JP2014239123A - Processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method capable of efficiently producing the light-emitting chip which can efficiently extracting light mainly radiated from a back surface of a light-emitting layer.SOLUTION: A processing method comprises a division start point formation step; an adhesion step; a translucent substrate division step; and a wafer division step. In the division start point formation step, modified layers K are formed along division schedule lines on a wafer where light-emitting layers 2a are formed on each regions defined by a plurality of division schedule lines on a surface. In the adhesion step, the translucent substrate formed of a material transmitting light radiated from the light-emitting layer 2a, is adhered to a back surface of a wafer with a translucent resin 2e transmitting light radiated from the light-emitting layer 2a. In the translucent substrate division step, the translucent substrate is cut along the division schedule lines by a cutting blade to divide into a plurality of translucent members 2c. In the wafer division step, the wafer is divided into a plurality of chips 2b by applying external force to the wafer along the division schedule lines and using the modified layer K as a starting point.

Description

  The present invention relates to a processing method for manufacturing a light emitting chip for forming a light emitting device such as a light emitting diode.

  Optical devices such as LEDs (Light Emitting Diodes) and LDs (Laser Diodes) are formed on each crystal growth substrate by growing an epitaxial layer (crystal layer) and partitioned by grid-shaped division lines. The Thereafter, for example, the individual optical devices are manufactured by dividing the crystal growth substrate along the planned division lines into individual pieces.

  In an InGaN-based chip that emits green or blue light, sapphire is generally used as a crystal growth substrate, and an n-type GaN semiconductor layer, an InGaN light-emitting layer, and a p-type GaN semiconductor are sequentially formed on the sapphire substrate. The layer is grown epitaxially. An external extraction electrode is formed on each of the n-type GaN semiconductor layer and the p-type GaN semiconductor layer to form an optical device.

  In an optical device such as an LED, higher luminance is required, and an improvement in light extraction efficiency is desired (for example, see Patent Document 1). If the sapphire substrate is too thin, the light emitted from the back side of the GaN semiconductor layer (light emitting layer) is transmitted through the sapphire substrate, reflected by the package substrate, and reentered the GaN semiconductor layer (light emitting layer) side. There is a problem that the luminance is lowered and the luminance is lowered accordingly.

  On the other hand, by increasing the thickness of the sapphire substrate, light emitted from the back side of the GaN semiconductor layer (light emitting layer) is emitted to the outside without entering the GaN semiconductor layer (light emitting layer) again even if it is reflected by the package substrate. Therefore, although the brightness can be improved, it is extremely difficult to process a thick sapphire substrate. Therefore, the applicant of the present invention emits light mainly from the back surface of the GaN semiconductor layer (light emitting layer) by sticking a translucent member to the back surface side of the thin package substrate having the light emitting layer formed on the front surface. A light-emitting chip that can efficiently extract light is proposed.

Japanese Patent Laid-Open No. 4-10670

  However, since the light-emitting chip and the light-transmitting member are fine, it takes a considerable amount of time to attach the light-transmitting members to the back surface of the light-emitting chip with resin, and the work is complicated and the productivity is high. There is a problem that is bad.

  The present invention has been made in view of the above problems, and an object thereof is to provide a processing method capable of efficiently producing a light-emitting chip that can efficiently extract light emitted mainly from the back surface of the light-emitting layer. It is to be.

  In order to solve the above-described problems and achieve the object, the processing method of the present invention includes a chip having a light emitting layer on the surface and a translucent resin having translucency on the back side of the chip. And a light-emitting chip formed from a light-transmitting member formed of a material that transmits light emitted from the light-emitting layer, and a plurality of division lines on the surface of the substrate. A division starting point forming step for forming a division starting point along the planned division line for dividing the wafer into a wafer in which a region is divided and a light emitting layer is formed in the divided region, and formation of the division starting point After the process is performed, the light emitted from the light-emitting layer is formed on a translucent substrate formed of a material having at least an area equivalent to the wafer on the back surface of the wafer and transmitting light emitted from the light-emitting layer. Translucent resin that passes through Adhering step for adhering, and translucent substrate that, after carrying out the adhering step, cuts the translucent substrate with a cutting blade along the planned dividing line and divides the translucent substrate into a plurality of translucent members A wafer dividing step of applying an external force along the scheduled dividing line of the wafer and dividing the wafer into a plurality of chips starting from the dividing starting point after performing the dividing step and the translucent substrate dividing step; It is characterized by providing.

  Further, in the processing method, the division starting point in the division starting point forming step is a division starting groove formed on the surface by subjecting the wafer to ablation processing or cutting using a cutting blade from the light emitting layer side. It is preferable that

  Further, in the processing method, the division starting point in the division starting point forming step is formed inside the wafer by irradiating a laser beam having a wavelength that passes through the wafer from the back side along the planned dividing line. A modified layer is preferred.

  According to the processing method of the present invention, a translucent substrate having translucency is attached to a substrate having a light emitting layer, and the translucent substrate is divided. For this reason, it is possible to efficiently produce a light-emitting chip in which a translucent member is attached to the back surface of a substrate having a GaN semiconductor layer (light-emitting layer) capable of improving luminance.

FIG. 1A is a perspective view schematically showing a configuration example of a light-emitting diode including a light-emitting chip manufactured by the processing method according to the embodiment, and FIG. 1B is a processing according to the embodiment. It is a perspective view which shows the structural example of the wafer processed into the light emitting chip by the method. FIG. 2 is a side cross-sectional view illustrating an outline of a division starting point forming step of the processing method according to the embodiment. FIG. 3 is a side cross-sectional view illustrating an outline of a sticking step of the processing method according to the embodiment. FIG. 4 is a side sectional view showing an outline of a translucent substrate dividing step of the processing method according to the embodiment. FIG. 5 is a side sectional view showing an outline of the wafer dividing step of the processing method according to the embodiment. FIG. 6 is a side sectional view showing an outline of a main part of the wafer dividing step of the processing method according to the embodiment. FIG. 7 is a side cross-sectional view illustrating an outline of the division starting point forming step of the processing method according to the first modification of the embodiment. FIG. 8 is a side cross-sectional view illustrating an outline of the division start point forming step of the processing method according to the second modification of the embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the structures described below can be combined as appropriate. Various omissions, substitutions, or changes in the configuration can be made without departing from the scope of the present invention.

Embodiment
A processing method according to the embodiment will be described with reference to FIGS. FIG. 1A is a perspective view schematically showing a configuration example of a light-emitting diode including a light-emitting chip manufactured by the processing method according to the embodiment, and FIG. 1B is a processing according to the embodiment. FIG. 2 is a side cross-sectional view illustrating an outline of a division starting point forming step of the processing method according to the embodiment, and FIG. 3 is a processing method according to the embodiment. 4 is a side sectional view showing the outline of the translucent substrate dividing step of the processing method according to the embodiment, and FIG. 5 is a wafer division of the processing method according to the embodiment. FIG. 6 is a side sectional view showing an outline of the main part of the wafer dividing step of the processing method according to the embodiment.

  The processing method which concerns on embodiment is a processing method which manufactures the light emitting chip 2 of the light emitting diode 1 shown to Fig.1 (a). As shown in FIG. 1A, the light emitting diode 1 includes a lead frame 3 serving as a base and a light emitting chip 2 supported and fixed to the lead frame 3.

  The lead frame 3 is formed in a columnar shape, and two lead members 3a and 3a connected to an external power source (not shown) via wiring (not shown) or the like are provided on the bottom surface. Two connection terminals 3b and 3b that are insulated from each other are arranged on the surface of the lead frame 3 at a predetermined interval, and a light emitting chip is formed by a translucent resin (not shown) between the connection terminals 3b and 3b. 2 is bonded and fixed. The connection terminals 3b, 3b and the lead members 3a, 3a correspond one-to-one, and the corresponding ones are connected.

  The light emitting chip 2 is formed of a chip 2b having a light emitting layer 2a on the surface, and a translucent member 2c attached to the back side of the chip 2b with a translucent resin 2e having translucency. . The chip 2b includes a substrate layer 2d having a rectangular planar shape and a light emitting layer 2a provided on the surface of the substrate layer 2d. In the embodiment, the substrate layer 2d is a GAN substrate made of GaN (gallium nitride), a SiC substrate made of SiC (silicon carbide), a sapphire substrate made of sapphire, or the like.

  The light emitting layer 2a includes a plurality of semiconductor layers (GaN semiconductor layers) formed using a GaN-based semiconductor material. The light emitting layer 2a includes an n-type semiconductor layer (for example, n-type GaN layer) in which electrons are majority carriers, a semiconductor layer (for example, InGaN layer), and a p-type semiconductor layer (for example, p-type GaN) in which holes are majority carriers. Layer) is sequentially epitaxially grown. Further, two electrodes (not shown) are formed on the surface of the light-emitting chip 2 and are connected to the n-type semiconductor layer and the p-type semiconductor layer, respectively, and apply a voltage to the light-emitting layer 2a. These electrodes are connected to connection terminals 3b and 3b via lead wires 4a and 4a. The light emitting layer 2a emits light when a voltage is applied, that is, emits light.

  The translucent member 2 c is disposed on the back surface of the substrate layer 2 d of the light emitting chip 2. The translucent member 2c is formed of a material that transmits light emitted from the light emitting layer 2a. As a material for forming the translucent member 2c, glass or transparent resin can be used. It is desirable that the translucent member 2c has a thickness equal to or greater than that of the substrate layer 2d.

  In the light emitting diode 1, the light transmissive member 2c of the light emitting chip 2 is adhered to the surface of the lead frame 3 with a light transmissive resin (not shown), and light is emitted to the connection terminals 3b and 3b through the lead wires 4a and 4a. It is obtained by connecting to the electrode of the chip 2. The light emitting diode 1 has a dome-shaped lens member 5 attached to the outer peripheral edge of the lead frame 3 so as to cover the surface side of the light emitting chip 2 and guide light emitted from the light emitting layer 2a in a predetermined direction.

  In the light emitting diode 1, when a voltage is applied to the light emitting layer 2a, electrons flow from the n-type semiconductor layer and holes flow from the p-type semiconductor layer to the semiconductor layer. As a result, recombination of electrons and holes occurs in the semiconductor layer, and light having a predetermined wavelength is emitted. In the embodiment, since the semiconductor layer to be the light emitting layer is formed using a GaN-based semiconductor material, blue or green light corresponding to the band gap of the GaN-based semiconductor material is emitted. Light generated in the semiconductor layer is mainly emitted from the front and back surfaces of the light emitting layer 2a. The light emitted from the surface of the light emitting layer 2a is extracted outside the light emitting diode 1 through the lens member 5 and the like.

  On the other hand, in the light emitting diode 1, a part of the light emitted from the back surface of the light emitting layer 2a is at the interface between the substrate layer 2d and the translucent resin 2e and at the interface between the translucent resin 2e and the translucent member 2c. Although reflected, another part permeate | transmits these interfaces and is taken out outside from the side surface etc. of the translucent member 2c. As described above, the light emitting diode 1 according to the embodiment includes the translucent member 2c that transmits the light emitted from the light emitting layer 2a on the back side of the light emitting chip 2 including the light emitting layer 2a on the front surface. The ratio of the light reflected at the interface with the light 3 and returning to the light emitting layer 2a can be kept low, the light emitted mainly from the back surface of the light emitting layer 2a can be efficiently extracted, and the light extraction efficiency can be increased. It is.

  The processing method according to the embodiment is a processing method for subjecting a wafer W on which a plurality of the light emitting layers 2a described above are formed on the surface Wa to division start point formation processing, pasting processing, translucent substrate division processing, and wafer division processing. And a dividing starting point forming step, a sticking step, a translucent substrate dividing step, and a wafer dividing step. The wafer W to be processed constitutes the substrate layer 2d and is composed of GaN (gallium nitride), SiC (silicon carbide), sapphire, or the like. As shown in FIG. 1B, the wafer W is formed by dividing a plurality of regions on a surface Wa of the substrate by a plurality of division lines, and a light emitting layer 2a is formed in each of the divided regions.

  First, in the division starting point forming process, as shown in FIG. 2, the protective tape T1 is attached to the surface Wa of the wafer W (shown in FIG. 1B), and the annular frame F is attached to the outer edge of the protective tape T1. To wear. Then, the surface Wa of the wafer W is held on the chuck table (not shown) of the laser processing apparatus 10 via the protective tape T1. Then, while moving the chuck table holding the wafer W and the laser beam irradiating means 12 of the laser processing apparatus 10 along the planned dividing line, the laser beam having a wavelength that passes through the wafer W from the back surface Wb side is scheduled to be split. Irradiate along. Then, a modified layer K (corresponding to a division starting point) is formed along the planned division line inside the wafer W.

  The modified layer K is a starting point for dividing the wafer W and is a region where the density, refractive index, mechanical strength and other physical characteristics are different from those of the surroundings. This means, for example, a melt treatment region, a crack region, a dielectric breakdown region, a refractive index change region, and a region in which these regions are mixed. As described above, the division starting point is the modified layer K formed inside the wafer W by irradiating a laser beam having a wavelength that passes through the wafer W from the back surface Wb side along the planned division line. It progresses to the sticking process after a division | segmentation starting point formation process.

  In the sticking step, after the split starting point forming step is performed, a liquid translucent resin 2e is applied to the surface of the translucent substrate R having at least an area equivalent to the wafer W, and as shown in FIG. The photosensitive resin 2e is opposed to the back surface Wb of the wafer W. The translucent substrate R is brought close to the back surface Wb of the wafer W, and the translucent substrate R is adhered to the back surface Wb of the wafer W with the translucent resin 2e. The translucent substrate R is a substrate formed of a material that transmits light emitted from the light emitting layer 2a such as glass or transparent resin. The translucent resin 2e transmits light emitted from the light emitting layer 2a. When the translucent resin 2e is cured, the translucent substrate R is fixed to the wafer W. Then, the process proceeds to the translucent substrate dividing step.

  And in a translucent board | substrate division | segmentation process, after implementing a sticking process, the surface Wa of the wafer W is hold | maintained on the chuck table (not shown) of the cutting device 20 via the protective tape T1. While the chuck table and the cutting blade 22 of the cutting apparatus 20 are relatively moved along the scheduled division line, the translucent substrate R is cut by the cutting blade 22 along the planned division line. The translucent board | substrate R is separated into pieces along the division | segmentation planned line with the cutting blade 22, and is divided | segmented into the some translucent member 2c. Then, the process proceeds to the wafer dividing step.

  In the wafer dividing step, after the translucent substrate dividing step is performed, first, the wafer W is held in the annular frame F, as shown in FIG. 51. Then, the pressing blade 52 of the braking device 50 is pressed against each division line of the wafer W, and an external force is applied along each division line of the wafer W. Then, as shown in FIG. 6, the wafer W is divided into a plurality of chips 2 b, that is, the light emitting chips 2, starting from the modified layer K. After dividing the wafer W along all the division lines, the individually divided light emitting chips 2 are removed from the protective tape T1.

  According to the processing method which concerns on embodiment, the translucent board | substrate R which has translucency is affixed on the wafer W which has a GaN semiconductor layer (light emitting layer), and the translucent board | substrate R is divided | segmented. For this reason, the processing method according to the embodiment can easily form the transparent member 2c having a uniform thickness, and can efficiently extract light emitted mainly from the back surface of the light emitting layer 2a. The light emitting chip 2 can be produced efficiently. Further, according to the processing method according to the embodiment, since the wafer W is divided starting from the modified layer K, even if the wafer W is made of hard sapphire or the like, it can be easily divided and the light emitting chip 2 can be efficiently manufactured. Can be produced.

[Modification 1]
A processing method according to Modification 1 of the embodiment of the present invention will be described with reference to FIG. FIG. 7 is a side cross-sectional view illustrating an outline of the division starting point forming step of the processing method according to the first modification of the embodiment. In addition, the same code | symbol is attached | subjected to the part same as embodiment, and description is abbreviate | omitted.

  In the split starting point forming step of the processing method according to the first modification of the embodiment, the back surface Wb side of the wafer W is held on a chuck table (not shown) of the cutting device 20. Then, the wafer W is subjected to cutting using the cutting blade 22 from the light emitting layer 2a side while relatively moving the chuck table holding the wafer W and the cutting blade 22 of the cutting device 20 along the scheduled dividing line. . Then, a division start groove S (corresponding to the division start point) is formed on the surface Wa of the wafer W along the planned division line.

  As described above, in the processing method according to the first modification of the embodiment, the division starting point is the division starting groove formed on the surface Wa by cutting the wafer W using the cutting blade 22 from the light emitting layer 2a side. S. After the division starting point forming step, the protective tape T1 is attached to the surface Wa of the wafer W, and the annular frame F is attached to the outer edge portion of the protective tape T1, and then the attaching step and the light-transmitting effect as in the embodiment. The process proceeds sequentially to the substrate splitting process and the wafer splitting process.

  According to the processing method according to the first modification of the embodiment, the translucent member 2c having a uniform thickness can be easily formed as in the above-described embodiment, and the light is emitted mainly from the back surface of the light emitting layer 2a. The light-emitting chip 2 that can efficiently extract the emitted light can be efficiently produced. Moreover, according to the processing method which concerns on the modification 1 of embodiment, even if the wafer W is comprised with hard sapphire, the light emitting chip 2 can be produced efficiently.

[Modification 2]
A processing method according to Modification 2 of the embodiment of the present invention will be described with reference to FIG. FIG. 8 is a side cross-sectional view illustrating an outline of the division start point forming step of the processing method according to the second modification of the embodiment. In addition, the same code | symbol is attached | subjected to the part same as embodiment, and description is abbreviate | omitted.

  In the split starting point forming step of the processing method according to the second modification of the embodiment, the back surface Wb side of the wafer W is held on a chuck table (not shown) of the ablation processing device 30. Then, the wafer W is irradiated with the laser beam from the laser beam irradiation means 32 from the light emitting layer 2a side while the chuck table holding the wafer W and the laser beam irradiation means 32 of the ablation processing device 30 are relatively moved along the division line. Then, ablation processing is performed. Then, a division start groove S (corresponding to the division start point) is formed on the surface Wa of the wafer W along the planned division line.

  As described above, in the processing method according to the second modification of the embodiment, the division starting point is the division starting groove S formed on the surface Wa by ablating the wafer W from the light emitting layer 2a side. After the division starting point forming step, the protective tape T1 is attached to the surface Wa of the wafer W, and the annular frame F is attached to the outer edge portion of the protective tape T1, and then the attaching step and the light-transmitting effect as in the embodiment. The process proceeds sequentially to the substrate splitting process and the wafer splitting process.

  According to the processing method according to the second modification of the embodiment, similarly to the above-described embodiment, it is possible to easily form the transparent member 2c having a uniform thickness and emit light mainly from the back surface of the light emitting layer 2a. The light-emitting chip 2 that can efficiently extract the emitted light can be efficiently produced. Moreover, according to the processing method which concerns on the modification 2 of embodiment, even if the wafer W is comprised with hard sapphire, the light emitting chip 2 can be produced efficiently.

  The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the scope of the present invention.

2 Light-Emitting Chip 2a Light-Emitting Layer 2b Chip 2c Translucent Member 2e Translucent Resin 22 Cutting Blade W Wafer Wa Front Wb Back K Modified Layer (Division Start)
S Dividing origin groove (dividing origin)
R translucent substrate

Claims (3)

A chip having a light emitting layer on the surface, and a translucent member formed of a material that is attached to the back side of the chip with a light transmitting resin and transmits light emitted from the light emitting layer And a processing method for manufacturing a light emitting chip formed from:
A plurality of regions are defined by a plurality of scheduled division lines on the surface of the substrate, and a division starting point is formed along the planned division lines for dividing the wafer into a wafer in which a light emitting layer is formed in the partitioned regions. A split starting point forming step to be formed;
After performing the division starting point forming step, a translucent substrate formed of a material having an area equivalent to at least the wafer on the back surface of the wafer and transmitting light emitted from the light emitting layer is formed from the light emitting layer. A sticking step of sticking with a translucent resin that transmits the emitted light;
After carrying out the attaching step, the translucent substrate is cut by a cutting blade along the planned dividing line, and is divided into a plurality of translucent members;
After performing the translucent substrate dividing step, a wafer dividing step of applying an external force along the scheduled dividing line of the wafer and dividing the wafer into a plurality of chips starting from the dividing starting point;
A processing method comprising:   2. The division starting point in the division starting point forming step is a division starting point groove formed on the surface by subjecting the wafer to ablation or cutting using a cutting blade from the light emitting layer side. Processing method.   The split starting point in the split starting point forming step is a modified layer formed inside the wafer by irradiating a laser beam having a wavelength that passes through the wafer from the back side along the planned split line. Item 1. The processing method according to Item 1.

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