JP2014045097A - Recycled substrate manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove a nitride layer from a laminated semiconductor wafer without influencing crystallinity of a substrate and an irregular shape of a substrate surface, by preventing even a physical change such as warpage and deformation caused by heat.SOLUTION: A recycled substrate manufacturing method of recycling a laminated semiconductor substrate by removing a buffer layer 3 of an AlN layer determined as defective from the laminated semiconductor substrate in which the buffer layer 3 of the AlN layer determined as defective is formed on a sapphire substrate 2, and newly forming a buffer layer 3 of an AlN layer comprises: a cleaning process of performing a cleaning treatment by a hydrogen peroxide solution on the laminated semiconductor substrate; and a second cleaning process of performing a cleaning treatment by a compound liquid of sulfuric acid and the hydrogen peroxide solution on the laminated semiconductor substrate (laminated semiconductor wafer) after the first cleaning process.

Description

  The present invention relates to a method for manufacturing a regenerated substrate in which a nitride layer is removed from a laminated semiconductor wafer having a defective nitride layer formed on a semiconductor substrate, and a nitride layer is newly formed to regenerate the laminated semiconductor wafer. .

  This type of conventional substrate recycling technology removes a laminated nitride layer from a laminated semiconductor wafer in order to reuse the substrate for the laminated semiconductor wafer having a laminated nitride layer formed on the substrate. . This is disclosed in Patent Document 1 and Patent Document 2.

  FIG. 11 is a longitudinal sectional view showing the entire configuration of a conventional heating device disclosed in Patent Document 1. As shown in FIG.

  In FIG. 11, the heating device 100 includes a heating furnace 101, an exhaust device 102 that exhausts atmospheric gas in the heating furnace 101, and a control unit 103 that controls operations of the heating furnace 101 and the exhaust device 102. Yes.

  The heating furnace 101 includes a chamber 104, a heater 105, a stage 106, a thermometer 107 and a pressure gauge 108. The chamber 104 is a stainless steel container capable of forming a sealed space. A laminated semiconductor wafer 109 to be heated is placed on the stage 106 in the chamber 104, and the laminated semiconductor wafer 109 is heated.

  The chamber 104 is provided with an opening / closing door 110. When the stacked semiconductor wafer 109 is taken in or out, the opening / closing door 110 is opened to open the chamber 104. When heating is performed, the opening / closing door 110 is closed to make the chamber 104 a sealed space.

  Further, a duct 111 for discharging the atmospheric gas in the chamber 104 is attached. When the pressure in the chamber 104 is reduced, the exhaust gas 102 is used to discharge the atmospheric gas in the chamber 104 from the duct 111.

  A laminated semiconductor wafer 109 on the stage 106 to be processed has a substrate 112 and a laminated semiconductor layer 113 formed on the substrate 112. The laminated semiconductor wafer 109 is heated by the heater 105 in the heating apparatus 100 to a temperature that is not lower than the sublimation point of the laminated semiconductor layer 113 and lower than the melting point of the substrate 112. As a result, in the laminated semiconductor wafer 109, the laminated semiconductor layer 113 is sublimated, and the laminated semiconductor layer 113 is removed from the substrate 112 therebelow. The stacked semiconductor layer 113 is, for example, a GaN layer, an AlGaN layer, an InGaN layer, or the like.

  FIG. 12 is a diagram showing the flow of each process of the method for manufacturing a regenerated substrate using the heating device of FIG.

  In FIG. 12, a removal step of removing the laminated semiconductor layer 113 formed on the substrate 112 from the laminated semiconductor wafer 109 to be subjected to the regeneration process to make the substrate 112 available again, and hot phosphoric acid or the like. And a cleaning step of performing surface cleaning using a cleaning agent.

  The removal process includes an installation process (step S101) for installing the laminated semiconductor wafer 109 on the heating apparatus 100, a decompression process (step S102) for reducing the pressure inside the chamber 101 of the heating apparatus 100, and raising the temperature of the laminated semiconductor wafer 109. And a temperature raising step (step S103). Further, the removing step includes a temperature holding step (step S104) for holding the laminated semiconductor wafer 109 at a predetermined temperature for a certain period of time, and lowering the temperature of the substrate 112 remaining after the laminated semiconductor layer 113 is removed from the laminated semiconductor wafer 109. And a temperature lowering step (step S105). In the temperature raising step, the laminated semiconductor wafer 109 is heated to a temperature of 800 degrees Celsius or higher and 2000 degrees Celsius or lower.

  In the cleaning step, first, the substrate 112 left after the stacked semiconductor layer 113 is removed is immersed in Bronsted acid or heated Bronsted acid. For example, the substrate 112 is immersed in hot phosphoric acid (190 degrees Celsius) as an example of Bronsted acid for about 1 minute. Thereafter, the substrate 112 is immersed in pure water in order to wash away phosphoric acid adhering to the substrate 112.

  FIG. 13 is a diagram showing each processing flow of the conventional method of manufacturing a recycled substrate disclosed in Patent Document 2.

  In FIG. 13, first, in a blasting process, a blast material is sprayed onto the laminated semiconductor wafer 200 to be processed, and the laminated semiconductor layer 202 on the substrate 201 is removed from the laminated semiconductor wafer 200. Subsequently, in the heat treatment step, the substrate 202 from which the stacked semiconductor layer 202 has been removed is heated. Further, in the polishing process, a process for polishing the surface of the substrate 201 is performed on the substrate 201 that has been subjected to the heat treatment.

  In the heat treatment step, the substrate 201 from which the stacked semiconductor layer 201 has been removed is placed in an atmosphere heated to about 1400 degrees Celsius. In addition, it is preferable that the temperature of this atmosphere is the range of 800 degreeC or more and 1800 degreeC or less. The heating time of the substrate 201 is 4 hours.

JP 2011-66355 A JP 2011-86672 A

  In the conventional method for manufacturing a regenerated substrate disclosed in Patent Documents 1 and 2, 800 degrees Celsius with respect to the laminated semiconductor wafers 109 and 200 that cannot be used due to adhesion of foreign matters or different film thicknesses. If the laminated semiconductor layer is peeled off at a high temperature as described above, or if the laminated semiconductor layer is mechanically peeled off such as blasting or polishing, the crystallinity of the substrates 112 and 201 may be affected. There is a risk of warping or cracking due to heat, or affecting the uneven shape of the substrate surface due to mechanical treatment.

  The present invention solves the above-described conventional problems, and removes the nitride layer on the substrate by removing the nitride layer on the substrate only by wet treatment at a much lower temperature than the high-temperature heat treatment. A method of manufacturing a regenerated substrate that can produce a regenerated substrate by removing a nitride layer from a laminated semiconductor wafer while suppressing physical changes such as warping and cracking due to heat without affecting the uneven shape of the surface. The purpose is to provide.

  The method for manufacturing a recycled substrate according to the present invention includes removing a nitride layer from a laminated semiconductor substrate having a nitride layer determined to be defective formed on the semiconductor substrate, and forming a new nitride layer on the semiconductor substrate. In a method for manufacturing a regenerated substrate for regenerating a laminated semiconductor substrate, a first cleaning step of cleaning the laminated semiconductor substrate with a hydrogen peroxide solution, and the laminated semiconductor substrate after the first cleaning step And a second cleaning step of performing a cleaning process with a mixed solution of sulfuric acid and hydrogen peroxide solution, whereby the above object is achieved.

  Preferably, the nitride layer in the method for producing a recycled substrate of the present invention is an AlN film.

  Further preferably, in the second cleaning step in the method for manufacturing a regenerated substrate of the present invention, the laminated semiconductor substrate is cleaned at a liquid temperature of 130 degrees Celsius to 170 degrees Celsius.

  Furthermore, preferably, the immersion time of the laminated semiconductor substrate in the mixed solution in the second cleaning step in the method for producing a recycled substrate of the present invention is 1 minute or more and 20 minutes or less.

  Further preferably, in the second cleaning step in the method for manufacturing a recycled substrate of the present invention, the laminated semiconductor substrate is cleaned at a concentration of the sulfuric acid of 60 Wt percent (wt%) to 90 Wt percent.

  Further preferably, in the second cleaning step in the method for manufacturing a regenerated substrate of the present invention, the stacked semiconductor substrate is cleaned at a concentration of the hydrogen peroxide solution of 2.5 Wt percent to 4 Wt percent.

  Further preferably, in the first cleaning step in the method for producing a regenerated substrate of the present invention, the concentration of the hydrogen peroxide solution is 25 Wt percent to 35 Wt percent at a room temperature of 20 degrees Celsius ± 10 degrees Celsius. Wash.

  Further preferably, in the first cleaning step in the method for manufacturing a recycled substrate of the present invention, the stacked semiconductor substrate is cleaned at a concentration of the hydrogen peroxide solution of 25 Wt percent to 35 Wt percent.

  Further preferably, in the second cleaning step in the method for manufacturing a regenerated substrate of the present invention, the laminated semiconductor substrate is cleaned at a liquid temperature of 130 degrees Celsius to 160 degrees Celsius.

  Further preferably, the immersion time of the laminated semiconductor substrate in the mixed solution in the second cleaning step in the method for producing a recycled substrate of the present invention is 1 minute or more and 5 minutes or less.

  Further preferably, in the second cleaning step in the method for manufacturing a recycled substrate according to the present invention, the laminated semiconductor substrate is cleaned at a concentration of the sulfuric acid of 79 Wt percent to 81 Wt percent.

  Further preferably, in the second cleaning step in the method for manufacturing a regenerated substrate of the present invention, the stacked semiconductor substrate is cleaned at a concentration of the hydrogen peroxide solution of 3.1 Wt percent to 3.5 Wt percent.

  Further preferably, the nitride layer in the method for producing a recycled substrate of the present invention has a two-layer structure of an AlN film and a nitride semiconductor layer formed thereon, and before the first cleaning step, A nitride semiconductor layer removing step for removing the nitride semiconductor layer is further included.

  Further preferably, the removal of the nitride semiconductor layer in the method for producing a recycled substrate of the present invention is performed by heating in a chlorine atmosphere, a hydrogen atmosphere or a vacuum.

  Further preferably, the AlN film in the method for producing a recycled substrate of the present invention has a thickness of 15 nm to 50 nm.

  Further preferably, the semiconductor substrate in the method for producing a regenerated substrate of the present invention has a concavo-convex surface.

  Further preferably, the semiconductor substrate in the method for manufacturing a regenerated substrate of the present invention is a sapphire substrate.

  Further preferably, after the second cleaning step in the method for manufacturing a regenerated substrate of the present invention, a drying step of cleaning the semiconductor substrate and then performing a drying process, and adding the nitride layer on the semiconductor substrate after the drying step And a nitride layer forming step of forming a film.

  Further preferably, the nitride layer forming step in the method for manufacturing a recycled substrate of the present invention further includes an AlN film forming step of newly forming an AlN layer on the semiconductor substrate.

  Further preferably, the nitride layer forming step in the method for manufacturing a regenerated substrate of the present invention includes an AlN film forming step of newly forming an AlN film on the semiconductor substrate, and the nitride on the AlN film. A nitride semiconductor layer forming step of newly forming a semiconductor layer.

  With the above configuration, the operation of the present invention will be described below.

  In the present invention, the nitride layer is removed from the laminated semiconductor substrate in which the defective nitride layer is formed on the semiconductor substrate, and the nitride layer is newly formed on the semiconductor substrate to reproduce the laminated semiconductor substrate. In the method for manufacturing a substrate, a first cleaning step of performing a cleaning process with a hydrogen peroxide solution on a laminated semiconductor substrate in which a nitride layer determined to be defective is formed on the semiconductor substrate, and a step after the first cleaning step And a second cleaning process for cleaning the laminated semiconductor substrate with a mixed solution of sulfuric acid and hydrogen peroxide water.

  As described above, the first cleaning step of performing the cleaning process with the hydrogen peroxide solution on the laminated semiconductor substrate in which the nitride layer determined to be defective is formed on the semiconductor substrate, and the laminated semiconductor after the first cleaning step And a second cleaning step in which the substrate is cleaned with a mixed solution of sulfuric acid and hydrogen peroxide solution, and the laminated nitride layer on the semiconductor substrate can be formed only by wet processing at a much lower temperature than in the prior art. In order to remove the nitride layer that has been judged to be defective from the top of the laminated semiconductor wafer while suppressing physical changes such as warping and cracking due to heat without affecting the crystallinity and uneven shape of the substrate as in the past. The recycled substrate can be manufactured by removing.

  As described above, according to the present invention, the first cleaning step of performing the cleaning process with the hydrogen peroxide solution on the laminated semiconductor substrate in which the nitride layer determined to be defective is formed on the semiconductor substrate, and the first cleaning And a second cleaning step in which the laminated semiconductor substrate after the process is cleaned with a mixed solution of sulfuric acid and hydrogen peroxide solution. Since the multi-layer nitride layer is removed from the top, multi-layer nitridation is performed from the multi-layer semiconductor wafer while suppressing physical changes such as warping and cracking due to heat without affecting the crystallinity and uneven shape of the substrate. It is possible to manufacture a recycled substrate by removing the physical layer and newly forming a laminated nitride layer.

It is a process flowchart for demonstrating the manufacturing method of the reproduction | regeneration board | substrate in Embodiment 1 of this invention. It is a longitudinal cross-sectional view which shows typically the schematic unit structure of the PSS substrate with an AlN film | membrane of FIG. It is an X-ray waveform diagram showing that a peak waveform due to the substance of AlN does not appear by X-ray waveform measurement on the PSS substrate after the drying process. It is an X-ray waveform diagram showing the crystallinity of AlN before the first cleaning step. It is an X-ray waveform diagram showing the crystallinity of AlN formed after the second cleaning step. It is an image figure which shows the uneven | corrugated cross-sectional shape of the sapphire substrate surface before a 1st washing | cleaning process. It is an image figure which shows the uneven | corrugated cross-sectional shape of the sapphire board | substrate surface after a 2nd washing | cleaning process. It is a figure which shows each confirmation result of the removal of an AlN layer, the change of uneven | corrugated shape, and foreign material removal with respect to each density | concentration of the 1st washing | cleaning process of FIG. 1, and a 2nd washing | cleaning process. It is a longitudinal cross-sectional view which shows typically the unit LED chip structure of the laminated semiconductor wafer formed using the PSS board | substrate with an AlN film | membrane of FIG. It is a process flowchart for demonstrating the manufacturing method of the reproduction | regeneration board | substrate in Embodiment 2 of this invention. It is a longitudinal cross-sectional view which shows the whole structure of the conventional heating apparatus currently disclosed by patent document 1. FIG. It is a figure which shows the flow of each process of the manufacturing method of the reproduction | regeneration board | substrate using the heating apparatus of FIG. It is a figure which shows each process flow of the manufacturing method of the conventional reproduction | regeneration board | substrate currently disclosed by patent document 2. FIG.

  Hereinafter, Embodiment 1 of the method for manufacturing a recycled substrate of the present invention will be described in detail with reference to the drawings. In addition, each thickness, length, etc. of the structural member in each figure are not limited to the structure to illustrate from a viewpoint on drawing preparation.

(Embodiment 1)
FIG. 1 is a process flowchart for explaining a method of manufacturing a recycled substrate in Embodiment 1 of the present invention. FIG. 2 is a longitudinal sectional view schematically showing a schematic unit configuration of the PSS substrate with the AlN film of FIG.

1 and 2, the method for manufacturing a recycled substrate according to the first embodiment is a substrate receiving step for receiving a PSS (patterned sapphire substrate) substrate 21 with an AlN film, which is a laminated semiconductor wafer as a laminated semiconductor substrate. Step S1), a first cleaning step (Step S2) for performing a cleaning process with hydrogen peroxide (H ₂ O ₂ ) on the PSS substrate 21 with an AlN film, and a PSS with AlN after the first cleaning step The substrate is cleaned with a mixed solution of sulfuric acid (H ₂ SO ₄ ) and hydrogen peroxide (H ₂ O ₂ ) (sulfuric acid / hydrogen peroxide; H ₂ SO ₅ ) to remove the AlN film as the buffer layer. After the second cleaning process (step S3) and the second cleaning process, the PSS substrate (sapphire substrate 2), which is a semiconductor wafer as a semiconductor substrate, is cleaned and then dried. A process (step S4), an AlN film forming process (step S5) for newly forming an AlN layer (buffer layer) as a nitride layer on the PSS substrate (sapphire substrate 2) after the drying process, and an AlN film And a substrate removal step (step S6) for removing the attached PSS substrate 21.

  A semiconductor substrate (semiconductor wafer) is changed from a laminated semiconductor wafer (laminated semiconductor substrate) that has become unusable due to a defect determined by the manufacturing method of the recycled substrate of the first embodiment due to adhesion of foreign matter or a different film thickness. The AlN layer as the nitride layer formed thereon is removed, and an AlN layer is newly formed as a nitride layer on the semiconductor substrate (semiconductor wafer) to regenerate the laminated semiconductor wafer as the laminated semiconductor substrate.

  As shown in FIG. 2, the PSS substrate 21 with an AlN film is a semiconductor substrate having a thickness of about 1300 μm with a concavo-convex shape formed on the surface thereof. For example, a film thickness of about 15 nm to 50 nm made of aluminum nitride (AlN) on a sapphire substrate 2. A buffer layer 3 that is an AlN layer is formed. The AlN film (buffer layer 3) formed on the sapphire substrate 2 of the laminated semiconductor wafer as a laminated semiconductor substrate that has become unusable due to foreign matter adhering or a different film thickness is removed and a new AlN film (buffer layer 3) is removed. It is necessary to form the buffer layer 3).

In the first cleaning step, hydrogen peroxide (H) having a liquid concentration of 25 wt% to 35 wt% (more preferably 30 wt% to 32 wt%) with respect to the PSS substrate 21 with an AlN film at an ordinary temperature of 20 degrees Celsius ± 10 degrees Celsius. ₂ O ₂ ) for 0.4 to 0.6 minutes, here 0.5 minutes. The range of 25 wt% to 35 wt% of the concentration of hydrogen peroxide water (H ₂ O ₂ ) in the first cleaning step is the above error range of 30 wt% to 32 wt%, and there is no problem from the actual test results. It was.

In the second cleaning step, the liquid temperature of a mixed solution of sulfuric acid (H ₂ SO ₄ ) and hydrogen peroxide (H ₂ O ₂ ) (sulfuric acid perwater; H ₂ SO ₅ ) is 130 degrees Celsius to 170 degrees Celsius. A mixed solution of sulfuric acid (H ₂ SO ₄ ) having a temperature range of 150 ° C. and having a concentration of 60 to 90 wt% and hydrogen peroxide (H ₂ O ₂ ) having a concentration of 2.5 to ₄ wt% The AlN layer on the semiconductor substrate is removed by water; H ₂ SO ₅ ).

  In the drying process, the PSS substrate after the second cleaning process is subjected to a drying process after a predetermined cleaning, and as shown in the X-ray waveform of FIG. 3, the half width of the X-ray waveform is -arcsec. It can be seen that the peak waveform due to the AlN material does not appear and the AlN layer is completely removed from the surface of the semiconductor substrate.

  The AlN film forming step is an AlN layer made of aluminum nitride (AlN) having a thickness of about 15 nm to 50 nm on, for example, a sapphire substrate 2 (PSS substrate) as a semiconductor substrate having a thickness of about 1300 μm and having an uneven shape formed on the surface. A certain buffer layer 3 is newly formed.

  4 shows the crystallinity of the AlN layer (buffer layer 3) formed after the second cleaning step from the half-value width 304 arcsec of the X-ray waveform of FIG. 4 showing the crystallinity of the AlN layer (buffer layer 3) before the first cleaning step. The half width of the X-ray waveform of FIG. 5 is 315 arcsec, indicating that the AlN layer has good crystallinity.

  The height of the concavo-convex cross-sectional image shown in FIG. 6 of the sapphire substrate 2 before the first cleaning step is 470.73 nm, and the height of the concavo-convex cross-sectional image shown in FIG. 7 of the sapphire substrate 2 after the second cleaning step. The width of the cross-sectional image of the concavo-convex shape shown in FIG. 6 of the sapphire substrate 2 is 1.36 μm from the width of the cross-sectional image of the sapphire substrate 2 shown in FIG. 7 of the sapphire substrate 2 after the second cleaning step. Has a width of 1.37 μm. This indicates that the height and width of the sectional image of the concavo-convex shape of the sapphire substrate 2 are not changed at all within the error range before and after the first and second cleaning steps.

  FIG. 8 is a view showing the presence / absence of removal of the AlN layer, the change in the concavo-convex shape, and the confirmation result of the foreign matter removal for each concentration in the first cleaning step and the second cleaning step in FIG.

As shown in FIG. 8, in the first cleaning step, the PSS substrate 21 with an AlN film, which is a laminated semiconductor wafer as a laminated semiconductor substrate, is immersed at a room temperature of 20 degrees Celsius ± 10 degrees Celsius and an immersion time of 0.5 minutes. In addition, the cleaning treatment is performed at a concentration of hydrogen peroxide (H ₂ O ₂ ) of 30 Wt percent to 32 Wt percent at the time of bathing.

Next, in the second cleaning step, the liquid temperature of sulfuric acid (H ₂ SO ₄ ) and hydrogen peroxide water (H ₂ O ₂ ) (sulfuric acid / hydrogen peroxide) is 130 degrees Celsius to 160 degrees Celsius, When the immersion time of the laminated semiconductor substrate in the mixed solution is 1 minute or more and 20 minutes or less (more preferably 1 minute or more and 5 minutes or less, or 1 minute or more and 2 minutes or less), sulfuric acid (H ₂ SO ₄ ) This is a laminated semiconductor wafer as a laminated semiconductor substrate having a concentration of 79 Wt percent to 81 Wt percent at the time of bathing and a concentration of 3.1 Wt percent to 3.5 Wt percent of a hydrogen peroxide solution (H ₂ O ₂ ) at the time of bathing. By cleaning the PSS substrate 21 with the AlN film, the AlN layer as a nitride layer formed on the semiconductor substrate (semiconductor wafer) can be completely removed without any remaining film.

  In this case, the presence / absence of the removal of the AlN layer, the change in the concavo-convex shape and the confirmation result of the removal of the foreign matter were all “OK” without any problem. This is shown in FIG.

However, in FIG. 8, when only the immersion time in the mixed solution (sulfuric acid / hydrogen peroxide; H ₂ SO ₅ ) is set to be as short as 0.5 minutes under the same conditions as described above, the AlN layer is dissolved with or without removal. There was a residue, the uneven shape changed, and a foreign object remained, and the result of confirmation was “NG” with a problem. This is shown in FIG.

In the second cleaning step, the immersion time of the PSS substrate 21 with the AlN film as the laminated semiconductor substrate in the mixed solution (sulfuric acid / hydrogen peroxide; H ₂ SO ₅ ) is set to 1 minute to 20 minutes. If the immersion time in (sulfuric acid / hydrogen peroxide; H ₂ SO ₅ ) is 20 minutes, the AlN layer as a nitride layer is completely removed without any film residue even when the thickness of the AlN layer is as thick as 50 nm. Can do. Even if the immersion time in the mixed solution (sulfuric acid / hydrogen peroxide; H ₂ SO ₅ ) exceeds 20 minutes, there is no point in removing the AlN layer.

  In the second cleaning step, the temperature of the liquid mixture (sulfuric acid / hydrogen peroxide) is 130 degrees Celsius to 170 degrees Celsius. The liquid temperature of the liquid mixture (sulfuric acid hydrogen peroxide) is 145 degrees Celsius to 155 degrees Celsius. The error range, and from the actual test results, there was no problem with the presence or absence of the removal of the AlN layer, the change in the concavo-convex shape, and the removal of foreign matter.

In the second washing step, bath preparation at concentration levels ranging of 60Wt percent ~90Wt percent, said bath preparation when concentrations 79Wt percent ~81Wt of sulfuric acid _(H 2 SO ₄₎ of sulfuric acid _(H 2 SO ₄₎ There was no problem from the actual test results.

In the second cleaning step, the concentration range of concentrations 2.5Wt percent ~4Wt percent during vatting of hydrogen peroxide _(H 2 _{O 2),} the initial make-up of the hydrogen peroxide _(H 2 _{O 2)} The concentration at the time was within an error range of 3.1 Wt percent to 3.5 Wt percent, and there was no problem from the actual test results.

  Here, a unit chip configuration of a laminated semiconductor wafer as a laminated semiconductor substrate in which LEDs as a plurality of nitride semiconductor light emitting elements formed using the PSS substrate 21 with an AlN film in FIG. 2 are formed in a matrix will be described. .

  FIG. 9 is a longitudinal sectional view schematically showing a unit LED chip configuration of a laminated semiconductor wafer formed using the PSS substrate 21 with the AlN film of FIG.

  In FIG. 9, a nitride semiconductor light emitting device 1 using a PSS substrate 21 with an AlN film regenerated by the method for manufacturing a regenerated substrate according to the first embodiment is a sapphire substrate having a thickness of about 1300 μm and having an uneven surface. A buffer layer 3 made of aluminum nitride (AlN) and having a thickness of about 15 nm to 50 nm is formed on the substrate 2. The sapphire substrate 2 and the buffer layer 3 constitute a PSS substrate 21 with an AlN film. These sapphire substrate 2, buffer layer 3 and non-doped GaN layer 4 GaN layer constitute an AlN film as a single crystal substrate and a PSS substrate 22 with a GaN layer.

Furthermore, in the nitride semiconductor light emitting device 1 of the first embodiment, the n-type contact layer 5 having a film thickness of about 5 μm made of GaN doped with silicon (Si) 1 × 10 ¹⁸ / cm ³ on the single crystalline substrate 21. (High carrier concentration n ⁺ layer) is formed. A multi-layer 6 is formed on the n-type contact layer 5, and a light-emitting layer 7 having a multi-quantum well structure is formed on the multi-layer 6.

The multiple layer 6 is formed by alternately stacking a plurality of _first layers made of In _x Ga _1-x N (0 <x <0.3) and second layers made of GaN. In this multilayer 6, for example, five pairs of a first layer made of In _0.03 Ga _0.97 N with a thickness of 3 nm and a second layer made of GaN with a thickness of 20 nm are stacked. .

The first layer of the multi-layer 6 has a concentration of Si as one conductivity type impurity of 5 × 10 ¹⁶ cm ⁻³ to 1 × 10 ¹⁸ cm ⁻³ (more preferably 1 × 10 ¹⁷ cm ^{− 3} to 1 × 10 ¹⁸ cm ⁻³ ), and the electrostatic breakdown energy (mJ / cm ² ) received by the light emitting layer 7 is 20 to 40 (more preferably, 20 to 35). Yes.

The well layer of the light emitting layer 7 having a multiple quantum well structure is made of In _y Ga1-yN (0 ≦ y <0.3) containing at least In. As described above, the light emitting layer 7 having a multiple quantum well structure includes, for example, three pairs of a well layer made of In _0.2 Ga _0.8 N having a thickness of 3 nm and a barrier layer made of GaN having a thickness of 20 nm. Laminated.

Furthermore, in the nitride semiconductor light emitting device 1 of the first embodiment, the light emitting layer 7 is made of p-type Al _0.15 Ga _0.85 N having a thickness of 25 nm doped with 2 × 10 ¹⁹ / cm ^{3 of} Mg. An electron blocking layer 8 that is a p-type layer is formed. A p-type contact layer 9 made of p-type GaN having a thickness of 100 nm doped with 8 × 10 ¹⁹ Mg is formed on the electron block layer 8.

  On the p-type contact layer 9, a translucent thin film electrode 10 (ITO) is formed by metal vapor deposition. A p-electrode 11 is formed on a part of the translucent thin film electrode 10.

On the other hand, an end portion of the n-type contact layer 5 is exposed partway, and an n-electrode 12 is formed thereon. On top of the p-electrode 11 and the n-electrode 12, a protective film 13 for moisture resistance made of a SiO ₂ film as a Si _x O _y film is formed.

  As described above, according to the first embodiment, the buffer layer 3 that is the AlN layer determined to be defective is removed from the stacked semiconductor substrate formed on the sapphire substrate 2, and the AlN layer is newly added. In a method for manufacturing a regenerated substrate in which a certain buffer layer 3 is formed to regenerate a laminated semiconductor substrate, a first cleaning step in which the laminated semiconductor substrate is cleaned with a hydrogen peroxide solution, and after the first cleaning step And a second cleaning step of cleaning the laminated semiconductor substrate (laminated semiconductor wafer) with a mixed solution of sulfuric acid and hydrogen peroxide solution.

  As a result, the laminated nitride layer (AlN layer) on the semiconductor substrate is peeled off only by wet processing at a much lower temperature than in the prior art. Physical changes such as warping and cracking can also be suppressed, and a recycled substrate can be manufactured by removing the nitride layer (AlN layer) from the laminated semiconductor wafer.

(Embodiment 2)
In the first embodiment, the case where an AlN film is newly formed after removing the AlN film as the nitride layer determined to be defective in the first cleaning process and the second cleaning process has been described. Then, the nitride layer determined to be defective is a two-layer structure of an AlN film and a nitride semiconductor layer (GaN layer) formed thereon, and before the first cleaning step and the second cleaning step. A case where the semiconductor device further includes a nitride semiconductor layer removing step for removing the nitride semiconductor layer (GaN layer) will be described.

  FIG. 10 is a process flow chart for explaining a method for manufacturing a regenerated substrate in Embodiment 2 of the present invention.

In FIG. 10, the method for manufacturing a recycled substrate according to the second embodiment includes a substrate receiving step for receiving a PSS (patterned sapphire substrate) substrate 22 with an AlN film and a GaN layer, which are stacked semiconductor wafers as stacked semiconductor substrates. Step S11), a nitride semiconductor layer removing step (Step S12) for removing the GaN layer as the nitride semiconductor layer from the PSS substrate 22 with the AlN film and the GaN layer, and the PSS with the AlN film from which the GaN layer has been removed. A first cleaning step (step S13) in which the substrate 21 is cleaned with hydrogen peroxide (H ₂ O ₂ ), and sulfuric acid (H ₂ SO) for the AlN-attached PSS substrate after the first cleaning step. ₄₎ and hydrogen peroxide (H 2 _{O 2)} mixture (second wash for performing a cleaning process sulfate by peroxide) removing the AlN film layer remaining without the After the step (step S14), the second cleaning step, the drying step (step S15) for drying the PSS substrate (sapphire substrate 2), which is a semiconductor wafer as a semiconductor substrate, and the PSS substrate after the drying step An AlN film formation step (step S16) for newly forming an AlN film as a nitride layer on (sapphire substrate 2), and a nitride semiconductor layer for forming a GaN layer as a nitride semiconductor layer on the AlN film A film forming process (step S17) and a substrate take-out process (step S18) for taking out the AlN film and the PSS substrate 22 with the GaN layer as a single crystal substrate are included.

  In the nitride semiconductor layer removing step of step S12, when the GaN layer as the nitride semiconductor layer is removed from the AlN film and the PSS substrate 22 with the GaN layer, the nitride semiconductor layer is heated in a chlorine atmosphere, a hydrogen atmosphere or a vacuum. Do it.

  A semiconductor substrate (semiconductor wafer) is changed from a laminated semiconductor wafer (laminated semiconductor substrate) that has become unusable due to a defect determined by the method for manufacturing a recycled substrate according to the second embodiment due to adhesion of foreign matter or a different film thickness. A GaN layer (nitride semiconductor layer) as a nitride layer formed thereon and an AlN layer (nitride layer) are removed, and an AlN layer and a GaN layer are newly formed as a nitride layer on a semiconductor substrate (semiconductor wafer). By forming the laminated semiconductor wafer, the laminated semiconductor wafer as the laminated semiconductor substrate is regenerated.

  The method for manufacturing a recycled substrate according to the second embodiment is different from the method for manufacturing a recycled substrate according to the first embodiment in the nitride semiconductor layer removing step (step S12) and the nitride semiconductor layer forming step (step S17). This is the difference between the substrate receiving process (step S11) for receiving the PSS (patterned sapphire substrate) substrate 22 with the AlN film and the GaN layer and the substrate handled in the substrate extracting process (step S18). Yes. The other first cleaning process (step S13), the second cleaning process (step S14), the drying process (step S15), and the AlN film forming process (step S16) are the same as those in the first embodiment. The effect is exactly the same.

As described above, according to the second embodiment, the AlN layer and the GaN layer determined to be defective are formed on the sapphire substrate 2, the AlN film as the laminated semiconductor substrate, and the GaN layer and the AlN layer from the PSS substrate 22 with the GaN layer. In the manufacturing method of a regenerated substrate in which an AlN layer and a GaN layer are newly formed thereon and a AlN film and a PSS substrate 22 with a GaN layer are regenerated as a laminated semiconductor substrate, a GaN layer as a nitride semiconductor layer is formed. The first step of removing the nitride semiconductor layer to be removed and performing a cleaning process with hydrogen peroxide (H ₂ O ₂ ) on the PSS substrate 21 with the AlN film as the laminated semiconductor substrate in order to remove the next AlN layer. step of washing and, sulfuric acid relative to AlN film coated PSS substrate 21 of a laminated semiconductor substrate after the first cleaning step _(H 2 SO ₄ And a second cleaning step is provided to perform the washing treatment with a mixed solution of hydrogen peroxide (H 2 _{O 2).}

  As a result, the laminated nitride layer (AlN layer) on the semiconductor substrate is peeled off only by wet processing at a much lower temperature than in the prior art. Physical changes such as warping and cracking can also be suppressed, and a recycled substrate can be manufactured by removing the nitride layer (AlN layer) from the laminated semiconductor wafer.

  In addition, as mentioned above, although this invention was illustrated using preferable Embodiment 1, 2 of this invention, this invention should not be limited and limited to this Embodiment 1,2. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge, from the description of specific preferred embodiments 1 and 2 of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  The present invention relates to a method for manufacturing a regenerated substrate in which a nitride layer is removed from a laminated semiconductor wafer having a defective nitride layer formed on the semiconductor substrate, and a new nitride layer is formed to regenerate the laminated semiconductor wafer. In the field, a first cleaning step of performing a cleaning process with a hydrogen peroxide solution on a laminated semiconductor substrate in which a nitride layer determined to be defective is formed on the semiconductor substrate, and a laminated semiconductor substrate after the first cleaning step And a second cleaning step of performing a cleaning process with a mixed solution of sulfuric acid and hydrogen peroxide solution, so that a laminated nitride layer can be formed on the semiconductor substrate only by wet processing at a much lower temperature than in the prior art. Therefore, as in the past, without affecting the crystallinity and uneven shape of the substrate, it is possible to suppress the physical change such as warping and cracking due to heat and remove the laminated nitride layer from the laminated semiconductor wafer, new By forming a laminated nitride layer can be produced recycled substrate.

1 Nitride semiconductor light emitting device 2 Sapphire substrate (semiconductor substrate)
3 Buffer layer (nitride layer; AlN layer)
4 Non-doped GaN layer (nitride layer; nitride semiconductor layer)
5 n-type contact layer 6 multi-layer 7 light-emitting layer with multiple quantum well structure 8 electron block layer 9 p-type contact layer 10 translucent thin film electrode 11 p-electrode 12 n-electrode 13 protective film 21 PSS substrate with AlN film (laminated semiconductor substrate) ; Laminated semiconductor wafer)
22 PSS substrate with AlN film and GaN layer (laminated semiconductor substrate; laminated semiconductor wafer)

Claims (20)

Manufacture of a regenerated substrate that removes the nitride layer from the laminated semiconductor substrate on which the defective nitride layer is formed on the semiconductor substrate, and forms a new nitride layer on the semiconductor substrate to regenerate the laminated semiconductor substrate In the method
A first cleaning process for cleaning the laminated semiconductor substrate with hydrogen peroxide water, and a cleaning process with a mixed solution of sulfuric acid and hydrogen peroxide water for the laminated semiconductor substrate after the first cleaning process And a second cleaning step of performing a reproduction substrate manufacturing method.   The method for manufacturing a regenerated substrate according to claim 1, wherein the nitride layer is an AlN film.   3. The method for manufacturing a recycled substrate according to claim 2, wherein, in the second cleaning step, the laminated semiconductor substrate is cleaned at a liquid temperature of 130 degrees Celsius to 170 degrees Celsius.   The manufacturing method of the reproduction | regeneration board | substrate of Claim 3 which makes immersion time of the said laminated semiconductor substrate in the said liquid mixture of a said 2nd washing | cleaning process 1 minute or more and 20 minutes or less.   5. The method for manufacturing a recycled substrate according to claim 4, wherein, in the second cleaning step, the laminated semiconductor substrate is cleaned at a concentration of the sulfuric acid of 60 Wt percent to 90 Wt percent.   6. The method for manufacturing a recycled substrate according to claim 5, wherein, in the second cleaning step, the stacked semiconductor substrate is cleaned at a concentration of the hydrogen peroxide solution of 2.5 Wt percent to 4 Wt percent.   3. The manufacturing of the regenerated substrate according to claim 2, wherein, in the first cleaning step, the stacked semiconductor substrate is cleaned at a normal temperature of 20 degrees Celsius ± 10 degrees Celsius at a concentration of the hydrogen peroxide solution of 25 Wt percent to 35 Wt percent. Method.   8. The method for manufacturing a recycled substrate according to claim 7, wherein in the first cleaning step, the stacked semiconductor substrate is cleaned at a concentration of the hydrogen peroxide solution of 25 Wt percent to 35 Wt percent.   4. The method for manufacturing a recycled substrate according to claim 3, wherein, in the second cleaning step, the laminated semiconductor substrate is cleaned at a liquid temperature of 130 degrees Celsius to 160 degrees Celsius.   The method for manufacturing a regenerated substrate according to claim 4, wherein an immersion time of the laminated semiconductor substrate in the mixed solution in the second cleaning step is 1 minute or more and 5 minutes or less.   6. The method for manufacturing a recycled substrate according to claim 5, wherein in the second cleaning step, the laminated semiconductor substrate is cleaned at a concentration of the sulfuric acid of 79 Wt percent to 81 Wt percent.   The method for manufacturing a recycled substrate according to claim 6, wherein, in the second cleaning step, the stacked semiconductor substrate is cleaned at a concentration of the hydrogen peroxide solution of 3.1 Wt percent to 3.5 Wt percent.   The nitride semiconductor layer has a two-layer structure of an AlN film and a nitride semiconductor layer formed thereon, and the nitride semiconductor layer removing step of removing the nitride semiconductor layer before the first cleaning step The manufacturing method of the reproduction | regeneration board | substrate of Claim 1 which further has these.   The method for manufacturing a regenerated substrate according to claim 13, wherein the removal of the nitride semiconductor layer is performed by heating in a chlorine atmosphere, a hydrogen atmosphere, or a vacuum.   The method for manufacturing a recycled substrate according to claim 2, wherein the AlN film has a thickness of 15 nm to 50 nm.   The method for manufacturing a reclaimed substrate according to claim 1, wherein the semiconductor substrate has an uneven surface.   The method for manufacturing a regenerated substrate according to claim 16, wherein the semiconductor substrate is a sapphire substrate.   After the second cleaning step, a drying step of cleaning the semiconductor substrate and then drying, and a nitride layer forming step of newly forming the nitride layer on the semiconductor substrate after the drying step The manufacturing method of the reproduction | regeneration board | substrate of Claim 1 or 12.   19. The method for manufacturing a regenerated substrate according to claim 18, wherein the nitride layer forming step further includes an AlN film forming step of newly forming an AlN layer on the semiconductor substrate.   The nitride layer forming step includes an AlN film forming step for newly forming an AlN film on the semiconductor substrate, and a nitride semiconductor layer forming step for newly forming the nitride semiconductor layer on the AlN film. The method for producing a recycled substrate according to claim 18, further comprising a film process.