JP2022125562A - Peripheral portion processing apparatus and peripheral portion processing method - Google Patents

Abstract

To improve the processing accuracy of a processing region when the peripheral edge of a substrate is processed.SOLUTION: A peripheral portion processing apparatus that processes a peripheral edge region on one surface side of a substrate by irradiating the peripheral edge region with light, includes a holding and rotating unit that holds and rotates the substrate, a light emitting unit arranged on the other surface side of the substrate held by the holding and rotating unit and emitting the light, and a reflecting unit arranged on one surface side of the substrate held by the holding and rotating unit, reflecting the light from the light emitting unit, and irradiating a peripheral edge region on the one surface side of the substrate, and the light emitting unit is arranged such that a part of the light emitting width of the light emitted from the light emitting unit is blocked by the end portion of the substrate held by the holding and rotating unit, and the light emitting width of the light emitted from the light emitting unit has a width equal to or greater than the radial length of the substrate in the peripheral edge region.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a peripheral edge processing apparatus and a peripheral edge processing method.

2. Description of the Related Art Conventionally, the periphery of a coating film such as a resist film formed on a substrate such as a semiconductor wafer (hereinafter sometimes simply referred to as a wafer) has been processed.

Patent Document 1 discloses a film stripping apparatus for stripping a film formed on a substrate, which includes holding means for holding the substrate and an ultrashort pulse laser beam applied to the interface between the substrate and the film through the film. irradiation means for processing the substrate and peeling the film by irradiating a beam, wherein the fluence of the ultrashort pulse laser beam irradiated to the interface by the irradiation means is such that the ultrashort pulse laser beam causes the substrate to peel off. is larger than the processing threshold fluence required to process the film and smaller than the processing threshold fluence required to process the film with an ultrashort pulse laser beam.

JP 2013-21263 A

The technique according to the present disclosure improves the processing accuracy of the processing area when processing the peripheral edge of the substrate.

One aspect of the present disclosure is a peripheral edge processing apparatus that processes a peripheral edge region on one surface side of a substrate by irradiating it with light, comprising: a holding and rotating unit that holds and rotates the substrate; a light-emitting portion arranged on the other surface side of the substrate held on the substrate to emit the light; a reflecting portion that irradiates a peripheral edge region on one surface side, and the light emission is such that part of the light emission width of the light emitted from the light emitting portion is blocked by the edge portion of the substrate held by the holding and rotating portion. A portion is arranged, and the light emission width of the light emitted from the light emitting portion has a width equal to or greater than the radial length of the substrate in the peripheral region.

Advantageous Effects of Invention According to the present disclosure, it is possible to improve the processing accuracy of the processing region when processing the peripheral portion of the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side cross-sectional explanatory diagram schematically showing the outline of a configuration of a peripheral edge processing apparatus according to an embodiment; FIG. 2 is an explanatory plan view schematically showing the outline of the configuration of the peripheral portion processing apparatus of FIG. 1; FIG. 2 is an explanatory diagram showing the positional relationship between a laser emitting unit and a mirror in the peripheral edge processing apparatus of FIG. 1; FIG. 4 is an explanatory diagram for explaining the operation of the peripheral edge processing apparatus according to the embodiment; FIG. 10 is an explanatory diagram for explaining the action when the angle of the mirror is changed; FIG. 10 is an explanatory diagram for explaining the influence of the optical path length when the height position of the peripheral edge region of a warped wafer is changed; It is explanatory drawing explaining the relationship of each distance between a wafer, a laser emission part, and a mirror. FIG. 4 is an explanatory diagram showing how a laser beam is obliquely emitted from a laser emitting unit; It is explanatory drawing which shows a mode that the laser emission part was arrange|positioned at the upper surface side of a wafer, and the mirror was arrange|positioned at the lower surface side. FIG. 10 is an explanatory diagram showing the action when a concave mirror is used for a warped wafer;

2. Description of the Related Art In the manufacturing process of semiconductor devices and the like, there is a step of forming a resist film as a coating film for pattern formation on the surface of a substrate such as a semiconductor wafer (hereinafter sometimes referred to as "wafer"). After this process, a process for removing an unnecessary resist film formed on the periphery of the wafer, a so-called edge bead removal process (hereinafter sometimes referred to as "EBR process") may be performed.

Regarding this point, the technique described in Patent Document 1 irradiates a laser beam onto the peripheral edge region of the wafer while rotating the wafer, thereby peeling the wafer.

When processing the peripheral portion of the wafer, the processing width must be uniform over the entire peripheral portion of the wafer. However, when a wafer is placed on a holding and rotating part such as a spin chuck, there is a possibility that the placement position of the wafer may be misaligned by a transfer device that transfers the wafer. It is also possible that the spin chuck itself is eccentric.

In such a case, when the wafer held on the spin chuck is rotated, the position of the peripheral portion of the wafer fluctuates due to such positional deviation and eccentricity, for example, when observed at a fixed point in plan view. In the technique described in Patent Document 1, a fixed point on the peripheral edge of the wafer is continuously irradiated with a laser beam from above.

Therefore, the technique according to the present disclosure suppresses fluctuations in the processing width of the peripheral portion of the wafer and improves the processing accuracy of the processing region in the peripheral portion even if the wafer is misaligned or eccentric as described above.

Hereinafter, this embodiment will be described with reference to the drawings. In this specification, elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

FIG. 1 schematically shows a longitudinal side surface of a peripheral edge processing apparatus 1 according to an embodiment, and FIG. 2 is a diagram schematically showing a plan view of the same. This peripheral portion processing apparatus 1 is configured as an apparatus for forming a resist film as a coating film on the surface of a wafer W, and then removing unnecessary resist film on the peripheral portion.

This peripheral edge processing apparatus 1 has a housing 2 . An air supply unit 3 is provided in the upper part of the housing 2 to supply clean air downward from an FFU (not shown) as a downward flow.

A spin chuck 10 as a holding/rotating portion that holds and rotates the wafer W is provided below the air supply portion 3 in the housing 2 . The spin chuck 10 is configured to horizontally hold a wafer W, which is a circular substrate with a diameter of 300 mm, for example, by vacuum suction. The spin chuck 10 is connected to a rotation drive section 11 including a motor and the like. The rotation drive unit 11 rotates the spin chuck 10 around the vertical axis at a rotation speed corresponding to a control signal output from the control unit 100, which will be described later.

Transfer of the wafer W to and from the spin chuck 10 by a transfer device (not shown) is performed by raising and lowering three support pins 12 (only two pins are shown in the figure for convenience of illustration) that support the back surface of the wafer W. will be The support pins 12 are provided on a base 13 , and the base 13 can be raised and lowered by driving an elevating mechanism 14 .

A guide ring 20 having a mountain-shaped cross section is provided on the lower side of the spin chuck 10 , and an annular outer peripheral wall 21 extending downward is provided on the outer peripheral edge of the guide ring 20 . A cup 22 is arranged so as to surround the spin chuck 10 and the guide ring 20 .

The upper side of the cup 22 is open so that the wafer W can be delivered to the spin chuck 10 . A gap 23 is formed between the inner peripheral surface of the cup 22 and the outer peripheral wall 21 of the guide ring 20 to form a discharge passage. A bottom portion 22a of the cup 22 is provided with an exhaust pipe 24 standing upward from the bottom portion 22a. A drain port 25 is provided in the bottom portion 22a of the cup 22. As shown in FIG.

The edge processing apparatus 1 includes a resist nozzle 30 that supplies resist liquid onto the wafer W held by the spin chuck 10 . The resist nozzle 30 has a discharge port 30a formed on the lower end surface. The resist nozzle 30 is connected via a resist liquid supply path 31 to a resist liquid supply source 32 in which resist liquid is stored. The resist liquid supply source 32 includes a pump, pumps the resist liquid to the resist nozzle 30 side, and discharges the pressure-fed resist liquid from the discharge port 30a. The supply and stop of the resist solution and the amount of supply to the resist nozzle 30 are controlled based on the control signal output from the controller 100 .

The resist nozzle 30 is supported by a horizontally extending arm 33 as shown in FIG. The resist nozzle 30 is connected to a moving mechanism 34 via an arm 33 . The moving mechanism 34 can move along a guide rail 35 extending in the lateral direction and can raise and lower the arm 33 . The moving mechanism 34 moves according to the control signal from the control unit 100, and the movement of the moving mechanism 34 moves the resist nozzle 30 between the standby position 36 provided outside the cup 22 and the upper center of the wafer W. can move. The moving distance, moving speed, and moving direction of the moving mechanism 34 are also controlled by control signals from the control unit 100 .

The edge processing apparatus 1 has a laser light emitting section 40 as a light emitting section. The laser emitting unit 40 is arranged below the edge of the wafer W held by the spin chuck 10 and above the guide ring 20 . As shown in FIG. 1, the laser emitting unit 40 emits a laser beam B vertically upward.

1 and 2, the laser emitting unit 40 can move horizontally and radially of the wafer W held by the spin chuck 10 by a driving member (not shown). Therefore, in the peripheral edge processing apparatus 1 according to the embodiment, the light emission width BW from the laser light emitting unit 40 is the maximum movement width of the laser light emitting unit 40 thus moved, that is, the position closest to the center and the position closest to the outer periphery. is the track width of the laser beam B emitted between .

A laser beam B emitted from the laser emitting portion 40 is emitted toward a mirror 50 as a reflecting portion. A mirror 50 is arranged above the edge of the wafer W held by the spin chuck 10 . In this embodiment, as shown in FIG. 1, it is arranged in the vicinity of the ceiling in the housing 2, that is, directly below the air supply section 3. As shown in FIG. The mirror 50 is supported, for example, by a support member (not shown). Also, the angle of the reflecting surface of the mirror 50 with respect to the wafer W is variable and can be fixed at an arbitrary angle.

The positional relationship between the laser emitting section 40 and the mirror 50 is arranged as shown in FIG. That is, part of the emission width BW of the laser light B from the laser emission unit 40 is blocked by the edge of the wafer W held by the spin chuck 10, and the emission width BW of the laser light B reaching the mirror 50 is reduced to , are arranged so that they are reflected by the mirror 50 to irradiate the edge region A of the wafer W held by the spin chuck 10 . Also, the angle of the reflecting surface of the mirror 50 with respect to the wafer W is adjusted so that such irradiation of the peripheral region A can be realized.

Adjustment of the movement speed and movement width of the above-described laser emission unit 40, adjustment of the angle of the mirror 50, adjustment of the irradiation position to the peripheral region A, etc., movement speed of the laser emission unit 40 and rotation speed of the spin chuck 10, starting and stopping, etc. are controlled by a control unit 100 which will be described later.

That is, the peripheral edge processing apparatus 1 having the above configuration is controlled by the controller 100 as described above. The control unit 100 is configured by a computer including, for example, a CPU and memory, and has a program storage unit (not shown). The program storage unit stores programs for controlling various processes in the peripheral edge processing apparatus 1 . The program may be recorded in a computer-readable storage medium H and installed in the control unit 100 from the storage medium. The storage medium H may be temporary or non-temporary.

Next, a peripheral edge processing method using the peripheral edge processing apparatus 1 having the above configuration will be described. First, the wafer W loaded into the edge processing apparatus 1 is placed on the spin chuck 10 as shown in FIG. Then, the arm 33 supporting the resist nozzle 30 moves from the standby position 36 to the center position of the wafer W, and discharges the resist liquid to the center position of the wafer W from the discharge port 30a while rotating the wafer W. The resist liquid thus ejected is spread and applied over the entire surface of the wafer W by a spin coating method. The resist liquid may be applied by a known pre-wet method in which a solvent for the resist liquid is supplied to the wafer W in advance before the resist liquid is applied.

When the supply of the resist solution is finished, the resist nozzle 30 is immediately retracted, and the wafer W is rotated to perform the drying process of the resist solution. When such so-called drying by shaking off is completed, the spin chuck 10 rotates and the held wafer W rotates. It emits light toward Then, the laser beam reflected by the mirror 50 performs a peripheral edge process, which is one aspect of the present disclosure, that is, a process of removing an unnecessary resist film on the peripheral edge of the surface of the wafer W. FIG.

According to the peripheral edge processing technique of the present disclosure in the embodiment, as shown in FIG. It is occluded by the edge of W. Then, the width BWA of the laser light reflected by the mirror 50 is narrowed by the amount blocked by the edge. When the wafer W is eccentric, the width BWA fluctuates according to the movement of the edge of the wafer W as it rotates. That is, it changes following the amount of eccentricity of the wafer W. FIG.

More specifically, as shown in FIG. 4, for example, when the rotation center Q of the wafer W deviates (eccentrically) from the reference center P of rotation of the wafer W, a portion of the rotating wafer W is shifted. As shown on the right side of FIG. 4, eccentricity causes the edge of the wafer W to shift toward the inside (toward the center) of the wafer W. At other portions, as shown on the left side of FIG. , the end portion of is shifted to the outside (outward side). For convenience of illustration, each case is shown at the same time.

As shown on the right side of FIG. 4, when the edge of the wafer W is shifted inward (toward the center) due to eccentricity, the emission width BW of the laser light may not be blocked by the edge of the wafer W. Occur. In this case, the width BWA of the reflected light reflected by the mirror 50 is the same as the emission width BW of the laser light B, and the processing width (radial width) of the peripheral region of the wafer W is also wide.

On the other hand, as shown on the left side of FIG. The width BWA of the reflected light reflected by the mirror 50 becomes smaller than the light emission width BW of the laser light B because it is largely blocked. That is, the processing width (width in the radial direction) in the peripheral region of the wafer W is narrowed.

Therefore, according to the peripheral edge processing technique of the present disclosure in the embodiment, the processing width fluctuates following the amount of eccentricity of the wafer W. FIG. Therefore, even if the wafer W is eccentrically held on the spin chuck 10, the eccentricity can be absorbed, and the processing of the peripheral region of the wafer W can be made uniform over the entire circumference. can be improved. The emission width BW of the laser light preferably has a length equal to or greater than the width of the peripheral region A in the radial direction.

As described above, when the laser light emitting unit 40 is reciprocally moved (scanned) while the held wafer W is rotating to emit the laser light B toward the mirror 50, for example, the following points are required. The rotational speed of the wafer W and the moving speed of the laser emitting unit 40 should be determined in consideration of the above. That is, (1) if the rotation of the wafer W is too slow, some parts are irradiated with the laser beam B and some parts are not. It is expected that the energy required for removing the resist film will be insufficient.

Regarding the above (1), the minimum number of revolutions is determined by the width of the light source of the laser beam B of the laser emitting unit 40 to be used. For example, if the moving speed of the reciprocating movement (scanning) of the laser emitting unit 40 is 1 mm/s, the light source width is 600 rpm or more when the light source width is 0.1 mm, 60 rpm or more when the light source width is 1 mm, and 6 rpm or more when the light source width is 10 mm. Become. Regarding the above (2), it depends on the output of the laser beam B, so it cannot be determined univocally, but it is thought that it can be used at 3000 rpm or less, which is the same as a general spin module.

From the above, for example, when the light source width of the laser beam B is 0.1 mm or less, the rotation speed of the wafer W is 600 rpm to 3000 rpm, and when the light source width is 1 mm or more and less than 10 mm, it is 60 rpm to 2000 rpm, and the light source width is 10 mm or more. 1 rpm to 1500 rpm is appropriate. For these reasons, if the circumferential speed (linear speed) of the peripheral region of the wafer W to be processed is sufficiently faster than the moving speed of the laser emitting unit 40, the intended purpose of the technology of the present disclosure is can be achieved.

The angle of the mirror 50 with respect to the wafer W can be changed when it is desired to change the processing width of the peripheral region (the radial width processed by the reflected light from the mirror 50) itself. For example, as shown in FIG. 5, the angle .theta. between the laser beam B emitted in the vertical direction from the laser emitting section 40 and the reflection of the mirror 50 may be changed. For example, when the processing width is desired to be 1 mm, the angle θ is set to 1 degree, and when the processing width is desired to be 3 mm, the processing width is set to 3 degrees, thereby changing the processing width. A galvanomirror or a MEMS mirror can be used as the mirror 50 .

Also, the angle θ described above is determined, for example, in consideration of the following points. That is, the laser beam B directed from the mirror 50 to the wafer W is preferably close to perpendicular to the upper surface of the wafer W, for example, within a range of ±45 degrees with respect to the axis perpendicular to the upper surface of the wafer W in terms of processing width accuracy. Since the laser beam B directed toward the mirror 50 is set so that part of it is blocked by the wafer W, the reflection angle is approximately 45 degrees or less so as not to waste space on the lateral side of the wafer W. It should be set so that In addition, it is preferable that the angle .theta.

By the way, the wafer W itself held by the spin chuck 10 may have a warp. In that case, the height position of the peripheral portion of the wafer W fluctuates up and down with rotation when observed at a fixed point. If so, the processing width itself may vary accordingly.

In order to cope with this, the distance L from the reflection point of the mirror 50 shown in FIG. 6 to the surface of the normal wafer W should be set long. That is, let Δ be the change in the height position of the wafer W due to warpage, let θ be the angle between the laser beam B emitted in the vertical direction from the laser emitting unit 40 and the reflected light from the mirror 50, and let θ be the amount of change in the processing width due to warpage. Assuming Δw, it can be expressed as follows.

Δw = (L + ΔL) tan θ - L tan θ
= ΔL tan θ
≈ΔLθ

That is, when the angle .theta. is small, it can be considered that a change proportional to the angle .theta. Therefore, in order to reduce θ without narrowing the processing width, the distance L from the reflection point of the mirror 50 to the normal surface of the wafer W (the optical path length from the surface of the wafer W to the reflection point of the mirror 50) should be long. good. As a result, as shown in FIG. 6, when the wafer W is concave upward, the height position of the peripheral region rises by .DELTA.L, and even if the processing width changes by .DELTA.w, this can be suppressed. can. Similarly, when the wafer W is upwardly convex, even if the height position of the peripheral edge region is lowered by ΔL and the processing width is changed by Δw, this can be suppressed. This makes it possible to keep the amount of change in these Δw within the adjustable range of the processing width that depends on the emission width BW of the laser light.

As a result of verification, for example, when the wafer W has a warp of 1 mm, θ should be set to 0.04 or less (2.2 degrees or less) in order to keep the change in the processing width within 0.04 mm or less. , the required length of the distance L is 130 mm in order to make the adjustment width of the processing width 5 mm or more with an angle change of 2.2 degrees or less. That is, when the distance L is 130 mm or more, the fluctuation of the processing width can be suppressed to 0.04 mm or less when processing a wafer W having a warp of 1 mm in the height direction.

When mounting the laser emitting unit 40 and the mirror 50 on the actual machine, securing the space becomes a problem. As shown in FIG. It is preferable to make it shorter than the distance K from the point to the wafer W. Space can be easily secured on the lower surface side of the wafer W, and space can be saved. At the same time, the distance L from the reflection point of the mirror 50 to the normal surface of the wafer W can be lengthened.

In the above example, the laser light B from the laser light emitting unit 40 is also emitted in the vertical direction. This makes it possible to irradiate the edge side area of the wafer W with the reflected light from the mirror 50 to process not only the so-called bevel portion of the wafer W but also the side edge surface called APEX. Become. In this case, the laser emitting unit 40 may be moved horizontally or may be moved obliquely as shown in FIG.

Furthermore, in the above examples, the laser emitting unit 40 is arranged on the lower surface side of the wafer W, and the mirror 50 is arranged on the upper surface side of the wafer W. Alternatively, the laser emitting unit 40 may be arranged on the upper surface side of the wafer W, and the mirror 50 may be arranged on the lower surface side of the wafer W. As a result, the peripheral region on the lower surface side of the wafer W can be processed.

In the examples described above, the mirror 50 has a flat reflecting surface, but as shown in FIGS. A mirror 55 having a curved reflective surface may also be used. In this case, the irradiation width of the reflected light irradiated to the peripheral region of the wafer W from the mirror 50 narrows toward the wafer W. It is better to set it so that it is positioned

By doing so, as shown in FIG. 10(a), the warpage causes the peripheral edge region of the wafer W to be higher than the peripheral edge region of the normal wafer W without warpage shown in FIG. 10(b). When the height is lower or, as shown in FIG. 10(c), even when the height position is higher than the height position of the peripheral edge region of the normal wafer W, the reflected light that is actually irradiated to the peripheral edge region in each case accordingly. Since the width BWA varies, it is possible to absorb the influence of warpage and suppress variations in the processing width. That is, the width BWA of the reflected light is wider at higher positions and narrower at lower positions. can be kept small.

Note that the laser emission unit 40 in the above example secures the emission width BW in the present disclosure by moving, but the emission from one emission source originally has the emission width BW as the emission unit. If so, there is no need to move the light emitting unit itself. Also, the light from the light-emitting section is light close to coherent light such as laser light, but a light-emitting section that emits light linearly through an aperture may be employed, and a laser light source is not necessarily employed.

Furthermore, in each of the above examples, the technique of the present disclosure has been described as a peripheral edge process for removing an unnecessary resist film R, but the present invention is not limited to this. The technique according to the present disclosure is also applied when performing other modification treatments. In such a case, not only laser light but also ultraviolet light or the like may be used to emit light.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The embodiments described above may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

REFERENCE SIGNS LIST 1 peripheral edge processing device 10 spin chuck 40 laser emitting unit 50 mirror 100 control unit B laser light R resist film W wafer

Claims (10)

A peripheral edge processing apparatus for treating a peripheral edge region on one surface side of a substrate by irradiating it with light,
a holding and rotating part that holds and rotates the substrate;
a light emitting unit arranged on the other surface side of the substrate held by the holding and rotating unit and emitting the light;
a reflecting part arranged on one surface side of the substrate held by the holding and rotating part, reflecting the light from the light emitting part, and irradiating a peripheral edge region on the one surface side of the substrate;
the light emitting unit is arranged such that a part of the light emission width of the light emitted from the light emitting unit is blocked by the edge of the substrate held by the holding and rotating unit;
The periphery processing apparatus, wherein the light emission width of the light emitted from the light emitting section is equal to or greater than the length of the periphery region in the radial direction of the substrate. 2. The peripheral edge processing apparatus according to claim 1, wherein said light emission width is a light emission width achieved by moving said light emitting section in a radial direction of said substrate held by said holding and rotating section. 2. The peripheral edge processing apparatus according to claim 1, wherein said light emission width is a light emission width of light emitted from one light emitting portion. 4. The apparatus according to any one of claims 1 to 3, wherein said one surface is a front surface of a substrate, said reflecting portion is arranged above the substrate held by said holding and rotating portion, and said light emitting portion is arranged on the back side of said substrate. The peripheral edge processing apparatus according to any one of claims 1 to 3. 5. The peripheral edge processing apparatus according to claim 4, wherein the distance from said light emitting section to said substrate is shorter than the distance from said reflecting section to said substrate. 4. The peripheral edge processing apparatus according to claim 1, wherein the one surface is the back surface of the substrate, and the reflecting section is arranged below the substrate held by the holding and rotating section. The peripheral edge according to any one of claims 1 to 6, wherein the light irradiated from the reflecting portion to the peripheral edge area is irradiated to the peripheral edge area at an angle of 45 degrees or less with respect to a vertical axis. part processing equipment. The reflecting section has a reflecting surface curved concavely outward,
The irradiation width of the light irradiated from the reflecting portion to the peripheral edge region narrows toward the substrate, and the position where the irradiation width is the smallest is set to be located on the other side of the substrate relative to the one surface. The peripheral edge processing apparatus according to any one of claims 1 to 7, wherein 9. The peripheral edge processing apparatus according to claim 1, wherein said reflector has a variable angle with respect to said substrate. A peripheral edge processing method for treating a peripheral edge region on one side of a substrate by irradiating it with light,
From the other surface side of the substrate held by the holding and rotating part that holds and rotates the substrate,
light is emitted to a reflecting portion arranged on one surface side of the substrate held by the holding and rotating portion;
At the time of light emission, part of the emitted light is blocked by the edge of the substrate held by the holding and rotating part;
The peripheral portion processing method, wherein the emission width of the light from the other surface side is equal to or greater than the length of the peripheral portion region in the radial direction of the substrate.

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