JP2005072422A - Semiconductor element epitaxial layer separating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor element epitaxial layer separating method capable of separating a substrate and an epitaxial layer from each other steadily in a short time, producing less environmental impact, and manufacturing at low cost. <P>SOLUTION: At least one aperture 4 is formed by selective etching, which starts at a part of the rear surface of the substrate 2 of a semiconductor element 10 having an etch stop layer 3 sandwiched between the substrate 2 and an epitaxial layer 1, and ends upon reaching the etch stop layer 3. Next, the etch stop layer 3 is selectively removed by selective etching performed via the etching-provided aperture 4, thus separating the substrate 2 and the epitaxial layer 1 from each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for separating an epitaxial layer of a semiconductor element, and more particularly to a lift-off technique for an epitaxial layer such as an optical semiconductor element which is highly demanded to be thin.

  Since optical semiconductor elements and the like are used in combination with other semiconductor elements and optical components, the demand for thinning is particularly high. In order to satisfy these requirements, there has been proposed an epitaxial lift-off technique in which an epitaxial layer of a semiconductor element is used after being separated and removed from a substrate portion (see Patent Document 1, Patent Document 2, and Non-Patent Document 1).

  4A to 4C are views for explaining a first example of a conventional epitaxial lift-off method.

  In this conventional method, first, as shown in FIG. 4A, the surface of a semiconductor element (light emitting element) 50 in which an AlAs etching layer 53 is provided between a GaAs substrate portion 52 and an epitaxial layer 51 is formed. The semiconductor wafer 61 is fixed to the support substrate 60 with the semiconductor wax 61 facing down. In FIG. 4A, 51A represents a light emitting portion, and 55 represents an electrode portion.

Next, as shown in FIG. 4B, the etching layer 53 is selectively etched from the lateral direction by wet etching with HF and H ₂ O (1:10). In FIG. 4B, an arrow E2 indicates the direction of progress of etching.

  Finally, as shown in FIG. 4C, etching in the E2 direction proceeds to completely dissolve the etching layer 53, so that the base material portion 52 is separated from the epitaxial layer 51.

  FIG. 5 is a diagram for explaining a second example of the conventional epitaxial lift-off method.

As shown in FIG. 5, after using a semiconductor element 50 in which an AlAs etching stop layer 54 is provided between a GaAs substrate 52 and an epitaxial layer 51, the surface of the semiconductor element 50 is solidified with a semiconductor wax 61. Then, the base material part 52 is wet-etched with NH ₄ OH and H ₂ O ₂ (1: 200) from the back surface to the etching stop layer 54 (arrow E3) to completely dissolve and remove the base material part 52.
JP 2000-101139 A Japanese Patent Laid-Open No. 11-340569 C. Camperi-Ginestet, M .; Hargis, N .; Jokerst, and M.M. Allen, IEEE Transactions Photonics Technology Letters, Vol. 3, No. 12, pp. 1123-1126, 1991.

  According to the conventional method, a thin film epitaxial layer can be obtained by removing the base material portion, but it has various problems.

  Specifically, in the first example of the conventional epitaxial lift-off method, a thin etching layer 53 provided between the base material portion 52 and the epitaxial layer 51 is etched from the lateral direction. The etching layer 53 has a thickness of about 50 nm to 200 nm. On the other hand, the chip has a diameter of about 100 to 500 μm, and when used in the form of an array, it may be about several mm. . Therefore, in the case of a large array, there is a problem that it takes a very long time to sequentially etch the wide and thin etching layer 53 over the entire array through the thin etching layer 53 from the periphery.

  Further, if the semiconductor wax 61 rises above the etching layer 53 when the semiconductor element (light emitting element) 50 is fixed, the end surface of the etching layer 53 is hidden, so that the etching itself cannot be performed. There was also a problem.

  Conversely, if the semiconductor wax 61 does not crawl above the etching layer 53, the side surface of the epitaxial layer 51 may be exposed, but a material such as AlGaAs is used for this portion. There is a problem that etching is performed in the same manner as the etching layer 53.

  In the second example of the conventional epitaxial lift-off method, the entire base portion 52 having a thickness of about 100 μm to 600 μm is melted and removed by etching, leaving the epitaxial layer 51 having a thickness of about 1 μm to 10 μm. It will be. GaAs and InP are used for the base material portion 52 to be melted, but Ga and In are rare metal materials and expensive materials, and As is a harmful substance, so these materials are dissolved in large quantities. Disposal has been problematic from a resource and environmental standpoint. Further, in order to treat harmful GaAs waste liquid, it is necessary to use an expensive waste liquid treatment apparatus, and there is a problem that the manufacturing cost increases.

  Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and the object of the present invention is to reduce the amount of the base material portion dissolved by etching and efficiently remove the base material portion. It is an object of the present invention to provide an inexpensive method for separating an epitaxial layer of a semiconductor device that can save resources and has a low environmental load.

  Furthermore, another object of the present invention is to provide an inexpensive semiconductor element with a low environmental load, and to provide a base part of a semiconductor element that can be easily discarded and recycled.

  In order to solve the above problems, in the present invention, there is provided an epitaxial layer separation method for a semiconductor element that separates a base material part and an epitaxial layer from a semiconductor element having an etching stop layer between the base material part and the epitaxial layer, At least one etching window is opened by selectively etching a part of the base material part from the back surface side until reaching the etching stop layer, and the etching stop layer is selectively removed by etching through the etching window.

  For example, the semiconductor element is a backside light emitting element, and at least one of the etching windows is in a position where radiation can be extracted through the etching window. Alternatively, the semiconductor element is a back-side light receiving element, and at least one of the etching windows is at a position where light can be irradiated to the light receiving portion through the etching window.

Preferably, the base portion is made of GaAs, and the etching stop layer is made of at least one material selected from the group consisting of AlGaAs, AlAs, Al ₂ O ₃ , InAs, CdSe, CdTe, CdS, and ZnTe. Or the substrate portion is made of InP, and the etching stop layer is at least selected from the group consisting of GaAs, AlGaAs, AlAs, Al ₂ O ₃ , InAs, CdSe, CdTe, CdS, and ZnTe. Consists of one material.

Preferably, the etching window formed in the base part made of GaAs is dry etching using a gas of SiCl ₄ : SF ₆ (2: 1) or a 50% citric acid solution: H ₂ O ₂ (5 1) or at least one of wet etching using NH ₄ OH: H ₂ O ₂ (1:20 to 200).

Alternatively, the etching window formed in the InP base material portion uses at least one of dry etching using Cl ₂ gas or wet etching using Br ₂ : CH ₃ OH (1:10). Formed.

In order to selectively remove the AlGaAs, AlAs, and Al ₂ O ₃ etching stop layers, for example, wet etching using HF: H ₂ O (1:10) is used.

In order to selectively remove the InAs etching stop layer, for example, wet etching with HCl: H ₂ O (1: 5 to 20) may be used.

In order to selectively remove the CdSe etching stop layer, for example, wet etching using HNO ₃ : CH ₃ COOH (1: 1) may be used.

For selectively removing the CdTe etching stop layer, for example, wet etching using HNO ₃ : HF (1: 1) or HNO ₃ : HCl: H ₂ O (1: 1: 0.5) is used. May be.

In order to selectively remove the CdS etching stop layer, for example, wet etching using HNO ₃ : CH ₃ COOH: H ₂ O (6: 6: 1) or HCl vapor may be used.

  In order to selectively remove the ZnTe etching stop layer, for example, wet etching with NaOH may be used.

In order to selectively remove the GaAs etching stop layer, a 50% citric acid solution: H ₂ O ₂ (5: 1) or NH ₄ OH: H ₂ O ₂ (1:20 to 200) is used. Any of the wet etching processes used may be used.

  The thickness of the etching stop layer is preferably in the range of 50 nm to 1 μm.

  Further, it is preferable that the etching stop layer is selectively removed by etching after temporarily fixing the surface of the semiconductor element having the etching window on the support substrate with a wax for semiconductor.

  Further, it is preferable that the etching stop layer is selectively removed by etching after the semiconductor element having the etching window opened is flip-chip bonded to the wiring board.

  Further, after flip chip bonding the semiconductor element to the wiring board, an underfill material is inserted and solidified between the wiring board and the semiconductor element, and then the etching stop layer is selectively etched away. preferable.

  Further, after inserting and solidifying an underfill material between the wiring substrate and the flip-chip bonded semiconductor element, the semiconductor element is coated with wax on the side surface of the epitaxial layer and the wiring substrate to cover the surface, Thereafter, the etching stop layer is preferably selectively removed by etching.

  In the present invention, a desired semiconductor element can be obtained by separating the base material portion and the epitaxial layer from the semiconductor element and leaving only the epitaxial layer on the support substrate or the wiring board by the epitaxial layer separation method. .

  Moreover, in this invention, a base material part is obtained by isolate | separating a base material part and an epitaxial layer from the said semiconductor element with the said epitaxial layer separation method. Only the portion of the etching window is removed from the base material portion.

  According to the present invention, since the amount of the base material portion to be melted by etching can be reduced, it is possible to provide a manufacturing method that saves resources and has a low environmental load. In addition, since the etching stopper layer can be etched in a short time and the surroundings can be easily protected with wax or the like, an inexpensive manufacturing method with little damage to the epitaxial layer due to etching can be provided.

  In addition, since the semiconductor element manufactured by the epitaxial lift-off method of the present invention is not easily damaged by transportation, mounting, or etching, a highly reliable thin semiconductor element can be provided. In addition, since this semiconductor element does not have a harmful GaAs base material, harmful substances on the market can be greatly reduced.

  Moreover, since the base material part manufactured by the epitaxial lift-off method according to the present invention can be easily collected, it can be used as a recycled material.

  Hereinafter, the best embodiment of the present invention will be described with reference to the drawings.

  1A to 1C, 2A to 2C, and 3A to 3B are explanatory views showing an embodiment of an epitaxial lift-off method according to the present invention in the order of steps. is there.

  FIG. 1A is a diagram showing an embodiment of a semiconductor element according to the present invention. The epitaxial layer 1 is formed on the base material portion 2 with the etching stop layer 3 interposed therebetween, and is a light emitting element 10 having a light emitting portion 1A and electrodes 5a and 5b on the epitaxial layer 1 side. Here, the base material portion 2 is made of GaAs or InP, and the etching stop layer 3 is made of AlGaAs (Al composition 50% or more), InAs, CdSe, CdTe, CdS, or ZnTe. Unless otherwise noted, the base material portion 2 will be described as GaAs, and the etching stop layer 3 will be described as AlGaAs.

  As the thickness of the etching stop layer 3 is increased, the etching can be surely stopped. However, as the thickness of the etching stop layer 3 is increased, it naturally takes time to form the etching stop layer 3. Therefore, the thickness of about 100 to 200 nm is usually appropriate. is there.

  FIG.1 (b) is a figure which shows the middle condition of the etching process which forms the etching window 4 in the base material part 2 which is the 1st process of this invention.

  The light emitting element 10 shown in FIG. 1A is inverted, and a part of the base material portion 2 is etched from the back surface (in the direction of arrow E0) using the Ni mask 6 in order to form the etching window 4 at a predetermined position. It shows the situation on the way.

  FIG.1 (c) is a figure which shows the condition which the etching process which forms an etching window in the base material part which is the 1st process of this invention was complete | finished. The etching reaches the etching stop layer 3 and the formation of the etching window 4 is completed.

Reactive ion etching (RIE), which is one of dry etching methods, can be used as a method for forming a deep hole of a predetermined size in the GaAs substrate portion 2, but it is necessary to stop the etching with an AlGaAs etching stop layer 3. Therefore, reactive ion etching (RIE) using a gas of SiCl ₄ : SF ₆ (2: 1) having selective etching characteristics between GaAs and AlGaAs is used.

However, when the device is thin, a 50% citric acid solution having selective etching characteristics with GaAs and AlGaAs: H ₂ O ₂ (5: 1) or NH ₄ OH: H ₂ O ₂ (1: 20-200) can also be used. Moreover, you may use both processes together instead of processing only by either one. When wet etching is performed, although not shown, it is natural that the lower surface and side surfaces of the light emitting element are protected with a wax for semiconductor or the like.

  In FIG. 1C, only one position corresponding to the light emitting portion 1A is etched. However, when the element is large or the light emitting portion 1A is not centered with respect to the outer shape of the element, light emission is performed. A plurality of etching windows 4 may be formed by etching a plurality of locations other than the portion 1A. For example, when the semiconductor element is a backside light emitting element, it is preferable that at least one of the etching windows 4 is at a position where the emitted light can be extracted through the etching window 4. When the semiconductor element is a back-side light receiving type light receiving element, it is preferable that at least one of the etching windows 4 is at a position where light can be irradiated to the light receiving portion through the etching window 4.

  Although not shown, the second process includes an optical property inspection / selection process. Since the etching window 4 is opened at a position corresponding to the light emitting portion 1A in the first step, the light emission characteristics of the light emitting element 10 can be measured. In the case where the light-emitting element 10 is a back-light-emitting type of visible light, the optical characteristics cannot be measured if the base material portion 2 is present. Even in the case of a light emitting element that emits light having a long wavelength that passes through the GaAs base material portion 2, it is important to perform inspection and selection of the light emission characteristics in the final form without the base material portion 2. By performing inspection and selection in this process, it becomes possible to pass only non-defective products to the subsequent process, and efficient production becomes possible. Although this step can be omitted depending on the situation such as yield, it is preferable to carry out this step as described above.

  FIG. 2A is a diagram showing a state after flip-chip bonding, which is the third step of the present invention. The light emitting element 10 in which the etching window 4 shown in FIG. 1C is formed is flip-chip bonded to the wiring substrate 20 on which the bonding pads 21 are formed, and the electrode portion 5 of the light emitting element 10 and the wiring substrate 20 are bonded. Pad 21 is connected.

  In this process, although the etching window 4 is open, the base material portion 4 remains firmly, so that it can be easily handled using a conventional flip chip bonder without applying stress to the epitaxial layer 1 and easily. Can be mounted at a predetermined position.

  FIG.2 (b) is a figure which shows the condition after performing the underfill filling which is the 4th process of this invention. 2 shows a state in which the light-emitting element 10 is fixed by filling the gap between the flip-chip bonded light-emitting element 10 and the wiring substrate 20 shown in FIG.

  It is desirable that the underfill material 22 has a large filler content and a small thermal expansion coefficient so that the epitaxial film 1 after thinning is not subjected to stress due to expansion and contraction due to heat of the underfill material 22. Further, it is desirable that the gap between the light emitting element 10 and the wiring board 20 be as small as about several μm to 20 μm or less because the underfill material 22 becomes thinner and the expansion / contraction amount due to heat is reduced.

  Normally, the electrode portions 5a and 5b of the light emitting element 10 are the anode and the cathode. However, when a dummy electrode is added to stabilize the position of the element and increase the connection strength, or the optical element is an electrode. However, in some cases, it is not necessary to reinforce with the underfill material 22, but it is preferable to reinforce with the underfill material 22 in view of reliability and the like.

  FIG.2 (c) is a figure which shows the condition after performing the wax coating for semiconductors which is the 5th process of this invention. The semiconductor wax here is an adhesive having resistance to the etching solution. A state in which a semiconductor wax 23 is applied to the side surface of the epitaxial layer 1 of the light emitting element 10 filled with the underfill material 22 shown in FIG. This step is for preventing etching in a subsequent etching step such as when AlGaAs is used for the epitaxial layer 1 of the light emitting element 10 or when the wiring substrate 20 is made of alumina ceramics. Depending on the material of the element 10 and the wiring board 20, it may be unnecessary.

FIG. 3A is a diagram showing a situation where the etching stop layer, which is the sixth step of the present invention, is being etched. In order to selectively remove the etching stop layer 3 of AlGaAs (Al composition: 50% or more), wet etching with HF: H ₂ O (1:10) is used. An arrow E1 indicates a situation in which the etching stop layer 3 is being etched through the etching window 4. Unlike the conventional example shown in FIG. 4B, the etching is performed from the etching window 4 instead of from the periphery of the light emitting element 10, so that the etching is performed by the underfill material 22 for fixing the element, the semiconductor wax 23 for protecting the element, or the like. Since E1 is not inhibited, stable etching is possible.

  Further, as described with reference to FIG. 1B, even when the light emitting element 10 is large or the light emitting part 1A is not at the element center, a plurality of etching windows 4 are arranged so that the epitaxial layer 1 and the substrate part are arranged. Since the distance for etching the thin etching stop layer 3 sandwiched between 2 can be shortened, the etching of the etching stop layer 3 can be completed in a short time.

  FIG. 3B is a view showing a situation where the semiconductor wax 23 which is the seventh step of the present invention is removed. The semiconductor element in which the etching stop layer 3 is completely removed and the base portion 2A is only the epitaxial layer 1 is shown. (Light-emitting element) The situation separated from 10A is shown.

  However, if the protection of the epitaxial layer 1 and the wiring substrate 20 is not necessary as described in the fifth step shown in FIG. In this case, the base material portion 2 is separated from the epitaxial layer 1 when the sixth etching step is completed.

  As described above, according to the epitaxial lift-off method as shown in FIGS. 1A to 1C, 2A to 2C, and FIGS. 3A to 3B, harmful GaAs dissolved by etching is removed. Since the amount of the base material portion 2 can be reduced and the AlGaAs etching stop layer 3 can be reliably etched in a short time, an inexpensive manufacturing method that saves resources and has a low environmental load can be provided.

  Further, as shown in FIG. 3B, the semiconductor element (light emitting element) 10A and the substrate portion 2A only of the epitaxial layer 1 separated by the epitaxial method of the present invention are a semiconductor element showing an embodiment of the present invention. And a semiconductor element substrate portion.

  Since the semiconductor element 10A of the present invention is thinned only by the epitaxial layer 1 after being fixed at a necessary position, it is not easily affected by stress during transportation and mounting, and is protected by a semiconductor wax 23 during etching. Therefore, no damage is caused by etching, so that stable characteristics can be realized. In addition, since this semiconductor element does not have a harmful GaAs base material, harmful substances on the market can be greatly reduced.

  The separated semiconductor element substrate portion 2A of the present invention has an etching window 4 but is separated in almost the same shape, so that it can be easily recovered and used as a recycled material.

  In the above description, the semiconductor element is described as a light emitting element. However, in the light receiving element, the light receiving characteristic is measured in place of the light emitting characteristic in the inspection process of the second process, and all other processes are the same. It can be carried out.

  The semiconductor element may be an array of the light emitting element and the light receiving element, or an array in which the light emitting element and the light receiving element are mixed.

In the above description, the substrate portion 2 is described as GaAs. However, when the substrate portion 2 is InP, the etching window 4 is formed by dry etching using Cl ₂ gas and Br ₂ : CH _3. It can be formed using at least one process of wet etching using OH (1:10).

In the above description, the etching stop layer 3 has been described as AlGaAs. However, when the etching stop layer 3 is InAs, HCl: H ₂ O (1: 5 to 20) may be used.

When the etching stop layer 3 is CdSe, wet etching with HNO ₃ : CH ₃ COOH (1: 1) may be used to selectively remove the etching stop layer 3 by etching.

Further, when the etching stop layer 3 is CdTe, HNO ₃ : HF (1: 1) or HNO ₃ : HCl: H ₂ O (1: 1) is used to selectively remove the etching stop layer 3 by etching. : 0.5) may be used.

Further, when the etching stop layer 3 is CdS, wet etching with HNO ₃ : CH ₃ COOH: H ₂ O (6: 6: 1) or HCl vapor is used to selectively remove the etching stop layer 3 by etching. Etching may be used.

  When the etching stop layer 3 is ZnTe, wet etching with NaOH may be used to selectively remove the etching stop layer 3 by etching.

  In the semiconductor device described above, when the substrate 2 is made of GaAs, the etching stop layer 3 is selected from the group consisting of AlGaAs, AlAs, Al2O3, InAs, CdSe, CdTe, CdS, and ZnTe. It is composed of at least one material.

  Alternatively, when the substrate 2 is made of InP, the etching stop layer 3 is at least one selected from the group consisting of GaAs, AlGaAs, AlAs, Al2O3, InAs, CdSe, CdTe, CdS, and ZnTe. Consists of two materials.

In order to selectively remove the etching stop layer 3 of AlGaAs, AlAs, and Al ₂ O ₃ by wet etching, wet etching using HF: H ₂ O (1:10) is used.

In order to selectively remove the GaAs etching stop layer 3 by etching, a 50% citric acid solution: H ₂ O ₂ (5: 1) or NH ₄ OH: H ₂ O ₂ (1:20 to 200) using any process of wet etching.

  The above-described composition of the semiconductor element and each etching condition are representative examples in which selective etching can be performed efficiently. Therefore, even if the composition and etching conditions are slightly changed and the efficiency of selective etching deteriorates, If selective etching is possible, it is included in the scope of the present invention.

  As a semiconductor device, any semiconductor device having a similar structure having an etching stopper layer 3 that can be selectively etched between the epitaxial film 1 and the base material portion 2 can be applied. An opto-electric composite element including another electric circuit or an electric circuit only including no optical element can be applied.

  In addition, the invention shown to the following additional remarks can be derived from the content disclosed above.

(Additional remark 1) It is the epitaxial layer separation method of the semiconductor element which isolate | separates a base material part and an epitaxial layer from the semiconductor element which has an etching stop layer between a base material part and an epitaxial layer,
Opening at least one etching window by selectively etching a part of the base material part from the back surface side until reaching the etching stop layer,
A method for separating an epitaxial layer of a semiconductor device, wherein the etching stop layer is selectively removed by etching through the etching window.

    (Additional remark 2) The said semiconductor element is a light emitting element of a back surface light emission type | mold, At least 1 of the said etching window exists in the position which can take out radiated light through an etching window, The epitaxial layer separation of the semiconductor element of Additional remark 1 Method.

    (Additional remark 3) The said semiconductor element is a light-receiving element of a back surface light receiving type, At least 1 of the said etching window exists in the position which can irradiate light to a light-receiving part through an etching window, The additional remark 1 characterized by the above-mentioned. A method for separating an epitaxial layer of a semiconductor device.

(Supplementary Note 4) The base material portion is made of GaAs, and the etching stop layer is at least one material selected from the group consisting of AlGaAs, AlAs, Al ₂ O ₃ , InAs, CdSe, CdTe, CdS, and ZnTe. Or the base material portion is made of InP, and the etching stop layer is selected from the group consisting of GaAs, AlGaAs, AlAs, Al ₂ O ₃ , InAs, CdSe, CdTe, CdS, and ZnTe. The method for separating an epitaxial layer of a semiconductor element according to appendix 1, wherein the epitaxial layer is separated from at least one material.

(Supplementary Note 5) etching window formed in said base portion constructed of _{GaAs, SiCl 4: SF 6 (2} : 1) dry etching or citric acid 50% solution using a _gas: H _{2 O} 2 ( 5: 1) or at least one of wet etching processes using NH ₄ OH: H ₂ O ₂ (1:20 to 200). Epitaxial layer separation method.

(Supplementary Note 6) The etching window formed in the InP base material portion is at least one of dry etching using Cl ₂ gas or wet etching using Br ₂ : CH ₃ OH (1:10). The method for separating an epitaxial layer of a semiconductor element as set forth in appendix 4, wherein the method is formed using

(Supplementary note 7) Supplemental note 4 is characterized in that wet etching with HF: H ₂ O (1:10) is used to selectively remove the etching stop layer of AlGaAs, AlAs, and Al ₂ O _3. A method for separating an epitaxial layer of a semiconductor device as described in 1.

(Supplementary note 8) The semiconductor element according to supplementary note 4, wherein wet etching with HCl: H ₂ O (1: 5 to 20) is used to selectively remove the InAs etching stop layer by etching. Epitaxial layer separation method.

(Supplementary Note 9) The wet etching of HNO ₃ : CH ₃ COOH (1: 1) is used to selectively remove the CdSe etching stop layer. The semiconductor device according to Supplementary Note 4, Epitaxial layer separation method.

(Supplementary Note 10) Wet etching with HNO ₃ : HF (1: 1) or HNO ₃ : HCl: H ₂ O (1: 1: 0.5) to selectively remove the etching stop layer of CdTe. The method for separating an epitaxial layer of a semiconductor element according to appendix 4, wherein the method is used.

(Supplementary Note 11) A feature of using wet etching with HNO ₃ : CH ₃ COOH: H ₂ O (6: 6: 1) or HCl vapor to selectively remove the CdS etching stop layer. The method for separating an epitaxial layer of a semiconductor element according to appendix 4.

    (Supplementary note 12) The method for separating an epitaxial layer of a semiconductor element according to supplementary note 4, wherein wet etching with NaOH is used to selectively remove the etching stop layer of ZnTe.

(Additional remark 13) In order to selectively remove the etching stop layer of GaAs, 50% citric acid solution: H ₂ O ₂ (5: 1) or NH ₄ OH: H ₂ O ₂ (1:20 The method for separating an epitaxial layer of a semiconductor device according to appendix 4, wherein any one of wet etching processes using (200) to (200) is used.

    (Additional remark 14) The thickness of the said etching stop layer exists in the range of 50 nm-1 micrometer, The epitaxial layer separation method of the semiconductor element of Additional remark 1 characterized by the above-mentioned.

    (Supplementary note 15) The supplementary note 1, wherein the etching stop layer is selectively removed by etching after temporarily fixing the semiconductor element with the etching window open to a support substrate with an adhesive. An epitaxial layer separation method for semiconductor devices.

    (Supplementary note 16) The method for separating an epitaxial layer of a semiconductor element according to supplementary note 1, wherein the etching stop layer is selectively removed by etching after the semiconductor element having the etching window opened is flip-chip bonded to a wiring board. .

    (Supplementary Note 17) After the semiconductor element is flip-chip bonded to the wiring board, an underfill material is inserted and solidified between the wiring board and the semiconductor element, and then the etching stop layer is selectively etched away. Item 18. The method for separating an epitaxial layer of a semiconductor element according to appendix 16, wherein:

    (Supplementary Note 18) After an underfill material is inserted and solidified between the wiring substrate and the flip-chip bonded semiconductor element, an adhesive is applied to the side surface portion of the epitaxial layer of the semiconductor element and the wiring substrate to cover the surface. Then, the method for separating an epitaxial layer of a semiconductor device according to appendix 16, wherein the etching stop layer is selectively removed by etching.

    (Supplementary Note 19) A semiconductor element obtained by separating the base material portion and the epitaxial layer from the semiconductor element by the epitaxial layer separation method according to Supplementary Note 1 and leaving only the epitaxial layer on the support substrate or the wiring substrate.

    (Supplementary Note 20) The base material portion obtained by separating the base material portion and the epitaxial layer from the semiconductor element by the epitaxial layer separation method of Supplementary Note 1 and removing only the etching window portion from the original base material portion. .

It is a figure for demonstrating one Embodiment of the epitaxial layer isolation | separation method (epitaxial lift-off method) of the semiconductor element which concerns on this invention. (A) is a figure which shows one form of the semiconductor element which concerns on this invention, (b) is a figure which shows the middle condition of the etching process which forms an etching window in the base material part which is the 1st process of this invention. (C) is a figure which shows the condition which the etching process which forms an etching window in the base-material part which is the 1st process of this invention complete | finished. It is a figure for demonstrating one Embodiment of the epitaxial layer isolation | separation method (epitaxial lift-off method) of the semiconductor element which concerns on this invention. (A) is a figure which shows the condition after performing the flip chip bonding which is the 3rd process of this invention, (b) is the situation after performing the underfill filling which is the 4th process of this invention. (C) is a figure which shows the condition after performing the wax application | coating for semiconductors which is the 5th process of this invention. It is a figure for demonstrating one Embodiment of the epitaxial layer isolation | separation method (epitaxial lift-off method) of the semiconductor element which concerns on this invention. (A) is a figure which shows the condition which is etching the etching stop layer which is the 6th process of this invention, (b) shows the condition which removed the wax for semiconductor which is the 7th process of this invention. FIG. It is a figure for demonstrating an example of the conventional epitaxial lift-off method. (A) is a figure which shows the condition which stuck the semiconductor element on the support substrate, (b) is a figure which shows the state in the middle of etching the semiconductor element obtained by (a), (c) It is a figure which shows the condition where the etching of the semiconductor element obtained by b) was complete | finished. It is a figure for demonstrating another example of the conventional epitaxial lift-off method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Epitaxial layer 1A Light emission part 2, 2A Base material part 3 Etching stop layer 4 Etching window 5, 5a, 5b Electrode part 6 Ni mask 10, 10A Semiconductor element (light emitting element)
20 Wiring Board 21 Pad Part 22 Underfill Material 23 Wax for Semiconductor 50 Semiconductor Element (Light Emitting Element)
51 Epitaxial layer 51A Light emitting part 52 Base part 53 Etching layer 54 Etching stop layer E0, E1, E2, E3 Etching direction

Claims (5)

An epitaxial layer separation method for a semiconductor element that separates a base material part and an epitaxial layer from a semiconductor element having an etching stop layer between the base material part and the epitaxial layer,
Opening at least one etching window by selectively etching a part of the base material part from the back surface side until reaching the etching stop layer,
A method for separating an epitaxial layer of a semiconductor device, wherein the etching stop layer is selectively removed by etching through the etching window.   The semiconductor element is a backside light emitting type light emitting element or a backside light receiving type light receiving element, and at least one of the etching windows is in a position where radiation can be extracted through the etching window or in a position where light can be emitted to the light receiving portion. The method for separating an epitaxial layer of a semiconductor device according to claim 1. The base portion is made of GaAs, and the etching stop layer is made of at least one material selected from the group consisting of AlGaAs, AlAs, Al ₂ O ₃ , InAs, CdSe, CdTe, CdS and ZnTe,
Alternatively, the base portion is made of InP, and the etching stop layer is at least one material selected from the group consisting of GaAs, AlGaAs, AlAs, Al ₂ O ₃ , InAs, CdSe, CdTe, CdS, and ZnTe. The method for separating an epitaxial layer of a semiconductor device according to claim 1, comprising:   After temporarily fixing the surface of the semiconductor element with the etching window open to the support substrate with an adhesive, or after flip-chip bonding the semiconductor element with the etching window to the wiring board, or the etching The semiconductor element with the window opened is flip-chip bonded to the wiring substrate, and the surface and side surfaces of the epitaxial layer of the semiconductor element and the surface of the wiring substrate are coated with an adhesive, and then the etching stop layer is selectively etched. The method for separating an epitaxial layer of a semiconductor device according to claim 1, wherein the method is removed. A semiconductor element having only an epitaxial layer left on a support substrate or a wiring board, obtained by separating a base material portion and an epitaxial layer from the semiconductor element by the epitaxial layer separation method of claim 1, or an original The base material part which removed only the part of the said etching window from the base material part.

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