JP2020141070A - Method and device for removing film on semiconductor substrate by laser - Google Patents

Abstract

To provide a method and a device for removing a film on a semiconductor substrate by laser capable of uniformly removing a film including a metal film such as TEG formed on a street of a semiconductor substrate in a laminated manner.SOLUTION: A method for removing a film on a semiconductor substrate by a laser according to the present invention removes a film by scanning a plurality of lasers 5 in parallel with respect to the film including a metal film formed on a street 3 in a semiconductor substrate 1 in which a plurality of elements 2 are formed in a matrix on the substrate, and the street 3 is provided between the adjacent elements 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for removing a film containing a metal film such as TEG formed on a semiconductor substrate by a laser.

The semiconductor manufacturing process is divided into a process of manufacturing a substrate (wafer) that serves as a support for a semiconductor, a process of forming an electronic circuit on the substrate to manufacture an element (semiconductor chip), and a manufactured semiconductor substrate. It is divided into a process of cutting out (chipging) the elements individually and a process of assembling a semiconductor using the elements.
As a method of cutting out an element from a semiconductor substrate, for example, a method of forming a scribe line on the semiconductor substrate with a scribing wheel, dividing the substrate along the scribe line, and cutting out the element individually can be mentioned.

By the way, the surface of the semiconductor substrate is divided in a grid pattern, and a plurality of regions are formed. The grid-like line is a planned division line called a street. Further, an element is formed in each of the divided regions.
Various film-like laminates are formed on the upper surface of the street. If the film-like laminate remains, problems will occur when forming a scribe line on the street or when dividing the semiconductor substrate. Therefore, the film-like laminate is removed before forming the scribe line. As a technique for removing the film-like laminate, for example, Patent Documents 1 to 3 are disclosed.

Japanese Patent No. 5645593 Japanese Unexamined Patent Publication No. 2013-197108 Japanese Patent No. 4741822

As various film-like laminates formed on the upper surface of a semiconductor substrate (for example, a street), for example, a metal film including a test circuit called TEG (Test Element Group), an alignment mark, and a Pl film. (Polarizing film) and the like.
A laminated film (laminated film) is formed on the upper surface of the street. Since the laminated film has a different laminated state, it has irregularities on the street of the semiconductor substrate, and the situation is not uniform. That is, the structure (thickness) of the laminated film is different.

On the street, for example, basically only the Pl film is formed (thickness: about 2 μm). Further, in the portion where the alignment mark is formed on the street, for example, (Pl film + SiO ₂ ) is formed (thickness: about 3 μm).
In the portion where TEG is formed on the street (Street TEG), for example, (Pl film + Metal Al + SiO ₂ ) is formed (thickness: about 5 μm).

Further, in the portion where the Pattern TEG is formed on the semiconductor substrate, for example, (Pl film + Metal Al + SiO ₂ + Poly Si + SiO ₂ ) is formed (thickness: about 10 μm).
When TEG or the like is formed on the semiconductor substrate in this way, the thickness becomes thicker than that of other portions. That is, in the semiconductor substrate, the thickness of the laminated film differs depending on the portion, and the configuration differs.

Even if an attempt is made to remove a TEG or the like formed on a semiconductor substrate (for example, a street) by using a conventional technique such as Patent Documents 1 to 3, the TEG or the like cannot be uniformly removed. For example, if the laser output is increased, even if the TEG can be removed, the intersection of the streets (thin film such as Pl film only) will be scraped deeper, but cross cut. If this is the case, the intersection will be cut deeper than necessary, which is not desirable (see FIG. 3). Therefore, when forming a scribe line, there is a possibility that the situation will be like a broken line instead of a straight line. When the semiconductor substrate breaks, it causes deformation and cracking.

Further, if the laser output is lowered, the TEG cannot be reliably removed. That is, although the scribe line is formed on the semiconductor substrate, it is difficult to form the scribe line because the TEG remains and the portion of the substrate is not exposed.
That is, if a scribe line is not formed on the semiconductor substrate on the street, for example, when the semiconductor substrate is divided, there is a possibility that a problem such as a crack may develop on the element side.

Therefore, in view of the above problems, the present invention has a coating film on the semiconductor substrate by a laser, which is formed in a laminated manner on the upper surface of the semiconductor substrate, for example, on a street, and can uniformly remove a coating film containing a metal film such as TEG. It is an object of the present invention to provide a removing method and a film removing device.

In order to achieve the above object, the following technical measures have been taken in the present invention.
In the method for removing a film on a semiconductor substrate by a laser according to the present invention, in a semiconductor substrate in which a plurality of elements are formed in a matrix on the substrate and streets are provided between the adjacent elements, the elements are formed on the streets. It is characterized in that the coating film is removed by scanning a plurality of lasers in parallel with respect to the coating film containing the metal film.

Preferably, when removing the coating film, a plurality of the lasers having a width smaller than the width of the street may be scanned in parallel.
Preferably, when removing the coating film, when scanning a plurality of lasers in parallel, streaky ridges are formed at adjacent intervals of the laser removing portion from which the coating film is removed by irradiation of the laser. It should be done.

Preferably, at the intersection of the two streets, a convex portion is formed at the center where the plurality of laser removing portions intersect with each other.
Preferably, when removing the coating film, at least two or more lasers are scanned, and the interval between scanning the lasers is at least 20 μm or more.
Preferably, the semiconductor substrate is a SiC substrate.

Further, in the laser-based film removing device on a semiconductor substrate according to the present invention, in a semiconductor substrate in which a plurality of elements are formed in a matrix on the substrate and streets are formed between the adjacent elements, the streets are formed on the streets. A film removing device on a semiconductor substrate using a laser having a film removing portion that removes the coating by scanning a plurality of lasers in parallel with respect to the formed coating containing the metal film, wherein the coating removing portion is When a plurality of lasers thinner than the width of the street are scanned in parallel and a plurality of lasers are scanned in parallel, streaks are formed at adjacent intervals of the laser removing portions where the coating film is removed by irradiation of the laser. The convex portion is formed at the intersection of the two streets intersecting with each other, and the convex portion is formed at the center where the plurality of laser removing portions intersect with each other.

According to the present invention, a coating film formed in a laminated manner on the upper surface of a semiconductor substrate, for example, on a street and containing a metal film such as TEG can be uniformly removed.

It is a figure which showed the outline of the film removal process which constitutes the film removal method on the semiconductor substrate by the laser of this invention schematically. It is an image of a street showing the situation after scanning one laser and irradiating the laser to remove a film containing a metal film. After scanning one laser and irradiating the laser to remove the coating film containing the metal film, an image showing the situation at the intersection of the streets and a cross-sectional view (section AA) at the intersection. It is an image of a street showing a situation after scanning two lasers and irradiating the laser to remove a coating film containing a metal film, and a cross-sectional view (cross section BB) of the street. Two lasers are scanned, and after irradiating the laser to remove the coating film containing the metal film, an image showing the situation of the street at the intersection and a cross-sectional view (cross section CC) at the intersection.

Hereinafter, a method for removing a film on a semiconductor substrate 1 by a laser 5 and an embodiment of a film removing device according to the present invention will be described with reference to the drawings.
It should be noted that the embodiments described below are examples that embody the present invention, and the specific examples do not limit the configuration of the present invention.
The substrate 1 (wafer) serves as a support substrate for the element 2, and is formed in a disk shape. In this embodiment, the substrate is made of SiC and is a SiC layer that serves as a support substrate for the element 2.

As shown in FIG. 1, the semiconductor substrate 1 is formed by, for example, a plurality of elements 2 (semiconductor chips) on which an electronic circuit is formed are arranged and arranged in a grid pattern on the surface of a substrate made of SiC. Has been done.
That is, in the semiconductor substrate 1, a plurality of elements 2 are formed in a matrix on the SiC substrate, and a street 3 (scheduled division line) is provided between the adjacent elements 2. The streets 3 are formed in a grid pattern on the semiconductor substrate 1.

In such a semiconductor substrate 1, in order to manufacture the element 2 (semiconductor chip) on which an electronic circuit is formed, various treatments are performed on the surface of the substrate made of SiC. Therefore, on the street 3, for example, a film (laminated film) having various configurations such as a metal film including a test circuit called TEG (Test Element Group), an alignment mark, and a Pl film (polarizing film) is formed. It will be formed.

A scribe line is formed on the street 3 in the scribe process. If the laminated film is present on the street 3, it becomes difficult to divide the semiconductor substrate 1 along the scribe line at the time of breaking, and there is a possibility that cracks or the like may occur on the element 2 side.
Therefore, it is necessary to uniformly remove the laminated film formed on the street 3. Among the laminated films, the TEG is thicker than the alignment mark and the Pl film. That is, on the street 3, laminated films having different thicknesses are formed, so that the situation is uneven. That is, the surface of the street 3 is not in a uniform situation.

Therefore, in the present invention, the laminated film formed on the street 3 and having a different thickness such as TEG is surely removed. As a result, a scribe line can be formed on the street 3, the semiconductor substrate 1 can be divided along the scribe line, and the elements 2 can be individually divided.
The method for removing a film on a semiconductor substrate 1 by a laser 5 according to the present invention is a method for removing a coating film on a semiconductor substrate 1 in a semiconductor substrate 1 in which a plurality of elements 2 are formed in a matrix on the substrate and streets 3 are provided between the adjacent elements 2. This is a method of removing a coating film by scanning a plurality of lasers 5 in parallel with respect to a coating film containing a metal film formed on the street 3.

As shown in FIG. 1, as a procedure for removing a film containing a metal film such as TEG using the laser 5, the TEG is performed in the film removing section provided with the laser irradiation unit 4 before performing the scribing step. The TEG and the like are removed by scanning a plurality of lasers 5 whose focus is focused by the laser irradiation unit 4 in parallel with the street 3 on which the film including the metal film such as the above is formed. By carrying out the step of removing this film, the TEG is surely removed, and in the scribe step, a single scribe line can be formed with respect to the street 3.

When removing the coating film, it is preferable to scan a plurality of lasers 5 thinner than the width of the street 3 in parallel. Preferably, at least two or more lasers 5 may be scanned when removing the coating.
Further, when removing the coating film, when scanning a plurality of lasers 5 in parallel, streaky ridges 7 are formed at adjacent intervals of the laser removing portions 6 from which the coating film is removed by irradiation of the laser 5. It is good to do so.

When removing the coating film, it is preferable that the convex portion 8 is formed at the center where the plurality of laser removing portions 6 intersect at the intersection portion 3a where the two streets 3 intersect.
When removing the film, the laser 5 was scanned against the film containing the metal film formed on the street 3 to verify that the film was removed.
In this embodiment, the semiconductor substrate 1 having a width of 90 μm on the street 3 was used and verified.

The purpose was to replace it with a condensing lens with a short focal length and verify the conditions under which TEG can be removed. In this embodiment, the condensing lens: F300 mm was replaced with F150 mm. Another object of the present invention is to reduce the processing depth of the laser 5 at the intersection portion 3a of the street 3.
As a target, the removal width of the coating film on the street 3 was set to 40 μm or more, and the processing width by the laser 5 was set to less than 80 μm.

First, as an example of verification, a process of scanning one laser 5 to remove a coating was performed on a Pattern TEG (In-TEG). At this time, the laser 5 was defocused (focus was blurred) and the spot diameter was changed.
In the present embodiment, the spot diameter of the laser 5 is changed to Φ35 μm and Φ40 μm. Further, regarding the processing conditions for removing the film by the laser 5, the scanning speed is 300 mm / s.

In the Pattern TEG, a film such as (Pl film + Metal Al + SiO ₂ + Poly Si + SiO ₂ ) is formed on the SiC layer (thickness: about 10 μm).
As a result, when the spot diameter was Φ35 μm, the output was 5 W, and the TEG (coating) could be removed uniformly. Further, when the spot diameter = Φ40 μm, the output = 6 W, and the TEG (coating) could be uniformly removed.

However, when the output of the laser 5 is lowered, problems such as the SiC layer not being exposed and burrs appearing on the processing line occur.
Next, one laser 5 was scanned against the street 3 to remove the coating film on the street 3.
Regarding the processing conditions for removing the film by the laser 5, the scanning speed is 300 mm / s. Regarding the laser 5, the spot diameter was Φ35 μm and the output of the laser 5 was 5 W. Further, in the street 3, a film of only the Pl film is formed on the SiC layer (thickness: about 2 μm).

As shown in FIG. 2, as a result, under the conditions of spot diameter = Φ35 μm and output = 5 W, the film of only the Pl film was removed, the film removal width was 46 μm, and the processing width by the laser 5 was 61 μm. .. That is, the target removal width of the coating film = 40 μm or more and the processing width by the laser 5 = 80 μm or less are satisfied.
Further, the intersection portion 3a where the two streets 3 intersect was observed.

As shown in FIG. 3, as a result of observation, when the spot diameter = Φ35 μm and the output = 5 W, the size of the intersection portion 3a of the street 3 was 39 μm × 35 μm.
Further, the processing depth of the laser 5 at the intersection portion 3a of the street 3 was 7.7 μm (cross section AA). That is, it was found that the SiC layer of the intersection portion 3a of the street 3 is deeply processed although the region is small.

Here, the repetition frequency, scanning speed, and the like of the laser 5 were changed, the pitch between pulses of the laser 5 was widened, and one laser 5 was scanned to remove the TEG.
In this embodiment, the inter-pulse pitch of the laser 5 is changed from 3 μm to 6 μm. Regarding the processing conditions for removing the film by the laser 5, the repetition frequency = 80 kHz, the scanning speed = 480 mm / s, and the spot diameter = Φ40 μm. However, the scanning target was Pattern TEG.

As a result, it became difficult to uniformly remove the TEG in the portion where the laser 5 is difficult to process. Further, even if the output of the laser 5 was increased, the processing state became unstable.
Therefore, the street 3 was just focused (focused), the laser 5 was shifted, the two lasers 5 were scanned, and the TEG on the street 3 was removed.

Regarding the processing conditions for removing the film by the laser 5, the output of the laser 5 is 2 W, the scanning speed is 300 mm / s, and the spot diameter is Φ24 μm. The shift width of the laser 5 is 20 μm.
As shown in FIG. 4, as a result, under the conditions of spot diameter = Φ24 μm and output = 2 W, the film removal width was 50 μm and the processing width by the laser 5 was 59 μm. That is, the target removal width of the coating film is 40 μm or more, and the processing width by the laser 5 satisfies 80 μm or less. The processing depth of the laser 5 on the street 3 was 4.3 μm (cross section BB).

When two lasers 5 are scanned in parallel and with a shift width of 20 μm, two laser removing portions 6 are formed. It was confirmed that streaky ridges 7 were formed at the distance between the two laser removing portions 6 adjacent to each other.
Similarly, it was confirmed that the ridge portion 7 was formed even when two lasers 5 were scanned with a shift width of 30 μm.

That is, when the shift width of the laser 5 is scanned twice with a shift width of 20 μm or more, the SiC layer is not exposed at the adjacent intervals of the laser removing portions 6, and the convex portions 7 which are the portions where only the coating film is removed are formed. I understood. The interval for scanning the laser 5 is preferably at least 20 μm or more.
Further, in order for the ridge portion 7 to pass straight through the cutting edge of the scribing wheel, the shift width of the laser 5 may be set to 30 μm.

When the shift width of the laser 5 was scanned twice at 10 μm, the ridges 7 were not formed at the adjacent intervals of the laser removing portions 6. That is, the shift width of the laser 5 = 10 μm was almost the same as the situation when one laser 5 was scanned.
The ridge portion 7 serves as a line for guiding the cutting edge of the scribing wheel when forming a scribe line. In other words, the ridge portion 7 is the basis of the cut line of the semiconductor substrate 1.

Further, the intersection portion 3a where the two streets 3 intersect was observed.
As shown in FIG. 5, as a result of observation, when the spot diameter = Φ24 μm and the output = 3 W, the size of the intersection portion 3a of the street 3 is 51 μm × 53 μm.
Further, the processing depth of the laser 5 at the intersection portion 3a of the street 3 was 2.9 μm at the central portion (cross section CC). That is, it was found that the processing depth of the laser 5 was shallow at the intersection portion 3a of the street 3.

However, at the intersection portion 3a where the two streets 3 intersect, a raised convex portion 8 is formed at the center (the center of the grid shape) where the two laser removing portions 6 intersect (orthogonally) with each other. It was confirmed.
The convex portion 8 becomes a point where the cutting edge of the scribing wheel comes into contact, and a scribe line is also formed at the intersection portion 3a of the street 3. That is, the convex portion 8 shortens the break of the line in the intersection portion 3a when the scribe line is formed. Even when the cutting edge of the scribing wheel deviates from the convex portion 8 and passes by the convex portion 8, both sides of the convex portion 8 also become relatively convex portions, so that the break of the line can be shortened when the scribe line is formed. it can.

By forming the convex portion 8, the cutting edge of the scribing wheel enters the center of the intersection portion 3a of the street 3, and it is possible to prevent the scribe line from being formed (in a broken line shape) without flying. Will be able to. That is, a scribe line equivalent to a continuous scribe line is formed. As a result, it is possible to reduce the occurrence of cracking due to scribe line skipping when the semiconductor substrate 1 breaks.

The summary of the above verification is shown below.
Regarding the laser 5, it was replaced with a condensing lens having a short focal length (F300 mm → F150 mm), and the conditions under which TEG could be removed were verified. Further, when the spot diameters were Φ35 μm and Φ40 μm, the output of the laser 5 was changed and verified, and it was confirmed that the TEG could be uniformly removed.
Examples of processing conditions and processing results for removing the coating film by the laser 5 are shown in (1) to (3) below.

(1) Spot diameter = Φ50 μm, output = 10 W, scanning speed = 300 mm / s, coating removal width = 63 μm, processing width by laser 5 = 80 μm, size of intersection 3a of street 3 = 51 μm × 44 μm, intersection The processing depth of the laser 5 in 3a = 4.8 μm.
(2) Spot diameter = Φ40 μm, output = 6 W, scanning speed = 300 mm / s, coating removal width = 53 μm, processing width by laser 5 = 67 μm, size of intersection 3a of street 3 = 41 μm × 33 μm, intersection The processing depth of the laser 5 in 3a = 7.3 μm.

(3) Spot diameter = Φ35 μm, output = 5 W, scanning speed = 300 mm / s, coating removal width = 46 μm, laser 5 processing width = 61 μm, street 3 intersection 3a size = 39 μm × 35 μm, intersection The processing depth of the laser in 3a = 7.7 μm.
According to the results of (1) to (3), by reducing the spot diameter of the laser 5, the removal width of the coating film = 40 μm or more and the processing width by the laser 5 = less than 80 μm could be achieved.

However, although the size of the intersection portion 3a of the street 3 has become smaller, the SiC layer has been deeply processed.
Therefore, I tried to remove the TEG by widening the inter-pulse pitch of the laser 5 (3 μm → 6 μm), but it was difficult to uniformly remove the TEG in the part where the laser 5 was difficult to process, and the output of the laser 5 was increased. However, the processing condition became unstable.

From this, when the laser 5 was shifted and the just-focused laser 5 was scanned twice to remove the TEG (coating) on the street 3, the shift width of the laser 5 was 20 to 30 μm, and two lasers were used. The SiC layer was not exposed between the laser removing portions 6, and the convex portion 7 which was a portion where only the coating film was removed was formed.
Further, at the intersection portion 3a of the street 3, the convex portion 8 is formed at a portion where the two laser removing portions 6 (convex portions 7) intersect with each other.

By forming the convex portion 8, the cutting edge of the scribing wheel comes into the center of the intersection portion 3a of the street 3, and it is possible to reduce the occurrence of cracking due to scribe line jumping. Even if the cutting edge of the scribing wheel deviates from the center of the intersection 3a of the street 3 and passes beside the center of the intersection 3a, both sides of the center of the intersection 3a also become relatively convex parts, and the scribe line jumps. It is possible to reduce the occurrence of cracking due to.

In the present invention, when scanning the laser 5 to remove a coating film such as TEG in the street 3, the TEG is uniformly removed by scanning two focused lasers 5 at regular intervals. can do.
As described above, according to the knowledge of the inventor of the present application, the spot diameter of the laser 5 is preferably Φ20 to 100 μm. The shift width of the laser 5 is preferably 20 to 30 μm. That is, the spot diameter and shift width of the laser 5 preferably have a size that does not exceed the width of the street 3.

The output of the laser 5 is preferably 2 to 10 W. Further, as the laser, a UV laser, a green laser, a pulse laser and the like are desirable.
Since the width of the street 3 was 90 μm in the present embodiment, the removal width of the coating film was set to 40 μm or more, and the processing width by the laser 5 was set to 80 μm or less. This is an example, and the removal width of the coating film and the processing width by the laser 5 depend on the width of the street 3.

Further, as the film removing device on the semiconductor substrate by the laser of the present invention, in the semiconductor substrate 1 in which a plurality of elements 2 are formed in a matrix on the substrate and streets 3 are formed between the adjacent elements 2. A film removing device on a semiconductor substrate using a laser having a film removing portion for removing a film by scanning a plurality of lasers 5 in parallel with respect to a film containing a metal film formed on the street 3. When the removing unit scans a plurality of lasers 5 narrower than the width of the street 3 in parallel and scans a plurality of lasers 5 in parallel, the coating is removed by the irradiation of the laser 5 at adjacent intervals of the laser removing unit 6. , A streak-shaped ridge portion 7 is formed, and a ridge portion 8 is formed at a center where a plurality of laser removing portions 6 intersect with each other at an intersection portion 3a where two streets 3 intersect.

When the step of removing the coating film is completed, the semiconductor substrate 1 is moved to the scribe step.
The scribe step is a step of forming a scribe line as a guide for division with respect to the street 3 of the semiconductor substrate 1 in the scribe portion. First, the semiconductor substrate 1 is installed in the scribe portion. The scribe section is equipped with a scribing tool.
A rotatable scribing wheel is attached to the scribing tool. The outer circumference of the scribing wheel is a cutting edge that forms a scribe line. The scribing wheel has a cutting edge coated with diamond (for example, single crystal diamond) on the outer circumference.

The cutting edge of the scribing wheel is brought into contact with the street 3 of the semiconductor substrate 1 perpendicularly. Specifically, the cutting edge of the scribing wheel is brought into contact with the convex portion 7 formed between the two laser removing portions 6.
When the scribing wheel is run while pressing with a predetermined load, the scribing wheel rolls on the convex portion 7 of the street 3, and a single scribe line is formed on the surface of the semiconductor substrate 1. ..

That is, the scribe line is ideally formed on the ridge portion 7 formed between the two laser removing portions 6. Further, even when the ridge portion 7 is displaced from the ridge portion 7 and formed along any of the two laser removing portions 6 on both sides of the ridge portion 7, the side of the ridge portion 7 is relatively the ridge portion. Therefore, the same effect can be obtained.
When the scribe process is completed, the semiconductor substrate 1 is moved to the break process.

The break step is a step of dividing the semiconductor substrate 1 along a scribe line that serves as a guide for division at the break portion. First, the semiconductor substrate 1 on which the scribe line is formed is installed in the break portion.
In the break portion, the semiconductor substrate 1 is installed with the scribe line facing downward so that the scribe line is at the center position. The break portion is provided with a break member having a blade at the tip. The break member is brought closer to the position corresponding to the scribe line from the surface side on which the scribe line is not formed.

Press the cutting edge of the break member to press the position corresponding to the scribe line. Then, the semiconductor substrate 1 is divided along the scribe line.
As described above, according to the present invention, a coating film formed in a laminated manner on the upper surface of the semiconductor substrate 1, for example, a street 3 and containing a metal film such as TEG can be uniformly removed.
By uniformly removing the film containing the metal film such as TEG, the scribe line can be formed linearly, and the semiconductor substrate 1 can be divided without causing cracks or the like on the element 2 side. ..

It should be noted that the embodiments disclosed this time are exemplary in all respects and are not restrictive.
In particular, in the embodiments disclosed this time, matters not specified, for example, operating conditions, operating conditions, dimensions of components, weight, etc., do not deviate from the range normally practiced by those skilled in the art, and are normal. If you are a person skilled in the art, you are adopting items that can be easily assumed.

1 Semiconductor substrate (SiC substrate)
2 Element 3 Street 3a Intersection 4 Laser irradiation unit 5 Laser 6 Laser removal 7 Convex 8 Convex

Claims (7)

In a semiconductor substrate in which a plurality of elements are formed in a matrix on the substrate and streets are provided between the adjacent elements.
A method for removing a film on a semiconductor substrate by a laser, which removes the film by scanning a plurality of lasers in parallel with respect to the film containing the metal film formed on the street. The method for removing a coating film on a semiconductor substrate by a laser according to claim 1, wherein when removing the coating film, a plurality of the lasers having a width smaller than the width of the street are scanned in parallel. When removing the coating film, when scanning a plurality of lasers in parallel, streaky ridges are formed at adjacent intervals of the laser removing portion from which the coating film is removed by irradiation of the laser. The method for removing a coating film on a semiconductor substrate by a laser according to claim 1 or 2. The film removal on a semiconductor substrate by a laser according to claim 3, wherein a convex portion is formed at the center where the plurality of laser removing portions intersect with each other at an intersection portion where the two streets intersect. Method. When removing the coating, at least two or more lasers are scanned.
The method for removing a film on a semiconductor substrate by a laser according to any one of claims 1 to 4, wherein the interval for scanning the laser is at least 20 μm or more. The method for removing a coating film on a semiconductor substrate by a laser according to any one of claims 1 to 5, wherein the semiconductor substrate is a SiC substrate. In a semiconductor substrate in which a plurality of elements are formed in a matrix on a substrate and streets are formed between the adjacent elements, a plurality of lasers are applied in parallel to a coating film containing a metal film formed on the streets. A film removing device on a semiconductor substrate using a laser having a film removing portion for removing the film by this scanning.
The film removing part
A plurality of the lasers, which are narrower than the width of the street, are scanned in parallel.
When scanning a plurality of the lasers in parallel, streaky ridges are formed at adjacent intervals of the laser removing portions from which the coating film is removed by irradiation of the laser.
A laser-based film removing device on a semiconductor substrate, characterized in that a convex portion is formed at the center where a plurality of the laser removing portions intersect with each other at an intersection portion where the two streets intersect.