HK1153430B - Scribing wheel and method for scribing brittle material substrate - Google Patents

Description

Scribing wheel and scribing method for brittle material substrate

Technical Field

The present invention relates to a scribing wheel suitable for forming a scribe line on a surface of a brittle material substrate and a scribing method for forming a scribe line on a surface of a brittle material substrate, and more particularly, to a scribing wheel suitable for forming a scribe line on a surface of a brittle material (hard brittle material) such as sapphire, silicon, or the like, which is harder than glass, such as a ceramic substrate (multilayer substrate (HTCC) made of high-temperature fired ceramic, a multilayer substrate (LTCC) made of low-temperature fired ceramic, or the like, and a substrate with built-in electronic components).

Background

In recent years, LTCC substrates have been drawing attention as a means for realizing higher density and smaller size of modules, and are considered to be particularly preferable for high-frequency modules of communication devices. The productivity in the cutting process is required to be improved and the cutting cost is required to be reduced in the manufacturing process.

In a method of cutting a ceramic substrate such as an LTCC substrate, V grooves are formed along lines to be cut of green sheets before firing, and after firing, the green sheets are broken along the V grooves to be cut into individual pieces.

For example, in the case of an LTCC substrate, each side of the green sheet shrinks by 10% or more based on the length thereof during firing. Further, the shrinkage rate varies depending on the portion of the green sheet. Since the cutting position is determined by forming the V-groove before firing, if there is an error depending on the position and the shrinkage ratio, there is also an error in the size of the piece obtained by cutting after firing, and as a result, the yield is lowered. Further, since the substrate is fired after the V-groove is formed, the substrate is likely to be bent during firing in terms of shape, and the quality of the cut surface is reduced. Further, when the green sheet before firing after forming the V-groove or the substrate before breaking after firing is conveyed, there is a risk that a crack outside a predetermined range is generated along the V-groove and a hindrance is generated at the time of conveyance. Further, from the point of suppressing the warpage during firing, there is a method of forming V grooves from both the upper surface and the lower surface of the green sheet, but the alignment is difficult.

A method of cutting a ceramic substrate such as an LTCC substrate is also widely used for cutting a semiconductor wafer by dicing.

However, there are the following problems in slicing. (1) Since the processing speed is generally 5 to 10mm/s, the time required is very long and the productivity is very low. (2) Since the thickness of the dicing saw is a quantity of chips, loss of material (kerf loss) cannot be avoided. (3) The cut surface is easily chipped. (4) Since cooling and washing water are required, it is not only applicable to environmentally friendly mql (minimum quantity illumination) but also to a substrate after mounting. (5) A step of adhering and peeling off the dicing tape is required. (6) The quality of the cut surface is greatly affected by diamond particles. (7) The service life of the knife is short, and the operation cost is high. In particular, since the problem of the processing speed imposes a large equipment investment when the throughput is increased, the processing speed is increased and the demand for development of a cutting method which is less expensive than slicing is continuously increased.

Cutting by laser scribing is also considered, but there are problems of (1) leaving a slit-like irradiation mark on a cut surface due to pulse irradiation, which causes a problem in quality, (2) generation of waste (off gas) by hot working, (3) reduction of dielectric characteristics by hot working, and (4) high apparatus cost.

Here, as a method for cutting a glass substrate, there has been widely used a method for cutting a ceramic substrate, in which a scribe wheel is pressed against a substrate and rotated to form a scribe line on the surface of a brittle material substrate, thereby generating a vertical crack from the surface of the substrate (scribing step), and then a stress is applied to the substrate to grow the vertical crack to the back surface of the substrate (breaking step). Cutting points that do not generate glass chips is considered to be more preferable than grinding and cutting using a diamond dicing saw (or wheel) or a diamond dicing saw that generates glass chips.

However, since a ceramic substrate is generally harder than a glass substrate, even when the ceramic substrate is cut by cutting, there are problems that (1) it is difficult to press in the scribing wheel and to form a scribe line, (2) it is difficult to stretch a crack generated by the scribe line in the thickness direction of the substrate and to form a deep vertical crack, and therefore it is difficult to break the crack, (3) it is difficult to form the scribe line at a specific position because the straightness of the wheel is lowered by a perforation of the ceramic substrate, and an error occurs in the press-in amount of the scribing wheel, and the life of the scribing wheel is shortened.

Although the cutting has been used for a long time as a cutting method of sapphire, silicon, or the like, the cutting of sapphire, silicon, or the like has been continuously dependent on the cutting by a dicing saw (or wheel) or a dicing saw using diamond-containing fine powder due to poor productivity.

In cutting the glass substrate, it is also important to prevent horizontal cracks or chips from being generated by scribing. In cutting a glass substrate, anyone can easily break the glass substrate by extending a vertical crack deeply in the thickness direction of the glass substrate, but for example, alkali-free glass for liquid crystal displays, the depth of a vertical crack which can be generated without a horizontal crack or a notch by a scribe line is only about 13% of the thickness of the glass substrate, and a breaking step is indispensable (non-patent document 1). Further, there is an idea of cutting the ceramic substrate for electronic parts by dicing, but when dicing is performed using a conventional general scribing wheel, the vertical crack generated by scribing is spread very shallowly, and thus, a plurality of (Multi-pass) scribing lines are necessary for dicing with good yield.

The present applicant has made various proposals to date for a scribing wheel used for scribing a glass substrate. For example, as shown in fig. 8, there has been proposed a scribing wheel 1' in which a plurality of grooves 13 are formed at specific intervals on a blade front edge (peripheral ridge) 12 which is a ridge line of a blade (outer peripheral portion) 11 formed on a peripheral portion of a disk-shaped wheel (for example, patent document 1). That is, as the mother glass substrate of a flat panel display (hereinafter referred to as FPD) such as a liquid crystal panel becomes larger, a problem of yield in a breaking step and difficulty in reversing a large bonded mother glass substrate for breaking are required to develop a processing method that does not break. Accordingly, the present applicant has developed a "no break scribing wheel" that updates the concept of the breaking of the substrate. Patent document 1 discloses: in a scribing wheel for glass, grooves are formed in ridge lines (circumferential ridges) at a predetermined depth, and vertical cracks are extended to a depth exceeding a conventional limit to facilitate a breaking step, or even extended to 80% or more of the thickness of a substrate to make the breaking step unnecessary (high-penetration type).

Further, there have been proposed a scribing wheel for dividing a bonded glass substrate into individual scribing wheels in a batch, a scribing wheel for preventing a slide of a scribing line performed in a process of manufacturing a mother glass substrate in increasing the glass hardness for an FPD (patent document 2), a scribing wheel for extending a so-called vertical crack obliquely to a glass surface in a special-shaped cutting so as to easily pass a circular object (patent document 3), and the like.

With the high-penetration scribing wheel described in patent document 1, not only a glass substrate but also a brittle material harder than glass (a hard and brittle material such as ceramic) can be easily pressed in, and a vertical crack can be deeply stretched in the thickness direction of the substrate. However, even if a highly permeable scribing wheel used for a glass substrate is used directly for cutting a hard and brittle material, the cutting edge 12 is worn away in a short time and is not practical. Further, although the scribing wheel described in patent document 2 can prevent a certain degree of slip, it is not possible to deeply stretch the vertical crack in the thickness direction of the substrate. The scribing wheel described in patent document 3 is hardly sufficient even at the point of extension or life of a vertical crack.

[ non-patent document 1 ] Dr's paper of 12 years, Youngang university of technical science: small handstand type hand-drawing and breaking method for liquid crystal glass "

[ patent document 1 ] Japanese patent laid-open No. 9-188534

WO 2007/004700

[ patent document 3 ] Japanese patent laid-open No. 2000-219527

Disclosure of Invention

The commercial life of the score wheel is determined primarily by the degree of wear of the ridge, i.e. the leading edge of the blade. Since the blade front edge is worn and rounded, a vertical crack is not sufficiently generated during scribing, and thus improvement of wear resistance of the scribing wheel is strongly required.

Further, in the past, hard ceramic substrates among brittle material substrates have been cut by wet grinding with a dicing saw or the like, but since treatment with chips or cutting liquid inevitably occurs, it has been examined whether the above-mentioned cutting method using a scribing wheel which can be performed dry without such additional treatment is feasible. However, when a hard brittle material (hard brittle material) such as a ceramic substrate is scribed by using a conventional scribing wheel, the wear of the edge becomes severe, and the commercial life of the scribing wheel becomes very short. Further, there is a problem that the vertical crack is not sufficiently deep.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a scribing wheel which has a long service life with less wear of a blade front edge, can generate a deep vertical crack if necessary, and generates a vertical crack of a specific depth with less wear of the blade front edge even when a hard material (hard-to-scribe material) which makes scribing difficult such as a ceramic substrate is used.

The present inventors have conducted extensive studies to achieve the above object, developed a sintered diamond suitable for this purpose, and found that the above object can be achieved by making the outer diameter of a scribing wheel smaller, making the depth of a groove formed in the edge of a blade deeper than a conventional product for glass, and making the length of a ridge line between grooves to be equal to or more than a specific length, thereby completing the present invention. With this configuration, the life of the scribing wheel can be prolonged even when a hard material difficult to scribe such as a ceramic substrate is scribed. That is, the outer diameter of the scribing wheel is made small, the contact area between the ceramic substrate and the scribing wheel is made small, large stress is generated, vertical cracks can be deeply generated by deepening the groove, and the length of the ridge line between the grooves is lengthened, thereby prolonging the service life. Further, the scribing wheel for generating the vertical crack deeper can reduce the load applied to the scribing wheel when the vertical crack having the same depth as that of the conventional scribing wheel is generated, and thus the life of the scribing wheel can be prolonged. The vertical crack is 60% or more of the thickness of the hard and brittle material such as a ceramic substrate, and can be broken with high yield (for example, by hand folding).

The scribing wheel of the invention is provided with a blade (outer peripheral part) with a V-shaped section on the circumference part of a disc-shaped wheel, and a plurality of grooves are formed on the front edge (peripheral ridge) of the blade which is the ridge line of the blade at specific intervals, and is characterized in that: the outer diameter of the wheel is in the range of 1mm to 5mm (preferably 1mm to 3mm), the angle of the tip (edge angle) of the blade having a substantially V-shaped cross section is 90 to 160 degrees (preferably 100 to 140 degrees), the depth of the groove is 25 μm or more, and the length of the ridge line between the grooves is 25 μm or more.

Here, the pitch of the plurality of grooves is preferably in the range of 50 μm to 200 μm.

From the viewpoint of further lengthening the life of the scribing wheel, it is preferable that the ratio of the width of the groove to the length of the ridge line between the grooves is 1.0 or more.

The scribing wheel of the present invention is preferably made of a diamond sintered body (particularly, a diamond sintered body in which the average particle diameter of diamond particles constituting the diamond wheel is 0.5 μm or less and the diamond content is 85 vol% or more).

In addition, a scribing method of the present invention is a scribing method for forming a scribe line on a surface of a brittle material substrate by pressing and rotating a scribing wheel, which has a blade having a substantially V-shaped cross section formed in a circumferential portion of a disk-shaped wheel and a plurality of grooves formed at predetermined intervals on a blade front edge which is a ridge line of the blade, against the brittle material substrate, the scribing wheel including: the scribing wheel is made of a scribing wheel having an outer diameter of 1mm to 5mm (preferably 1mm to 3mm), an angle of a tip end (a blade leading edge angle) of the blade having a substantially V-shaped cross section of 90 to 160 degrees (preferably 100 to 140 degrees), a depth of the groove of 25 μm or more, and a length of a ridge line between the grooves of 25 μm or more.

The scribing method of the present invention is particularly suitable for scribing brittle materials harder than glass (materials hard and brittle materials hard and difficult to scribe, such as ceramic substrates, sapphire, silicon, and the like).

In the method for cutting a ceramic substrate according to the present invention, the scribing wheel is pressed against and rotated on the ceramic substrate to form a scribe line on the surface of the ceramic substrate, and a continuous crack (vertical crack) extending to 60% or more in the thickness direction of the ceramic substrate is formed in a single pass and then broken along the scribe line.

The invention provides the use of the scribing wheel for scribing the ceramic substrate.

The scribing wheel of the present invention has the outer diameter of the wheel, the depth of the grooves, and the length of the ridge line between the grooves in a specific range, so that the wheel has a long service life with less wear of the front edge of the blade, can produce deeper vertical cracks as needed, has less wear of the front edge of the scribing blade even when a hard substrate (hard and brittle material) such as a ceramic substrate is scribed, and can produce vertical cracks of a specific depth over a long period of time (long travel distance).

In the scribing method of the present invention, since the scribing wheel is used, the load applied to the scribing wheel can be reduced more than before when the vertical crack having the same depth as before is generated, and the life of the scribing wheel can be prolonged. Further, it is also necessary to generate a deep vertical crack and to cut the substrate only by scribing. Even a hard and brittle material substrate (hard and brittle material) such as a ceramic substrate can be cut by scribing and breaking (cutting).

According to the present invention, since the hard and brittle materials such as ceramic substrates can be cut by dry cutting at a speed close to 10 times that of the cutting by a dicing saw, for example, by cutting the hard and brittle materials using a scribing wheel, it is possible to provide a method for cutting hard and brittle materials such as ceramic substrates, which can improve productivity and yield of cutting the hard and brittle materials such as ceramic substrates, reduce production costs, and is environmentally friendly.

According to the present invention, since the protrusion having a specific height is formed at a specific pitch by forming the groove having a specific depth at the peripheral ridge of the scribing wheel at a specific pitch, when the hard and brittle material such as the ceramic substrate is brought into contact with the groove, a continuous vertical crack extending to 60% or more of the thickness direction of the brittle material substrate (even if the hard and brittle material such as the ceramic substrate) can be formed by a large concentrated stress generated by the protrusion, and thus the brittle material substrate (even if the hard and brittle material such as the ceramic substrate) can be cut by a single pass (One-pass) with high efficiency, high yield, and environmental friendliness.

Drawings

Fig. 1 is a front view showing an example of the scribing wheel of the present invention.

Fig. 2 is a side view of the scoring wheel of fig. 1.

Fig. 3 is an enlarged view showing another example of the groove shape.

Fig. 4 is a graph showing the effect of ridge length L and groove depth D on the travel distance of the scribing wheel.

Fig. 5 is a schematic view showing an example of a holder using the scribing wheel of the present invention.

Fig. 6 is a front view of a scribing apparatus for carrying out the scribing method of the present invention.

Fig. 7 is a side view of the scoring device of fig. 6.

Fig. 8 is a schematic view showing a conventional scribing wheel.

1: a scribing wheel 2: holding tool

3: the scribing device 4: substrate (brittle material substrate)

5: marking head 11: blade (outer peripheral part)

12: edge leading edge (circumferential ridge) 13: trough

14: ridge line D: depth of groove

W: width L of groove: length of ridge between grooves

P: pitch of grooves

Detailed Description

The scribing wheel of the present invention will be described in more detail below, but the present invention is not limited to these embodiments.

Fig. 1 and 2 show a scribing wheel according to an embodiment of the present invention. Fig. 1 is a front view as seen from the direction of the rotation axis of the scribing wheel, and fig. 2 is a side view. As shown in fig. 2, a blade 11 having a substantially V-shaped cross section is formed on the circumferential portion of the disk-shaped wheel.

The blade leading edge angle θ of the blade 11 is generally an obtuse angle, and the specific angle is appropriately set according to the material and thickness of the substrate to be cut, but is generally in the range of 90 to 160 degrees (e.g., 100 to 140 degrees). As shown in fig. 1, a plurality of V-shaped grooves 13 are formed at specific intervals on the edge line of the blade 11, i.e., the blade front edge 12. The plurality of grooves 13 formed in the edge margin 12 are intentionally formed on a micrometer scale, and are different from grinding scratches that are inevitably formed in grinding for forming the ridge line of the edge margin.

The outer diameter of the scribing wheel 1 of the invention is required to be 1 mm-5 mm. If the outer diameter of the wheel is less than 1mm, workability and durability may be deteriorated, and if the outer diameter is more than 5mm, a vertical crack may not be formed deep into the substrate at the time of scribing. More preferably, the outer diameter of the wheel is in the range of 1mm to 3 mm. The thickness of the scribing wheel is preferably 0.5mm to 1.2 mm. If the thickness of the scribing wheel is thinner than 0.5mm, the workability and durability may be deteriorated, whereas if it is thicker than 1.2mm, the material and manufacturing cost of only the scribing wheel may be increased. More preferably, the thickness is in the range of 0.5mm to 1.1 mm.

The depth D (shown in fig. 1) of the groove 13 formed in the edge front edge 12 of the scribing wheel 1 is important to be 25 μm or more. The depth D of the groove 13 is set to 25 μm or more, so that the vertical crack formed on the substrate by scribing can be sufficiently deep for a long period of time (long scribing distance). More preferably, the depth D of the groove is 30 μm or more. The depth D of the groove 13 is generally 60 μm or less from the viewpoint of workability.

The groove 13 of the scribing wheel in fig. 1 is triangular, but the shape of the groove 13 is not limited thereto, and may be trapezoidal (fig. a), U-shaped, semicircular (fig. b), rectangular (fig. c), or the like as shown in fig. 3. In the present invention, the depth D of the groove refers to the distance from the ridge 14 to the deepest portion of the groove 13.

It is also important that the length L (shown in fig. 1) of the ridge line 14 between the grooves is 25 μm or more. If the length L of the ridge line 14 is less than 25 μm, the life of the scribing wheel is shortened even if the depth D of the groove 13 is set to 25 μm or more. The length L of the ridge between the grooves is preferably 30 μm at the lower limit and 75 μm at the upper limit.

Fig. 4 shows experimental data for examining the relationship between the depth D of the groove 13 and the length L of the ridge line 14 between grooves. This figure shows the relationship between the length L of the ridge line 14 between grooves of each scribing wheel and the travel distance, taking the travel distance as the vertical axis and the length L of the ridge line between grooves as the horizontal axis, and varying the groove depth D. The "travel distance" herein indicates a scribing distance of the scribing wheel until the vertical crack becomes 60% or less of the thickness of the substrate. Therefore, a longer travel distance indicates more excellent scribing wheel. The test conditions were as follows.

Evaluation substrate: HTCC substrate (thickness: 0.635mm, commercially available)

Scribing speed: 100mm/sec

The cut setting amount: 0.15mm

The cutting method comprises the following steps: inside-inside cutting (cutting by scribing from the inside of one edge of the substrate to the inside of the other edge)

Cutting direction: unidirectional scribing

The shape of the scribing wheel is as follows: 2.0mm in diameter, 0.65mm in thickness, 0.8mm in inner diameter (opening diameter of through hole for pin to pass through), and 110 degrees in blade leading edge angle

Groove pitch: 45 to 165 μm

Groove length: 25 to 100 μm

Length of ridge between grooves: 10 to 75 μm

Loading of the front edge of the blade: 18N

When the travel distance is 15m or more as the sorting reference of the scribing wheel, as is clear from fig. 4, the travel distance does not exceed 15m even if the length L of the ridge line between the grooves is changed in the conventional scribing wheel having the groove depth D of 15 μm and 20 μm. On the other hand, when the length L of the ridge line between the grooves is 25 μm or more with a scribing wheel having a groove depth D of 30 μm or 50 μm, the travel distance is 15m or more.

The pitch P (shown in FIG. 1) of the grooves 13 formed in the edge 12 is preferably in the range of 50 to 200. mu.m. If the pitch P of the grooves 13 is less than 50 μm, the wear of the edge 12 of the scribing wheel 1 may increase, and the durability may decrease. If the pitch P of the grooves 13 exceeds 200 μm, vertical cracks cannot be formed deep in the substrate. More preferably, the pitch P of the grooves 13 is in the range of 70 μm to 170 μm.

The ratio of the width W (shown in FIG. 1) of the grooves to the length L of the ridge line between the grooves may be selected from the range of 0.5 to 5, but is usually preferably 1.0 or more (particularly 1.0 to 3.5). That is; the width W of the groove is preferably equal to or longer than the length L of the ridge between grooves. The travel distance is increased by setting the ratio of the groove width W to the length L of the ridge line between the grooves to be within the above range.

The scribing wheel of the present invention can be manufactured by a conventionally known method. For example, a disc-shaped original plate is cut from a material substrate having an appropriate thickness (for example, 0.5 to 1.2mm) to be made into a scribing wheel, and the circumferential edge portions of both surfaces of the original plate are cut so that the thickness becomes thinner radially outward, and a blade having a substantially V-shaped cross section is formed on the circumferential portion. In this case, the blade leading edge angle is preferably in the range of 90 to 160 degrees (particularly 100 to 140 degrees) as described above. Thereafter, a groove is formed in the edge of the edge, which is the ridge line of the edge, by a conventionally known processing method such as laser processing, electric discharge processing, and grinding. Since the scribing wheel of the present invention has a small diameter and requires fine processing accuracy in forming the groove, the laser processing is suitable for the above processing method. The laser generator used is preferably a YAG high-frequency laser or a carbon dioxide gas laser.

As a material for the scribing wheel, sintered diamond, which is a conventionally known material, is preferably used.

The diamond sintered body suitable for use as the material of the scribing wheel of the present invention is preferably one composed of a bonding phase of diamond particles and a remainder, and adjacent diamond particles are bonded to each other. By bonding adjacent diamond particles to each other, excellent wear resistance and strength can be obtained.

The diamond particles used herein preferably have an average particle diameter of 0.5 μm or less. The long life of the scribing wheel can be realized by reducing the average particle size and increasing the proportion of small diamond particles.

The content of diamond particles is usually 75 to 90 vol% based on the whole diamond sintered body, and the content of diamond particles in the diamond sintered body used in the present invention is preferably 85 vol% or more based on the whole diamond sintered body. The term "vol" as used herein means a ratio to the total volume of diamond particles in the entire volume of the diamond sintered body including the pores. Since the binder phase has a hardness smaller than that of the diamond particles, the content of the diamond particles is 85 vol% or more, thereby preventing a decrease in hardness and reducing the particle size of the diamond, and thus the binder phase has excellent strength such as impact resistance and wear resistance.

The bonding phase comprises bonding material and additive. An iron group element is generally suitably used as the binder. The iron group element includes cobalt, nickel and iron, and cobalt is preferable. The content of the binder for this use is preferably in the range of 10 to 30 vol%, particularly preferably 10 to 20 vol%, with respect to the whole diamond sintered body.

For example, carbides of at least 1 or more elements selected from the group consisting of titanium, zirconium, vanadium, niobium, and chromium are suitably used as the additives.

The diamond sintered body suitable for use as the material of the scribing wheel of the present invention can be produced, for example, by mixing diamond particles, a binder and an additive, and then sintering the mixture at a high temperature and an ultrahigh pressure at which diamond is thermodynamically stable.

The sintering is carried out by holding the mixture in a metal container of an ultrahigh pressure generator at a pressure of preferably 5GPa to 8GPa and a temperature of 1500 ℃ to 1900 ℃ for 10 minutes.

The scribing method using the scribing wheel described above is described below.

Fig. 5 shows an overview of the holder on which the scribing wheel is mounted. In the holder 2, the scribing wheel 1 is rotatably supported by a support housing 22 via a pin 21. The holder 2 is attached to the tip of a scribing head having an elevating and pressing mechanism (a pneumatic cylinder, a servo motor, etc.) attached to a scribing device described below, and the scribing wheel 1 is pressed against a brittle material substrate 4 such as a glass substrate and rotated on the surface of the substrate 4 by the elevating and pressing mechanism of the scribing head. Thereby, the scribe line SL is formed on the substrate 4, and a vertical crack is generated. At this time, although the load applied to the scribing wheel 1 and the scribing speed are appropriately determined depending on the kind, thickness, etc. of the substrate 4, the load applied to the scribing wheel 1 is usually in the range of 5 to 50N (preferably 15 to 30N), and the scribing speed is in the range of 50 to 300 mm/sec. Next, a stress is applied from, for example, the surface of the substrate 4 opposite to the surface on which the scribe line SL is formed using a breaking device, not shown, and the substrate is cut by growing the vertical crack K to the opposite surface of the substrate 4.

Examples of the substrate 4 on which the scribing wheel 1 of the present invention can scribe include a substrate made of a brittle material such as glass, ceramic, silicon, or sapphire. The scribing wheel is particularly suitable for scribing hard and brittle materials (ceramic, silicon, sapphire and other brittle materials harder than glass). Since the scribing wheel 1 of the present invention can obtain a vertical crack deeper than conventional ones, the load applied to the scribing wheel 1 can be reduced to form a vertical crack of the same level as conventional ones, and the life of the product can be prolonged. In addition, as the brittle material substrate, a hard brittle material such as a hard ceramic substrate or silicon or sapphire may be cut by a cutting method including scribing and breaking. In particular, in recent years, the transition from HTCC (High Temperature Co-fired Ceramics) to LTCC (low Temperature Co-fired Ceramics) which is relatively easy to process, which is a substrate used in a High-frequency module related to a communication device, has been accelerated, and the cutting method using the scribing method of the present invention is more effectively used.

Fig. 6 and 7 show schematic views of the scribing apparatus. Fig. 6 is a front view and fig. 7 is a side view of the scribing device 3. In fig. 6, the stage 31 rotates in the horizontal direction and moves in the Y direction (left-right direction in fig. 6). On the upper surface of the stage 31, the substrate 4 to be processed is sucked and fixed to the stage 31 by vacuum suction. The positional deviation at the time of setting the substrate 4 is detected by the alignment mark recognized by the pair of CCD cameras 34a and 34b from the mark of the substrate 4. For example, the stage 31 is rotated by an amount of- θ when the substrate 4 is deviated by an angle θ, and the stage 31 is moved by an amount of-Y (leftward Y in fig. 6) in the Y direction when the substrate 4 is deviated by + Y (rightward Y in fig. 6) in the Y direction. A rail 32 (shown in fig. 7) extends in the X direction above the stage 31, and the scribing head 5 is reciprocated along the rail 32 by a cutter shaft motor 33 (shown in fig. 7). In the lower part of the scribing head 5, a holder 2, which is provided with a scribing wheel 1 rotatably about a pin 21 (see fig. 5) in the horizontal direction, is rotatably provided about a vertical axis.

A scribing line can be formed on the upper surface of the substrate 4 by relatively moving the scribing wheel 1 and the substrate 4 arranged horizontally in a horizontal plane while pressing the scribing wheel 1 mounted on the lower end of the holder 2 against the surface of the substrate 4 with a specific pressure (this force is referred to as a scribing load). For example, moving the scribing head 5 in the X direction causes the scribe line in the X direction to be scribed on the upper surface of the substrate 4, and repeating the scribing operation each time the stage 31 is moved in the Y direction. Then, the scribing line in the direction orthogonal to each scribing line formed in the previous process is scribed by performing the same scribing operation after rotating the table 31 by 90 degrees by a driving source not shown. The scribing wheel 1 is pressed against the surface of the substrate 4 with a specific pressure, and the stage 31 is moved in the Y direction, thereby forming a scribe line in the Y direction on the upper surface of the substrate 4.

Then, the substrate on which the scribe line is formed is subjected to a stress applied to a surface opposite to the surface on which the scribe line is formed by the breaking device, whereby a vertical crack grows to the opposite surface of the substrate, and the substrate is cut. In the case of forming a deep vertical crack by scribing, the substrate is cut by scribing alone without using a breaking device.

The scribing wheel of the present invention is dry (without using cooling or cleaning liquid), has a long service life with less wear of the blade front edge, can generate a deep vertical crack if necessary, has less wear of the blade front edge even when a hard brittle material substrate (hard brittle material) such as a ceramic substrate (for example, HTCC substrate or LTCC substrate), silicon, sapphire or the like is scribed, and can generate a vertical crack of a specific depth for a long period of time (long scribing distance), and is useful.

Claims (7)

1. A scribing wheel, wherein a blade having a substantially V-shaped cross section is formed on the circumference of a disk-shaped wheel, and a plurality of grooves are formed at specific intervals on the blade front edge which is the ridge line of the blade, characterized in that:

the outer diameter of the wheel is in the range of 1 mm-5 mm;

the angle of the front end of the blade with the V-shaped section is 90-160 degrees;

the depth of the groove is more than 25 μm;

the length of the ridge between the grooves is 25 μm or more;

the ratio of the width of the groove to the length of the ridge between the grooves is 1.0 or more.

2. The scribing wheel according to claim 1, wherein the pitch of the plurality of grooves is in a range of 50 μm to 200 μm.

3. The scribing wheel according to claim 1, wherein the scribing wheel is composed of a diamond sintered body in which the average particle diameter of the diamond particles is 0.5 μm or less and the diamond content is 85 vol% or more.

4. A scribing method for forming a scribe line on a surface of a brittle material substrate by pressing and rotating the scribing wheel, in which a blade having a substantially V-shaped cross section is formed on a circumferential portion of a disk-shaped wheel and a plurality of grooves are formed at predetermined intervals on a blade front edge which is a ridge line of the blade, on the brittle material substrate, characterized in that:

a scribing wheel having an outer diameter of 1mm to 5mm, an angle of a tip of the blade having a substantially V-shaped cross section of 90 to 160 degrees, a depth of the groove of 25 μm or more, a length of the ridge line between the grooves of 25 μm or more, and a ratio of a width of the groove to a length of the ridge line between the grooves of 1.0 or more is used as the scribing wheel.

5. The scribing method according to claim 4, wherein the brittle material substrate is made of at least one hard brittle material selected from the group consisting of ceramic, sapphire, and silicon.

6. A method of cutting a ceramic substrate, comprising pressing and rotating the scribing wheel according to any one of claims 1 to 3 against a ceramic substrate to form a scribe line on the surface of the ceramic substrate, forming a continuous crack extending to 60% or more of the thickness direction of the ceramic substrate, and then breaking the ceramic substrate along the scribe line.

7. Use of the scribing wheel according to any one of claims 1 to 3 for scribing a ceramic substrate.