KR102286670B1 - Processing method for substrate and processing apparatus for substrate - Google Patents

Abstract

Disclosed are a substrate processing process and a substrate processing apparatus capable of simultaneously performing cutting of a substrate and deburring in a cutting area by branching and irradiating a laser source into a plurality of laser beams. A substrate processing method includes a cutting step of cutting a substrate by irradiating a first laser beam having a first focal position, and a second focal position different from the first focal position in the rear along the cutting direction of the first laser beam. and a treatment step of removing burrs from the cutting area where the substrate is cut by irradiating a second laser beam with are investigated at the same time.

Description

Substrate processing method and substrate processing apparatus

The following description relates to a substrate processing method and a substrate processing apparatus for cutting a substrate using a laser.

A process of cleaving or dicing a substrate uses a diamond saw or laser ablation for a silicon wafer.

Here, the diamond saw process has a problem of low yield due to a low processing speed and low quality because a chipped kerf is left after cutting.

On the other hand, the cutting process using a laser has a slow processing speed and a wide cutting width of 10-20 μm, and defects or contamination may occur due to molten residues generated in the cutting process. In addition, since the processing depth per one time is shallow, when the thickness of the substrate is thick, it must be cut repeatedly several times. In this case, the overall processing speed and throughput are lowered by multiple processing. That is, the process of cutting the substrate with a laser is limited by the material and thickness of the substrate.

The content described as the above background art is possessed or acquired by the inventor in the process of derivation of the present invention, and cannot necessarily be acknowledged as a known art disclosed to the general public prior to the filing of the present invention.

An object of the embodiment is to provide a substrate processing method and a substrate processing apparatus capable of minimizing the generation of particles during processing and preventing the occurrence of defects or contamination in a cutting area.

The problems to be solved in the embodiments are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

A substrate processing method according to an embodiment will be described. A substrate processing method includes a cutting step of cutting a substrate by irradiating a first laser beam having a first focal position, and a second focal position different from the first focal position in the rear along the cutting direction of the first laser beam. and a treatment step of removing burrs from the cutting area where the substrate is cut by irradiating a second laser beam with are investigated at the same time.

According to one side, in the cutting step, the focal position of the first laser beam is located on the substrate surface. In addition, the first laser beam is split into a plurality of beams, and is irradiated on a straight line along a cutting direction for cutting the substrate. In addition, the first laser beam is branched into a plurality of sub-beams having different focal positions, and among the plurality of sub-beams, a leading first beam along the cutting direction of the substrate has a focal position located on the surface of the substrate, and The sub-beams behind one beam have a focal point positioned inside in the thickness direction of the substrate.

According to one side, in the treatment step, the second laser beam has a larger irradiation area reaching the substrate than the first laser beam. For example, the focal position of the second laser beam is located above the surface of the substrate, or the focal position of the second laser beam is located inside in the thickness direction of the substrate. And the second laser beam is branched into a plurality of beams, and is irradiated on a straight line with respect to the first laser beam along a cutting direction for cutting the substrate.

Meanwhile, a substrate processing apparatus according to another exemplary embodiment will be described. The substrate processing apparatus includes a laser source, and a branching unit configured to irradiate the laser source by branching the laser source into a first laser beam having a first focal position and a second laser beam having a second focal position, wherein the branching unit comprises: A treatment in which the substrate is cut by irradiating a first laser beam, and the second laser beam is irradiated on a straight line with the first laser beam along the cutting direction of the substrate to remove burrs in the cut region where the substrate is cut will do

According to one side, the branch portion may include a convex spherical incident surface on which the laser source is incident, and a focusing lens having a plurality of concavities and convexities on the opposite emitting surface. Alternatively, the branching portion, the incident surface to which the laser source is incident is flat, and the opposite exit surface is provided in front of a splitter lens having a plurality of concavities and convexities and a laser beam is emitted from the splitter lens, and focusing on a convex spherical surface It may include a lens.

As described above, according to embodiments, the cutting of the substrate and the deburring in the cutting area may be simultaneously performed by branching and irradiating one laser source into a plurality of laser beams having different focal positions.

Effects of the substrate processing method and the substrate processing apparatus according to the embodiment are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a schematic diagram of a substrate processing apparatus according to an embodiment.
2A and 2B are views illustrating an example of a branch in the substrate processing apparatus of FIG. 1 .
3 is a schematic diagram of a branched laser beam.
4 is a schematic diagram for explaining a substrate processing method according to an embodiment.
5 to 6B are photographs of a substrate by a substrate processing method according to an exemplary embodiment.
7 to 8B are photographs of a substrate treated according to a comparative example.

Hereinafter, embodiments will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in the description of the embodiment, if it is determined that a detailed description of a related known configuration or function interferes with the understanding of the embodiment, the detailed description thereof will be omitted.

In addition, in describing the components of the embodiment, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the components from other components, and the essence, order, or order of the components are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but another component is between each component. It will be understood that may also be "connected", "coupled" or "connected".

Components included in one embodiment and components having a common function will be described using the same names in other embodiments. Unless otherwise stated, a description described in one embodiment may be applied to another embodiment, and a detailed description in the overlapping range will be omitted.

Hereinafter, a substrate processing method and a substrate processing apparatus will be described with reference to FIGS. 1 to 4 . For reference, FIG. 1 is a schematic diagram of a substrate processing apparatus 10 according to an exemplary embodiment, and FIGS. 2A and 2B are views illustrating an example of the branching part 12 . And FIG. 3 is a schematic diagram of the branched laser beams 110 and 120, and FIG. 4 is a schematic diagram for explaining a substrate processing method according to an embodiment.

Referring to FIG. 1 , the substrate processing apparatus 10 includes a single laser source 11 and a branching unit 12 for irradiating by branching the laser source 11 into a plurality of laser beams 110 and 120 . is composed

However, only a part of the substrate processing apparatus 10 illustrated in FIG. 1 is simplified and illustrated, and the configuration of the substrate processing apparatus 10 is not limited by the drawings.

For example, the laser source 11 may use a femtosecond laser.

Also, in the present embodiment, the substrate 1 may be a silicon wafer for manufacturing a semiconductor device. In addition, the shape of the substrate 1 may have various shapes such as a circle, a square, and the like.

The branching portion 12 connects the laser source 11 to the first laser beam 110 for cutting the substrate 1 and the portion where the substrate 1 is cut (hereinafter referred to as a “cutting region”) RD. It is branched into a second laser beam 120 for removing the burr 1a. Here, the cut region RD includes a cut portion of the substrate 1 and a portion of its periphery.

Referring to FIGS. 2A and 2B , the branching unit 12 splits the beam generated from the laser source 11 using diffractive optical elements (DOE).

For reference, in FIGS. 2A and 2B , only the lens of the branching part 12 is illustrated in a simplified manner.

For example, as shown in FIG. 2A , the branch 12 includes a focusing lens 210 . The focusing lens 210 may have an incident surface 211 on which the laser beam is incident is formed as a convex spherical surface, and a plurality of irregularities on the exit surface 212 on which the branched beam is emitted.

Alternatively, as shown in FIG. 2B , the branching unit 12 may include a plurality of lenses 220 and 230 . The branching part 12 may include a splitter lens 220 having irregularities and a focusing lens 230 having a convex spherical surface, which is provided in front from which a beam is emitted from the splitter lens 220 . For example, the splitter lens 220 may be a flat lens in which the incident surface 221 is flat, and the exit surface 222 may have a shape in which a plurality of irregularities are formed.

However, the shape of the branching portion 12 is not limited by the drawings, and may have various shapes capable of branching a laser beam generated from the laser source 11 into a plurality of laser beams 110 and 120 .

3 and 4 , the first laser beam 110 has a first focal position F1, and the second laser beam 120 has a second focal position F2 different from the first focal position F1. ) has In addition, the first laser beam 110 and the second laser beam 120 are irradiated on a straight line along a direction P in which the substrate 1 is cut (hereinafter referred to as a "cutting direction").

The first laser beam 110 has a first focal point F1 on the surface of the substrate 1 . By setting the first focal point F1 on the surface of the substrate 1 to be cut in this way, the energy density at the portion where the first laser beam 110 reaches the substrate 1 is high, so that the substrate 1 is cut. can do.

The second laser beam 120 has a second focal point F2 positioned therein in the depth direction of the substrate 1 .

Here, when the first laser beam 110 is irradiated to the substrate 1 , the substrate 1 is cut to a predetermined depth, and burrs 1a are generated around the cutting region RD. The burr 1a is formed by condensing a portion of the substrate 1 melted by the first laser beam 110 around the cut region RD, and protrudes from the surface of the substrate 1 .

However, by setting the second focus position F2 , the area in which the second laser beam 120 reaches the substrate 1 becomes wider than that of the first laser beam 110 , so that the cutting is performed by the first laser beam 110 . The burr 1a may be removed while the laser beam is irradiated to an area wider than the cut area RD. In this case, since the energy density of the second laser beam 120 reaching the substrate 1 is lower than that of the first laser beam 110 , the substrate 1 is not cut and only the burr 1a is removed.

According to this embodiment, the substrate 1 is cut by simultaneously irradiating the first laser beam 110 and the second laser beam 120 on a straight line along the cutting direction, and at the same time, the burr ( Treatments to remove 1a) are carried out simultaneously. And, since the first laser beam 110 and the second laser beam 120 are branched from one laser source 11, the first laser beam 110 and the second laser beam 120 can be simultaneously irradiated. , can effectively cut and treat the substrate 1 . In addition, since a separate process for removing the burr 1a can be omitted, the process can be simplified.

Meanwhile, in the drawing, the focal position F2 of the second laser beam 120 is exemplified as being located inside in the thickness direction of the substrate 1 , but as shown in FIGS. 1 and 3 , the second laser beam ( Setting the focal position F3 of the second laser beam 120 ′ to be located above the surface of the substrate 1 so that the area where the 120 reaches the substrate 1 is wider than the first laser beam 110 . It is also possible Alternatively, both the second laser beam 120 having the focal position F2 located inside the substrate 1 and the second laser beam 120 ′ having the focal position F3 located above the substrate 1 are used. It is also possible

Meanwhile, in order to increase the cutting efficiency of the substrate 1 , the first laser beam 110 may be further branched into a plurality of beams 111 , 112 , 113 , and 114 along the cutting direction P . In this case, the branched beams 111 , 112 , 113 , and 114 are irradiated to the substrate 1 on a straight line along the cutting direction P with the first laser beam 110 . In addition, the branched beams 111 , 112 , 113 , and 114 may have the same focal position as the first laser beam 110 , or may be positioned inside in the thickness direction of the substrate 1 . Alternatively, the branched beams 111 , 112 , 113 , and 114 may be positioned inside in the thickness direction of the substrate 1 .

Meanwhile, in the drawings, the branching of the first laser beam 110 into four is illustrated, but this is only an example, and the number of branches of the first laser beam 110 may be variously changed. However, the first laser beam 110 may be set such that at least one of the plurality of branched beams is set so that the first focal point F1 is located on the surface of the substrate 1 .

Hereinafter, a state after the substrate 1 is cut by the substrate processing method according to the present embodiment will be described. Here, FIGS. 5 to 6B are pictures after cutting the substrate 1 according to the present embodiment, and FIGS. 7 to 8B are pictures after cutting the substrate 1 according to the comparative example.

For reference, FIGS. 5 and 7 are photos after cutting the substrate 1 by irradiating a laser with respect to the substrate 1 without a protective film.

Referring to FIG. 5 , when the substrate 1 is cut by irradiating a plurality of branched laser beams 110 and 120 to the substrate 1 without a protective film, the substrate 1 is cut in the cut region RD. It can be seen that there are no burrs around. That is, according to the present embodiment, it can be seen that the cutting of the substrate 1 and the removal of the burr in the cutting region RD are simultaneously performed by the plurality of branched laser beams 110 and 120 . Here, FIG. 5 shows one side of the cutting area RD by shifting the second laser beam 120 to one side with respect to the first laser beam 110 for cutting the substrate 1 , that is, FIG. 5 . The second laser beam 120 was irradiated to the portion indicated by A, and the second laser beam 120 was not irradiated to the opposite side. In addition, since the second laser beam 120 was shifted to one side and irradiated, two 'V'-shaped regions were formed in the cut region RD.

On the other hand, referring to the portion indicated by C in FIG. 7 , when a non-branched laser is irradiated to cut the substrate 1 without a protective film, burrs 1a are formed around both sides of the cutting region RD in the substrate 1 . can be seen to exist.

And, FIGS. 6A and 8A are photos after cutting the substrate 1 by irradiating a laser with respect to the substrate 1 having the protective film 2, and FIGS. 6B and 8B are the protection in FIGS. 6A and 8A, respectively. These are photos of the state in which the film (2) has been peeled off.

Referring to the portion indicated by B in FIGS. 6A and 6B , when a plurality of branched laser beams 110 and 120 are irradiated to the substrate 1 having the protective film 2 , the substrate 1 is cut, and with It can be seen that there is no burr in the periphery of the cut region RD of the substrate 1 , that is, it is removed. This can also be confirmed through a photograph of a state in which the protective film 2 is peeled off from the substrate 1 as shown in FIG. 6b . That is, according to the present embodiment, even in the presence of the protective film 2 , the cutting of the substrate 1 and the removal of the burr in the cutting region RD are simultaneously performed by the plurality of branched laser beams 110 and 120 , it can be seen that there is Similarly, in FIGS. 6A and 6B , the second laser beam 120 was shifted to one side of the cutting region RD, that is, to the portion indicated by B in FIGS. 6A and 6B , and the second laser beam 120 . It can be seen that no burrs are formed in the irradiated portion indicated by B.

On the other hand, referring to the portion indicated by D in FIG. 8A , even when the laser is irradiated to the substrate 1 having the protective film 2 , the burrs 1a are located around both sides of the cut region RD in the substrate 1 . can be seen to exist. In addition, referring to FIG. 8B , it can be seen that the burr 1a is present even after the substrate 1 is cut and the protective film 2 is removed.

As described above, although the embodiments have been described with reference to the limited drawings, various modifications and variations are possible from the above description by those of ordinary skill in the art. For example, the described techniques are performed in an order different from the described method, and/or the described components of structures, devices, etc. are combined or combined in a different form than the described method, or other components or equivalents are used. Appropriate results can be achieved even if substituted or substituted by

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims described below, but also all of the claims and all equivalents or equivalent modifications will fall within the scope of the spirit of the present invention.

1: substrate
10: substrate processing apparatus
11: laser source
12: branch
210, 220, 230: lens
110: first laser beam
111, 112, 113, 114: branched beam
120, 120': second laser beam
F1, F2, F3: focus position
RD: cutting area
P: cutting direction

Claims (10)

A cutting step of cutting the substrate 1 by irradiating a first laser beam 110 having a first focal position F1; and
By irradiating a second laser beam 120 having a second focal position F2 different from the first focal position F1 behind the first laser beam 110 in the cutting area where the substrate 1 is cut. , a treatment step of removing the burr from the cutting area;
including,
The cutting step and the treatment step are performed simultaneously,
The first laser beam 110 and the second laser beam 120 are branched from one laser source 11 and simultaneously irradiated to the substrate 1 .
According to claim 1,
In the cutting step, the focal position of the first laser beam 110 is a substrate processing method located on the surface of the substrate (1).
3. The method of claim 2,
The first laser beam 110 is branched into a plurality of sub-beams 111, 112, 113, 114,
The plurality of branched sub-beams (111, 112, 113, 114) are simultaneously irradiated along a cutting direction for cutting the substrate (1).
4. The method of claim 3,
The first laser beam 110 is branched into a plurality of sub-beams 111, 112, 113, and 114 having different focal positions,
Among the plurality of sub-beams 111 , 112 , 113 , and 114 , a leading first beam 111 along the cutting direction of the substrate 1 has a focal point located on the surface of the substrate 1 , and the first beam Sub-beams (112, 113, 114) at the rear of the substrate processing method in which the focal position is located inside in the thickness direction of the substrate (1).
According to claim 1,
In the treatment step, the second laser beam 120 has a larger irradiation area reaching the substrate 1 than the first laser beam 110 .
6. The method of claim 5,
A focal point F2 of the second laser beam 120 is located above the surface of the substrate 1 or located inside in the thickness direction of the substrate 1 .
6. The method of claim 5,
The second laser beam 120 is split into a plurality of beams, and is irradiated on a straight line from the rear of the first laser beam 110 in a cutting direction for cutting the substrate 1 .
laser source 11; and
The laser source 11 is divided into a first laser beam 110 having a first focal position F1 and a second laser beam 120 having a second focal position F2, and the first laser beam a branching portion 12 for simultaneously irradiating 110 and the second laser beam 120 along the cutting direction of the substrate 1;
including,
The branching portion 12 is a cutting region in which the substrate 1 is cut by irradiating the first laser beam 110 to cut the substrate 1 , and at the same time to irradiating the second laser beam 120 to cut the substrate 1 . Substrate processing equipment for treatment to remove burrs from
9. The method of claim 8,
The branching part 12 has a convex incident surface on which the laser source 11 is incident, and a focusing lens 210 having a plurality of concavities and convexities on the opposite exit surface.
9. The method of claim 8,
The branch 12 is,
a splitter lens 220 in which an incident surface on which the laser source 11 is incident is flat, and an exit surface on the opposite side is formed with a plurality of concavities and convexities; and
a focusing lens 210 having a convex spherical surface and provided in front of which the laser beam is emitted from the splitter lens 220;
Substrate processing apparatus comprising

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