JP2007021514A - Scribe formation method, substrate with planned dividing lines - Google Patents

Abstract

PROBLEM TO BE SOLVED To provide a scribe line forming method capable of satisfactorily dividing a substrate even in the vicinity of an end portion of the planned dividing line when a planned dividing line composed of a modified region is formed by condensing a laser beam inside the substrate. Then, we propose a substrate with planned dividing lines.
A scribe formation method for a substrate P, in which a laser beam is condensed inside the substrate P, and the substrate P and the laser beam are moved relative to each other, thereby dividing the planned line composed of a modified region S1 in the substrate P. A step of forming S, and a step of condensing laser light around the end portion of the planned division line S to form a division assisting portion V formed of the second modified region U.
[Selection] Figure 4

Description

  The present invention relates to a scribe forming method for forming a planned dividing line on a substrate and a substrate with a planned dividing line.

As a method for dividing a glass substrate widely used in a liquid crystal device or the like into a plurality of methods, a method is generally used in which grooves (division lines, scribe lines) are cut on the surface of the substrate and the substrate is divided along the grooves. Yes. However, such a method has a problem that chips are generated because a groove is physically provided in the substrate.
For this reason, a technique has been proposed in which a laser beam is condensed inside the substrate, thereby forming a planned dividing line composed of an altered region inside the substrate (Patent Document 1).
JP 2002-192370 A

However, in the above-described technique, as shown in FIG. 8, in the vicinity of the side end surface of the substrate, a part of the laser light protrudes outside the substrate, so that it is difficult to satisfactorily form the modified region inside the substrate. It is. Alternatively, even if the modified region can be formed, the quality modified density is lower than other regions such as the central portion of the substrate.
As described above, in the method using laser light, it is not possible to form the planned dividing line near the side end face of the substrate. In addition, there is a region where the modified region cannot be formed due to the presence of an electrode pattern or the like formed on the substrate, not near the side end surface of the substrate.
For this reason, when a board | substrate is divided | segmented along a division | segmentation planned line, there exists a problem that an unnecessary crack will generate | occur | produce in the edge part vicinity of a division | segmentation planned line, for example, the side edge surface vicinity of a board | substrate. In particular, when an electrode pattern or the like is formed on the substrate, there is a disadvantage that the electrode pattern or the like is damaged.

  The present invention has been made in view of the above-described circumstances, and is good even in the vicinity of the end portion of the planned dividing line when the planned dividing line composed of the modified region is formed by condensing the laser beam inside the substrate. Another object of the present invention is to propose a method for forming a scribe line and a substrate with planned dividing lines.

In order to solve the above-described problems, the following means are employed in the scribe forming method and the substrate with the planned dividing lines according to the present invention.
A first invention is a method for forming a scribe on a substrate, wherein a laser beam is condensed inside the substrate and the substrate and the laser beam are moved relative to each other to form a division line composed of a modified region in the substrate. And a step of condensing the laser beam around the end portion of the planned dividing line to form a dividing auxiliary portion made of the second modified region.
According to this invention, since the crack generated along the planned dividing line is propagated to the dividing auxiliary portion formed of the second modified region, the occurrence of unnecessary cracking or the like in the region where the planned dividing line is not formed. Can be prevented.

Further, in the case where the step of forming the division assisting portion includes the step of forming the second modified region in the vicinity of the side end surface of the substrate, it is in the vicinity of the side end surface of the substrate where it is difficult to form the planned dividing line. However, by forming the division assisting portion in this portion, it is possible to prevent the occurrence of unnecessary cracks in the vicinity of the side surface of the substrate.
In addition, the step of forming the division assisting portion includes the step of forming the second modified region at a position different from the planned dividing line in the thickness direction of the substrate. By moving in the thickness direction of the substrate, it is possible to form the division assisting portion including the second modified region near the side end surface of the substrate.
In addition, the step of forming the division assisting portion includes a step of forming the second modified region so as to overlap the planned division line in the thickness direction of the substrate. Is reliably propagated to the division assisting portion, and unnecessary cracks and the like are prevented from occurring in a region where the planned dividing line is not formed.
In addition, in the case where an ultrashort pulse laser beam is used as the laser beam, the modified region and the second modified region can be satisfactorily formed inside the substrate.

According to a second aspect of the present invention, there is provided a substrate on which a planned dividing line made of a modified region is formed, and a dividing auxiliary portion made of a second modified region is arranged around an end of the planned dividing line. I made it.
According to the present invention, when a crack is generated along the planned dividing line, the crack is propagated to the dividing auxiliary portion formed of the second modified region, so that an unnecessary crack in the region where the planned dividing line is not formed. Etc. can be prevented.

Further, in the case where the division assisting portion is disposed near the side end surface of the substrate, even if the portion near the side end surface of the substrate where it is difficult to form the planned dividing line, the division assisting portion is formed in this portion. The occurrence of unnecessary cracks in the vicinity of the side surface of the substrate can be prevented.
Further, in the case where the division assisting portion is arranged at a position different from the planned dividing line in the thickness direction of the substrate, the laser beam condensing position is moved in the thickness direction of the substrate, thereby further It becomes possible to arrange the division assisting part composed of the second modified region in the vicinity of the side end face.
In addition, in the case where the division assisting part is disposed so as to partially overlap the planned dividing line in the thickness direction of the substrate, cracks generated along the planned dividing line are surely transmitted to the dividing auxiliary part. Thus, the occurrence of unnecessary cracks and the like in the region where the planned dividing line is not formed is prevented.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a scribe forming method and a substrate with planned dividing lines of the present invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram showing a schematic configuration of the scribe forming apparatus 10.
The scribe forming apparatus 10 includes a laser light source 11 that generates laser light L, a laser light source control unit 14 that controls the laser light source 11 to adjust the output and pulse width of the laser light L, and a concentrator that collects the laser light L. A Z-axis drive unit 15 for moving the light lens 12, the condensing lens 12 and the like in the Z-axis direction, a mounting table 17 for mounting the substrate P, and an X-axis for moving the mounting table 17 in the X-axis direction A stage 18, a Y-axis stage 19 for moving the mounting table 17 in the Y-axis direction orthogonal to the X-axis direction, a stage controller 20 that controls the X-axis stage 18, the Y-axis stage 19, and the like are provided.

An ultrashort pulse laser is used for the laser light L emitted from the laser light projecting unit 13 including the laser light source 11 and the condensing lens 12. For example, a femtosecond laser having a pulse width of 300 fs, an output of 170 mW, a repetition rate of 1 kHz, a wavelength of 800 nm, and a magnification of 100 times (NA 0.8) is used.
An ultrashort pulse laser such as a femtosecond laser has a very short pulse width even if the output is small, so that the instantaneous output power in one pulse becomes large.
Therefore, when the ultra-short pulse laser is focused and irradiated, energy is injected instantaneously before heat conduction occurs, so high-precision and high-quality processing is achieved with almost no thermal or chemical damage around the irradiated area. it can. By utilizing the phenomenon of multiphoton absorption, three-dimensional processing into a transparent material such as glass or diamond that normally allows light to pass through is possible.

  The Z-axis drive unit 15 moves the focal point of the laser light L in the Z-axis direction by moving the laser projection unit 13 in the Z-axis direction. That is, the Z-axis direction is a direction orthogonal to the surface Ps of the substrate P, and is also the direction of the focal depth of the laser light L incident on the substrate P through the condensing lens 12 or the like. Therefore, the focal point of the laser beam L can be positioned at an arbitrary position inside the substrate P by moving the laser projection unit 13 in the Z-axis direction by the Z-axis drive unit 15.

  The X-axis stage 18 and the Y-axis stage 19 move the substrate P in the X-axis direction and the Y-axis direction, so that the focal point of the laser light L condensed in the substrate P is within the substrate P in the X-axis direction and the Y-axis. Can be moved in the direction.

  As the substrate P, a light transmissive substrate made of quartz, soda glass, or the like is used. By using the light transmissive substrate, the laser light L can be favorably condensed inside the substrate P.

Next, the scribe forming method according to this embodiment will be described.
2 and 3 are diagrams showing a scribe forming method, in which FIG. 2 is a sectional view of the substrate, and FIG. 3 is a plan view of the substrate.

First, the substrate P is mounted on the mounting table 17. Then, the laser projection unit 13 is moved in the Z-axis direction by the Z-axis drive unit 15 and positioned so that the laser beam L is focused on the lowermost part of the substrate P.
Specifically, the focal position of the laser light L is adjusted to the lowest part of the substrate P, that is, a position close to the back surface Pt. The focal position is estimated by obtaining the refractive index of the substrate P in advance.

  Next, a femtosecond laser is irradiated from the laser projector 13 to form a modified region at the bottom. At the same time, as shown in FIG. 3, the X-axis stage 18 and the Y-axis stage 19 are driven to move the substrate P relative to the laser projector 13. The scanning speed of the X axis stage 18 and the Y axis stage 19 is, for example, about 20 mm / s.

In the scribe formation method using a femtosecond laser, a laser beam L is transmitted through the substrate P and multiphoton absorption is generated inside the substrate P, thereby forming a modified region having fine cracks and the like. .
That is, the substrate P does not generate heat or melt by absorbing the laser light L. For this reason, the laser beam L is hardly absorbed at a portion other than the focal point of the substrate P, for example, the surface Ps, and melting or the like does not occur.

  In this way, as shown in FIG. 2 and FIG. 3B, the planned dividing line S composed of the line-shaped modified region S <b> 1 is formed at the bottom so as to cross the substrate P. Since the line-shaped modified region S1 is a region weaker than the peripheral region, the substrate P can be divided into a plurality of portions along the modified region S1.

Incidentally, when the modified region S1 is formed inside the substrate P, it is difficult to form the modified region S1 at the side end portion of the substrate P.
This is because a part of the laser light L protrudes out of the substrate P as shown in FIG. That is, since the laser beam L cannot be sufficiently condensed in the substrate P, it is difficult to form a modified region inside the substrate P. Alternatively, even if formed, the reforming density is low and it does not function as the planned dividing line S.
For this reason, conventionally, as shown in FIG. 3B, the modified region S1 is not formed in the side end portion T of the substrate P, that is, an unprocessed region.
When the substrate P is divided along the planned dividing line S composed of the modified region S1, unnecessary cracks often occur in the side end portion T, that is, the unprocessed region. For example, a crack progresses in a direction that is not parallel to the planned dividing line S, or a plurality of cracks occur and the side end portion T of the substrate P is missing.

  Accordingly, the division assisting portion V including the modified region U formed separately from the planned division line S is formed around both ends of the planned division line S. That is, by forming the modified region U in the side end portion T that is the periphery of both ends of the planned dividing line S, the cracks generated in the planned dividing line S are propagated to the modified region U. It is possible to prevent unnecessary cracking at the side end T.

Incidentally, as described above, it is difficult to form the modified region S1 in the side end portion T. Therefore, the modified region U cannot be formed at the side end T by the same method as the method for forming the modified region S1.
For this reason, as a method for forming the modified region U, the modified region U is formed at a position different from the planned dividing line S in the thickness direction (Z-axis direction) of the substrate P. This is because if the condensing position of the laser light L moves in the + Z direction, the laser light L will not protrude from the substrate P even if the condensing position is closer to the side end face. Therefore, it is possible to form the modified region U near the side end surface.

FIG. 4 is a schematic diagram illustrating a method for forming the modified region U.
As a method of forming the modified region U, after forming the planned dividing line S composed of the modified region S1, the Z-axis drive unit 15 is driven to move the condensing position of the laser light L in the + Z-axis direction. . Further, the X-axis stage 18 and the Y-axis stage 19 are driven to move the condensing position of the laser beam L to a position near the end of the modified region S1 and close to the side end surface.
Then, as shown in FIG. 4A, the division assisting portion V formed of the modified region U is formed in the substrate P by irradiating the laser light L from the laser projecting portion 13 at this position.
Further, as shown in FIG. 4B, a plurality of modified regions U may be formed by gradually changing the condensing position of the laser light L in the Z-axis direction and the X and Y-axis directions. This is because it is possible to form the division assisting portion V that is close to the end portion of the planned dividing line S (partially overlaps) and also close to the side end surface of the substrate P.

  In this way, the division assisting portion V including the modified region U is formed at the side end portion T of the substrate P. As a result, when the substrate P is divided along the planned dividing line S, the generated cracks are reliably propagated to the dividing auxiliary portion V formed of the modified region U. Occurrence is suppressed.

The substrate P is divided by applying a relatively small force to the substrate P. That is, a crack is generated and proceeds along the planned dividing line S, and the substrate P is divided (divided).
As a method for applying a force to the substrate P, for example, a bending stress or a shearing stress is applied to the substrate P along the planned dividing line S, or a thermal stress is generated by applying a temperature difference to the substrate P.

Although the case where it forms only in the side edge part T was demonstrated as a formation method of the division | segmentation auxiliary | assistance part V which consists of the modification | reformation area | region U, it does not restrict to this.
For example, as shown in FIG. 5, the modified region U may be formed so as to partially overlap the upper part (+ Z axis direction) of the planned dividing line S. Thereby, when a crack occurs in the planned dividing line S, the crack propagates directly to the dividing auxiliary part V. For this reason, generation | occurrence | production of an unnecessary crack is further prevented.

Although the case where the laser projection unit 13 is moved in the + Z-axis direction has been described as a method for forming the division assisting unit V including the modified region U, the present invention is not limited thereto.
For example, as shown in FIG. 6, the division auxiliary portion V including the modified region U may be formed by irradiating the laser beam L from the side end surface direction of the substrate P and condensing it in the substrate P. In this case, the division assisting part V can be formed at the same position in the Z-axis direction as the planned division line S.

Moreover, although the side edge part T was demonstrated as an example as a site | part which an unnecessary crack generate | occur | produces, it is not restricted to this.
For example, the same applies when the planned dividing line S cannot be formed in a continuous straight line. For example, as shown in FIG. 7, after forming a broken division planned line S, the division assisting portion V composed of a plurality of modified regions U is formed in the unprocessed region. Thereby, even if it is the dividing line S of a broken line shape, it becomes possible to advance a crack along the dividing line S reliably, and to divide the board | substrate P favorably.

  In the embodiment described above, in order to make the explanation easy to understand, the case where only one line (straight line) -shaped division planned line S is formed has been described, but the present invention is not limited thereto. It may be a case where a plurality of division lines are formed in parallel. Moreover, you may form the curve and grid-like division | segmentation planned line.

Although the case where the substrate P is moved in the X-axis direction and the Y-axis direction by the X-axis stage and the Y-axis stage and the laser projector 13 is moved in the Z-axis direction by the Z-axis drive unit has been described, the present invention is not limited to this. .
The laser projector 13 may be fixed and the substrate P may be moved in the X-axis, Y-axis, and Z-axis directions. Conversely, the substrate P may be fixed and the laser projector 13 may be moved in the X-axis, Y-axis, and Z-axis directions.

Examples of the substrate P include displays such as liquid crystal devices and organic EL devices. This is mainly a TFT substrate in which electronic devices, wiring patterns, and the like are formed on the back surface Pt of the substrate P. When the planned dividing line S is formed on such a substrate P, cracks at portions other than the planned dividing line S are almost eliminated, so that damage to electronic devices and wiring patterns due to the division of the substrate P is prevented. The
Further, the substrate P is not limited to a TFT substrate or the like, and may be a transparent substrate in which a microlens is formed.

  Further, although the case where the substrate is a light transmissive substrate such as a glass substrate has been described, a substrate made of a translucent or opaque material may be used as long as the laser light L is transmitted. In this case, the modified region may be formed by melting or changing the crystal structure in addition to the case where the modified region is formed from a fine crack or the like.

It is a conceptual diagram which shows schematic structure of the scribe formation apparatus of this embodiment. It is sectional drawing which shows the scribe formation method of this embodiment. It is a top view which shows the scribe formation method of this embodiment. It is a schematic explanatory drawing of the formation method of a division | segmentation auxiliary | assistant part. It is a schematic explanatory drawing of the other formation method of a division | segmentation auxiliary | assistant part. It is a schematic explanatory drawing of the other formation method of a division | segmentation auxiliary | assistant part. It is a schematic explanatory drawing of the other formation method of a division | segmentation auxiliary | assistant part. It is sectional drawing which shows the conventional scribe formation method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Scribe formation apparatus, 11 ... Laser light source, 13 ... Laser projector part,
L: Laser light, P: Substrate, S: Planned dividing line, S1: Modified region (other region),
T: Side end (unprocessed region), U: Modified region (second modified region), V: Divided auxiliary portion

Claims (9)

A step of condensing a laser beam inside the substrate and relatively moving the substrate and the laser beam to form a planned dividing line made of a modified region in the substrate;
The step of condensing the laser beam around the end of the planned division line to form a division assisting portion consisting of a second modified region;
A scribe forming method characterized by comprising:   2. The scribe forming method according to claim 1, wherein the step of forming the division assisting portion includes a step of forming the second modified region in the vicinity of a side end surface of the substrate.   The step of forming the division assisting portion includes the step of forming the second modified region at a position different from the planned dividing line in the thickness direction of the substrate. The scribe forming method described in 1.   3. The step of forming the division assisting portion includes a step of forming the second modified region so as to overlap the planned division line in the thickness direction of the substrate. Scribe forming method.   The scribe forming method according to any one of claims 1 to 4, wherein an ultrashort pulse laser beam is used as the laser beam. A substrate on which a planned dividing line consisting of a modified region is formed,
A substrate with planned dividing lines, characterized in that a division assisting portion made of a second modified region is arranged around an end of the planned dividing line.   The board | substrate with a division | segmentation planned line of Claim 6 arrange | positioned in the vicinity of the side end surface of the said board | substrate.   The board | substrate with a division | segmentation planned line of Claim 6 or Claim 7 with which the said division | segmentation auxiliary | assistance part is arrange | positioned in the position different from the said division | segmentation planned line in the thickness direction of the said board | substrate. The board | substrate with a division | segmentation planned line of Claim 6 or 7 with which the said division | segmentation auxiliary | assistant part is overlapped and arrange | positioned on the said division | segmentation planned line in the thickness direction of the said board | substrate.

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