JP6589381B2 - Method for forming vertical crack in brittle material substrate and method for dividing brittle material substrate - Google Patents

Description

  The present invention relates to a method for dividing a brittle material substrate, and more particularly to a method for forming a vertical crack when dividing a brittle material substrate.

  A manufacturing process of a flat display panel or a solar cell panel generally includes a step of dividing a substrate (mother substrate) made of a brittle material such as a glass substrate, a ceramic substrate, or a semiconductor substrate. For such cutting, a technique is widely used in which a scribe line is formed on the substrate surface using a scribe tool such as a diamond point or a cutter wheel, and a crack (vertical crack) is extended from the scribe line in the thickness direction of the substrate. Yes. When the scribe line is formed, the vertical crack may be completely extended in the thickness direction and the substrate may be divided, but the vertical crack may be only partially extended in the thickness direction. In the latter case, after the scribe line is formed, stress is applied which is called a break process. The substrate is divided along the scribe line by causing the vertical crack to advance completely in the thickness direction by the break process.

  As a technique for extending a vertical crack by forming a scribe line, a technique for forming a linear processing trace, which is also referred to as an assist line, and serves as a starting point (trigger) in extending a vertical crack is already known. (For example, refer to Patent Document 1).

Japanese Patent Application Laid-Open No. 2015-74145

  For example, a technique using an assist line as disclosed in Patent Document 1 is different from a technique not using this in that a scribe tool such as a cutter wheel or a diamond point is formed on a substrate when forming a scribe line for cutting. There is an advantage that the applied force (impact) can be reduced. For example, even if the scribe line is formed by applying a weak force (load) that makes it difficult to extend the vertical crack, the vertical crack can be suitably extended from the scribe line using the assist line as a trigger. is there.

  However, a high yield (reliable division) is required especially in the division of the brittle material substrate made in the production process of the mass-produced product. However, the technique disclosed in Patent Document 1 does not necessarily generate the vertical crack starting from the assist line. There is no guarantee of certainty about the extension.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method capable of forming a vertical crack with high certainty at a predetermined dividing position of a brittle material substrate.

In order to solve the above-mentioned problem, the invention of claim 1 is a method of forming a vertical crack at a dividing position when dividing a brittle material substrate in the thickness direction, and has a linear shape on one main surface of the brittle material substrate. A trench line forming step for forming a trench line that is a groove portion, and an assist line that is a processing trace that intersects the trench line by causing a scribing wheel having a blade edge uniformly on the outer peripheral portion to press and roll on the one main surface. An assist line forming step of forming, in the trench line forming step, the trench line is formed so that a crackless state is maintained immediately below the trench line, and in the assist line forming step, Formation of the assist line in a horizontal plane with the scribing wheel To form the assist line in a state inclined at a predetermined inclination angle from the direction, to extend the vertical crack in the thickness direction of the brittle material substrate from the trench line an intersection point between the trench line and the assist line as a starting point In the assist line forming step, along with the formation of the assist line, an uneven distribution of assist cracks from the assist line toward the inside of the brittle material substrate occurs in one side region of the assist line, localized regions of the assist cracks shall be determined the trench line and forming position of the assist line so that the planned extension direction of the vertical cracks on the trench line, characterized in that.

Invention of Claim 2 is a formation method of the vertical crack in the brittle material substrate of Claim 1, Comprising: The said assist line and the said trench line in the vicinity of the reverse side of the planned extension direction of the vertical crack on the said trench line It forms so that it may cross | intersect.

Invention of Claim 3 is a formation method of the vertical crack in the brittle material substrate of Claim 1 or Claim 2 , Comprising: In the said assist line formation process, the advancing direction front side of the said scribing wheel is the said horizontal direction in the said horizontal plane. Inclining from the direction in which the assist line is formed toward the planned extension direction side of the vertical crack on the trench line.

Invention of Claim 4 is a formation method of the vertical crack in the brittle material substrate in any one of Claim 1 thru | or 3 , Comprising: The said inclination | tilt angle is 1.0 degree or more and 5.0 degrees or less, It is characterized by that.

The invention according to claim 5 is the method for forming vertical cracks in the brittle material substrate according to claim 4 , wherein the inclination angle is 2.5 ° or more and 5.0 ° or less.

A sixth aspect of the present invention is the method for forming a vertical crack in a brittle material substrate according to any one of the first to fifth aspects, wherein the assist line is formed after the trench line is formed. And

The invention according to claim 7 is a method of dividing the brittle material substrate in the thickness direction, and the vertical crack is formed in the brittle material substrate by the vertical crack forming method according to any one of claims 1 to 6. It is characterized by comprising a vertical crack forming step and a break step for breaking the brittle material substrate along the vertical crack.

According to the first to seventh aspects of the present invention, since the vertical crack can be extended with high certainty at the predetermined cutting position of the brittle material substrate, the brittle material substrate is reliably cut at the cutting position. It becomes possible to do.

1 is a diagram schematically showing a configuration of a scribe device 100. FIG. It is a figure shown about the attitude | position of the scribing wheel 51 in the scribe apparatus 100. FIG. It is a top view of the brittle material substrate W illustrating the state after the formation of the trench line TL. It is a figure which shows schematically the structure of the diamond point 150 used for formation of trench line TL. It is zx partial sectional drawing containing the vertical cross section of trench line TL. It is a top view of the brittle material substrate W illustrating the state when the assist line AL is formed. 4 is a top view of a brittle material substrate W illustrating how a vertical crack VC extends along with the formation of an assist line AL. FIG. 4 is a top view of a brittle material substrate W illustrating how a vertical crack VC extends along with the formation of an assist line AL. FIG. It is zx partial sectional drawing containing the vertical cross section of trench line TL and the vertical crack VC. It is a schematic diagram which shows the mode of the assist line AL vicinity at the time of the vertical crack VC being formed. It is an example of imaging of a brittle material substrate W formed with an assist line AL. It is a partial enlarged image of the assist line AL formed at different inclination angles θ. It is the graph which plotted VC establishment rate with respect to the load applied at the time of formation of the assist line AL about each of different inclination | tilt angles (theta) of Example 1. FIG. It is the graph which plotted VC establishment rate with respect to the load applied at the time of formation of the assist line AL about each of different inclination | tilt angles (theta) of Example 2. FIG.

<Scribe device>
FIG. 1 is a diagram schematically showing a configuration of a scribing apparatus 100 used in the embodiment of the present invention. The scribing device 100 is generally used when a brittle material substrate W such as a glass substrate, a ceramic substrate, or a semiconductor substrate is divided in the thickness direction DT at a predetermined dividing position to reduce the size. In the embodiment, the scribing apparatus 100 is mainly used for forming an assist line AL (see FIG. 6 or the like) for extending a vertical crack at a dividing position on the one main surface SF1 side of the brittle material substrate W. In the present embodiment, assist line AL is a trench formed on main surface SF1 in such a manner as to intersect with trench line TL (see FIG. 3 and the like) formed at a dividing position on main surface SF1 side. This is a processing mark that becomes a starting point (trigger) when a vertical crack is extended just below the line TL. Further, the trench line TL is a fine line-shaped groove (concave portion) immediately below the trench crack TL. Details of the assist line AL and the trench line TL will be described later.

  The scribing apparatus 100 mainly includes a table 1 on which the brittle material substrate W is placed and a scribing head 2 that holds the scribing tool 50.

  The scribing apparatus 100 includes one or both of a table moving mechanism and a scribing head moving mechanism (not shown). With these mechanisms, in the scribing apparatus 100, the scribing head 2 holds the scribing tool 50. The table 1 can move relative to the horizontal plane. Hereinafter, for the sake of simplicity, it is assumed that the scribe head 2 moves relative to the table 1 in the scribe direction DP shown in FIG.

  The scribe tool 50 is a tool for scribing the brittle material substrate W. The scribe tool 50 includes a scribing wheel (cutter wheel) 51, a pin 52, and a holder 53.

  The scribing wheel 51 has a disc shape (an abacus bead shape), and includes a cutting edge PF that is uniformly triangular along the outer periphery (consisting of a ridge line and a pair of inclined surfaces sandwiching the ridge line). . The scribing wheel 51 typically has a diameter of about several mm. The pin 52 is inserted perpendicularly to the position of the axis center AX of the scribing wheel 51. The holder 53 is held by the scribe head 2 and supports a pin 52 inserted through the scribing wheel 51 in such a manner that the scribing wheel 51 can rotate around the axial center AX. That is, the holder 53 pivotally supports the scribing wheel 51 integrated with the pin 52 so as to be rotatable around the axis center AX. More specifically, the holder 53 supports the pin 52 horizontally such that the surface formed by the cutting edge PF (outer peripheral portion) of the scribing wheel 51 extends in the vertical direction.

  The cutting edge PF is formed using a hard material such as cemented carbide, sintered diamond, polycrystalline diamond, or single crystal diamond, for example. From the viewpoint of reducing the surface roughness of the ridgeline and the inclined surface, the entire scribing wheel 51 may be made of single crystal diamond.

  In the scribing apparatus 100 having the above-described configuration, one main surface (hereinafter also referred to as an upper surface) of the brittle material substrate W that is horizontally mounted and fixed on the table 1 with the other main surface SF2 as a mounting surface. The scribing head 2 that holds the scribing tool 50 is moved in the scribing direction DP while the scribing wheel 51 is in pressure contact with SF1. Then, the scribing wheel 51 in pressure contact with the brittle material substrate W is rolled around the axis center AX in the direction indicated by the arrow RT with the cutting edge PF slightly entering the brittle material substrate W. Thereby, on the upper surface SF <b> 1 of the brittle material substrate W, plastic deformation along the moving direction of the scribing wheel 51 occurs with the press-contact rolling of the scribing wheel 51. In the present embodiment, the pressure rolling operation of the scribing wheel 51 that causes the plastic deformation is referred to as a scribing operation by the scribing wheel 51. The load applied to the brittle material substrate by the scribing wheel 51 when the scribing wheel 51 is pressed against the upper surface SF1 can be adjusted by a load adjusting mechanism (not shown) provided in the scribe head 2.

  FIG. 2 is a view showing the posture (inclination) of the scribing wheel 51 in the scribing apparatus 100. In the present embodiment, the scribing direction DP is a reference direction, and the scribing wheel 51 is inclined clockwise by an angle θ in the horizontal plane with respect to the scribing direction DP in a state of being held by the scribing head 2. Is defined as the inclination angle of the scribing wheel 51. The inclination angle θ is also an angle formed between the extending direction D1 of the orthogonal axis between the vertical plane formed by the cutting edge PF (ridge line) of the scribing wheel 51 and the horizontal plane and the scribe direction DP.

  In the present embodiment, as described above, the assist line AL is formed when the one brittle material substrate W is divided. The inclination angle θ at the time of forming the assist line AL is intentionally larger than 0 °. And That is, the assist line AL is formed while the scribing wheel 51 is intentionally tilted from the scribe direction DP in the horizontal plane. In addition, by determining the inclination angle θ in such a manner, the assist line AL is formed to have a specific property, and details thereof will be described later.

  Specifically, the scribing device 100 in which the inclination angle θ is set in the range of 1.0 ° to 5.0 ° is used for forming the assist line AL. Preferably, the inclination angle θ is set in the range of 2.5 ° to 5.0 °.

  The inclination of the scribing wheel 51 may be realized by inclining the scribe head 2, or may be realized by changing the attachment angle of the scribe tool 50 to the scribe head 2. It may be a mode realized in other modes.

<Vertical crack formation procedure>
Next, a procedure for forming a vertical crack at the dividing position using the assist line AL performed in the present embodiment will be described. FIG. 3 to FIG. 9 are diagrams showing stepwise how the vertical crack is formed. Hereinafter, the case where a plurality of cutting positions (cutting lines) parallel to a pair of opposite sides are set in advance with respect to the rectangular brittle material substrate W will be described as an example. Also, in each figure, the right-handed xyz coordinates in which the formation progress direction of the assist line AL is the x-axis positive direction, the formation progress direction of the trench line TL is the y-axis positive direction, and the upper vertical direction is the z-axis positive direction. It is attached.

  First, the trench line TL is formed. FIG. 3 is a top view (xy plan view) of the brittle material substrate W illustrating the state after the formation of the trench line TL. FIG. 4 is a diagram schematically showing a configuration of the scribe tool 150 used for forming the trench line TL. FIG. 5 is a zx partial cross-sectional view including a vertical cross section of the trench line TL. The formation position of the trench line TL shown in FIG. 3 corresponds to a dividing position when the brittle material substrate W is viewed in plan view from the upper surface SF1 side.

  In the present embodiment, a scribe tool 150 having a diamond point 151 is used for forming the trench line TL. The diamond point 151 has a truncated pyramid shape, for example, as shown in FIG. 4, and is provided with a top surface SD1 (first surface) and a plurality of surfaces surrounding the top surface SD1. More specifically, as shown in FIG. 4B, these plurality of surfaces include a side surface SD2 (second surface) and a side surface SD3 (third surface). The top surface SD1 and the side surfaces SD2 and SD3 face different directions and are adjacent to each other. At the diamond point 151, the cutting edge PS is formed by the ridgeline PS formed by the side surfaces SD2 and SD3 and the vertex PP formed by the three surfaces of the top surface SD1, the side surfaces SD2 and SD3. As shown in FIG. 4A, the diamond point 151 is held on the one end side of the shank 152 having a rod shape (columnar shape) in such a manner that the top surface SD1 is the lowest end portion.

  When the scribe tool 150 is used, as shown in FIG. 4A, the axial direction AX2 of the shank 152 is inclined by a predetermined angle from the vertical direction toward the front of the moving direction DA (positive direction of the y-axis). In this state, that is, with the top surface SD1 facing backward in the movement direction DA (y-axis negative direction), the diamond point 151 is brought into contact with the upper surface SF1 of the brittle material substrate W. Then, the cutting edge PF2 of the diamond point 151 is slid by moving the scribe tool 150 forward in the moving direction DA while maintaining such a contact state. As a result, plastic deformation along the moving direction DA of the diamond point 151 occurs. In the present embodiment, the sliding operation of the diamond point 151 that causes such plastic deformation is also referred to as a scribe operation by the diamond point 151.

  As shown in FIGS. 3 and 5, the trench line TL is a fine line-shaped groove formed on the upper surface SF1 of the brittle material substrate W so as to extend in the y-axis direction. The trench line TL is formed as a result of plastic deformation occurring in the upper surface SF1 of the brittle material substrate W by sliding the diamond point 151 in a state where the posture of the scribe tool 150 is symmetric with respect to the moving direction DA. . In such a case, as schematically shown in FIG. 5, the trench line TL is generally formed as a groove having a line-symmetric shape in a cross section perpendicular to the extending direction.

  As shown in FIG. 3, the trench line TL is formed from the start point T1 to the end point T2 in the positive y-axis direction indicated by the arrow AR1 at the dividing position defined on the upper surface SF1 of the brittle material substrate W. Hereinafter, a range relatively close to the start point T1 in the trench line TL is also referred to as an upstream side, and a range relatively close to the end point T2 is also referred to as a downstream side.

  In FIG. 3, the start point T1 and the end point T2 of the trench line TL are positioned slightly separated from the end of the brittle material substrate W, but this is not an essential aspect, and the brittleness to be divided Either one or both of them may be the end position of the brittle material substrate W depending on the type of the material substrate W, the use of the separated pieces, or the like. However, the mode in which the start point T1 is the end of the brittle material substrate W is formed on the cutting edge PF2 of the scribe tool 150 as compared to the case where the start point T1 is a position slightly separated from the end as illustrated in FIG. Since the applied impact is increased, attention should be paid from the viewpoint of the life of the blade edge PF2 and the occurrence of unexpected vertical cracks.

  In addition, the formation of the trench line TL at each of the plurality of dividing positions may be an embodiment in which the trench line TL is sequentially formed by using the scribe tool 150 in a processing apparatus (not shown) provided with one scribe tool 150. It may be formed in parallel using a processing apparatus for forming the line TL.

  When the trench line TL is formed, the load applied by the scribe tool 150 (corresponding to a force for pushing the scribe tool 150 from the vertically upward to the upper surface SF1 of the brittle material substrate W) is surely formed. However, it is set so that the extension of the vertical crack from the trench line TL does not occur in the thickness direction DT of the brittle material substrate W (FIG. 5).

  In other words, the formation of the trench line TL is performed so that the brittle material substrate W is continuously connected in the direction intersecting the trench line TL (a crackless state) immediately below the trench line TL. When the trench line TL is formed in such a manner, internal stress remains as a result of plastic deformation in the vicinity of the trench line TL of the brittle material substrate W (in a range within about 5 μm to 10 μm from the trench line TL). To do.

  For example, the trench line TL is formed by setting the load applied by the scribe tool 150 to a smaller value than when forming the scribe line accompanied by the extension of the vertical crack using the same scribe tool 150. Realized.

  In the crackless state, even if the trench line TL is formed, the vertical crack does not extend from the trench line TL. Therefore, even if a bending moment acts on the brittle material substrate W, the vertical crack is formed. As compared with the case where it is formed, the division along the trench line TL is less likely to occur.

  Following the formation of the trench line TL, a scribing apparatus including a scribing tool 50 having an inclination angle θ set in a range of 1.0 ° to 5.0 ° (preferably in a range of 2.5 ° to 5.0 °). By 100, an assist line AL is formed. FIG. 6 is a top view of the brittle material substrate W illustrating the state when the assist line AL is formed. 7 and 8 are top views of the brittle material substrate W illustrating the extension of the vertical crack VC accompanying the formation of the assist line AL. FIG. 9 is a zx partial cross-sectional view including a vertical cross section of the trench line TL and the vertical crack VC.

  In the present embodiment, as shown in FIG. 6, the assist line AL has a start point A1 in the positive x-axis direction indicated by an arrow AR2 (so as to be orthogonal to the trench line TL) in the vicinity of the downstream side of the trench line TL. To the end point A2 are processing marks formed by causing plastic deformation on the upper surface SF1 of the brittle material substrate W.

  More specifically, the assist line AL is formed in such a manner that the formation progress direction of the assist line AL indicated by the arrow AR2 is made coincident with the scribe direction DP (x-axis positive direction). Therefore, the assist line AL is formed in a state where the front in the traveling direction of the scribing wheel 51 is inclined to the y-axis negative direction side, which is upstream from the position where the assist line AL is formed.

  In such a case, the scribing wheel 51 rolls in the scribing direction DP while the scribing wheel 51 is in pressure contact with the upper surface SF1 of the brittle material substrate W. However, since the inclination angle θ is not 0 °, the force received by each of the pair of inclined surfaces forming the cutting edge PF is different. Specifically, the scribing wheel 51 moves in the scribe direction DP while the slope facing the positive y-axis receives greater resistance from the brittle material substrate W than the slope facing the negative y-axis. Be made. Therefore, the assist line AL is formed as a wider processing mark as the inclination angle θ is larger (see FIG. 12), and the cross-sectional shape thereof becomes asymmetric. Note that the assist line AL is not formed for the purpose of extending the vertical crack immediately below the trench line TL as in the case of forming the trench line TL. The applied load can also be set to a smaller value as compared to the case where the same scribing wheel 51 is used to form a scribe line with vertical crack extension.

  When the assist line AL is formed in the above-described manner under a condition in which the load applied by the scribing wheel 51 is equal to or greater than a predetermined threshold value, the assist line AL crosses the trench line TL. As indicated by an arrow AR3 in FIG. 7, sequentially from the position of the intersection C with each trench line TL toward the expected extension direction of the vertical crack VC (upstream of the trench line TL in the case of FIG. 7). As shown in FIG. 9, the extension of the vertical crack VC from the trench line TL to the thickness direction DT of the brittle material substrate W occurs.

  Eventually, as shown in FIG. 8, the extension of the vertical crack VC from the trench line TL occurs at all the dividing positions. That is, triggered by the formation of the assist line AL (triggered by the assist line AL), until the trench line TL has been formed, the crack-less state of each of the brittle material substrates W has been divided. A vertical crack VC extending from the trench line TL is formed.

  This is because when the scribe tool 150 including the diamond point 151 is used to form the trench line TL, the vertical crack VC generated immediately below the trench line TL has a property of extending to the side on the top surface SD1 side. It is. That is, the vertical crack VC generated in the vicinity of the assist line AL has a property of extending in a specific direction. In the present embodiment in which the trench line TL is formed in such a manner that the top surface SD1 of the diamond point is arranged on the upstream side of the trench line TL, after the assist rain AL is formed, it is vertical on the upstream side of the trench line TL. Although the crack VC extends, it is difficult to extend in the reverse direction.

  In this manner, the brittle material substrate W on which the vertical crack VC is formed at the dividing position is given to a predetermined break device (not shown). In the break device, a break process for extending the vertical crack VC to the lower surface SF2 of the brittle material substrate W is performed by applying a bending moment to the brittle material substrate W by a so-called three-point bending or four-point bending method. . By passing through the break process, the brittle material substrate W is divided at the dividing position.

  In the case of the above procedure, since the formation of the trench line TL at the dividing position is not accompanied by the extension of the vertical crack VC, the vertical crack is formed at the same time as the scribe line is formed. There is an advantage that the load applied to the scribe tool 50 can be reduced as compared with the case where it is performed. Such an advantage contributes to extending the life of the scribe tool 50 used for cutting at the cutting position.

<Details of vertical crack extension>
FIG. 10 is a schematic diagram showing a state in the vicinity of the assist line AL when the vertical crack VC is formed by forming the assist line AL following the formation of the trench line TL. FIG. 11 shows an example of imaging of the brittle material substrate W formed with the assist line AL.

  As shown in FIG. 10A, when the assist line AL is formed in the positive x-axis direction (in the direction perpendicular to the y-axis), which is the scribe direction DP, the entire position of the assist line AL is formed inside the brittle material substrate W. Assist cracks AC, which are innumerable cracks starting from the assist line AL, are located in a lateral region on the negative side in the y-axis direction relative to the assist line AL (in FIG. 10, the lower side in the drawing than the assist line AL). Randomly occur. This can be confirmed, for example, from FIG. 11B in which the cross section of the brittle material substrate W is observed. In FIG. 11A in which the upper surface SF1 is observed, the assist line AL is confirmed, and in the region RE below the assist line AL surrounded by the closed curve, a line shape is formed inside the brittle material substrate W. Assist cracks AC that are continuous are slightly transmitted.

  More specifically, the assist crack AC generally occurs in a form extending from the arbitrary position of the assist line AL in the direction of (+ x, -y, -z). Schematically, when the upper surface SF1 is viewed in plan, it is unevenly distributed in a range of about several tens of μm from the assist line AL in the negative y-axis direction from the assist line AL. However, although illustration is omitted in FIG. 10, since the formation of the assist crack AC is a phenomenon that occurs stochastically, the assist crack AC also occurs in other ranges although the ratio is small.

  Since the assist crack AC is unevenly distributed over the entire assist line AL, the assist crack AC is generated with high probability even in the vicinity of a portion where the assist line AL intersects the trench line TL. As described above, since internal stress remains in the vicinity of the trench line TL, when the assist line AL is formed so that the assist crack AC is formed on the planned extension direction side of the vertical crack VC, the assist crack is generated. When AC reaches the region where the residual internal stress is present, the residual internal stress is released in the vicinity of the trench line TL. As a result, as indicated by an arrow AR4 in FIG. 10B, the vertical crack from the trench line TL toward the expected extension direction of the vertical crack VC (upstream of the trench line TL in the present embodiment). VC stretching occurs. This is the details of the extension of the vertical crack VC by the method according to this embodiment described above.

  Moreover, in the method according to the present embodiment, scribing is intentionally inclined with the inclination angle θ set to 1.0 ° to 5.0 ° (preferably 2.5 ° to 5.0 °) as described above. By forming the assist line AL using the wheel 51, a large number of assist cracks AC are unevenly distributed on the side where the scribing wheel 51 is inclined forward in the traveling direction, and the side where the assist cracks AC are formed. The position where the assist line AL and the trench line TL are formed is set so that the dividing position extends. Thereby, the certainty of extension of the vertical crack VC from the trench line TL at the dividing position is enhanced. That is, the formation of the assist line AL using the intentionally inclined scribing wheel 51 employed in this embodiment limits the extension location of the vertical crack VC and increases the certainty of the extension. It has become. That is, when the brittle material substrate W is divided, the direction of the inclination of the scribing wheel 51, the formation position of the assist line AL, and the formation position of the trench line TL are determined according to the division position. The vertical crack VC can be reliably extended.

  In addition, when θ is smaller than 1.0 °, the uneven distribution of the assist crack AC does not occur, and the reliability of crack extension decreases, which is not preferable. Further, as the inclination angle θ increases, rolling of the scribing wheel 51 tends to become difficult when the assist line AL is formed.

  As described above, according to the present embodiment, when the brittle material substrate is divided at a predetermined dividing position, the vertical crack is not generated immediately below the forming position corresponding to the dividing position. Of the assist line in a mode in which the assist crack is unevenly distributed on the upstream side of the trench line, which is the planned extension direction of the vertical crack VC, using a scribing wheel intentionally inclined in a horizontal plane. By performing the formation, the vertical crack can be extended with high certainty at the dividing position. When the vertical crack is reliably formed, the brittle material substrate can be reliably cut at the cutting position in a break process as a subsequent process. In such a case, the load applied by the scribing wheel when forming the trench line and the assist line can be set to a value smaller than that in the case of performing a scribe operation accompanied by vertical crack extension.

<Example 1>
The trench line TL and the assist line AL were formed a plurality of times while changing the assist line AL formation conditions by the procedure shown in the above-described embodiment, and the occurrence of the vertical crack VC extension was evaluated. As the brittle material substrate W, a 0.2 mm thick glass substrate was used.

  Specifically, the assist line AL differs in the inclination angle θ from three levels of 0 °, 1.2 °, and 2.0 °, and loads applied to the scribing wheel 51 are 0.4N, 0.8N, and 1.1N. , 1.5N, 1.9N, 2.3N, and 2.6N, and formed under 21 conditions. The moving speed of the scribe head 2 was 100 mm / sec. As the scribing wheel 51, a wheel having a wheel diameter of 2.0 mm, a thickness of 0.65 mm, a diameter of the insertion hole of the pin 52 of 0.8 mm, and a blade edge angle of 100 ° was used. FIG. 12 is a partially enlarged image of the assist line AL formed at each inclination angle θ when the load applied to the scribing wheel 51 is 1N.

  In addition, the trench line TL was formed by fixing 100 loads applied to the scribe tool 150 and forming 100 lines for each formation condition of the assist line AL.

  FIG. 13 shows the load applied at the time of forming the assist line AL with the occurrence rate of vertical crack VC from all 100 trench lines TL (hereinafter referred to as VC establishment rate) for each of three inclination angles θ. Is a graph plotted against.

  As shown in FIG. 13, when the inclination angle θ is 0 °, only a VC establishment rate of about 60% (when the load is 1.5 N) can be obtained, whereas the inclination angle θ is 1. In the case of 2 °, a VC formation rate of 95% or more is obtained when the load applied to the scribing wheel 51 is 1.9 N or more, and the load applied to the scribing wheel 51 when the inclination angle θ is 2.0 °. By setting the value to 1.5N or more, a VC establishment rate of 100% was obtained.

  These results show that when the inclination angle θ is 1.2 °, the vertical crack VC can be almost surely extended from the trench line TL by applying a load of at least 1.9 N to the scribing wheel 51. Indicates that when the inclination angle θ is 2.0 °, the vertical crack VC can be reliably extended from the trench line TL by applying a load of at least 1.5 N to the scribing wheel 51.

  In addition, if the scribing operation is performed using the scribing wheel 51 under the same conditions and the vertical crack is extended along with the formation of the scribe line, it is necessary to apply a load of at least about 3 to 4N. The result of the example also shows that the assist line AL can be formed by applying a load smaller than the load applied by the scribing wheel 51 during the scribing operation accompanied by the extension of the vertical crack. Furthermore, since the trench line TL can be formed by applying a load that is equal to or smaller than that of the assist line AL, the method according to the above-described embodiment is directly applied to the vertical crack by the scribe operation. It can be said that it is a technique that enables the extension of vertical cracks by applying a low load compared to the technique of extending the crack.

<Example 2>
In order to investigate the relationship between the inclination direction of the scribing wheel 51 and the vertical crack VC, the VC establishment rate was evaluated for the case where the inclination angle θ was set to −1.2 °. Conditions other than the inclination angle θ were the same as those in Example 1. Note that the case where the inclination angle θ is negative is, for example, based on FIG. 2, the extending direction D1 of the orthogonal axis between the vertical plane and the horizontal plane formed by the cutting edge PF (outer peripheral portion) of the scribing wheel 51 is illustrated in FIG. This corresponds to the case where the scribing wheel 51 is inclined so as to face the opposite side to the scribing direction DP shown in FIG. 2, and will be described with reference to FIG. This corresponds to the case where the process is performed in a state inclined toward the positive side of the y-axis which is the downstream side.

  FIG. 14 plots the VC establishment rate against the load applied when forming the assist line AL for each of the case where the inclination angle θ is −1.2 ° and the case where the inclination angle θ is 1.2 ° shown in the first embodiment. It is a graph.

  As shown in FIG. 14, when the inclination angle θ is −1.2 °, the VC establishment rate increases as the load applied by the scribing wheel 51 increases. However, even at 2.6 N, it remains at about 70%. . This is more than the case where the inclination angle θ is 1.2 °, as shown in the first embodiment, that the VC establishment rate of 95% or more is obtained when the load applied by the scribing wheel 51 is at least 1.9N. Are also inferior results.

  The result is that the direction in which the scribing wheel 51 is tilted when the assist line AL is formed is set to the expected extension direction side of the vertical crack, so that the trench can be reliably applied while applying a smaller load than when tilting to the opposite side. It indicates that the vertical crack VC can be extended from the line TL.

<Modification>
In the above-described embodiment, the assist line AL is formed after the trench line TL is formed. However, the formation order of the trench line TL and the assist line AL may be reversed.

  In the above-described embodiment, the trench line TL and the assist line AL are orthogonal to each other on the upper surface SF1 of the brittle material substrate W, but this is not an essential aspect, and the trench line associated with the formation of the assist line AL. As long as the extension of the vertical crack from the TL is suitably realized, the trench line TL and the assist line AL may be obliquely intersected.

  In the above-described embodiment, the trench line TL is formed by the scribe tool 150 in a state where the axial direction AX2 of the shank 152 is inclined toward the front of the moving direction DA, that is, the top surface SD1 is moved in the moving direction DA. This is done by sliding the diamond point 151 in a posture facing backward, but instead, in a state where the axial direction AX2 of the shank 152 is inclined toward the rear of the moving direction DA, that is, Alternatively, the trench line TL may be formed by sliding the diamond point 151 in a posture in which the top surface SD1 faces the front in the moving direction DA.

  Alternatively, in the above-described embodiment, the diamond point 151 is used to form the trench line TL. Instead, the trench line TL is formed by pressing and rolling the scribing wheel 51 of the scribing device 100. It is also possible to use this mode. For example, the scribe device 100 for forming the trench line TL in which the inclination angle θ is fixedly set to 0 ° in advance and the inclination angle θ in the range of 1.0 ° to 5.0 ° (preferably 2.5). Realized by separately preparing the scribing device 100 for forming the assist line AL that is fixedly set (in the range of ° to 5.0 °) and forming the trench line TL and the assist line AL using each of them. Is done. Alternatively, it can be realized by providing one scribe device 100 with a scribe tool 50 for forming the trench line TL and a scribe tool 50 for forming the assist line AL. Alternatively, the scribe device 100 may be provided with an inclination angle variable means (not shown) and set to a predetermined inclination angle θ when the assist line AL is formed. However, when forming the trench line TL, the inclination angle θ is not limited to 0 °.

  However, in the case of the latter two aspects, unlike the above-described embodiment, the planned extension direction of the vertical crack is on the downstream side of the trench line TL. Therefore, in these aspects, the assist line AL is formed in the vicinity of the upstream side of the trench line TL in a state where the scribing wheel 51 is inclined so that the inclination angle θ is negative as in the second embodiment. To. More specifically, the assist line AL may be formed in a state where the front in the traveling direction of the scribing wheel 51 is inclined to the y-axis negative direction side downstream from the position where the assist line AL is formed.

  Also in this case, as in the above-described embodiment, the assist line AL is formed in a manner in which the assist crack AC is unevenly distributed on the downstream side of the trench line TL that is the expected extension direction of the vertical crack VC. In the planned extension direction, vertical crack extension from the trench line TL preferably occurs. As a result, the vertical crack VC can be extended with high certainty at the dividing position where the trench line TL is formed.

1 Table 2 Scribe head 50, 150 Scribe tool 51 Scribing wheel 52 Pin 53 Holder 100 Scribing device 151 Diamond point 152 Shank A1 Start point A2 (Assist line TL) End point AC Assist crack AL Assist line AX Axis center C (intersection of trench line TL and assist line AL) DP scribing direction PF (cutting wheel 51) cutting edge SF1 (brittle material substrate W) one main surface (upper surface)
SF2 (of brittle material substrate W) other main surface (lower surface)
T1 Start point (of the trench line TL) T2 End point (of the trench line TL) TL Trench line VC Vertical crack W Brittle material substrate

Claims (7)

A method of forming a vertical crack at a dividing position when dividing a brittle material substrate in the thickness direction,
A trench line forming step of forming a trench line which is a line-shaped groove on one main surface of the brittle material substrate;
An assist line forming step of forming an assist line which is a processing mark intersecting with the trench line by pressing and rolling a scribing wheel having a blade edge uniformly on the outer peripheral portion;
With
In the trench line forming step, the trench line is formed so that a crackless state is maintained immediately below the trench line,
In the assist line forming step, the assist line is formed in a state where the scribing wheel is inclined at a predetermined inclination angle from a direction in which the assist line is formed in a horizontal plane,
Extending a vertical crack from the trench line in the thickness direction of the brittle material substrate starting from the intersection of the trench line and the assist line ,
In the assist line forming step, along with the formation of the assist line, an uneven distribution of assist cracks from the assist line toward the inside of the brittle material substrate occurs in one side region of the assist line,
Wherein shall be determined and localized region of the assist cracks plan extension direction of the vertical cracks on the trench line so as to the trench line and a formation position of the assist line,
A method of forming vertical cracks in a brittle material substrate, characterized in that A method for forming vertical cracks in a brittle material substrate according to claim 1 ,
Forming the assist line so as to intersect the trench line in the vicinity of the opposite side of the planned extension direction of the vertical crack on the trench line;
A method of forming vertical cracks in a brittle material substrate, characterized in that A method for forming a vertical crack in a brittle material substrate according to claim 1 or 2 ,
In the assist line forming step, the front side in the traveling direction of the scribing wheel is tilted from the direction in which the assist line is formed in the horizontal plane toward the planned extension direction side of the vertical crack on the trench line,
A method of forming vertical cracks in a brittle material substrate, characterized in that A method for forming a vertical crack in a brittle material substrate according to any one of claims 1 to 3 ,
The inclination angle is 1.0 ° or more and 5.0 ° or less.
A method of forming vertical cracks in a brittle material substrate, characterized in that A method for forming vertical cracks in a brittle material substrate according to claim 4 ,
The inclination angle is 2.5 ° to 5.0 °,
A method of forming vertical cracks in a brittle material substrate, characterized in that A method for forming a vertical crack in a brittle material substrate according to any one of claims 1 to 5 ,
Forming the assist line after forming the trench line;
A method of forming vertical cracks in a brittle material substrate, characterized in that A method of dividing a brittle material substrate in the thickness direction,
A vertical crack forming step of forming a vertical crack in the brittle material substrate by the method of forming a vertical crack according to any one of claims 1 to 6 ,
A breaking step of breaking the brittle material substrate along the vertical crack;
A method for dividing a brittle material substrate, comprising: