0 degree, the substrate W is in the tilt posture as shown in FIG. 2B, and at this time, the spin chuck 2 also has the same tilt. Accordingly, the substrate W held by the spin base 21 is rotated by the operation of the chuck rotation mechanism 22 about the rotation axis AX having a tilt angle θ with respect to the vertical axis, with the center Cw as the rotation center.

  When the substrate W to be processed is carried into the substrate processing apparatus 1 and when the processed substrate W is unloaded, the support legs 33 and 34 are controlled such that the stage 31 becomes horizontal. For this reason, at the time of delivery of the substrate W with the outside, the substrate W can be in a horizontal posture, and access from the outside becomes easy. On the other hand, when processing of the substrate peripheral portion to be described later, for example, film removal processing is performed, the support legs 33 and 34 are controlled such that the substrate W is in the inclined posture.

  The inclination angle θ may be, for example, 45 degrees to 60 degrees, but is not limited thereto. However, it should be avoided that the substrate surface Wf is directed downward. That is, as shown in FIG. 2C, when considering the normal vector Vn in the direction from the back surface Wb side to the front surface Wf side perpendicular to the front surface Wf, the normal vector Vn is vertically downward, ie A posture having a component in the -Z direction is avoided. Therefore, the inclination of the substrate W is maximized when the substrate surface Wf is vertical. At this time, the normal vector Vn faces in the horizontal direction. More generally, the normal vector Vn includes at least a component in the horizontal direction, and may further include a component in the vertical upward direction, that is, the (+ Z) direction.

  Returning to FIG. 1, the description of the device configuration will be continued. The lower end of the substrate W held in the inclined posture by the spin chuck 2, that is, the box-shaped portion whose upper portion is opened so as to surround a portion of the peripheral portion Wp which is located the lowermost by the substrate W being inclined. A liquid container 51 is provided. The liquid Lq is supplied to the liquid container 51 from the liquid supply unit 82 of the control unit 8. The liquid container 51 temporarily holds the supplied liquid Lq, and causes the peripheral portion Wp, which is the lower end of the substrate W, to touch the liquid surface. Therefore, a portion including the lowermost portion of the peripheral portion Wp located at the lowest position is immersed in the liquid Lq. Below, the part which exists in the liquid among the board | substrates W is called a "liquid immersion site | part."

  As described in detail later, a constant amount of liquid Lq is constantly supplied to the liquid container 51 from the liquid supply unit 82, and a liquid flow of the liquid Lq is formed in the liquid container 51. The liquid discharged from the liquid container 51 is recovered by the liquid supply unit 82.

  As the liquid Lq, it is desirable that the liquid Lq be less in absorption and scattering with respect to the laser light beam L1 described later and less in contamination and corrosion with respect to the substrate W. For this purpose, for example, pure water or isopropyl alcohol (IPA), or a mixed liquid of pure water and IPA can be suitably used. In addition, "pure water" here shall contain DIW, carbonated water, ozone water, and hydrogen water. Among these, DIW is used in this embodiment. The surface tension of the liquid can be adjusted by adding IPA to pure water.

  Above the liquid container 51, an imaging unit 52 having an imaging function such as a CCD camera is provided. The imaging unit 52 is connected to the image processing unit 85 provided in the control unit 8, captures an image of the inside of the liquid container 51 according to a control command from the image processing unit 85, and transmits an image signal to the image processing unit 85 Do. The imaging unit 52 images the peripheral portion Wp of the substrate W immersed in the liquid Lq of the liquid container 51. The image processing unit 85 determines whether the substrate W is held at an appropriate position or whether the laser beam is correctly incident on the processing target position of the peripheral portion Wp based on the image obtained by imaging.

  In addition, the gas nozzle 53 is provided at a position closer to the center Cw of the substrate W than the imaging unit 52. The gas nozzle 53 discharges the gas supplied from the gas supply unit 86 provided in the control unit 8, for example, an inert gas such as nitrogen gas or a gas such as dry air downward. The action of the air flow generated by the gas discharged from the gas nozzle 53 will be described later.

  The laser irradiation unit 4 includes a laser light source 49 that emits a laser beam, and an optical system 40 that adjusts the optical path of the laser light L emitted from the laser light source 49 and causes the laser beam L to enter the peripheral portion Wp of the substrate W. The laser light source 49 is controlled by a light source control unit 81 provided in the control unit 8 and has a wavelength and power density according to the purpose of various processing such as peeling of a film formed on the peripheral portion Wp of the substrate W. It emits laser light. For example, a femtosecond laser capable of emitting ultrashort pulse laser light can be suitably used as the laser light source 49.

  The laser light source 49 is disposed outside the chamber 6, while the optical system 40 is disposed inside the chamber 6. The laser light L emitted from the laser light source 49 is incident on the optical system 40 through the light guide window 61 provided on the wall surface of the chamber 6 and transparent to the laser light L.

  The optical system 40 has reflection mirrors 41 and 42 that change the optical path of the laser light L incident through the light guide window 61 and make the light incident on the peripheral portion Wp of the substrate W. The positions of the reflection mirrors 41 and 42 on the optical path are controlled by the light source control unit 81, and the optical path of the laser light is adjusted by these. The laser light beam L1 whose light path is adjusted by the reflection mirrors 41 and 42 is incident on the liquid immersion site immersed in the liquid Lq in the peripheral portion Wp. Thus, the peripheral portion Wp is processed by the laser beam L1. As the substrate W rotates, the beam incident position at the peripheral portion Wp changes every moment, and the peripheral portion Wp is processed over the entire circumference by rotation of one or more rounds.

  FIG. 3 shows in more detail the incident position of the laser beam on the substrate. More specifically, FIG. 3 (a) is a view of the incident position of the laser light beam in the (-X) direction, and FIG. 3 (b) is a view of the same position in the (+ Y) direction. . As shown in FIG. 3A, the laser light beam L1 horizontally travels in the (+ Y) direction and enters the side wall surface 511 of the liquid container 51. The liquid container 51 is made of a material transparent to the laser beam L1, for example, quartz glass, and has a vertical side wall surface 511 and a horizontal bottom surface 512.

  The laser beam L1 also enters the side wall surface 511 of the liquid container 51 at a position lower than the horizontal liquid level LS of the liquid Lq held in the liquid container 51. The laser beam L1 incident on the liquid container 51 passes through the transparent side wall surface 511 and is incident on the peripheral portion Wp via the liquid Lq in the liquid container 51. In the figure, reference symbol BS indicates the beam spot of the laser light beam L1 incident on the substrate W, but the spot size is not limited to that shown but is arbitrary. Further, a region DR indicated by a dotted line in FIG. 3B indicates a region in which a device is formed on the substrate surface Wf. In the processing of the peripheral portion Wp, it is necessary to prevent the liquid from adhering to the device formation region DR.

  As shown in FIG. 3B, the liquid Lq supplied from the liquid supply unit 82 is connected to the (+ X) side end of the liquid container 51 via a pipe 821. On the other hand, a pipe 822 for refluxing the liquid Lq discharged from the liquid container 51 to the liquid supply unit 82 is connected to the (−X) side end of the liquid container 51. Therefore, the direction D1 in which the liquid flow of the liquid Lq flows in the liquid container 51 is the direction from the (+ X) side to the (−X) side, that is, the left direction in the drawing. On the other hand, the direction D2 in which the peripheral portion Wp in a state of being immersed in the liquid Lq in the liquid container 51 moves along with the rotation of the substrate W is a direction from the (−X) side to the (+ X) side In the figure, it is rightward and opposite to the flow direction D1 of the liquid Lq.

  The reason for this will be described. First, the processing is performed by causing the laser beam L1 to enter the liquid immersion site immersed in the liquid Lq in the peripheral portion Wp, so that processing debris generated by laser irradiation is scattered in the surrounding atmosphere and adheres to the substrate W To prevent There is also an effect of suppressing the temperature rise of the substrate W due to the laser irradiation.

  The generated machining waste is taken into the liquid Lq. Therefore, in a state where the liquid Lq is stagnant, machining waste separated from the substrate W reattaches to the substrate W. The machining waste scatters the incident laser light beam and the sufficient light energy can not be incident on the substrate W Etc. problems may occur. In order to avoid these problems, the liquid Lq is made to flow and carry away the chips from the incident position of the laser light beam. By sequentially replacing the liquid Lq in the vicinity of the beam spot BS, there is also an effect of preventing the generation of bubbles due to the temperature rise of the liquid Lq.

  Here, focusing on one point at the peripheral portion Wp, the point moves by the rotation of the substrate W and enters the liquid Lq, and after receiving laser irradiation in the liquid, moves upward above the liquid level LS. Separate from the liquid Lq. The position where the peripheral edge Wp separates from the liquid Lq, that is, the portion on the peripheral edge Wp in contact with the liquid surface LS in FIG. 3B corresponds to the most downstream side ((+ X) side) in the moving direction D2 of the peripheral edge Wp In position, it is desirable that the liquid Lq be as clean as possible. If the liquid Lq contains processing waste in this portion, the processing waste may be detached from the liquid Lq in a state of being attached to the substrate W.

  By supplying the liquid Lq from the (+ X) side end of the liquid container 51, the cleanest liquid Lq comes into contact with the substrate W immediately before the peripheral portion Wp leaves the liquid Lq. Is prevented from remaining on the For this purpose, the direction D1 of the liquid flow is set opposite to the direction D2 of movement of the peripheral portion Wp due to the rotation of the substrate W. In order to prevent turbulent flow of the liquid Lq in the vicinity of the beam spot BS, the rotational speed of the substrate W and the flow velocity of the liquid Lq are made relatively small.

  Next, the relationship between the incident direction of the laser light beam L1 and the shape of the liquid container 51 will be described. As described above, the laser beam L1 travels along a horizontal light path and enters the liquid container 51 through the vertical side wall surface 511 of the liquid container 51. The reason for doing this is as follows. The laser beam L1 enters the side wall surface 511 of the liquid container 51 from the atmosphere in the chamber 6, and enters the liquid Lq from the side wall surface 511 of the liquid container 51. At this time, if the incident angle to the side wall surface 511 of the liquid container 51 and the incident angle to the liquid Lq are not orthogonal, the laser light beam L1 is refracted and the optical path is bent. This makes it difficult to control the incident position of the laser beam L1 to the peripheral portion Wp. In order to avoid this problem, the incident direction of the laser light beam L1 and the shape of the liquid container 51 are determined such that the laser light beam L1 is perpendicularly incident on the side wall surface 511 of the liquid container 51.

  The incident direction of the laser light beam L1 is not necessarily required to be horizontal, but from the viewpoint of mechanical design of the optical system 40, adjustment thereof, easiness of manufacturing the liquid container 51, etc., a special inclination is made in the incident direction. It is preferable to set it as a simpler horizontal (or vertical) direction than having it.

  In this embodiment, it is difficult to form a stable liquid film on the peripheral portion Wp with the substrate W held in the horizontal posture, and the liquid can not be prevented from flowing around from the peripheral portion Wp to the central portion of the substrate. W is inclined and held, and the lower end is immersed in the liquid Lq. In such a configuration, the gravity of the liquid Lq acting downward suppresses the wraparound of the liquid Lq from the peripheral portion Wp of the substrate W to the central portion.

  The inclination angle θ of the substrate W at this time is larger than 0 degrees and 90 degrees or less. For example, by holding the substrate W such that the inclination angle θ is 90 degrees, that is, the substrate surface Wf is a vertical surface, wraparound of the liquid from the peripheral portion Wp to the central portion can be suppressed. On the other hand, when the substrate W is inclined, that is, when the inclination angle θ is less than 90 degrees, further advantages occur as will be described next.

  FIG. 4 is a view for explaining the advantage in the case of holding the substrate obliquely. The substrate W is held obliquely and the substrate surface Wf is held on the upper side (that is, the inclination angle θ is set to a value larger than 0 degree and smaller than 90 degrees), and the lower end portion (a part of the peripheral portion Wp) from the liquid surface LS Consider the case of immersion in Lq. At this time, as shown in FIG. 4A, the width W2 of the area in contact with the liquid Lq is relatively large on the substrate back surface Wb side, but the area in contact with the liquid Lq is more limited on the substrate surface Wf side, The width W1 may be relatively small.

  A device forming region DR is provided on the substrate surface Wf side and at the center side of the peripheral portion Wp, and the liquid is not allowed to touch the region DR. As described above, by holding the substrate W obliquely with the substrate surface Wf side up, the laser incident position of the peripheral portion Wp is surely immersed in the liquid Lq, and the region on the substrate surface Wf to be in contact with the liquid Lq is It can be made smaller. Thus, the space between the region of the substrate W in contact with the liquid Lq and the device formation region DR can be increased, and adhesion of the liquid Lq to the device formation region DR can be effectively suppressed. Further, by eliminating the problem of adhesion of the liquid Lq, it becomes possible to set a wider device formation region DR on the substrate surface Wf, and it becomes possible to effectively utilize a wider area of the substrate W as a device. .

  In actual processing, it is considered that the area of the portion of the substrate W in contact with the liquid Lq may be larger than the above-mentioned value due to the meniscus caused by the surface tension of the liquid Lq. In this case, as shown in FIG. 4B, while a relatively large meniscus Mb is generated on the substrate back surface Wb side having an acute angle with the liquid surface LS, the angle formed with the liquid surface LS is The meniscus Mf becomes smaller on the side of the substrate surface Wf at which the obtuse angle is obtained. As described above, by holding the substrate W obliquely, it is possible to suppress an increase in the area of the portion in contact with the liquid Lq on the substrate surface Wf side even under the condition where the meniscus is generated.

  Further, as shown in FIG. 4A, when the imaging unit 52 is provided to observe the peripheral portion Wp, the substrate W is obliquely oriented, so that the optical axis direction of the imaging unit 52 is in the vertical direction Or it can be horizontal. When the substrate W is in the horizontal posture, the side surface portion of the substrate W can not be observed in the imaging system in which the optical axis is in the vertical direction. When the optical axis of the imaging system is inclined to observe the side surface portion of the substrate W, detection of the substrate W and the laser incident position becomes difficult due to the influence of refraction in imaging via the liquid surface LS. By tilting the substrate W, the optical axis of the imaging unit 52 can be in the vertical direction perpendicular to the liquid surface LS, and the influence of refraction can be eliminated, and the optical axis and the focal position can be easily adjusted.

  FIG. 5 is a view for explaining the operation of the gas nozzle. More specifically, FIG. 5A is a view of the positional relationship between the gas nozzle 53 and the substrate W in the (−X) direction, and FIG. 5B is a view of the same in the (+ Y) direction. FIG. As shown in FIG. 5A, on the side of the substrate surface Wf of the substrate W held at an angle, there is a gas nozzle 53 for discharging the gas supplied from the gas supply unit 86 downward toward the substrate surface Wf. It is provided. The gas discharged from the gas nozzle 53 generates a gas flow GF which flows toward the liquid surface LS along the substrate surface Wf.

  This gas flow GF can push back the liquid Lq coming from the liquid container 51 along the substrate surface Wf to the central portion of the substrate W, and the mist generated from the liquid Lq adheres to the substrate surface Wf. It can be prevented. That is, the gas flow GF acts as a protective layer that protects the substrate surface Wf from the liquid Lq. When the flow velocity of the gas flow GF is too fast, the liquid level LS may be disturbed, and the possibility of the adhesion of the liquid Lq to the substrate surface Wf may be increased. The flow rate of the gas flow GF is preferably relatively low as long as a downward flow along the substrate surface Wf can be reliably formed.

  The generation position of the gas flow GF in the X direction may be a position directed to a position near the beam spot BS as shown by a solid line in FIG. 5B, and the peripheral portion Wp is separated from the liquid surface LS as shown by a dotted line. It is good also as a position which goes to the vicinity of the position to be done. The solid line configuration in which the gas flow GF is directed to the vicinity of the beam spot BS is effective to prevent the mist generated around the beam spot BS by the laser irradiation from adhering to the substrate surface Wf. In addition, the configuration of the dotted line in which the gas flow GF is in the vicinity of the separation position of the peripheral portion Wp from the liquid surface LS improves the liquid removal of the liquid Lq remaining adhering to the peripheral portion Wp exposed to the external space from the liquid Lq. It is effective. There is also an effect of drying the substrate W.

  In order to make these effects compatible, a gas nozzle having a slit-like opening whose longitudinal direction is the X direction is used, and the entire range from the position near the beam spot BS to the separation position of the peripheral portion Wp from the liquid surface LS is A gas flow may be generated. In addition, a gas flow that radially spreads in the radial direction of the substrate W may be generated.

  FIG. 6 is a flowchart showing the operation of the substrate processing apparatus configured as described above. This process is executed by the control unit 8 executing a control program prepared in advance to control each unit. First, the stage 31 of the inclined stage unit 3 is positioned in the horizontal state (step S101), and in this state, the substrate W is carried into the chamber 6 and mounted on the spin base 21. The spin base 21 adsorbs and holds the substrate W (step S102).

  When the substrate W is held by the spin base 21, the stage 31 is inclined at a predetermined inclination angle and positioned obliquely (step S103). Next, the spin base 21 is rotated at a predetermined rotation speed by the chuck rotation mechanism 22, and thereby the substrate W is rotated around the inclined rotation axis AX (step S104). Subsequently, delivery of the liquid Lq (for example, DIW) from the liquid supply unit 82 to the liquid container 51 and supply of a gas (for example, nitrogen gas) from the gas supply unit 86 to the gas nozzle 53 are started (step S105), Thereby, a part including the lowermost part in the peripheral part Wp is immersed in the liquid Lq. The rotation start of the substrate W and the supply start order of the liquid Lq may be reversed or simultaneous with the above.

  In this state, laser irradiation is started (step S106). The laser beam L1 enters the peripheral portion Wp via the side wall surface 511 of the liquid container 51 and the liquid Lq, whereby the peripheral portion Wp is processed. In the process for peeling the film formed on the peripheral portion Wp, the film is peeled from the peripheral portion Wp in the beam spot BS to which the laser beam L1 is incident. The exfoliated film and the processing chips generated by the treatment are taken into the liquid Lq and carried away from the vicinity of the beam spot BS by the liquid flow. As the substrate W rotates, the irradiation position of the laser beam on the substrate surface changes, and the peripheral portion Wp is sequentially processed.

  By maintaining the state of being irradiated with the laser light while the substrate W is rotated once or more (step S107), the process ends for the entire peripheral portion Wp. When the processing for the entire peripheral portion Wp is completed, the laser irradiation, the supply of the liquid Lq and the gas, and the rotation of the substrate W are sequentially stopped (steps S108, S109, and S110). Subsequently, the stage 31 is returned to the horizontal state (step S111), the substrate W is unloaded out of the chamber 6 (step S112), and the series of processing ends.

  As described above, in this embodiment, the peripheral portion, such as film removal from the peripheral portion Wp, is rotated by rotating the substrate W while irradiating the peripheral portion Wp with laser light (more specifically, femtosecond laser light). Perform Wp processing. The laser beam is incident on the liquid immersion site immersed in the liquid Lq in the peripheral portion Wp. Therefore, the film and processing chips separated from the substrate W by the laser irradiation are taken into the liquid and are not scattered around.

  The substrate W enters the liquid from the liquid surface LS formed by the liquid Lq held in the liquid container 51, and gravity acts in a direction to move the liquid Lq away from the central portion of the substrate W. The possibility of the liquid flowing into the device formation region DR provided in the part is reduced. In particular, by setting the posture of the substrate W obliquely with the substrate surface Wf side provided with the device forming region DR up, the width of the portion where the peripheral portion Wp contacts the liquid Lq on the substrate surface Wf side is made smaller. be able to. As a result, the probability of the liquid flowing into the device formation region DR can be further reduced, and a wider device formation region DR can be secured.

  Further, in order to prevent adhesion of the liquid to the substrate surface Wf more reliably, in the above embodiment, a liquid flow is generated in the liquid Lq in which the substrate W is immersed, and a gas flow GF is generated along the substrate surface Wf. The generation of the liquid flow prevents the accumulation of processing debris around the substrate W. Further, by making the direction of the liquid flow opposite to the moving direction of the peripheral portion Wp in the liquid, the liquid present in the vicinity of the peripheral portion Wp which is separated from the liquid into the external space is made the most clean. Can. As a result, it is possible to prevent processing debris from remaining on the substrate W which has been removed from the liquid.

  In addition, by causing a gas flow GF along the substrate surface Wf from above the liquid surface LS toward the liquid surface LS, pushing back the liquid Lq which tends to wrap around to the central portion along the substrate surface Wf. Can. In addition, the substrate surface Wf can be protected from the mist generated around the liquid surface LS. As described above, by causing the gas flow GF along the substrate surface Wf, it is possible to effectively prevent the adhesion of the liquid to the substrate surface Wf and the remaining of the processing debris.

  As described above, in the above embodiment, the liquid container 51 functions as the "liquid holding means" of the present invention, and the spin chuck 2 and the inclined stage portion 3 function as the "substrate holding means" of the present invention as one. ing. Among these, the tilting stage portion 3 has a function as the "tilting mechanism" of the present invention. Moreover, the laser irradiation part 4 is functioning as a "laser irradiation means" of this invention. In the above embodiment, the liquid supply unit 82 and the pipes 821 and 831 integrally function as the “liquid flow generation unit” of the present invention, while the gas supply unit 86 and the gas nozzle 53 integrally form the “air flow generation of the present invention”. Function as a means. Further, in the above embodiment, the entire side wall surface 511 of the liquid container 51 functions as the “transparent window” of the present invention, and the imaging unit 52 functions as the “imaging unit” of the present invention.

  The present invention is not limited to the above-described embodiment, and various modifications can be made other than the above without departing from the scope of the invention. For example, the following modifications can be considered to the above embodiment.

  FIG. 7 is a view showing a modified example of the substrate processing apparatus. More specifically, FIG. 7 (a) shows a first modification, and FIG. 7 (b) shows a second modification.

  In the first modified example shown in FIG. 7A, on the side of the upper end portion of the liquid container 51 facing the liquid surface Wf, a cover member 513 that covers the upper part of the liquid level LS is provided. The structure of each part except this point is the same as that of the said embodiment. With such a configuration, it is possible to more reliably prevent adhesion of liquid droplets, mist or the like generated from the liquid surface LS to the substrate surface Wf.

  For example, when bubbles generated in the liquid disappear at the liquid surface due to the rise of the temperature of the peripheral portion Wp to which the laser beam L1 is incident, the liquid may cause droplets or mist. In order to protect the substrate surface Wf from these, a cover member 513 is provided in this modification. By providing the cover member 513 below the lower end of the device formation region DR, it is possible to reliably prevent the liquid from adhering to the device formation region DR. Even in this case, the gas flow along the substrate surface Wf is effective.

  Further, in the second modification shown in FIG. 7B, the configuration of the optical system of the laser irradiation unit is different, but the configuration of each part except this point is the same as that of the above embodiment. In the optical system 40a of this modification, the beam splitter 43 is disposed on the optical path of the laser beam reflected by the reflection mirror 41, and the laser beam L is split into two light beams L1 and L2. One laser beam L1 is incident on the peripheral portion Wp from the horizontal direction via the side wall surface 511 of the liquid container 51 and the liquid Lq, as in the above embodiment.

  The other laser light beam L2 has its optical path changed by the reflecting mirrors 44 and 45, and ultimately enters the bottom surface 512 of the liquid container 51 vertically as a vertically upward light beam. Therefore, the laser beam L2 is incident on the peripheral portion Wp from below via the transparent bottom surface 512 of the liquid container 51 and the liquid Lq.

  In the case where the peripheral portion Wp is a so-called beveled portion in which the end face is chamfered or rounded, it may not be possible to perform the necessary range of processing only by laser irradiation from one direction. Further, the peripheral portion Wp to be processed may include not only the side surface portion of the substrate W but also at least a part of the front surface Wf or the rear surface Wb. Also in this case, a necessary range for laser irradiation from one direction It can not be processed. By causing the laser light to be incident on the peripheral portion Wp from two directions, it is possible to simultaneously perform the above-described processing.

  At this time, both of the two light beams are perpendicularly incident on the wall surface of the liquid container 51, and are incident on a portion where the wall and the liquid are in contact (that is, there is no intervening gas). It is possible to suppress the influence and perform laser irradiation to the appropriate position of the substrate W. In this example, the laser beam L1 is horizontally incident from the side wall surface 511 which is a vertical surface of the liquid container 51 formed of a transparent material, and the laser beam L2 is incident from a bottom surface 512 which is a horizontal surface. By doing this, the influence of refraction is avoided.

  Further, in the above embodiment, the peripheral portion Wp is processed over the entire circumference by irradiating the laser light while rotating the substrate W, but the present invention can also be applied in a mode in which the substrate W is not rotated. It is. For example, when processing only a partial region of the peripheral portion Wp, the substrate W may not be rotated, and the laser light may be irradiated while the processing target region is immersed in the liquid.

  Moreover, in the said embodiment, although the optical system 40 is provided in the inside of the chamber 6 among the laser irradiation parts 4, it is not limited to this. For example, the optical system is provided outside the chamber, the optical path of the light L emitted from the laser light source 49 is adjusted by the optical system provided outside the chamber, and the adjusted light beam passes through the passage light window provided in the chamber. It may be configured to be incident on the substrate via the substrate. Further, the optical path of the light beam may be adjusted by interlocking optical systems respectively provided inside and outside the chamber.

  For example, although the liquid container 51 of the above embodiment is entirely formed of a material transparent to laser light, it is sufficient if at least a portion on which the laser light is incident is transparent to the laser light. Thus, for example, a transparent window may be provided at the incident position of laser light, and the liquid container may be formed of an opaque material in the other parts.

  Further, for example, in the above embodiment, the spin chuck 2 holding the substrate W is supported by the inclined stage portion 3 to switch the substrate W between the horizontal attitude and the inclined attitude. However, the spin base 21 is inclined in advance. The present invention is also applicable to an apparatus installed in a stationary state. When processing is performed with the substrate W in the vertical direction, that is, the main surface is a vertical surface, a handling device that handles the substrate in the vertical direction is known (see, for example, JP-A-10-209243), in combination with such known technology. Processing can be performed.

  Further, for example, although the liquid container 51 is provided in the chamber 6 for containing the substrate W in the above embodiment, the chamber may also have a function as a liquid container. That is, the liquid may be held in the lower part of the chamber or in a container integrated with the chamber to immerse the substrate W.

  Further, although the spin chuck 2 of the above embodiment vacuum-sucks the central portion of the back surface Wb of the substrate W, the holding mode of the substrate is not limited to this and is arbitrary. In addition, in the structure which a support member contact | abuts to the peripheral part Wp and supports the board | substrate W, when processing the peripheral part Wp over the perimeter, a support member may become an obstacle of a process. In this respect, although it is desirable to support the peripheral portion Wp in the open state as in the above embodiment, for example, in conjunction with the rotation of the substrate W, the support member is temporarily retracted when the laser beam is irradiated. The substrate holding means for supporting the peripheral portion Wp can also be used by using a configuration such as the above.

  As described above, as the specific embodiment has been illustrated and described, in the present invention, the substrate holding means is configured to rotate the substrate about a rotation axis passing through the center of the main surface and perpendicular to the main surface. It is also good. By rotating the substrate, the incident position of the laser beam to the substrate can be changed, and the substrate peripheral portion can be widely processed.

  In addition, the substrate may be held such that the angle formed by the main surface with respect to the horizontal surface is greater than 0 degrees and not more than 90 degrees. By tilting the substrate within this range, it is possible to perform processing by immersing only part of the peripheral portion Wp in the liquid that forms the horizontal liquid surface.

  In addition, with regard to a substrate whose one main surface is a device formation surface, it is preferable that the device formation surface be held higher than in the horizontal direction. By doing this, it is possible to more effectively avoid the wraparound of the liquid on the device formation surface.

  In addition, the liquid holding means may include a flow generation means for moving the liquid held by the liquid holding means to generate a liquid flow. By irradiating the substrate with the laser light in the flowing liquid, the processing waste generated from the substrate by processing is separated from the substrate, and the remaining processing waste on the substrate after processing is suppressed.

  In this case, the direction of the liquid flow is preferably opposite to the direction in which the peripheral portion of the substrate moves in the liquid. In such a configuration, since the cleanest liquid is supplied to the portion where the peripheral edge of the substrate is removed from the liquid surface, the remaining processing debris on the substrate separated from the liquid is more effectively suppressed.

  The liquid holding means may have a transparent window transparent to the laser light, and the laser irradiation means may be configured to make the laser light incident on the substrate through the transparent window and the liquid. By causing the laser light to be incident on the transparent window provided in the liquid holding means for holding the liquid, it is possible to cause the laser light to be incident on the substrate without interposing a gas layer between the liquid holding means and the liquid. In this case, it is preferable that the laser light be perpendicularly incident on the transparent window. Thereby, the refraction of the laser light at the transparent window can be further suppressed.

  Further, an air flow generating means may be provided which generates an air flow from the center of the substrate toward the liquid immersion site. In such a configuration, an air flow is generated in the direction of removing the liquid from the substrate surface, so that the wraparound of the liquid to the substrate surface can be suppressed more effectively. In addition, drying of the substrate can be promoted by air flow.

  In addition, the substrate holding means may be configured, for example, to suction and hold a central portion excluding the peripheral portion of the substrate. When processing the periphery of the substrate over the entire circumference, it is desirable that the periphery of the substrate be held in an open state. By holding the central portion of the substrate by suction, the substrate can be held in this manner.

  In addition, an imaging unit for imaging the incident position of the laser beam to the substrate may be provided. According to such a configuration, whether or not the laser light is incident on the appropriate position of the substrate can be grasped from the imaging result, so that the processing of the peripheral portion of the substrate can be performed stably. In particular, since the substrate is inclined, it is possible to capture an image of the peripheral portion of the substrate with the optical axis of the imaging means being in the horizontal direction or in the vertical direction.

  The substrate holding means may have an inclination mechanism for changing the posture of the substrate between a horizontal posture in which the main surface is horizontal and an inclination posture in which the main surface is inclined from the horizontal surface. It is difficult to handle the substrate in a tilted state at the time of loading of the substrate into the apparatus and unloading of the substrate from the apparatus. If a mechanism capable of setting the substrate in a horizontal posture is provided, loading and unloading of the substrate becomes easier, and the existing handling device can be used.

  The present invention can be applied to techniques for processing the peripheral portion of various substrates such as semiconductor wafers, for example, substrate processing techniques in general for removing a film formed on the peripheral portion.

1 substrate processing apparatus 2 spin chuck (substrate holding means)
3 Tilting stage (substrate holding means, tilting mechanism)
4 Laser irradiation part (laser irradiation means)
8 Control Unit 51 Liquid Container (Liquid Holding Means)
52 Imaging unit (imaging means)
53 Gas nozzle (air flow generating means)
82 Liquid supply section (liquid flow generating means)
86 Gas supply unit (air flow generation means)
511 (in liquid container 51) side wall surface (transparent window)
821, 822 Piping (flow generation means)
L, L1, L2 laser beam light Lq liquid W substrate Wf (for substrate W) surface, device formation surface Wb (for substrate W) back surface Wp (for substrate W) peripheral portion

Claims (13)

Liquid holding means for holding the liquid in a state in which the upper part of the liquid surface is open;
Substrate holding which holds a substantially disk-like substrate with its main surface inclined from the horizontal surface, and immersing a portion including the lowermost portion in the vertical direction of the peripheral portion of the substrate from the liquid surface in the liquid Means,
A laser irradiation unit for processing the peripheral portion by causing a laser beam to enter the liquid immersion site immersed in the liquid among the peripheral portion of the substrate via the liquid ;
A flow generation means for moving the liquid held by the liquid holding means to generate a liquid flow ;
During the treatment with the laser light,
The substrate holding means moves the peripheral portion of the substrate in the liquid by rotating the substrate about a rotation axis perpendicular to the main surface through the center of the main surface.
The liquid flow generation unit generates the liquid flow in a direction opposite to a direction in which the peripheral portion of the substrate moves in the liquid .   The substrate processing apparatus according to claim 1, wherein the substrate holding unit rotates the substrate about a rotation axis which passes the center of the main surface and is perpendicular to the main surface.   The substrate processing apparatus according to claim 1, wherein the substrate holding unit holds the substrate such that an inclination angle formed by the main surface with respect to a horizontal surface is greater than 0 degrees and equal to or less than 90 degrees.   The substrate processing apparatus according to any one of claims 1 to 3, wherein the substrate holding unit holds the substrate whose one main surface is a device forming surface such that the device forming surface is higher than a horizontal direction. . The liquid holding means has a transparent transparent window relative to the laser beam, the laser irradiation unit, any one of claims 1 to 4 through the transparent window and the liquid is incident the laser light to the substrate The substrate processing apparatus as described in. The substrate processing apparatus according to claim 5 , wherein the laser irradiation unit makes the laser beam perpendicularly incident on the transparent window. The substrate processing apparatus according to any one of claims 1 to 6 , further comprising an air flow generation unit configured to generate an air flow from the center of the substrate toward the liquid immersion site.   The substrate processing apparatus according to any one of claims 1 to 7, wherein the substrate holding unit suction-holds a central portion of the substrate excluding the peripheral portion. The substrate processing apparatus according to any one of claims 1 to 8 , further comprising an imaging unit configured to image an incident position of the laser beam on the substrate. 10. The substrate holding means according to any one of claims 1 to 9 , wherein the substrate holding means has an inclination mechanism for changing the posture of the substrate between a horizontal posture in which the main surface is horizontal and an inclination posture in which the main surface is inclined from a horizontal surface. The substrate processing apparatus as described. Holding the liquid with the upper part of the liquid level open;
Holding the substantially disc-like substrate with its main surface inclined from the horizontal surface, and immersing a portion including the lowermost portion in the vertical direction of the peripheral portion of the substrate from the liquid surface in the liquid; ,
Processing the peripheral portion by causing laser light to be incident on the liquid immersion site immersed in the liquid among the peripheral portion of the substrate via the liquid ;
The laser beam while moving the peripheral portion of the substrate in the Rutotomoni said liquid fluid so the circulated in a predetermined direction to be incident on the substrate,
The substrate processing method , wherein the flow direction of the liquid is opposite to the direction in which the peripheral portion of the substrate moves in the liquid . The substrate processing method according to claim 11 , wherein the substrate whose one main surface is a device formation surface is held such that the device formation surface faces upward than the horizontal direction. The substrate processing method according to claim 11 or 12 , wherein the laser beam is made to enter the substrate while generating an air flow from the center of the substrate toward the liquid immersion site.

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