JP2007299912A - Manufacturing method of light-emitting device and semiconductor wafer for manufacturing light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize occurrence of defective lamination of a transparent substrate, cracks of a compound semiconductor layer, and the like, in a manufacturing method of a light-emitting device wherein a substrate for growth is removed through etching after a compound semiconductor layer including a light-emitting layer portion on the substrate for growth grows by a MOVPE method, then the transparent substrate is laminated on the compound semiconductor layer with the substrate for growth removed. <P>SOLUTION: A process to remove projected type exposure portions 51 of a columnar semiconductor defective portion is performed prior to a laminating process after a substrate removing process, wherein the semiconductor defective portion remains on a second main surface of a layer 50 subject to device forming, without being dissolved by selective chemical etching. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a light emitting element and a semiconductor wafer for manufacturing a light emitting element.

JP 2001-68731 A JP 2002-203987 A

The light-emitting layer portion is formed of (Al _x Ga _1-x ) _y In _1-y P mixed crystal (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1; hereinafter also referred to as AlGaInP mixed crystal or simply AlGaInP). The light emitting device has a high brightness by adopting a double hetero structure in which a thin AlGaInP active layer is sandwiched between an n-type AlGaInP cladding layer and a p-type AlGaInP cladding layer having a larger band gap. An element can be realized. In general, the light emitting layer is grown by metal-organic vapor phase epitaxy (MOVPE).

  In the case of an AlGaInP light emitting device, a GaAs substrate is used as a growth substrate for the light emitting layer portion. However, GaAs absorbs a large amount of light in the emission wavelength region of the AlGaInP light emitting layer portion. Therefore, Patent Documents 1 and 2 disclose a method of once removing a GaAs substrate and newly bonding a GaP substrate.

  However, as a result of studies by the present inventors, when the AlGaInP light emitting layer portion is grown on the GaAs substrate by the MOVPE method and then the GaAs substrate is removed by chemical etching, the back surface (second main surface) of the light emitting layer portion removed from the substrate is formed. Projection-like inclusions may be formed, and when the GaP substrate is bonded as it is, a region causing a bonding failure is likely to be formed around the protrusion. Further, there is a problem that a thin compound semiconductor layer including a light emitting layer portion to be bonded is lifted from the GaP substrate around the protrusions, and stress is concentrated and cracks are easily generated when pressure is applied for bonding.

  An object of the present invention is to grow a compound semiconductor layer including a light-emitting layer portion on a growth substrate by MOVPE, and then etch away the growth substrate, and then add a transparent substrate to the compound semiconductor layer from which the growth substrate has been removed. In the method for manufacturing a light-emitting element to be bonded, it is difficult to cause a bonding failure of a transparent substrate, a crack to a compound semiconductor layer, and the like. It is to provide a semiconductor wafer.

Means for Solving the Problems and Effects of the Invention

In order to solve the above problems, a method for manufacturing a light-emitting device of the present invention includes
On the first main surface of the single crystal substrate for growth made of an opaque compound semiconductor, at least the light emitting layer portion of the compound semiconductor growth layer including the device target layer having the light emitting layer portion is epitaxially grown by the MOVPE method. MOVPE growth process to obtain
The non-elementization part including the single crystal substrate for growth located on the second main surface side of the elementization target layer of the intermediate laminate is removed in such a manner that at least a part in contact with the elementization target layer is dissolved by selective chemical etching. A substrate removal step;
A bonding step of bonding and bonding the transparent element substrate to the second main surface of the elementization target layer after removing the non-elementized portion is performed in this order,
In the MOVPE growth step, a columnar semiconductor defect made of a compound semiconductor that is different from the compound semiconductor that forms the second main surface of the elementization target layer so as to extend in the layer thickness direction between the elementization target layer and the non-elementization portion. And a protrusion removing step for removing the protruding exposed portion of the columnar semiconductor defect portion remaining undissolved by selective chemical etching on the second main surface of the elementization target layer after the substrate removing step. It is characterized by being carried out prior to the combining step.

  Further, in the semiconductor wafer for manufacturing a light emitting device of the present invention, the light extraction side electrode is formed so as to partially cover the first main surface of the device target layer made of the compound semiconductor having the light emitting layer portion. A transparent element substrate is bonded to the second main surface of the device layer to be processed, and the second layer of the device layer to be processed from the middle position in the layer thickness direction of the device layer to the second main surface. A columnar semiconductor defect made of a compound semiconductor that is different from the compound semiconductor forming the main surface is formed in a form in which the front end surface coincides with the second main surface, and the first main surface of the transparent element substrate is a columnar semiconductor defect. It is characterized in that it is tightly coupled in such a way as to be in contact with both the front end surface of the part and the peripheral region connected to the front end surface of the second main surface.

  According to the present invention, when a columnar semiconductor defect is formed in the MOVPE growth step so as to extend in the layer thickness direction between the element target layer and the non-element part, the element target is not dissolved by selective chemical etching. Since the bonding step is performed after removing the protruding exposed portion of the columnar semiconductor defect portion remaining on the second main surface of the layer, it becomes difficult to form a bonding failure region due to the protruding exposed portion, In addition, it is difficult to cause a problem that a thin and brittle device layer is cracked due to the stress concentration at the protrusion position when the bonding is pressed. As a result, the resulting semiconductor wafer for manufacturing a light-emitting element has a columnar semiconductor defect portion that is deeply buried in the compound semiconductor growth layer (elementization target layer), but the tip surface of the columnar semiconductor defect portion is (By the above protrusion removal step), the transparent element substrate is flush with the second main surface of the compound semiconductor growth layer to which the transparent element substrate is bonded, and the transparent element substrate is formed between the tip surface of the columnar semiconductor defect portion and the second main surface. It is tightly coupled so as to be in contact with both of the peripheral region connected to the tip surface. As a result, cracks and poor bonding regions are hardly generated around the columnar semiconductor defect portion, and the yield of light-emitting element chips obtained by dicing the semiconductor wafer for manufacturing light-emitting elements can be greatly improved.

  The main factors for forming columnar semiconductor defects in the compound semiconductor growth layer in the MOVPE growth step are, for example, as follows. That is, the group III metal particles generated by the decomposition of the raw material organic metal gas of the compound semiconductor growth layer fall on the compound semiconductor growth layer during or after growth, and dissolve the compound semiconductor growth layer by alloying. The columnar semiconductor defect portion is formed in such a manner that it erodes and deposits a foreign compound semiconductor in the liquid phase generated in the erosion hole.

In order to obtain a high-intensity light-emitting element, a GaAs single crystal substrate is used as the growth single crystal substrate, and the light-emitting layer portion has a composition formula (Al _x Ga _1-x ) _y In _1-y P (where 0 ≦ Among the compound semiconductors represented by x ≦ 1, 0 ≦ y ≦ 1), the first conductive materials each composed of a compound semiconductor (first III-V group compound semiconductor) having a composition lattice-matched with GaAs. The mold cladding layer, the active layer, and the second conductivity type cladding layer may be grown as having a double heterostructure laminated in this order. Note that the “compound semiconductor lattice-matched with GaAs” means that the lattice constant of the compound semiconductor expected in a bulk crystal state in which no lattice displacement is caused by stress is a1, and the lattice constant of GaAs is a0. A compound semiconductor having a lattice mismatch ratio represented by | a1-a0 | / a0} × 100 (%) within 1%. Further, among the compounds represented by “composition formula (Al _{x ′} Ga _{1−x ′} ) _{y ′} In _{1−y ′} P (where 0 ≦ x ′ ≦ 1, 0 ≦ y ′ ≦ 1), GaAs The compound that is lattice-matched with “AlGaInP that is lattice-matched with GaAs” or the like is described. The active layer may be configured as a single layer of AlGaInP, or may be configured as a quantum well layer in which barrier layers and well layers made of AlGaInP having different compositions are stacked alternately (the entire quantum well layer). Is regarded as a single active layer).

  When the above light emitting layer part is grown by MOVPE, the foreign compound semiconductor forming the columnar semiconductor defect part has a Ga or In content ratio higher than that of the light emitting layer part, and the main component of the V group element is P. It is very easy to form a polycrystalline compound semiconductor, and the protrusion-like exposed portion resulting therefrom is removed in advance, and then the transparent element substrate is bonded to the light emitting device having the light emitting layer portion. This greatly contributes to the improvement of chip manufacturing yield. In particular, when the transparent element substrate is composed of a brittle GaP single crystal, the adoption of the present invention can achieve prevention of cracks on the transparent element substrate side, which is more effective.

For removal of the protrusion-like exposed portion, the following forced removal process other than cleaning and etching may be employed.
-In the protrusion removal step, the protrusion-like exposed portion is cut out by mechanical grinding.
-In the protrusion removal step, the protrusion-like exposed portion is cut off by being folded while being sandwiched by a holding jig.
-In the protrusion removal process, the protrusion-like exposed part is removed by burning off by laser irradiation.
In the protrusion removal step, the protrusion-like exposed portion is removed with a water jet.
In either method, for example, while observing the second main surface side of the elementization target layer with a magnifying glass such as a stereomicroscope, it is possible to manually remove the protruding exposed portion, or to perform the work using a robot. It can also be automated.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a conceptual diagram showing a light emitting device 100 according to an embodiment of the present invention. In the light emitting device 100, the light extraction side electrode 9 is formed so as to partially cover the first main surface of the device formation target layer 50 made of a compound semiconductor having the light emitting layer portion 24. A transparent element substrate 90 is bonded to the second main surface. In the device target layer 50, the current diffusion layer 7 is formed on the light emitting layer portion 24, and the light extraction side electrode 9 is formed on the current diffusion layer 7. The transparent element substrate 90 is an n-type GaP single crystal substrate (hereinafter referred to as an n-type GaP single crystal substrate 90: transparent to the luminous flux from the light emitting layer portion 24 (having a larger band gap energy than the active layer 5). )), And the entire surface of the second main surface is covered with the back electrode 20. The light extraction side electrode 9 is formed substantially at the center of the first main surface of the current diffusion layer 7, and a region around the light extraction side electrode 9 is a light extraction region from the light emitting layer portion 24. A bonding pad 16 made of Au or the like for bonding the electrode wire 17 is disposed at the center of the light extraction side electrode 9.

The light emitting layer portion 24 is grown by the MOVPE method, and is represented by a composition formula (Al _x Ga _1-x ) _y In _1-y P (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1). Among the compound semiconductors, a compound semiconductor having a composition lattice-matched with GaAs is used. Specifically, the light emitting layer portion 24 is made of a non-doped (Al _x Ga _1-x ) _y In _1-y P (where 0 ≦ x ≦ 0.55, 0.45 ≦ y ≦ 0.55) mixed crystal. The active layer 5 is made of p-type (Al _z Ga _1-z ) _y In _1-y P (where x <z ≦ 1) and n-type (Al _z Ga _1-z ) _y In _It has a structure sandwiched between n-type cladding layers 4 made of _1-yP (where x <z ≦ 1). In the light emitting device 100 of FIG. 1, the p-type AlGaInP cladding layer 6 is disposed on the light extraction side electrode 9 side, and the n-type AlGaInP cladding layer 4 is disposed on the back electrode 20 side. Therefore, the energization polarity is positive on the light extraction side electrode 9 side. Here, the "non-doped" means an "not intentionally added with a dopant", the normal manufacturing process, the content of the dopant component inevitably mixed (e.g. ¹⁰ 13 ~10 16 ^atoms / cm ³ to a maximum extent) is not excluded also.

  On the other hand, the current spreading layer 7 is formed as a p-type GaP layer in which the dopant is Zn (Mg may be used, or Zn and Mg may be used in combination). The current diffusion layer 7 is formed by a hydride vapor phase epitaxy (HVPE) method, and the thickness thereof is, for example, 5 μm or more and 200 μm or less (as an example, 150 μm). Further, an n-type GaP connection layer 7p grown by the MOVPE method is formed between the current spreading layer 7 and the light emitting layer portion 24 in a form following the light emitting layer portion 24. That is, in the device target layer 50, the light emitting layer portion 24 and the n-type GaP connection layer 7p are grown by the MOVPE method, and the current diffusion layer 7 is grown by the HVPE method.

  As shown in FIG. 11, the elementalization target layer 50 has a compound semiconductor (this book) that forms the second main surface MP2 of the elementalization target layer 50 from the middle position in the layer thickness direction toward the second main surface MP2. In the embodiment, the columnar semiconductor defect portion 55 made of a compound semiconductor different from that of the n-type AlGaInP clad 4) is formed in such a form that the front end surface thereof coincides with the second main surface MP2 of the device layer 50. Yes. The n-type GaP single crystal substrate 90, which is a transparent element substrate, has a shape in which the first main surface MP1 is in contact with both the front end surface of the columnar semiconductor defect portion and the peripheral region connected to the front end surface of the second main surface. Are tightly bonded by bonding.

Hereinafter, a method for manufacturing the light emitting device 100 of FIG. 1 will be described.
First, as shown in FIG. 2, an n-type GaAs single crystal substrate 1 as a growth single crystal substrate (which is opaque to the luminous flux from the light emitting layer portion 24 (having a smaller band gap energy than the active layer 5). ). In step 1, the n-type GaAs buffer layer 1b is, for example, 0.5 μm on the first main surface of the substrate 1, then the etch stop layer 2 made of AlInP is 0.5 μm, and the light emitting layer portion 24 is each consists of _{(Al x Ga 1-x)} y in 1-y P, 1μm n -type cladding layer 4 of the (n-type dopant is Si), 0.6 .mu.m active layer (non-doped) 5, and 1 [mu] m p-type cladding Layer 6 (p-type dopant Mg: C from organometallic molecules can also contribute as p-type dopant) is grown epitaxially in this order. Next, in step 2, the connection layer 7p made of p-type GaP is heteroepitaxially grown on the light emitting layer portion 24 by the MOVPE method.

Epitaxial growth of each of these layers is performed by a known MOVPE method. The following materials can be used as source gases for the source components of Al, Ga, In (indium), and P (phosphorus);
Al source gas; trimethylaluminum (TMAl), triethylaluminum (TEAl), etc .;
Ga source gas; trimethylgallium (TMGa), triethylgallium (TEGa), etc .;
In source gas; trimethylindium (TMIn), triethylindium (TEIn), etc.
P source gas: trimethyl phosphorus (TMP), triethyl phosphorus (TEP), phosphine (PH ₃ ), etc.

Next, proceeding to step 3 in FIG. 3, the current diffusion layer 7 made of p-type GaP is homoepitaxially grown on the connection layer 7p by the HVPE method. Specifically, in the HVPE method, GaCl, which is a group III element, is heated and held at a predetermined temperature in a container, and hydrogen chloride is introduced onto the Ga, thereby causing GaCl by the reaction of the following formula (1). And is supplied onto the substrate together with H ₂ gas which is a carrier gas.
Ga (liquid) + HCl (gas) → GaCl (gas) + 1 / 2H ₂ (1)
The growth temperature is set to, for example, 640 ° C. or more and 860 ° C. or less. Further, P, which is a group V element, supplies PH ₃ onto the substrate together with H ₂ which is a carrier gas. Furthermore, Zn which is a p-type dopant is supplied in the form of DMZn (dimethyl Zn). GaCl is excellent in reactivity with PH _3, and the current diffusion layer 7 can be efficiently grown by the reaction of the following formula (2):
GaCl (gas) + PH ₃ (gas)
→ GaP (solid) + HCl (gas) + H ₂ (gas) (2)

  Through the steps so far, the compound semiconductor growth layer 60 is epitaxially grown on the GaAs single crystal substrate 1 by two kinds of vapor phase growth methods, and the intermediate stacked body 200 is formed. In the intermediate laminate 200, the light emitting layer portion 24, the connection layer 7p, and the current diffusion layer 7 are the device target layers 50, and the other portions (the etch stop layer 2, the buffer layer 1b, and the GaAs single crystal substrate 1). This is a non-elementized portion 70. On the other hand, in the MOVPE growth step, the light emitting layer portion 24 and the connection layer 7p of the elementization target layer 50, the etch stop layer 2 and the buffer layer 1b preceding this are grown. In the MOVPE growth step, the above-described columnar semiconductor defect portion 55 is formed in the elementization target layer 50 due to, for example, the following causes. That is, as shown in FIG. 6, the group III metal particles 52 generated by the decomposition of the source organic metal gas of the compound semiconductor growth layer (the buffer layer 1b and the etch stop layer 2 in the example of FIG. 6) are growing or growing. The compound semiconductor growth layer falls to the subsequent compound semiconductor growth layer (state A), erodes while dissolving the compound semiconductor growth layer by alloying (state B), and a foreign compound in the liquid phase 53 generated in the erosion hole 55h A columnar semiconductor defect 55 is formed in the form of depositing the semiconductor 54 (state C). Alloying progresses to the GaAs single crystal substrate 1 side, and the tip side of the columnar semiconductor defect portion 55 penetrates through the buffer layer 1b and the etch stop layer 2 and enters the GaAs single crystal substrate 1 inside. On the other hand, the base end side of the columnar semiconductor defect portion 55 is in the light emitting layer portion 24 (that is, the element formation target layer). Situated across.

  More specifically, peripheral structures such as a susceptor, a planetary, or a pull plate for supporting a substrate are arranged in a reaction container of MOVPE, and are heated to a high temperature (for example, 650 ° C. to 900 ° C.) by a high frequency coil or the like. In this state, while injecting the raw material organometallic gas from the injector disposed above the interior of the container into the interior space of the container, a gas serving as a group V source (for example, a P source gas such as phosphine) is supplied from another supply nozzle, Both are reacted to grow a III-V compound semiconductor on the substrate.

  When the light emitting layer portion 24 is composed of AlGaInP as described above, low-melting point Ga or In adheres to the injector as a group III metal, and when this falls to the growth layer side, the columnar semiconductor defect portion 55 becomes the light emitting layer. It is formed of a polycrystalline compound semiconductor (for example, GaP) in which the content ratio of Ga or In is higher than that of the portion 24 and the main group V element is P.

  At this time, since the peripheral structure is heated to a high temperature, the raw material organic metal gas supply injector is also heated by the radiant heat, and decomposition of the organic metal as the raw material occurs inside the injector (for example, trimethyl). Aluminum (TMAl): 240 ° C., trimethylgallium (TMGa): 222 ° C., trimethylindium (TMIn): 205 ° C.), and a group III metal is deposited in the injector. The deposited group III metal particles are jetted into the reaction vessel at a high speed through the injector together with the raw organic metal gas, and drop into the compound semiconductor substrate and the compound semiconductor layer during epitaxial growth.

  The group III metal particles 52 poured down as described above are alloyed with the compound semiconductor constituting the epitaxially grown compound semiconductor growth layer 60 and the GaAs single crystal substrate (growth single crystal substrate) 1. Since the temperature inside the reaction vessel is raised as described above, the alloyed portion of the compound semiconductor layer is melted to form the erosion hole 55h, and the erosion hole 55h is filled with the liquid phase 53 rich in III metal. On the other hand, the group V element source gas is normally supplied into the reaction vessel so that it becomes richer in the group V than the group III-V stoichiometric ratio of the obtained compound semiconductor with respect to the organometallic gas serving as the group III element source. Therefore, in the liquid phase generated in the erosion hole, a group III-V compound semiconductor having a composition different from that of the device layer (particularly, the light emitting layer) is deposited, and the columnar semiconductor defect portion 55 is formed.

  As shown in FIG. 7, the attachment of the group III metal particles 52 that cause the columnar semiconductor defect 55 can occur at various timings during the growth of the compound semiconductor growth layer 60. For example, if the group III metal particles 52a adhere immediately after the growth of the buffer layer 1b or the etch stop layer 2, a columnar semiconductor defect portion 55a that has penetrated into the GaAs single crystal substrate 1 relatively deeply. Further, when the group III metal particles 52b are attached during the growth of the light emitting layer portion 24, the columnar semiconductor defect portion 55b grows from the middle position in the thickness direction of the light emitting layer portion 24. In addition, after the light emitting layer portion 24 is grown, the group III metal particles 52c may adhere during the growth of the connection layer 7p. In this case, a columnar semiconductor defect portion 55c penetrating the light emitting layer portion 24 is generated.

  Further, when the group III metal particles 52d adhere after the growth of the connection layer 7p by MOVPE is completed, if the current diffusion layer 7 is grown without being removed, the current diffusion layer 7 is grown. In the process, the group III metal particles 52d are melted and alloyed, and a similar columnar semiconductor defect 55d is generated. In addition, the group III metal particles 52e may adhere in the HVPE growth vessel. In this case, the columnar semiconductor defect portion 55e is generated so as to penetrate the entire device target layer 50.

  Next, the process proceeds to step 4 in FIG. 4, and the GaAs single crystal substrate 1 is removed. The removal is performed by grinding from the second main surface side of the GaAs single crystal substrate 1 to reduce the thickness of the substrate to some extent, and then a first etching solution having a selective etching property with respect to GaAs (for example, mixed ammonia / hydrogen peroxide). Then, the GaAs single crystal substrate 1 is removed by etching together with the buffer layer 1b using a liquid, and then, as shown in Step 5, a second etching liquid (for example, hydrochloric acid: having selective etching property with respect to AlInP forming the etch stop layer 2). The etching stop layer 2 can be removed by etching using hydrofluoric acid for removing the Al oxide layer. Note that an AlAs release layer is formed instead of the etch stop layer 2 and is selectively etched to remove the GaAs single crystal substrate 1 in such a manner that the GaAs single crystal substrate 1 is peeled off from the device layer 50. It may be.

  As shown in the state D of FIG. 6, when the columnar semiconductor defect portion 5 grows so as to erode to the GaAs single crystal substrate (growth single crystal substrate) 1 side, as described above, the GaAs single crystal substrate 1 (and When the etch stop layer 2) is removed by etching, the tip of the columnar semiconductor defect portion 55 becomes a protrusion-like exposed portion 51 and protrudes to the second main surface of the device layer to be epitaxially grown.

  In the manufacturing process of a semiconductor wafer, it is common practice to remove particles adhering to the device forming surface by cleaning or etching. However, such particles are caused by foreign matters (dust etc.) adhering to the main surface of the wafer, and the cause of the occurrence is external. It could be removed. However, the protrusion-like exposed portion 51 to be removed here is a part of the columnar semiconductor defect portion 55 whose base end portion is buried in the compound semiconductor growth layer, and is removed by simple cleaning or etching. Removal cannot be expected. Therefore, it is necessary to consider the following forced removal process other than cleaning and etching for the removal of the protruding exposed portion 51.

  FIG. 8 shows an example in which the protruding exposed portion 51 is excised by a mechanical grinding process using a grinder G or the like. FIG. 9 shows an example in which the protruding exposed portion 51 is cut off by being folded in a state of being sandwiched by a sandwiching jig such as tweezers P. FIG. 10 shows an example in which the projection-like exposed portion 51 is irradiated with the laser beam LB from the laser light source S and burned off (or hollowed out in the depth direction). Furthermore, as shown in FIG. 13, it is also possible to adopt a water jet system in which the protruding exposed portion 51 is mechanically scraped by jetting a high-pressure water flow WJ from the water jet nozzle NZ to the protruding exposed portion 51. It is. In any of the methods, for example, the projection-like exposed portion can be manually removed while observing the second main surface side of the elementization target layer 50 with a magnifying glass such as a stereomicroscope, or the operation can be performed using a robot. Can also be automated. In particular, when the protrusion-like exposed portion 51 is formed of GaP polycrystal, the protrusion-like exposed portion 51 is relatively soft, so that the removal by grinding and folding is easier.

  In addition, when removing a protrusion with a laser, a residue may melt | dissolve around the laser irradiation position after the protrusion-like exposed part 51 is removed. Devices such as adjustment of laser power and narrowing of the irradiation range are necessary. However, there is no concern that material residue will remain according to mechanical removal methods such as grinding, folding, or water jet. In particular, when a water jet is used, it is advantageous because the broken pieces of the protrusion-like exposed portion 51 that has been destroyed can be blown off.

  The protrusion-like exposed portion 51 may be removed before the etch stop layer 2 is removed by etching, or after the etching removal. If the protruding exposed portion 51 is removed before the etch stop layer 2 is removed, there is an advantage that the scattered material residue can be removed simultaneously with the removal of the etch stop layer. In this case, when the etch stop layer 2 is AlInP, the etch stop layer 2 may be removed with an etchant made of hydrochloric acid, for example.

  As shown in Step 6 of FIG. 5, when the protruding exposed portion 51 is removed, the tip end surface of the columnar semiconductor defect portion 55 is substantially flush with the second main surface of the device layer 50. In this state, an n-type GaP single crystal substrate 90 (transparent element substrate) is bonded to the second main surface of the elementization target layer 50 as shown in Step 7. Specifically, the first main surface of the n-type GaP substrate 90 prepared separately is superimposed on the second main surface of the device target layer 50 and pressed, and further heated to 400 ° C. to 700 ° C. and bonded together. Heat treatment is performed. As shown in FIG. 12, if the protrusion-like exposed portion 51 remains, a void VO is generated around the protrusion-like exposed portion 51 and the bonding pressure is insufficient. It is easy to produce. Further, stress concentrates on the tip of the protruding exposed portion 51 due to the pressure applied at the time of bonding, and cracks tend to occur in the thin and brittle device layer 50. However, as shown in FIG. 11, if the protrusion-like exposed portion is removed in advance and then the bonding is performed, all of these problems can be solved.

  Through the above steps, a semiconductor wafer for manufacturing a light emitting element is completed. Then, the light extraction side electrode 9 and the back electrode 20 are formed on each chip region of the semiconductor wafer for manufacturing the light emitting element by vacuum vapor deposition, and the bonding pad 16 is disposed on the light extraction side electrode 9 to obtain an appropriate temperature. Bake for electrode fixing. Then, the wafer is diced into chips, and the back electrode 20 is fixed to a terminal electrode (not shown) that also serves as a support using a conductive paste such as Ag paste, while straddling the bonding pad 16 and another terminal electrode. The light emitting element 100 is obtained by bonding the Au wire 17 in a form and further forming a resin mold. Even after the protrusion-like exposed portion is removed, the columnar semiconductor defect portion 55 remains buried in the wafer. A chip in which the columnar semiconductor defect 55 is present can be excluded as a defect. However, the defect remains only on the chip where the columnar semiconductor defect 55 remains, and no cracks or poor bonding areas are spread around it, so that the chip defect occurrence rate can be kept to a minimum.

The schematic diagram which shows an example of the light emitting element used as the application object of this invention by laminated structure. Explanatory drawing which shows the manufacturing process of the light emitting element of FIG. Explanatory drawing following FIG. Explanatory drawing following FIG. Explanatory drawing following FIG. Explanatory drawing which shows typically the formation mechanism of a columnar semiconductor defect part. The schematic diagram which shows the various formation form of a columnar semiconductor defect part. Explanatory drawing which shows the 1st example of the removal method of a protrusion-shaped protrusion-like exposed part. Explanatory drawing which similarly shows a 2nd example. Explanatory drawing which similarly shows a 3rd example. The schematic diagram which expands and shows the characteristic part of the wafer for light emitting element manufacture of this invention. The schematic diagram which shows the problem of the conventional bonding method. Explanatory drawing which shows the 4th example of the removal method of a protrusion-form protrusion-like exposed part.

Explanation of symbols

1 n-type GaAs single crystal substrate (single crystal substrate for growth)
DESCRIPTION OF SYMBOLS 2 Etch stop layer 24 Light emitting layer part 7 Current diffusion layer 50 Element-ization target layer 51 Projection-like exposed part 55 Columnar semiconductor defect part 60 Compound semiconductor growth layer 70 Non-element part 90 n-type GaP single crystal substrate (transparent element substrate)

Claims (13)

On the first main surface of the single crystal substrate for growth made of an opaque compound semiconductor, at least the light emitting layer portion of the compound semiconductor growth layer including the device target layer having the light emitting layer portion is epitaxially grown by the MOVPE method, and the intermediate lamination is performed. A MOVPE growth process to obtain a body;
The non-elementized portion including the single crystal substrate for growth located on the second main surface side of the elementization target layer of the intermediate laminate is dissolved by selective chemical etching at least a portion in contact with the elementization target layer. Removing the substrate in a form;
A bonding step of bonding and bonding a transparent element substrate to the second main surface of the elementization target layer after removing the non-elementized portion is performed in this order,
In the MOVPE growth step, the compound semiconductor that forms the second main surface of the elementalization target layer is formed of a different compound semiconductor so as to extend in the layer thickness direction between the elementalization target layer and the non-elementalization part. A columnar semiconductor defect portion is formed, and a protrusion-like exposed portion of the columnar semiconductor defect portion that remains after being dissolved by the selective chemical etching on the second main surface of the elementization target layer after the substrate removal step is formed. A method for manufacturing a light-emitting element, wherein a protrusion removing step to be removed is performed prior to the bonding step.   In the columnar semiconductor defect portion, the group III metal particles generated by the decomposition of the source organic metal gas of the compound semiconductor growth layer fall on the compound semiconductor growth layer during or after the growth, and the compound semiconductor growth layer 2. The method for manufacturing a light-emitting element according to claim 1, wherein the light-emitting element is formed by eroding while being melted by alloying and depositing the foreign compound semiconductor in a liquid phase generated in the erosion hole. A GaAs single crystal substrate is used as the growth single crystal substrate, and the light emitting layer portion has a composition formula (Al _x Ga _1-x ) _y In _1-y P (where 0 ≦ x ≦ 1, 0 ≦ y ≦ Of the compound semiconductor represented by 1), the first conductivity type cladding layer, the active layer, and the second conductivity type cladding layer each composed of a compound semiconductor having a composition that lattice-matches with GaAs are stacked in this order. The method for manufacturing a light emitting device according to claim 1, wherein the light emitting device is grown as having a double hetero structure.   4. The heterogeneous compound semiconductor forming the columnar semiconductor defect portion is made of a polycrystalline compound semiconductor having a Ga or In content ratio higher than that of the light emitting layer portion and having a group V element mainly composed of P. Of manufacturing the light-emitting device.   The method for manufacturing a light-emitting element according to claim 1, wherein a GaP single crystal is used as the transparent element substrate.   The method for manufacturing a light emitting element according to claim 1, wherein in the protrusion removal step, the protrusion-like exposed portion is cut out by a mechanical grinding process.   6. The method for manufacturing a light emitting element according to claim 1, wherein in the protrusion removing step, the protruding exposed portion is cut off by being folded in a state of being sandwiched by a sandwiching jig.   6. The method for manufacturing a light emitting element according to claim 1, wherein in the protrusion removing step, the protrusion-like exposed portion is removed by burning off by laser irradiation. 7.   The method for manufacturing a light-emitting element according to claim 1, wherein the protrusion-like exposed portion is removed by a water jet in the protrusion removal step.   While the light extraction side electrode is formed so as to partially cover the first main surface of the elementization target layer made of the compound semiconductor having the light emitting layer portion, the transparent element substrate is formed on the second main surface of the elementization target layer. A compound that has a bonded structure and is different from the compound semiconductor that forms the second main surface of the device target layer from the midpoint in the layer thickness direction of the device target layer toward the second main surface A columnar semiconductor defect portion made of a semiconductor is formed in a form in which a front end surface coincides with the second main surface, and a first main surface of the transparent element substrate is formed between the front end surface of the columnar semiconductor defect portion and the second main surface. A semiconductor wafer for manufacturing a light-emitting element, characterized in that the semiconductor wafer is tightly bonded so as to be in contact with both of the peripheral region connected to the tip surface of the surface. Among the compound semiconductors represented by the composition formula (Al _x Ga _1-x ) _y In _1-y P (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1), the light-emitting layer portion includes GaAs and a lattice. 11. The first conductive clad layer, the active layer, and the second conductive clad layer each formed of a compound semiconductor having a matching composition are formed as having a double heterostructure laminated in this order. The semiconductor wafer for light emitting element manufacture of description.   12. The heterogeneous compound semiconductor forming the columnar semiconductor defect portion is made of a polycrystalline compound semiconductor having a Ga and In content ratio higher than that of the light emitting layer portion and having a group V element mainly composed of P. Semiconductor wafer for manufacturing light emitting devices.   The semiconductor wafer for manufacturing a light emitting element according to claim 10, wherein the transparent element substrate is made of a GaP single crystal.

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