JP2003124151A - Dicing method of sapphire substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dicing method of a sapphire substrate which can cut a sapphire substrate properly and improve yield without reducing the number of chips. SOLUTION: The dicing method of a sapphire substrate 12 for cutting the sapphire substrate 12 has a first process for cutting a surface of the sapphire substrate 12 and forming a first groove 40, a second process for sticking a sticking means to a surface of the sapphire substrate 12 and a third process for cutting the backside of the sapphire substrate 12 and forming a second groove 42, which is wider and deeper than the first groove 40, from a rear to at least a bottom part of the first groove 40. According to such a constitution, the sapphire substrate 12 can be cut smoothly and surely from the backside with good cutting separation while ensuring an effective area of a surface of the sapphire substrate 12. Therefore, yield can be greatly improved without reducing the number of chips in a dicing process of the sapphire substrate 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dicing a sapphire substrate, and more particularly to a method for dicing a sapphire substrate having a surface on which a gallium nitride compound semiconductor is laminated.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture, for example, a blue LED (light emitting diode) chip, a dicing method in which a sapphire substrate is cut by a blade rotating at a high speed has been adopted. However, the width of such a chip is, for example, 300μ.
It is extremely small, about m, and the sapphire substrate itself is hard and difficult to break. Therefore, in the above-mentioned dicing method, when the blade is thin (for example, 20 to 30 μm), the chips cannot be completely divided at the time of cutting, and a plurality of chips are cut out in a lump, and the yield is increased. Becomes very bad.

Therefore, in order to reliably cut the sapphire substrate and improve the yield, it is necessary to use a blade having a certain thickness (for example, a thickness of about 100 μm). However, if the blade is made thicker, the area required for cutting between chips becomes larger, so that the number of chips that can be taken from one sapphire substrate decreases.

In order to solve the above problems, Japanese Patent Laid-Open No. 60-211858 discloses that two types of blades having different thicknesses are used, and a thick blade is first formed from the back surface of the sapphire substrate. A dicing method is described in which a sapphire substrate is cut by forming deep and wide grooves and then forming shallow and narrow grooves with a thin blade from the surface of the sapphire substrate.

[0005]

However, in the above-mentioned conventional dicing method, since the deep groove is first formed in the back surface of the sapphire substrate, the sapphire substrate becomes fragile and unstable when cutting from the front side. There is a problem that it is difficult to cut the sapphire substrate.

Further, since a thin blade is used when cutting the sapphire substrate from the surface, there is a problem that the sapphire substrate is not easily separated.

The present invention has been made in view of the above problems of the conventional sapphire substrate dicing method, and an object of the present invention is to suitably cut a sapphire substrate,
It is an object of the present invention to provide a new and improved sapphire substrate dicing method capable of improving the yield without reducing the number of chips.

[0008]

In order to solve the above problems, according to a first aspect of the present invention, in a sapphire substrate dicing method for cutting a sapphire substrate, the surface of the sapphire substrate is cut to remove the first problem. Forming a groove, first
And a second step, in which the back surface of the sapphire substrate is cut so as to reach at least the bottom of the first groove and which is wider and deeper than the first groove. And a third step of forming the groove of (1), and a method of dicing a sapphire substrate.

The surface of the sapphire substrate means either one of the two planes of the sapphire substrate. When the surface of the sapphire substrate is determined, the plane opposite to the surface becomes the back surface of the sapphire substrate. Therefore, the front surface and the back surface of the sapphire substrate can be arbitrarily selected.

With this configuration, the cutting area required for the first groove on the surface of the sapphire substrate can be small, so that the effective area of the surface of the sapphire substrate can be secured. Moreover, since the second groove, which is relatively wide and deep, is formed from the back surface of the sapphire substrate, the sapphire substrate can be suitably cut,
The cut sapphire substrate may be separated. further,
Since the total area of the flat portion on the surface of the sapphire substrate after the first groove is formed is relatively large, it is possible to secure a sufficient adhesion area when the adhesive means is attached. Therefore, when cutting the back surface of the sapphire substrate, the sapphire substrate can be stably fixed and the sapphire substrate itself is not easily broken, so that smooth cutting is possible.

Further, if the gallium nitride compound semiconductor is laminated on the surface of the sapphire substrate, the sapphire substrate for manufacturing a semiconductor chip such as a blue light emitting diode can be preferably diced.

Further, the depth of the first groove is not more than one third of the thickness of the sapphire substrate, and the depth of the second groove is not less than two thirds of the thickness of the sapphire substrate. According to this structure, the sapphire substrate can be surely cut by forming the wide groove at a depth of ⅔ or more of the thickness of the sapphire substrate, so that the cut sapphire substrate can be more easily separated.

Further, the thickness of the first blade forming the first groove is 20 to 30 μm, and the thickness of the second blade forming the second groove is 50 to 120 μm.
With such a configuration, the first blade cuts the surface of the sapphire substrate to form the first groove having an appropriately small width, so that the effective area of the surface of the sapphire substrate can be sufficiently secured. it can. Further, since the second blade cuts the back surface of the sapphire substrate to form the second groove having an appropriately large width, the sapphire substrate can be surely cut and separated easily.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Referring to the accompanying drawings,
A preferred embodiment of the present invention will be described in detail. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, and duplicate description will be omitted.

(First Embodiment) First, a sapphire substrate according to a first embodiment of the present invention will be described in detail with reference to FIG. Note that FIG. 1A is a perspective view of the sapphire substrate 12 according to the present embodiment.
(B) is a sectional view of the sapphire substrate 12 according to the present embodiment.

The sapphire substrate 12 according to the present embodiment is one in which a gallium nitride compound semiconductor is laminated on the surface of a very hard substrate made of hexagonal sapphire crystal (that is, gallium nitride compound semiconductor). Wafer)
Say. As shown in FIG. 1A, the sapphire substrate 12 is, for example, a white transparent disk-shaped substrate having an outer diameter of, for example, 2 inches, and a size of, for example, 4 inches. Good. The thickness of the sapphire substrate 12 is, for example, about 100 μm. The sapphire substrate 12 may be a sapphire substrate 12 on which a gallium nitride-based compound semiconductor is laminated on the front surface and then polished or ground from the back surface to be thinned to the above thickness.

Such a sapphire substrate 12 is shown in FIG.
As shown in (b), the substrate 12 made of sapphire crystal
On the surface of a, for example, a gallium nitride-based compound semiconductor layer 12b having a thickness of, for example, several tens of μm is formed by utilizing a vapor phase growth method such as MOCVD method and MBE method. The gallium nitride-based compound semiconductor layer 12b is, for example, an epitaxially grown n-type GaN: Si layer, InG
aN active layer (or light emitting layer), A1GaN cladding layer,
It is composed of a p-type GaN: Mg cap layer and the like. Further, various electrodes (not shown) are formed on the surface of the gallium nitride-based compound semiconductor layer 12b by etching, for example. The gallium nitride-based compound semiconductor layer 12b is not limited to this example, and may have various laminated structures other than the above.

By stacking the gallium nitride-based compound semiconductor layer 12b in this manner, a plurality of semiconductor elements having, for example, substantially the same pattern and characteristics are arranged on the surface of the sapphire substrate 12 at equal intervals in the vertical and horizontal directions. It is formed in the open state. The width of such a semiconductor element is, for example, 300 μm
It is a degree. Along the streets between these semiconductor elements,
A semiconductor chip is manufactured by dicing (cutting along a cutting line shown by a broken line in FIG. 1B) and dividing the sapphire substrate 12 into a plurality of pieces. Note that, for example, approximately 13,500 semiconductor chips can be manufactured from the 2-inch sapphire substrate 12.

In recent years, such gallium nitride-based compound semiconductor chips have been used as, for example, blue light emitting diode (LED) chips, laser diode chips, etc., and have extremely high practical value. In addition, the sapphire substrate 12
Is very expensive. Therefore, it is possible to suppress chipping and cracks that occur during dicing, and to prevent a plurality of semiconductor chips from being cut out in a lump, thereby improving the yield and increasing the number of semiconductor chips that can be manufactured from one wafer. Is very important.

Next, an outline of the dicing apparatus used for dicing the sapphire substrate in this embodiment will be described with reference to FIG. FIG. 2 is an overall perspective view of the dicing apparatus 10 according to this embodiment.

As shown in FIG. 2, the dicing apparatus 10
The cutting unit 20 (also referred to as a dicing saw or a dicer) cuts or cuts the sapphire substrate 12.
And a chuck table 1 on which the sapphire substrate 12 is placed
5 and. The sapphire substrate 12 is supplied on the chuck table 15 while being fixedly supported by the frame 14 by an adhesive tape 13 as an adhesive means. The chuck table 15 is movable relative to the cutting unit 20, and the chuck table 15 can be moved while cutting a predetermined amount of the sapphire substrate 12 by a blade rotating at a high speed installed at the end of the cutting unit 20. The cutting progresses. On the contrary, the chuck table 15 may be fixed and the cutting unit 20 may move relatively to perform cutting.

The cutting unit 20 includes the sapphire substrate 12
Is cut along the streets on the machined surface to form ultra-thin grooves (also called kerfs or kerfs). After forming the plurality of grooves in a predetermined direction in a substantially band shape, the chuck table 15 is rotated by, for example, about 90 degrees, and a plurality of new grooves are formed in a substantially band shape in a direction substantially perpendicular to the direction of the formed groove. By doing so, one surface of the sapphire substrate 12 can be diced into a lattice shape, for example.

Next, the cutting unit in this embodiment will be described with reference to FIG. Note that FIG. 3 is a perspective view of the cutting unit 20 according to the present embodiment.

As shown in FIG. 3, the cutting unit 20 is
A ring-shaped blade 22, a flange 24 that holds the blade 22 from both sides, a shower nozzle 25 that supplies cutting water from the front in the cutting direction, a side nozzle 26 that supplies cutting water from both sides of the blade 22, and a wheel cover 28. ，
A spindle 30 for rotating the blade 20 via a flange 24.

The blade 22 is an electroformed blade (diamesh is # 400 to 1200, for example) in which abrasive grains such as diamond are electrodeposited with a bond material such as nickel, and has a substantially ring shape. The blade 22 has an extremely thin thickness, for example, 20 to 120 μm. In this embodiment, cutting is performed using, for example, two types of blades 22 having different thicknesses. That is, the thickness is, for example, about 20 to 30 μ.
m of the first blade 22a and has a thickness of, for example, about 50 to 1
The second blade 22b having a thickness of 20 μm will be described in detail later. The blade 22 according to the present embodiment
Is a ring shape, the present invention is not limited to such an example,
For example, a hub blade in which a hub and a cutting edge portion are integrally formed may be used.

The blade 22 is axially attached to the spindle 30 while being sandwiched by the flange 24.
It can rotate at high speed at k rpm. The blade 22 that rotates at a high speed cuts the outer periphery of the blade into the surface to be processed of the sapphire substrate 12 by a predetermined amount and cuts the surface to be processed along the streets to form an extremely thin groove. Cutting water is supplied during the cutting, and the blade 22 and the processing point are cooled.

The flange 24 is made of a relatively hard metal such as stainless steel, for example, and clamps the blade 22 from both sides to fix it. At this time, the flange 24 is
Since the substantially same region is sandwiched from both sides of the blade 22 with a uniform pressure, the blade 22 is not curved or deformed due to an unbalanced pressure, and the machined surface can be cut substantially linearly.

The shower nozzle 25 is arranged at a predetermined height from the processing surface on the front side of the blade 22 in the cutting direction, and has a hole or slit on the side facing the outer peripheral surface of the blade 22, and the hole or slit is used to cut the blade. Cutting water is discharged toward the tip of the blade 22 to cool the blade 22 and the processing point. The shower nozzle 25 may be formed integrally with the wheel cover 28, or may be provided above the blade 22 or on the rear side in the cutting direction. In addition, the cutting unit 20 does not always have to supply the shower nozzle 2 if sufficient cutting water can be supplied from the side nozzle 26.
It is not necessary to have 5.

The side surface nozzles 26 are installed on both sides of the blade 22 (one side is not shown in FIG. 3), for example, substantially parallel to the blade 22 and the processing surface, and slits provided on the side facing the blade 22. From the opening of the blade 22
Cutting water is discharged toward both sides to cool the blade 22 and the processing point. In addition, the side surface nozzle 26 is the blade 2
It may be provided only on one side of 2, and may not necessarily be provided.

The foil cover 28 not only prevents the cutting water from splashing around but also protects the blade 22.
It has a function of preventing the blade 22 from being exposed to prevent danger. The foil cover 28 is provided with various devices such as a shower nozzle 25 and a side nozzle, and can have various shapes according to the installation conditions and cutting conditions.

The spindle 30 is a rotary shaft for transmitting a driving force of a motor (not shown) or the like, is extended in the spindle housing 32, and has a flange 24 removably attached to one end thereof. The spindle 30 can rotate the blade 20 at a high speed via the flange 24.

Next, the method of dicing the sapphire substrate, which is a feature of this embodiment, will be described in detail with reference to FIGS. 4 and 5. 4. FIG. 4 is a flowchart showing an operation flow in the sapphire substrate dicing method according to this embodiment. Further, FIG. 5 is a cross-sectional view of the sapphire substrate 12 or the semiconductor chip 16 fixed to the adhesive tape 13 in each step of the sapphire substrate dicing method according to the present embodiment.

As shown in FIG. 4, first, in step S10
At 0, the first blade 22a is installed (step S100). This step is a preparation step for dicing the surface of the sapphire substrate 12. First, the cutting unit 20 of the dicing device 10 is provided with the first blade 22a having a relatively thin thickness. The thickness of the first blade 22a is, for example, about 20 to 30 μm. The reason for this is that if the thickness of the first blade 22a is excessively smaller than, for example, 20 μm, the sapphire substrate 12 cannot be cut appropriately, and if it is, for example, 3
If it is excessively larger than 0 μm, the sapphire substrate 12
This is because, on the surface of, the cutting area is enlarged and the effective area where the semiconductor element can be formed is reduced.

The sapphire substrate 12 which is the work piece
Is fixed to the frame 14 by an adhesive tape 13 such as a wafer tape attached to the back surface, and is supplied onto the chuck table 15 with its front surface facing upward.
As described above, the preparation for cutting the surface of the sapphire substrate 12 by the first blade 22a is completed.

Next, in step S110, the first blade 22a forms the first groove 40 on the surface of the sapphire substrate 12 (step S110). For example, the chuck table 15 is moved in a predetermined direction with the first blade 22a rotating at a high speed being cut into the surface of the sapphire substrate 12 with a predetermined cutting depth. In this manner, the surface of the sapphire substrate 12 (that is, the surface on which the gallium nitride-based compound semiconductor layer 12b is laminated) is cut (half cut) along the streets between the semiconductor elements by the first blade 22a.

By such cutting, as shown in FIG. 5A, the first groove 40 is formed on the surface of the sapphire substrate 12. The first groove 40 completely cuts the gallium nitride-based compound semiconductor layer 12b, and the bottom of the groove reaches the substrate 12a made of sapphire crystal. Note that FIG. 5 (a)
Although the bottom portion of the first groove 40 shown in FIG. 1 has a substantially semicircular cross section, it is not limited to such an example, and may have an arbitrary shape such as a substantially rectangular shape or a wedge shape depending on the shape of the cutting edge of the first blade 22a. May be

The width of the first groove 40 is, for example, about 20 to 3 depending on the thickness of the relatively thin first blade 22a.
It is 0 μm. Therefore, the width of the first groove 40 is, for example, 3
Compared with the width of the semiconductor device, which is 00 μm, for example, about 10
% Or less. The depth of the first groove 40 is, for example, about 30 μm, which is about 30% of the thickness of the sapphire substrate 12, for example, 100 μm. In this way, the first blade 22 is adjusted so that the depth of the first groove 40 is less than or equal to one third of the thickness of the sapphire substrate 12.
It is preferable to adjust the cutting depth of a.

By repeating the cutting with the first blade 22a as described above, a plurality of first grooves 40 are formed in the surface of the sapphire substrate 12 in a substantially same direction at predetermined intervals in a band shape. Further, after rotating the chuck table 15 by 90 degrees, for example, the cutting by the first blade 22a is repeated again to form the first grooves 40 in a band shape at a predetermined interval in a direction substantially perpendicular to the predetermined direction. . As a result, the surface of the sapphire substrate 12 is diced into, for example, a lattice shape, and the individual semiconductor elements are divided into, for example, a substantially square shape with one side of 300 μm. The shape of the dicing is not limited to this example, and may be a substantially rectangular shape, a substantially rhombic shape, or the like depending on the shape of the semiconductor element or the characteristics of the sapphire substrate 12.

As described above, in dicing the surface of the sapphire substrate 12, the relatively narrow and shallow first groove 40 is formed by using the thin first blade 22a.
It is possible to prevent chipping that occurs at the edge of the groove 40 and cracks that occur across the semiconductor element on the surface. Further, since the area required for cutting is small on the surface of the sapphire substrate 12, it is possible to secure a large area of the flat portion where the semiconductor element can be formed, that is, an effective area.

Further, in step S120, the adhesive tape 13 is attached to the surface of the sapphire substrate 12 (step S120). This step is a preparation step for dicing the back surface of the sapphire substrate 12. The sapphire substrate 12 is attached to the frame 14 via the adhesive tape 13.
Then, it is mounted again on the chuck table 15 with the back surface thereof facing upward.

Here, the stability when the sapphire substrate 12 is fixed by the adhesive tape 13 as described above will be described. Since the first groove 40 is formed on the surface of the sapphire substrate 12 according to the present embodiment, the flat portion is reduced by the amount of the first groove 40. Therefore, the area where the surface of the sapphire substrate 12 and the adhesive tape 13 can be bonded (hereinafter, referred to as a bonding area) is reduced as compared with the case where the groove is not formed. However, since the width of the first groove 40 is relatively narrow, the surface of the sapphire substrate 12 according to the present embodiment has a space between the surface of the sapphire substrate 12 and the adhesive tape 13 as compared with the conventional dicing method in which a wide groove is first formed. Therefore, it is possible to secure a relatively large bonding area. Therefore, it is possible to sufficiently prevent the sapphire substrate 12 from slipping off or peeling off from the adhesive tape 13 during cutting of the back surface described later.
Therefore, the sapphire substrate 12 can be stably fixed by first forming the narrow first groove 40.

Then, in step S130, the second blade 22b is installed (step S130). The first blade 22a installed in the cutting unit 20 in step S100 is replaced with the second blade 22b. The thickness of the second blade 22b is, for example, about 50 to 1
It is 20 μm, which is, for example, about 1.7 to 6 times thicker than the first blade 22a.

As described above, since the second blade 22b has a certain thickness, the sapphire substrate 12 that is extremely hard can be suitably cut, and the cut sapphire substrate 12 can be sufficiently cut. When the thickness of the second blade 22b is excessively smaller than 50 μm, the sapphire substrate 12 may not be deeply and sufficiently divided. When the thickness of the second blade 22b is excessively larger than 120 μm, for example, the cutting area becomes enormous and the shape of the formed semiconductor chip 16 is hindered, and the cutting resistance becomes excessive. .

Next, in step S140, the second blade 22b forms the second groove 42 on the back surface of the sapphire substrate 12 (step S140). The second blade 22b cuts the back surface of the sapphire substrate 12 by the same cutting method as the case of forming the first groove 40 in step S110. Further, at the time of such cutting, since the adhesion area between the surface of the sapphire substrate 12 and the adhesive tape 13 is relatively large as described above, the sapphire substrate 12 is stably fixed and is not easily broken. Therefore, smooth cutting is possible.

By the cutting with the second blade 22b as described above, the back surface of the sapphire substrate 12 is formed as shown in FIG.
As shown in, the second groove 42 is formed at a position corresponding to the first groove 40. Since the bottom of the second groove 42 reaches the bottom of the first groove 40, the sapphire substrate 12 can be cut by connecting with the first groove 40.
The bottom of the second groove 42 is not limited to the curved surface, and may have any shape, like the bottom of the first groove 40.

The width of the second groove 42 is, for example, about 50 to 1 depending on the thickness of the relatively thick second blade 22b.
The width is 20 μm, which is considerably larger than the width of the first groove 40. Therefore, the width of the flat portion left between the adjacent second grooves 42 on the back surface of the sapphire substrate 12 is, for example, about 2
It is about 00 μm, which is narrower than, for example, about 300 μm on the surface.

The depth of the second groove 42 is, for example, about 7
The thickness is 0 μm, which is about 70% with respect to the thickness of the sapphire substrate 12, for example, 100 μm. As described above, the second blade 22b is formed so that the depth of the second groove 42 is equal to or more than ⅔ of the thickness of the sapphire substrate 12.
It is preferable to adjust the cutting depth of.

In this way, from the back surface, the second and relatively deep second
By forming the groove 42, the sapphire substrate 12 can be sufficiently divided into both sides at the cut position, so that the semiconductor chip 16 to be described later can be cut off easily.

The cutting with the second blade 22b as described above is repeated to form a plurality of second grooves 42 at positions corresponding to the first grooves 40, whereby the sapphire substrate 1
The back surface of 2 can be diced in the same pattern as the front surface.
Thus, the sapphire substrate 12 can be suitably diced and cut into a plurality of semiconductor chips 16 having substantially the same shape.

Further, in step S150, the sapphire substrate 12 is divided into semiconductor chips 16 (step S).
150). The sapphire substrate 12 diced in the above process is removed from the adhesive tape 13 and divided into a plurality of semiconductor chips 16. At this time, the first groove 40 and the second groove 40
Since the sapphire substrate 12 is cut by the connection with the groove 42, the division is easy. Further, since the semiconductor chip 16 is sufficiently divided by the wide and deep second groove 42, the plurality of adjacent semiconductor chips 16 do not become a lump, and the semiconductor chips 16 can be separated from each other.

The semiconductor chip 1 divided in this way
As shown in FIG. 5C, 6 has a shape in which the surface on which the gallium nitride-based compound semiconductor is formed (that is, the front surface) is large and the back surface is small. The width of the front surface of the semiconductor chip 16 is, for example, 300 μm, which is, for example, about 1.5 times larger than the width of the rear surface, which is about 200 μm. Further, the surface of the semiconductor chip 16 is, for example, about 300 pieces.
It has, for example, a substantially square shape of μm, and its area (300 μm
× 300μm is the area of the back surface (200μm × 200μ
m), for example, about two times wider.

Therefore, the surface of the semiconductor chip 16 can secure a large area required for the gallium nitride compound semiconductor. In addition, the side surface of the semiconductor chip 16 has a shape that is scooped in order to obtain a certain distance from the adjacent semiconductor chip 16. Therefore, the adjacent semiconductor chip 1
The separation between the 6 is improved. Thus, it can be said that the semiconductor chip 16 has a rational and functional shape.

As described above, according to the sapphire substrate dicing method of this embodiment, first, the narrow and shallow first groove 40 is formed on the surface of the sapphire substrate 12, and then the
A wide and deep second groove is formed from the back surface, and the sapphire substrate 12 is cut and divided into a plurality of semiconductor chips 16. Therefore, it is superior in the following points in comparison with the conventional dicing method in which the back surface is first cut and then the front surface is cut.

First, when the back surface of the sapphire substrate 12 is cut, the adhesive area between the front surface and the adhesive tape 13 is large.
The sapphire substrate is stably fixed, smooth cutting is possible, and the sapphire substrate 12 is less damaged.

In addition to this, since the cutting area of the groove on the surface of the sapphire substrate 12 is small, the effective area of the flat portion on which the semiconductor element can be formed can be sufficiently secured. Therefore, the number of semiconductor chips 16 that can be manufactured from one sapphire substrate 12 is increased, and efficiency and mass production can be achieved.

Further, since the wide and thick second groove is formed from the back surface after cutting the front surface, it is possible to separate them from each other when dividing into semiconductor chips.

As a result, one sapphire substrate 12
The yield in the dicing process can be greatly improved without reducing the number of semiconductor chips that can be manufactured from.

The preferred embodiment of the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such an example. It is obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims, and naturally, these are also within the technical scope of the present invention. It is understood that it belongs.

For example, a sapphire substrate 1 to be diced
The gallium nitride compound semiconductor does not necessarily have to be laminated on the surface, and may be, for example, a sapphire substrate on which other semiconductors are laminated or only a substrate made of a sapphire crystal.

Further, although the first groove 40 and the second groove 42 according to the present embodiment are formed by one-time cutting with the blade 22, the present invention is not limited to this example. For example, in order to form the first groove 40 and / or the second groove 42, first, a wide blade is formed by cutting with a relatively thick blade,
Further, a narrow deep groove may be formed inside the groove (that is, multi-step cutting).

Although the dicing apparatus 10 is used for dicing the sapphire substrate in the present embodiment, the present invention is not limited to this example. For example, in order to form the first groove 40, a scribe line is used to form a scribe line in a grid pattern on the surface of the sapphire substrate 12 by linearly moving a hard needle whose tip is made of diamond or the like back and forth. You may.

[0062]

As described above, according to the dicing method for a sapphire substrate according to the present invention, the effective area of the surface of the sapphire substrate can be secured, and the sapphire substrate can be stably fixed when the back surface is cut and its damage is caused. Also few. Further, since the sapphire substrate can be reliably cut from the back surface with a thick blade, the cut sapphire substrate can be cut off. Therefore, the sapphire substrate can be smoothly and appropriately diced, and the yield in the dicing process can be significantly improved without reducing the number of chips that can be manufactured from one sapphire substrate.

[Brief description of drawings]

FIG. 1A is a perspective view of a sapphire substrate according to a first embodiment. FIG. 1B is a sectional view of the sapphire substrate according to the first embodiment.

FIG. 2 is an overall perspective view of the dicing apparatus according to the first embodiment.

FIG. 3 is a perspective view of the cutting unit according to the first embodiment.

FIG. 4 is a flowchart showing an operation flow in a method for dicing a sapphire substrate according to the first embodiment.

FIG. 5 is a sectional view of a sapphire substrate or a semiconductor chip fixed to an adhesive tape in each step of the sapphire substrate dicing method according to the first embodiment.

[Explanation of symbols]

10: Dicing device 12: Sapphire substrate 12b: gallium nitride-based compound semiconductor layer 16: Semiconductor chip 20: Cutting unit 22: Blade 22a: First blade 22b: Second blade 40: First groove 42: Second groove

Claims (4)

[Claims] 1. A method of dicing a sapphire substrate for cutting a sapphire substrate, the first step of cutting the surface of the sapphire substrate to form a first groove, and attaching an adhesive means to the surface of the sapphire substrate. A second step of cutting the back surface of the sapphire substrate to form a second groove extending from the back surface to at least the bottom of the first groove and wider and deeper than the first groove And a dicing method for a sapphire substrate, which comprises: 2. The dicing method for a sapphire substrate according to claim 1, wherein a gallium nitride-based compound semiconductor is laminated on the surface of the sapphire substrate. 3. The depth of the first groove is not more than one third of the thickness of the sapphire substrate, and the depth of the second groove is three minutes of the thickness of the sapphire substrate. 2. The method for dicing a sapphire substrate according to claim 1, wherein the dicing method is two or more. 4. The thickness of the first blade forming the first groove is 20 to 30 μm, and the thickness of the second blade forming the second groove is 50 to 120 μm.
The sapphire substrate dicing method according to claim 1, wherein the sapphire substrate is m.