JP2014195040A - Manufacturing method of led element, wafer substrate for led element manufacture and manufacturing device for led element - Google Patents

Abstract

An LED element manufacturing method and an apparatus therefor are provided that can obtain an LED element having excellent luminous efficiency more reliably and easily than in the past.
A wafer provided with an LED pattern on one main surface, each of which is formed by repeating two-dimensionally a unit pattern that constitutes one LED element, is divided into division areas provided in a grid pattern. Then, the method of manufacturing the LED element by dividing into pieces is a scribe process in which a scribe line is formed by performing laser scribe along a planned division area of the wafer before the LED pattern is formed, and a wafer subjected to the scribe process An LED pattern forming process for forming an LED pattern on the main surface, and an individualizing process for obtaining a plurality of LED elements by breaking the wafer that has undergone the LED pattern forming process into pieces by breaking along a scribe line. I made it.
[Selection] Figure 2

Description

  The present invention relates to a method for manufacturing an LED element, and relates to a method for manufacturing an LED element by dividing a substrate with a pattern in which unit patterns of LED elements are repeatedly arranged two-dimensionally on the substrate, and an apparatus therefor. About.

  In general, an LED element is formed by repeatedly forming a unit pattern of an LED element made of a group III nitride semiconductor layer such as GaN or a metal electrode on a substrate (wafer, mother substrate) such as a sapphire single crystal in two dimensions. A substrate with a pattern (a substrate with an LED pattern) is manufactured by a process of dividing the substrate into divided regions called streets provided in a grid and dividing the substrate into chips (chips). Here, the street is a narrow area that is a gap between two parts that become LED elements by division.

  A substrate with a pattern is formed on a wafer with a buffer layer made of a group III nitride, an n-type conductive layer (also called an n-type cladding layer, an n-type contact layer, etc.), a light emitting layer, a p-type conductive layer ( p-type cladding layer, p-type contact layer, etc.) are stacked, and then a p-electrode and an n-type conductive layer are exposed on the p-type conductive layer, and an n-electrode is formed on the exposed surface. (For example, refer to Patent Documents 1 to 3).

  In addition, as a technique for division, laser light that is ultrashort pulse light having a pulse width of the order of psec is irradiated under the condition that the irradiated area of each unit pulse light is discretely positioned along the planned processing line. By doing so, a method of forming a starting point for division along a planned processing line (usually a street center position) is already known (see, for example, Patent Document 4). In the technique disclosed in Patent Document 4, crack progress (crack progress) occurs due to cleavage or cleavage between the processing marks formed in each irradiation region of the single pulse light, and the substrate is moved along the crack. By dividing (breaking), singulation is realized.

  In addition, for the purpose of improving the light extraction efficiency of the LED element, an aspect in which the LED element pattern is formed after performing uneven processing on the surface of the wafer before forming the group III nitride semiconductor layer is also known (for example, (See Patent Document 2 and Patent Document 3). Patent Document 2 discloses a PSS (Patterned Sapphire Substrate) formed by performing a photolithography process and RIE (Reactive Ion Etching) to form a regular pattern in which a convex portion has a truncated cone shape on the surface of a sapphire wafer. An embodiment using is disclosed. Patent Document 3 discloses that ICP-RIE (Inductive Coupled Plasma Reactive Ion Etching) is performed after discretely attaching fine metal particles such as Ni and Pd to the surface of a sapphire wafer by vapor deposition. By doing so, a mode is disclosed in which random triangular protrusions are formed on the surface of the wafer.

Japanese Patent Laid-Open No. 10-200215 JP 2012-64811 A JP 2010-225787 A JP 2011-131256 A

  In the case of the technique disclosed in Patent Document 4, the singulation is performed on a substrate with a pattern in which unit patterns constituting LED elements are formed on a wafer. Ideally, crack growth during singulation should occur perpendicularly to the substrate surface, but according to the conventional procedure, the group III nitride semiconductor layer cracked obliquely during division, and other than the street In some cases, the III-nitride semiconductor layer of the element constituent part is damaged. Such damage reduces the luminous efficiency of the LED element.

  Further, depending on the LED element to be manufactured, the chip size, the layer configuration (material, thickness, etc.) of the substrate with the pattern, the street width, and the like vary, and the division needs to be performed well in each layer. For this reason, there are problems that processing restrictions are large and it is difficult to set processing conditions.

  Alternatively, the technique disclosed in Patent Document 4 is usually performed by using the surface opposite to the unit pattern forming surface of the wafer as the surface to be irradiated with laser light. When a reflector: Omni-Directional Reflector) or DBR (Distributed Bragg Reflector) is provided, there is a problem that it is difficult to perform good division.

  This invention is made | formed in view of the said subject, and it aims at providing the manufacturing method of the LED element which can obtain the LED element excellent in luminous efficiency more reliably and easily than before.

  In order to solve the above-mentioned problems, the invention of claim 1 provides a wafer in which an LED pattern formed by repetitively forming unit patterns each constituting one LED element is provided on one main surface in a lattice shape. Is a method of manufacturing an LED element by dividing into pieces and dividing into pieces, and laser scribing is performed along the divided area of the wafer base before forming the LED pattern. Obtained by a scribing process for forming a scribe line, an LED pattern forming process for obtaining the wafer by forming an LED pattern on the main surface of the wafer base material that has undergone the scribing process, and the LED pattern forming process. In addition, the wafer is separated into pieces by breaking along the scribe line to obtain a plurality of LED elements. , Characterized in that it comprises a.

  Invention of Claim 2 is a manufacturing method of the LED element of Claim 1, Comprising: The etching process which etches the said main surface of the said wafer base material in which the said scribe line was formed in the said scribe process is further provided In the LED pattern forming step, the LED pattern is formed on the main surface etched in the etching step.

  Invention of Claim 3 is a manufacturing method of the LED element of Claim 1, Comprising: The said main surface of the said wafer base material in which the said scribe line was formed in the said scribe process is etched, and an uneven surface is formed. An etching step, wherein in the LED pattern forming step, the LED pattern is formed on the main surface on which the uneven surface is formed.

  According to a fourth aspect of the present invention, in the method for manufacturing an LED element according to any one of the first to third aspects, in the scribing step, pulse laser light having a pulse width of the order of psec is used for the laser scribing. It is characterized by that.

  The invention of claim 5 is the method for manufacturing the LED element according to claim 4, wherein in the scribe step, the irradiated regions of the individual pulsed light of the pulsed laser light are made discrete. The scribe line is formed as a row of a plurality of processing marks separated from each other.

  A sixth aspect of the present invention is the LED element manufacturing method according to any one of the first to third aspects, wherein in the scribing step, pulse laser light having a pulse width of the order of nsec is used for the laser scribing. It is characterized by that.

  The invention according to claim 7 is the method of manufacturing the LED element according to claim 6, wherein the scribe line is continuously formed in the scribe process.

  The invention of claim 8 is the method of manufacturing the LED element according to claim 2 or claim 3, wherein in the scribing step, a pulse laser beam having a pulse width of nsec order is used for the laser scribing, and the etching is performed. In the process, the main surface of the wafer base material is etched, and the altered region formed along the scribe line is removed.

  The invention of claim 9 is the LED element manufacturing method according to any one of claims 1 to 8, wherein, in the LED pattern forming step, the wafer substrate is heated by heating the wafer substrate. It is characterized in that a stress is generated in the crack to cause a crack from the scribe line to propagate.

  A tenth aspect of the present invention is the method of manufacturing the LED element according to any one of the first to ninth aspects, wherein an alignment mark is formed on the main surface of the wafer base before the LED pattern is formed. An alignment mark forming step, wherein in the scribing step, the laser scribing is performed along the planned division region of the wafer base material on which the alignment mark is formed in the alignment mark forming step. And

  The invention according to claim 11 is that the LED pattern formed by two-dimensionally repetitively forming unit patterns each constituting one LED element is provided on one main surface and then divided in a grid pattern An LED element is manufactured by being divided in a region, and a wafer base material for LED element manufacturing, wherein the main surface of the wafer base material is an uneven surface, and along the planned division region The main surface includes an alignment mark used for positioning at the time of division, and a scribe line provided along the planned division region by performing laser scribing.

  The invention according to claim 12 is a divided division region in which a wafer provided with an LED pattern on one main surface formed by two-dimensionally repeating unit patterns each constituting one LED element is provided in a lattice shape. Is an LED element manufacturing apparatus for manufacturing an LED element by dividing it into individual pieces, and performing laser scribing along the planned division area of the wafer base before forming the LED pattern. Scribing means for forming a scribe line, LED pattern forming means for obtaining the wafer by forming an LED pattern on the main surface of the wafer substrate on which the scribe line is formed by the scribe means, and the LED pattern forming means The wafer obtained by the step is divided into pieces by breaking along the scribe line. Characterized in that it comprises a singulating means for obtaining an LED element.

  According to the first to twelfth aspects of the present invention, an LED element with excellent light extraction efficiency can be obtained with a higher yield than conventional.

2 is a schematic cross-sectional view showing the structure of an LED element 10. FIG. FIG. 5 is a diagram showing a procedure for producing the LED element 10. 3 is a cross-sectional view schematically showing a state in the middle of manufacturing the LED element 10. FIG. 4 is a diagram illustrating a state in which an alignment mark M is formed on a surface Wa of a wafer W. FIG. 1 is a diagram illustrating a configuration of a laser processing apparatus 100. FIG. It is a figure for demonstrating the laser scribe using the laser processing apparatus. It is a figure for demonstrating cleaning of scribe line SL1. It is a figure which illustrates the mode of the wafer W in the case of epitaxial growth. It is a figure which shows roughly about the mode of individualization by the break apparatus.

<LED element and its production procedure>
FIG. 1 is a schematic cross-sectional view showing the structure of an LED element 10 which is a production target by the manufacturing method according to the present embodiment. The LED element 10 includes an n-type layer 2, a light-emitting layer 3, and a p-type layer 4, which are each made of GaN, AlN, InN, or a group III nitride that is a mixed crystal thereof on the sapphire substrate 1. Are formed in this order, and an n-type electrode 5 is provided in an electrode forming region 5a in which a part of the n-type layer 2 is exposed, and a p-type electrode 6 is provided on the p-type layer 4. Have. Note that each of the n-type layer 2, the light emitting layer 3, and the p-type layer 4 is not limited to a single layer, and may be configured by stacking a plurality of layers. For example, the n-type layer 2 may be formed such that the lowermost layer is a buffer layer, and a contact layer, a clad layer, or the like is provided on the buffer layer. Alternatively, the light emitting layer 3 may be configured to have, for example, a multiple quantum well structure. Furthermore, the p-type layer 4 may be composed of a cladding layer, a contact layer, or the like.

  Moreover, the LED element 10 which concerns on this Embodiment shall make the interface of the sapphire substrate 1 and the n-type layer 2 into the uneven surface C for the purpose of the improvement of light extraction efficiency.

  Further, an ODR (Omni-Directional Reflector) or DBR (Distributed Bragg reflector) made of a metal thin film is formed on the main surface of the sapphire substrate 1 opposite to the main surface on which the above-described layers are formed. : Distributed Bragg Reflector) may be provided.

  FIG. 2 is a diagram illustrating a manufacturing procedure of the LED element 10 described above. FIG. 3 is a cross-sectional view schematically showing a state in the middle of manufacturing the LED element 10. In the present embodiment, a substrate (a substrate with an LED pattern) provided with an LED pattern PT formed by two-dimensionally repeating unit patterns each constituting one LED element 10 on a wafer W, It is assumed that manufacturing is performed by a so-called multi-chip process in which the area is divided into areas to be divided called streets ST (see FIG. 6) provided in a lattice shape and divided into chips (chips).

  In producing the LED element 10 in this manner, first, as shown in FIG. 3A, a wafer W is prepared (step S1). The thickness of the wafer W to be prepared is preferably about 380 μm to 430 μm. Then, an alignment mark M is formed on one main surface (hereinafter also referred to as a surface) Wa of the wafer W (step S2).

  The alignment mark M is used for positioning the wafer W in the subsequent singulation. FIG. 4 is a diagram illustrating a state in which the alignment mark M is formed on the surface Wa of the wafer W. In FIG. 4, on the surface Wa of the wafer W, two alignment marks M (M1, M2) are spaced apart in parallel to the orientation flat (orientation flat) OF, and two alignment marks M (M3) are perpendicular to the orientation flat OF. , M4) are illustrated as being spaced apart. Each alignment mark M is formed in a cross shape. However, the arrangement position and the number of the alignment marks M on the wafer W and the shape of the alignment marks M are not limited to this, and the alignment marks M may be provided in a manner suitable for positioning.

  The alignment mark M is preferably formed in the laser processing apparatus 100 used for laser scribing performed subsequently, that is, the alignment mark M and laser scribing are continuously performed. In such a case, the alignment mark M is formed as a processing mark by laser processing. However, the formation of the alignment mark M by laser processing is not an indispensable aspect, and the forming means is not limited as long as it can form at least the alignment mark M that can be used for singulation.

  The alignment mark M is formed and the wafer W is positioned during the subsequent laser scribe using the orientation flat OF.

  Following the formation of the alignment mark M, a scribe line SL is formed by laser scribing (step S3).

  Laser scribing is a process for forming a scribe line SL, which is a starting point of a break in singulation, on a substrate with a pattern. Conventionally, the laser scribe is performed after the formation of the LED pattern. However, the present embodiment is characteristic in that the laser scribe is performed prior to the formation of the LED pattern PT.

  FIG. 5 is a diagram illustrating the configuration of the laser processing apparatus 100 used for laser scribing. As described above, the laser processing apparatus 100 can also be used to form the alignment mark M.

  The laser processing apparatus 100 mainly includes a stage 101 for placing the wafer W thereon, and a controller 110 for controlling various operations (observation operation, alignment operation, processing operation, etc.) of the laser processing apparatus 100. By irradiating the wafer W placed on the wafer W with pulsed laser light (also simply referred to as laser light) LB emitted from the laser light source LS, various processing can be performed on the wafer W. Yes.

As the laser light source LS, an Nd: YAG laser is preferably used. Alternatively, an embodiment using an Nd: YVO ₄ laser or other solid-state laser may be used. Furthermore, the laser light source LS is preferably provided with a Q switch.

  As will be described later, the pulse width of the laser beam LB may be appropriately determined depending on the type of the scribe line SL to be formed. For example, the value may be set to an nsec order value or the psec order value. The wavelength of the laser beam LB preferably belongs to a wavelength range of 150 nm to 563 nm when the pulse width is on the order of nsec. In particular, when an Nd: YAG laser is used as the laser light source LS, its third harmonic (wavelength of about 355 nm) is the preferred embodiment. On the other hand, when the pulse width is on the order of psec, any wavelength of the fundamental wave, the second harmonic wave, and the third harmonic wave of the laser exemplified above may be used, but the wafer W provided with a multiple reflection film (DBR) is used. In the case of processing, it is preferable to use a fundamental wave. The pulse repetition frequency is preferably 10 kHz or more and 200 kHz or less.

  Details of the laser processing apparatus 100 will be described later.

  FIG. 6 is a diagram for explaining laser scribing using the laser processing apparatus 100. First, FIG. 6A is a partially enlarged view of the main surface Wa of the wafer W. FIG. More specifically, FIG. 6A shows a position that becomes the street ST when the LED pattern PT is formed on the wafer W. Here, the street ST is a narrow region that is a gap between two portions that become the LED elements 10 by division, and is defined in a lattice shape over substantially the entire main surface Wa of the wafer W. A scribe line SL is formed at a substantially central position in the width direction of each street ST. That is, a plurality of streets ST that are parallel to each other in each of two orthogonal directions are set in advance on the wafer W, and the wafer W is divided along the scribe line SL at each street ST.

  In FIG. 6A, the position near one intersection of the streets ST extending in two orthogonal directions is indicated by a broken line. For confirmation, such a street ST is not provided in the actual wafer W, and the position to be the street ST is merely determined in the pattern design.

  The scribe line SL is formed using the laser processing apparatus 100 so that the irradiated position of the laser beam LB moves along the street ST, in other words, the street ST is scanned by the laser beam LB. This is realized by relatively moving the emission source of the light LB and the wafer W.

  However, in more detail, the formation of the scribe line SL is roughly divided into two.

  The first is a mode in which a continuous scribe line SL (SL1) along the street ST is formed as shown in FIG. This means that, when scanning with the laser beam LB, the processing range of each laser beam LB emitted from the laser processing apparatus 100 by each single pulse beam (generally corresponding to the irradiated area of each individual pulse beam) is overlapped. It is realized by. When such a continuous scribe line SL1 is formed, the pulse width of the laser beam LB is preferably set to the nsec order, but a mode in which a pulse width of another size is applied may be used. When the pulse width of the laser beam LB is set to nsec order, it is preferably 50 nsec to 300 nsec.

  Note that the continuous scribe line SL1 may be formed as a processed groove having a V shape in cross section as shown in FIG. 3B, or an altered region having a V shape in cross section may be formed (see FIG. 3B). In other words, it may be formed in such a manner that the processed groove shown in FIG. 3B is filled with the altered region. The former is realized by evaporating and scattering sapphire that existed in the irradiated region of the laser beam LB, and the latter is realized by melting and modifying sapphire in the irradiated region by irradiation of the laser beam LB. The These can be selectively realized by changing the irradiation condition of the laser beam LB. Also, when forming the alignment mark M, the same processing conditions as those for the scribe line SL1 can be applied.

  On the other hand, the second is a mode in which a plurality of machining marks P are discretely formed along the street ST as shown in FIG. In this case, strictly speaking, the line ST is not formed on the street ST, but in the present embodiment, the formation of the line of the processing marks in such an aspect is performed by discrete scribing. This is referred to as the formation of the line SL (SL2).

  The formation of the discrete scribe lines SL2 is realized by separating the irradiated areas of the individual single-pulse lights of the laser light LB emitted from the laser processing apparatus 100 when scanning with the laser light LB. The formation of such discrete scribe lines SL2 is realized by setting the pulse width of the laser beam LB to the order of psec and appropriately adjusting the repetition frequency of the laser beam LB and the relative movement speed with respect to the wafer W. When the pulse width of the laser beam LB is set to the psec order, it is preferably set to 2 psec to 40 psec. In order to realize the singulation well, it is preferable to perform the processing under the condition that the irradiated regions of the individual single pulse lights are separated by about 2 μm to 20 μm.

  In addition, when discrete scribe lines SL2 are formed in this manner, sapphire melts, evaporates, and scatters in each processing mark P, and a crack that connects the two occurs between the processing marks P. .

  On the other hand, even in the thickness direction of the wafer W, cracks can develop from the lower end of the scribe line SL toward the other main surface (hereinafter also referred to as back surface) Wb, but the formation depth of the scribe line SL is at most several tens of μm. Therefore, the progress of such a crack usually does not reach the division of the wafer W. It should be noted that the progress of the crack in the thickness direction can also occur when the continuous scribe line SL1 is formed.

  Subsequent to the formation of the scribe line SL, the main surface Wa is etched (step S4). Such etching may be performed in order to make the main surface Wa the uneven surface C, or the melt may be removed. When etching is performed to make the wafer W PSS (Patterned Sapphire Substrate), the melt can be etched simultaneously.

  For example, after forming a resist mask so that the part used as a convex part is masked, the aspect which forms a regular convex part in the main surface Wa by performing RIE (Reactive Ion Etching) may be sufficient. Alternatively, by depositing metal fine particles such as Ni and Pd on the main surface Wa by vapor deposition as a mask, ICP-RIE (Inductive Coupled Plasma Reactive Ion Etching) is performed. A random triangular projection may be formed on the main surface Wa. In either case, the main surface Wa of the wafer W can be changed to the uneven surface C having various shapes by appropriately changing the mask manufacturing conditions and the etching conditions.

  In addition, about the formation place of the alignment mark M, the aspect which prevents it from being etched by using a mask may be sufficient, and when the alignment mark M is formed to such an extent that it does not lose | disappear by etching, the mask concerned is used. You don't have to.

  FIG. 3C illustrates the wafer W after the etching process. In addition, in FIG.3 (c), although the uneven | corrugated surface C in which the convex part became the cross sectional view triangle shape is illustrated, the formation aspect of an uneven surface is not restricted to this, For example, it is disclosed by patent document 1 As shown, a mode in which convex portions having a trapezoidal cross section may be formed.

  In addition, by passing through the process so far, the wafer W for LED element manufacture by which the main surface Wa is the uneven surface C and the alignment mark M and the scribe line SL are formed is obtained. It can be said that there is.

  When the continuous scribe line SL1 is formed with the laser beam LB having a pulse width of the nsec order, these etching processes have an effect of cleaning the scribe line SL1. FIG. 7 is a diagram for explaining the cleaning of the scribe line SL1.

  When the continuous scribe line SL1 is formed with the laser beam LB having a pulse width of nsec order, as shown in FIG. 7A, the processed groove forming the scribe line SL is made of sapphire re-solidified after evaporation. An altered region AR may be formed. Alternatively, in the case of processing conditions that cause melting modification, the scribe line SL is an altered region having a V-shaped cross section. Since these altered regions are mainly made of polycrystalline or amorphous sapphire, the remaining region becomes a factor of reducing the light extraction efficiency from the LED element 10. However, these altered regions are weaker in mechanical strength than the entire wafer W, and therefore, as shown in FIG. 7B, during the etching for forming the irregularities as described above. Furthermore, it is relatively easy to evaporate and remove. As a result, as shown in FIG. 7C, at the time when the uneven surface C is formed, the cleaning of the scribe line SL is realized.

  In the case where the discrete scribe line SL2 is formed by the pulse laser beam LB of the psec order, sapphire hardly remains on the processing mark P that forms the scribe line SL2. However, in such a case, it is not excluded to perform cleaning by etching as described above.

  The LED pattern PT described above is formed on the main surface Wa of the wafer W on which the uneven surface C is provided by etching (step S5). That is, the epitaxial growth of the group III nitride layer that becomes the n-type layer 2, the light emitting layer 3, and the p-type layer 4 and the formation of the n-type electrode 5 and the p-type electrode 6 are performed. FIG. 3D illustrates a state in which the LED pattern PT is formed on the uneven surface C of the wafer W.

  Various known epitaxial growth techniques can be applied to the epitaxial growth of the group III nitride layer. For example, it can be performed by a technique such as MOCVD (metal organic chemical vapor deposition) or MBE (molecular beam epitaxy). The actual epitaxial growth conditions (wafer temperature, raw material composition, raw material gas flow rate, raw material gas pressure, growth time, etc.) when each growth method is used are the n-type layer 2, the light emitting layer 3, and the p-type to be formed. It is determined according to the composition and thickness of the layer 4. For forming the n-type electrode 5 and the p-type electrode 6, various thin film forming methods such as vapor deposition and sputtering can be suitably used. The electrode material may be appropriately selected from various metal materials such as Ni, Pd, Pt, Au, and Al. Alternatively, the n-type electrode 5 and the p-type electrode 6 may be provided as a multilayer electrode in which metal layers having different compositions are laminated. The n-type electrode 5 is formed after the LED pattern PT is formed and a part of the n-type layer 2 is exposed as an electrode formation region 5a by a photolithography process and etching.

  FIG. 8 is a diagram illustrating the state of the wafer W during epitaxial growth. In this embodiment, a wafer W on which a scribe line SL and a concavo-convex surface C are formed as shown in FIG. 8A is subjected to an epitaxial growth process. As shown in FIG. W is heated. The heating temperature at that time varies depending on the composition of the layer to be formed, etc., but is generally about 600 ° C. to 1200 ° C. When the wafer W is heated in such a manner, stress is generated in the wafer W although illustration is omitted in FIG. And when the stress acts, the crack CR progresses from the scribe line SL toward the main surface Wb. The progress of the crack CR has an effect of facilitating a break at the time of the subsequent singulation. In this case, the crack does not progress until the wafer W is divided, as in the formation of the scribe line SL. Alternatively, it is possible to reduce the formation depth of the scribe line SL in comparison with the case where the scribe line SL is formed after the LED pattern PT is formed in anticipation of the progress of the crack CR due to heating during the epitaxial growth. .

  After performing laser scribing, the wafer W is polished from the back surface Wb side to a desired thickness (step S6).

  The polishing of the wafer W is preferably performed by chemical mechanical polishing (CMP). At the time of polishing, a protective sheet is attached to the main surface Wa side so that the wafer W is not divided. By this polishing, the thickness of the wafer W, which was about 380 μm to 430 μm, is set to about 80 μm to 200 μm. FIG. 3E illustrates a wafer W that has been polished up to the broken line shown in FIG.

  After the polishing is finished, finally, the substrate with the LED pattern is separated into pieces by breaking along the scribe line SL to obtain a large number of LED elements 10 as shown in FIG. 3F (step S7). . In addition, when providing ODR and DBR in LED element 10, after formation of LED pattern PT, before a break, the metal thin film used as ODR or DBR with respect to the main surface Wb by well-known methods, such as a vapor deposition method, is formed. What is necessary is just to form.

  FIG. 9 is a diagram schematically showing the state of singulation by the break device 200. The break device 200 is a device that breaks an object using a three-point support method. The break device 200 includes one upper break bar 201 and two lower break bars 202. The upper break bar 201 is a columnar member having a triangular cross section or an isosceles trapezoidal cross section, and the lower break bar 202 is a plate member.

  At the time of singulation, the substrate with a pattern on which the LED pattern PT is formed on the wafer W is horizontally supported so that the LED pattern PT is on the lower side, and the wafer W is positioned by the alignment mark M. The upper break bar 201 is disposed above the main surface Wb and immediately above the formation position of the scribe line SL in parallel with the scribe line SL, and the two lower break bars 202 are below the LED pattern PT. It arrange | positions in the position symmetrical with respect to the formation position of the scribe line SL. Then, the upper break bar 201 is brought into contact with the main surface Wb immediately above the formation position of the scribe line SL, and the two lower break bars 202 are formed into the LED pattern PT while maintaining a symmetric state with respect to the scribe line SL. Make contact. Thereby, the crack which has propagated from the scribe line SL reaches the main surface Wb due to the acting stress, and the substrate with pattern can be broken along the scribe line SL.

  Many LED elements 10 can be obtained by performing such a break with respect to all the scribe lines SL.

<Effects of performing laser scribing in advance>
As described above, in the LED element manufacturing method according to the present embodiment, after forming the scribe line SL by laser scribe on the wafer W on which the alignment mark M is formed, the uneven processing by etching and the formation of the LED pattern PT And then it is divided into pieces. Hereinafter, the effect of producing the LED element by the procedure will be described.

  First, when laser scribing is performed after the LED pattern PT is formed as in the prior art, there is a possibility that the LED pattern PT is damaged by the laser beam LB. Since laser scribing is performed in the state where PT is not formed, the LED pattern PT is not damaged.

  Second, in the case of the conventional procedure, in order to avoid the influence of the laser beam LB on the LED pattern PT as much as possible, laser scribing is performed with the main surface Wb opposite to the main surface Wa on which the LED pattern PT is formed as the irradiated surface. As a result, cracks that propagate from the scribe line SL at the time of the break reach the LED pattern PT, and the LED pattern PT may be divided instead of the street ST. In the case of the form, since laser scribing is performed from the main surface Wa side before the formation of the LED pattern PT, the LED element 10 can be obtained with a high yield because there is no division at the LED pattern PT. I can do it.

  Third, in the case of the conventional procedure, the street ST is irradiated with the laser beam LB in a state where the street ST is physically partitioned as a narrow region by the LED pattern PT. Although the restrictions were large, in the case of the present embodiment, although the position of the street ST is fixed, the actual processing target is the wafer W in which the LED pattern PT does not exist, and thus the degree of freedom in setting processing conditions is high. Thus, laser scribing can be performed under more suitable conditions.

  Fourth, it is difficult to produce an LED element having an ODR or DBR made of a metal thin film by the above-described conventional procedure because the metal thin film reflects laser light. In the case of the embodiment, since laser scribing is performed before forming the metal thin film, an LED element having ODR and DBR and having excellent light extraction efficiency can be produced without any problem.

  Fifth, when the continuous scribe line SL1 is formed with the laser beam LB having a pulse width of nsec order, an altered region is formed at the scribe line SL1, but this is removed by subsequent etching. As a result, the light extraction efficiency of the LED element can be improved.

  Sixth, since the crack CR develops from the scribe line SL when the wafer W is heated during the formation of the LED pattern after laser scribe, the conventional procedure is adopted for the formation depth of the scribe line SL. It can be made smaller than the case.

  Seventh, since the wafer W, which has been subjected to the formation of alignment marks, laser scribing and etching, is used for the formation of the LED pattern PT, the manufacturer who purchases the wafers and manufactures the LED elements is the alignment mark No need to form or laser scribe. As a result, the cost of the LED element is reduced.

  By obtaining the above effects, according to the present embodiment, an LED element having excellent light extraction efficiency can be obtained with a higher yield than conventional.

<Detailed configuration of laser processing equipment>
Finally, a detailed configuration of the laser processing apparatus 100 shown in FIG. 5 will be described. As described above, the laser processing apparatus 100 mainly includes the stage 101 on which the wafer W is placed, and the controller 110 that controls various operations of the laser processing apparatus 100.

  The stage 101 is movable in the horizontal direction by the moving mechanism 102. The moving mechanism 102 moves the stage 101 in a predetermined XY 2-axis direction within a horizontal plane by the action of a driving unit (not shown). Thereby, the movement of the laser beam irradiation position and the like are realized. The moving mechanism 102 can also perform a rotation (θ rotation) operation in a horizontal plane around a predetermined rotation axis independently of horizontal driving.

  Further, in the laser processing apparatus 100, surface observation for directly observing the wafer W from the side irradiated with the laser light (main surface Wa in the present embodiment) through an imaging unit (not shown), or mounting on the stage 101 is performed. Backside observation or the like can be performed through the stage 101 from the processed side (main surface Wb in the present embodiment).

  The stage 101 is formed of a transparent member such as quartz, and a suction pipe (not shown) serving as an intake passage for adsorbing and fixing the wafer W with the adhesive protection sheet AS attached to the main surface Wb is disposed inside the stage 101. Is provided. The suction pipe is provided, for example, by drilling a predetermined position of the stage 101 by machining.

  In a state where the wafer W to which the adhesive protection sheet AS is stuck is placed on the stage 101, the suction pipe is sucked by the suction means 103 such as a suction pump, for example, and the suction pipe is placed on the stage 101 placement surface side. The wafer W (and the adhesive protective sheet AS) is fixed to the stage 101 by applying a negative pressure to the suction hole provided at the tip.

  More specifically, in the laser processing apparatus 100, the laser light LB is emitted from the laser light source LS, reflected by a dichroic mirror 104 provided in a lens barrel (not shown), and then the laser light LB is converted into the stage 101. Then, the light is condensed by the condenser lens 105 so as to be focused on the part to be processed of the wafer W placed on the wafer W and irradiated onto the wafer W. The laser beam LB is emitted to the wafer W using the condenser lens 105 as a direct emission source. By combining the irradiation of the laser beam LB and the movement of the stage 101, the wafer W can be processed while the laser beam LB is scanned relative to the wafer W.

  In the laser processing apparatus 100, it is also possible to irradiate the laser beam LB in a defocused state in which the in-focus position is intentionally shifted from the surface of the wafer W as necessary during processing. Yes. In the present embodiment, it is preferable to set the defocus value (shift amount of the in-focus position in the direction from the surface of the wafer W toward the inside) in the range of 5 μm to 40 μm.

As the laser light source LS, an Nd: YAG laser is preferably used. Alternatively, an embodiment using an Nd: YVO ₄ laser or other solid-state laser may be used. Furthermore, the laser light source LS is preferably provided with a Q switch.

  Further, adjustment of the wavelength and output of the laser light LB emitted from the laser light source LS, the pulse repetition frequency, the pulse width, and the like are realized by the irradiation control unit 123 of the controller 110. When a predetermined setting signal according to the processing mode setting data D2 is issued from the processing unit 125 to the irradiation control unit 123, the irradiation control unit 123 sets the irradiation condition of the laser beam LB according to the setting signal.

It is preferable that the laser beam LB is radiated while being focused to a beam diameter of about 1 μm to 10 μm by the condenser lens 105. A case, a peak power density in the irradiation of the laser beam LB becomes approximately ^{1GW / cm 2 ~10GW / cm 2} .

  The polarization state of the laser light LB emitted from the laser light source LS may be circularly polarized light or linearly polarized light. However, in the case of linearly polarized light, for example, the angle between the two is within ± 1 ° so that the polarization direction is substantially parallel to the scanning direction from the viewpoint of the bending of the processed cross section in the crystalline work material and the energy absorption rate. It is preferable that it is made to exist. Further, when the emitted light is linearly polarized light, the laser processing apparatus 100 preferably includes an attenuator (not shown). The attenuator is disposed at an appropriate position on the optical path of the laser beam LB and plays a role of adjusting the intensity of the emitted laser beam LB.

  The controller 110 controls the operation of each unit described above and is referred to in the control unit 120 that realizes the processing of the wafer W in various modes, the program 130P that controls the operation of the laser processing apparatus 100, and processing. And a storage unit 130 for storing various data.

  The control unit 120 is realized by a general-purpose computer such as a personal computer or a microcomputer, for example, and various components can be obtained by the program 130P stored in the storage unit 130 being read and executed by the computer. Is realized as a functional component of the control unit 120.

  Specifically, the control unit 120 includes a drive control unit 121 that controls operations of various drive parts related to processing such as driving of the stage 101 by the moving mechanism 102 and focusing operation of the condensing lens 105, and the like. An imaging control unit 122 that controls imaging of the wafer W by the imaging unit that does not perform, an irradiation control unit 123 that controls irradiation of the laser light LB from the laser light source LS, and an operation of attracting and fixing the wafer W to the stage 101 by the suction unit 103 Are mainly provided with a suction control unit 124 that controls the processing and a processing unit 125 that executes processing to the processing target position in accordance with the given processing position data D1 and processing mode setting data D2.

  The storage unit 130 is realized by a storage medium such as a ROM, a RAM, and a hard disk. The storage unit 130 stores processing position data D1 describing the formation position of the scribe line SL on the wafer W, and conditions for individual parameters of the laser light and driving conditions of the stage 101 according to the processing mode ( Alternatively, machining mode setting data D2 describing such settable ranges) is stored. The storage unit 130 may be implemented by a computer component that implements the control unit 120, or may be provided separately from the computer, such as a hard disk.

  Various input instructions given by the operator to the laser processing apparatus 100 are preferably performed using a GUI realized in the controller 110. For example, a processing menu is provided on the GUI by the operation of the processing unit 125.

  In the laser processing apparatus 100 having the above-described configuration, the processing unit 125 acquires the processing position data D1 and the processing conditions corresponding to the selected processing mode from the processing mode setting data D2, and the conditions By controlling the operations of the corresponding units through the drive control unit 121, the irradiation control unit 123, and the like so that the operations according to the above are executed, the processing in various processing modes can be selectively performed. It is preferable that the processing mode can be selected according to a processing menu provided to the operator in the controller 110 by the operation of the processing unit 125, for example.

  Specifically, by changing the combination of the irradiation condition of the laser beam LB from the laser light source LS and the scanning condition of the laser beam LB with respect to the wafer W by moving the stage 101, the continuous scribe line SL1 can be formed or discrete. Various processes such as formation of a typical scribe line SL2 or formation of an alignment mark M can be performed under appropriate processing conditions.

<Modification>
In the above embodiment, laser scribing and etching are performed after the alignment mark is formed, but the alignment mark formation timing is not limited to this. For example, at the time of etching for forming the uneven surface C, an alignment mark may be formed together by the etching process.

  Further, when laser scribing is performed using the orientation flat OF as a reference, the scribing line can be used as an alignment mark in the steps after the laser scribing, and therefore the alignment mark does not have to be formed independently.

  In the LED element 10, it is not essential that the interface between the sapphire substrate 1 and the n-type layer 2 is an uneven surface C. Therefore, the etching of the wafer W in step S5 is not an essential aspect. However, from the viewpoint of increasing the light extraction efficiency, it is preferable that the interface is an uneven surface C.

DESCRIPTION OF SYMBOLS 1 Sapphire substrate 2 n-type layer 3 light emitting layer 4 p-type layer 5 n-type electrode 5a electrode formation area 6 p-type electrode 10 LED element 100 laser processing apparatus 101 stage 102 moving mechanism 103 suction means 104 dichroic mirror 105 condenser lens 110 controller DESCRIPTION OF SYMBOLS 120 Control part 130 Memory | storage part 200 Break apparatus 201 Upper break bar 202 Lower break bar AR Alteration area AS Adhesive protective sheet C Concavity and convexity CR Crack D1 Processing position data D2 Processing mode setting data LB Pulse laser beam (laser beam)
LS Laser light source M, M1, M2, M3, M4 Alignment mark OF Orientation flat P Process mark PT LED pattern SL, SL1, SL2 Scribe line ST Street W Wafer Wa, Wb (Wafer) main surface

Claims (12)

A wafer provided with an LED pattern, which is formed by repeating two-dimensionally repetitively forming unit patterns each constituting one LED element, on one main surface is divided into divided division regions provided in a lattice shape, A method of manufacturing an LED element by:
A scribing step of forming a scribe line by performing laser scribing along the division planned region of the wafer base before forming the LED pattern;
An LED pattern forming step for obtaining the wafer by forming an LED pattern on the main surface of the wafer base material that has undergone the scribing step;
An individualization step of obtaining a plurality of LED elements by dividing the wafer obtained by the LED pattern formation step into pieces by breaking along the scribe line;
The manufacturing method of the LED element characterized by the above-mentioned. It is a manufacturing method of the LED element according to claim 1,
An etching step of etching the main surface of the wafer base material on which the scribe line is formed in the scribe step;
Further comprising
In the LED pattern forming step, the LED pattern is formed on the main surface etched in the etching step.
The manufacturing method of the LED element characterized by the above-mentioned. It is a manufacturing method of the LED element according to claim 1,
An etching step of etching the main surface of the wafer base material on which the scribe line is formed in the scribe step to form an uneven surface;
Further comprising
In the LED pattern forming step, the LED pattern is formed on the main surface on which the uneven surface is formed.
The manufacturing method of the LED element characterized by the above-mentioned. A manufacturing method of the LED element according to any one of claims 1 to 3,
In the scribe process, a pulse laser beam having a pulse width of the order of psec is used for the laser scribe.
The manufacturing method of the LED element characterized by the above-mentioned. It is a manufacturing method of the LED element according to claim 4,
In the scribing step, the irradiation region of each single pulsed light of the pulsed laser light is made discrete, so that the scribe line is formed as a row of a plurality of processing marks separated from each other.
The manufacturing method of the LED element characterized by the above-mentioned. A manufacturing method of the LED element according to any one of claims 1 to 3,
In the scribe step, a pulse laser beam having a pulse width of the order of nsec is used for the laser scribe.
The manufacturing method of the LED element characterized by the above-mentioned. It is a manufacturing method of the LED element according to claim 6,
In the scribe process, the scribe line is continuously formed.
The manufacturing method of the LED element characterized by the above-mentioned. It is a manufacturing method of the LED element according to claim 2 or 3,
In the scribe process, a pulse laser beam having a pulse width of the order of nsec is used for the laser scribe,
In the etching step, etching the main surface of the wafer base and removing the altered region formed along the scribe line,
The manufacturing method of the LED element characterized by the above-mentioned. A method for manufacturing an LED element according to any one of claims 1 to 8,
In the LED pattern formation step, the wafer base material is heated to cause stress in the wafer base material, and a crack from the scribe line is developed.
The manufacturing method of the LED element characterized by the above-mentioned. A method for manufacturing an LED element according to any one of claims 1 to 9,
An alignment mark forming step for forming an alignment mark on the main surface of the wafer base before forming the LED pattern;
Further comprising
In the scribing step, the laser scribing is performed along the planned division region of the wafer base material on which the alignment mark is formed by the alignment mark forming step.
The manufacturing method of the LED element characterized by the above-mentioned. An LED pattern formed by two-dimensionally repetitively forming unit patterns each constituting one LED element is provided on one main surface, and then divided in a predetermined division area provided in a lattice shape. The LED element is manufactured by the wafer substrate for LED element manufacturing,
The main surface of the wafer base is an uneven surface;
And,
An alignment mark used for positioning when dividing along the planned division region;
A scribe line provided along the planned division area by performing laser scribe,
Is provided on the main surface. A wafer substrate for manufacturing an LED element. A wafer provided with an LED pattern, which is formed by repeating two-dimensionally repetitively forming unit patterns each constituting one LED element, on one main surface is divided into divided division regions provided in a lattice shape, An LED element manufacturing apparatus for manufacturing an LED element,
A scribing means for forming a scribe line by performing laser scribing along the planned division region of the wafer base before forming the LED pattern;
LED pattern forming means for obtaining the wafer by forming an LED pattern on the main surface of the wafer base material on which a scribe line is formed by the scribe means;
Individualizing means for obtaining a plurality of LED elements by dividing the wafer obtained by the LED pattern forming means into pieces by breaking along the scribe line;
A device for manufacturing an LED element.

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