CN1817562A - Polishing method of lithium aluminate wafer - Google Patents
Polishing method of lithium aluminate wafer Download PDFInfo
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- CN1817562A CN1817562A CN 200610024584 CN200610024584A CN1817562A CN 1817562 A CN1817562 A CN 1817562A CN 200610024584 CN200610024584 CN 200610024584 CN 200610024584 A CN200610024584 A CN 200610024584A CN 1817562 A CN1817562 A CN 1817562A
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- China
- Prior art keywords
- wafer
- crystal face
- polishing
- average roughness
- surface average
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- 238000005498 polishing Methods 0.000 title claims abstract description 52
- YQNQTEBHHUSESQ-UHFFFAOYSA-N lithium aluminate Chemical compound [Li+].[O-][Al]=O YQNQTEBHHUSESQ-UHFFFAOYSA-N 0.000 title claims abstract description 21
- 238000000034 method Methods 0.000 title claims abstract description 20
- 239000013078 crystal Substances 0.000 claims abstract description 73
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 14
- 229910003460 diamond Inorganic materials 0.000 claims abstract description 14
- 239000010432 diamond Substances 0.000 claims abstract description 14
- 230000007935 neutral effect Effects 0.000 claims abstract description 14
- 239000000843 powder Substances 0.000 claims abstract description 14
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 10
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 10
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 6
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 6
- 238000005530 etching Methods 0.000 claims abstract description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 5
- 239000007788 liquid Substances 0.000 claims abstract description 4
- 239000012530 fluid Substances 0.000 claims description 13
- 238000010792 warming Methods 0.000 claims description 6
- 230000000007 visual effect Effects 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 239000000428 dust Substances 0.000 claims description 3
- 239000004922 lacquer Substances 0.000 claims description 3
- 229910052681 coesite Inorganic materials 0.000 abstract 1
- 229910052906 cristobalite Inorganic materials 0.000 abstract 1
- 238000001035 drying Methods 0.000 abstract 1
- 238000010438 heat treatment Methods 0.000 abstract 1
- 238000007517 polishing process Methods 0.000 abstract 1
- 239000004576 sand Substances 0.000 abstract 1
- 239000000377 silicon dioxide Substances 0.000 abstract 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract 1
- 229910052682 stishovite Inorganic materials 0.000 abstract 1
- 229910052905 tridymite Inorganic materials 0.000 abstract 1
- 238000005516 engineering process Methods 0.000 description 7
- 239000000758 substrate Substances 0.000 description 7
- 238000002360 preparation method Methods 0.000 description 5
- 229910010093 LiAlO Inorganic materials 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052594 sapphire Inorganic materials 0.000 description 2
- 239000010980 sapphire Substances 0.000 description 2
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 1
- 208000012868 Overgrowth Diseases 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001657 homoepitaxy Methods 0.000 description 1
- 238000002248 hydride vapour-phase epitaxy Methods 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 238000012876 topography Methods 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
A method of polishing a lithium aluminate wafer comprising the steps of: cutting the lithium aluminate crystal grown by the pulling method into a wafer with a certain thickness by using an inner circle cutting machine; putting the wafer into hydrochloric acid or nitric acid with the concentration of 78-80%, heating to 80-100 ℃, preserving heat for 15-30 minutes, taking out, drying by using nitrogen, observing the conditions of etching pits on the front and back surfaces of the wafer by using a large-field microscope, and selecting the surface with few etching pits as the polishing surface of the next step; placing the surface to be polished of the wafer on a rubber disc, firstly selecting alumina powder to carry out coarse grinding and rough polishing on the surface to obtain a crystal face with the surface average roughness of 5-10 nm; fine polishing crystal face with pH 8-9 SiO2Polishing for 1-3 h to obtain a crystal face with the surface average roughness of 1-2 nm; and continuously polishing the crystal face by using neutral diamond sand liquid for 1.5-2.5 hours to obtain the lithium aluminate crystal face with the surface average roughness superior to 0.2 nm.
Description
Technical field
The present invention relates to lithium aluminate, particularly a kind of finishing method of lithium aluminate crystal wafer.
Background technology
In recent years, blue-green light LED, laser diode and related device thereof become the research focus with its great market application prospect, and be wherein outstanding with the research of GaN base system row material.At present, GaN base blue-green light LED (abbreviating LED as) has been realized commercialization.In 1997, Nichia company utilized life-span of blue light laser diode (abbreviating LD as) continuous operation of GaN development above 10000 hours.But at present luminous efficiency and the life-span of LED and LD all are difficult to be further improved, and this mainly is because the high defect concentration that the lattice mismatch of film and substrate and complicated and huge stress that thermal mismatching causes preparation technology cause.In order to address this problem, people have invented a lot of technology, as the epitaxial lateral overgrowth technology, and cushion technology, graph substrate technology etc.But the basic method that addresses this problem still will lean on homoepitaxy.There is the GaN body monocrystalline of very big technical difficulty, particularly bulk in the growth of GaN body monocrystalline because of its vapour pressure is too high.Therefore, people make great efforts to seek to replace the preparation method of the GaN thick film of GaN body monocrystalline, are equipped with the main flow research direction that GaN self-supporting substrate has become the novel GaN base of large-size high-quality substrate preparation as present with the HVPE legal system.But people go up preparation GaN base thick film at substrate (Sapphire, SiC etc.) commonly used, and all cracking phenomena in various degree appears in the stress problem, is difficult to obtain the GaN self-supporting substrate of practicability.γ-LiAlO
2Compare with Sapphire, and the little order of magnitude of the lattice mismatch between the GaN, the more important thing is in recent years at γ-LiAlO
2(100) successfully obtained on the face unpolarized M face GaN film (referring to Nature., 2000,406:865).Above advantage makes γ-LiAlO
2Become preparation GaN thick film preferred material.While γ-LiAlO
2Hardness is not high, and easily by acid corrosion, is easy to GaN thick film on it is peeled off, and obtains self-supporting GaN substrate.
But the polarity of lithium aluminate crystal substrate and the water-disintegrable quality of finish that has seriously influenced it, showing as surface average roughness is better than the 0.2nm wafer and is difficult to obtain [referring to J.Vac.Sci.Technol.B., 2003,21 (4): 1350], offshore company (U.S., Germany) has carried out certain research to its polishing at present, but all is difficult to break through the difficulty that surface roughness is better than 0.2nm.
Summary of the invention
The present invention seeks to provides a kind of lithium aluminate crystal wafer finishing method in order to obtain the lithium aluminate crystal wafer that surface average roughness is lower than 0.2nm, thereby prepares high-quality nonpolarity light emitting diode thereon.
The technological process of the finishing method of lithium aluminate crystal wafer of the present invention is as follows:
＜1〉with the lithium aluminate crystal of Czochralski grown, is cut to certain thickness wafer as required with interior garden cutting machine;
＜2〉this wafer being put into concentration is 78% hydrochloric acid or nitric acid, be warming up to 80-100 ℃, be incubated 15-30 minute, taking-up dries up with nitrogen, with the situation of big visual field microscopic examination wafer positive and negative etch pit, the burnishing surface of less one side as next step cheated in selective etching;
＜3〉the polished face with wafer is placed on the lacquer disk(-sc), selects for use alumina powder that it is roughly ground, and thick the throwing reaches the crystal face that surface average roughness is 5-10nm;
＜4〉crystal face is carried out essence and throw, with the SiO of PH=8-9
2Polishing fluid, polishing time are 1-3 hour, and obtaining surface average roughness is the crystal face of 1-2nm;
＜5〉adopt neutral diamond dust liquid, this crystal face is continued polishing, polishing time is 1.5-2.5 hour, obtains the lithium aluminate crystal wafer that surface average roughness is better than the crystal face of 0.2nm.
Advantage of the present invention is to choose suitable crystal face by chemical corrosion method, utilizes the hydrolysis property of lithium aluminate to come polished wafer then, method uniqueness, simple, but effect is obvious.
The specific embodiment
Down and the invention will be further described in conjunction with the embodiments.
Embodiment 1:
A kind of finishing method of lithium aluminate crystal wafer comprises the following steps:
＜1 〉, is cut to the wafer of thickness 0.5～1mm with interior garden cutting machine with the lithium aluminate crystal of the long 80mm of 2 inches diameter of Czochralski grown;
＜2〉this wafer being put into concentration is 78% hydrochloric acid or nitric acid, be warming up to 80 ℃, be incubated 15 minutes, taking-up dries up with nitrogen, with the situation of big visual field microscopic examination wafer positive and negative etch pit, the burnishing surface of few one side as next step cheated in selective etching;
＜3〉the polished face with wafer is placed on the lacquer disk(-sc), selects for use alumina powder that it is roughly ground, and thick the throwing reaches the crystal face that surface average roughness is 5nm through this technology;
＜4〉crystal face is carried out essence and throw, with the SiO of PH=8
2Polishing fluid, polishing time are 2 hours, and obtaining surface average roughness is the crystal face of 1.4nm;
＜5〉adopt neutral diamond dust liquid, this crystal face is continued polishing, polishing time 2.5 hours obtains the lithium aluminate crystal wafer that surface average roughness is better than the crystal face of 0.15nm.
Embodiment 2:
According to the lithium aluminate crystal of step in the above-mentioned technological process with the long 80mm of 2 inches diameter of Czochralski grown, be cut to the wafer of thickness 1mm with interior garden cutting machine, this wafer is put into the beaker that fills hydrochloric acid (concentration 80%), be warming up to 100 ℃ then, be incubated 30 minutes; Take out wafer, nitrogen dries up, and at the big positive and negative surface topography of visual field microscopic examination wafer, and chooses the less crystal face of etch pit as the polishing crystal face.To through the alumina powder corase grind, slightly to throw, surface average roughness is that the crystal face of 10nm carries out the essence throwing, chooses the SiO of PH=8
2Polishing fluid, polishing time are 3 hours, can obtain the crystal face that surface average roughness is 1.6nm, adopt neutral diamond polishing can obtain the crystal face that surface average roughness is 0.18nm in 1.5 hours then.
Embodiment 3:
Concrete grammar such as embodiment 1 put into nitric acid (concentration 80%) with wafer, are warming up to 80 ℃, and insulation 15min dries up and observes and choose the few crystal face of etch pit as the polishing crystal face.To through the alumina powder corase grind, slightly to throw, surface average roughness is that the crystal face of 10nm carries out the essence throwing, chooses the SiO of PH=8
2Polishing fluid, polishing time are 3 hours, can obtain the crystal face that surface average roughness is 1.6nm, adopt neutral diamond polishing can obtain the crystal face that surface average roughness is 0.18nm in 2 hours then.
Embodiment 4:
Concrete grammar such as embodiment 2 put into nitric acid (concentration 80%) with wafer, are warming up to 100 ℃, and insulation 30min dries up and observes and choose the few crystal face of etch pit as the polishing crystal face.To through the alumina powder corase grind, slightly to throw, surface average roughness is that the crystal face of 10nm carries out the essence throwing, chooses the SiO of PH=9
2Polishing fluid, polishing time are 3 hours, can obtain the crystal face that surface average roughness is 1.6nm, adopt neutral diamond polishing can obtain the crystal face that surface average roughness is 0.18nm in 2 hours then.
Embodiment 5
Technical process such as embodiment 1, characteristics are to through the alumina powder corase grind, slightly throw, surface average roughness is that the crystal face of 7.5nm carries out the essence throwing, chooses the SiO of PH=8
2Polishing fluid, polishing time are 2.5 hours, can obtain the crystal face that surface average roughness is 1.8nm, adopt neutral diamond polishing can obtain the crystal face that surface average roughness is 0.19nm in 2 hours then.
Embodiment 6
Technical process such as embodiment 1, characteristics are to through the alumina powder corase grind, slightly throw, surface average roughness is that the crystal face of 5nm carries out the essence throwing, chooses the SiO of PH=9
2Polishing fluid, polishing time are 1 hour, can obtain the crystal face that surface average roughness is 1.9nm, adopt neutral diamond polishing can obtain the crystal face that surface average roughness is 0.17nm in 2.5 hours then.
Embodiment 7
Technical process such as embodiment 1, characteristics are to through the alumina powder corase grind, slightly throw, surface average roughness is that the crystal face of 10nm carries out the essence throwing, chooses the SiO of PH=8
2Polishing fluid, polishing time are 2 hours, can obtain the crystal face that surface average roughness is 1.7nm, adopt neutral diamond polishing can obtain the crystal face that surface average roughness is 0.16nm in 2 hours then.
Embodiment 8
Technical process such as embodiment 1, characteristics are to through the alumina powder corase grind, slightly throw, surface average roughness is that the crystal face of 7.5nm carries out the essence throwing, chooses the SiO of PH=8
2Polishing fluid, polishing time are 1.5 hours, can obtain the crystal face that surface average roughness is 1.8nm, adopt neutral diamond polishing can obtain the crystal face that surface average roughness is 0.16nm in 2 hours then.
Embodiment 9
Technical process such as embodiment 1, characteristics are to through the alumina powder corase grind, slightly throw, surface average roughness is that the crystal face of 5nm carries out the essence throwing, chooses the SiO of PH=8
2Polishing fluid, polishing time are 1.5 hours, can obtain the crystal face that surface average roughness is 1.5nm, adopt neutral diamond polishing can obtain the crystal face that surface average roughness is 0.12nm in 2 hours then.
Embodiment 10
Technical process such as embodiment 1, characteristics are to through the alumina powder corase grind, slightly throw, surface average roughness is that the crystal face of 10nm carries out the essence throwing, chooses the SiO of PH=8
2Polishing fluid, polishing time are 2 hours h, can obtain the crystal face that surface average roughness is 1.6nm, adopt 2 hours h of neutral diamond polishing can obtain the crystal face that surface average roughness is 0.13nm then.
Embodiment 11
Technical process such as embodiment 1, characteristics are to through the alumina powder corase grind, slightly throw, surface average roughness is that the crystal face of 7.5nm carries out the essence throwing, chooses the SiO of PH=8
2Polishing fluid, polishing time are 1.75 hours, can obtain the crystal face that surface average roughness is 1.6nm, adopt neutral diamond polishing can obtain the crystal face that surface average roughness is 0.13nm in 2 hours then.
Claims (1)
1, a kind of finishing method of lithium aluminate crystal wafer is characterized in that comprising the following steps:
＜1〉with the lithium aluminate crystal of Czochralski grown, is cut to certain thickness wafer with interior garden cutting machine;
＜2〉this wafer is put into hydrochloric acid or the nitric acid that concentration is 78-80%, be warming up to 80-100 ℃, be incubated 15-30 minute, taking-up dries up with nitrogen, with the situation of big visual field microscopic examination wafer positive and negative etch pit, the burnishing surface of few one side as next step cheated in selective etching;
＜3〉the polished face with wafer is placed on the lacquer disk(-sc), at first selects for use alumina powder that it is roughly ground, and thick the throwing reaches the crystal face that surface average roughness is 5-10nm;
＜4〉crystal face is carried out essence and throw, with the SiO of PH=8-9
2Polishing fluid, polishing time are 1-3 hour, and obtaining surface average roughness is the crystal face of 1-2nm;
＜5〉adopt neutral diamond dust liquid, this crystal face is continued polishing, polishing time 1.5-2.5 hour, obtain the lithium aluminate crystal wafer that surface average roughness is better than the crystal face of 0.2nm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100245841A CN100450714C (en) | 2006-03-10 | 2006-03-10 | Polishing method of lithium aluminate wafer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100245841A CN100450714C (en) | 2006-03-10 | 2006-03-10 | Polishing method of lithium aluminate wafer |
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| Publication Number | Publication Date |
|---|---|
| CN1817562A true CN1817562A (en) | 2006-08-16 |
| CN100450714C CN100450714C (en) | 2009-01-14 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102263024A (en) * | 2011-07-18 | 2011-11-30 | 北京通美晶体技术有限公司 | Back side anticorrosion method of single side polishing wafer |
| CN101954617B (en) * | 2009-07-20 | 2013-02-06 | 上海半导体照明工程技术研究中心 | Method for performing chemical mechanical polishing on lithium aluminate wafer |
| CN108081117A (en) * | 2017-11-29 | 2018-05-29 | 浙江工业大学 | A kind of lithium tantalate polishing method based on mild abrasives fixation grinding tool |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2787996B2 (en) * | 1992-03-02 | 1998-08-20 | 信越化学工業株式会社 | Method for producing lithium tetraborate single crystal |
| US5389194A (en) * | 1993-02-05 | 1995-02-14 | Lsi Logic Corporation | Methods of cleaning semiconductor substrates after polishing |
| WO1999066565A1 (en) * | 1998-06-18 | 1999-12-23 | University Of Florida | Method and apparatus for producing group-iii nitrides |
| JP2006521984A (en) * | 2003-03-18 | 2006-09-28 | クリスタル フォトニクス，インコーポレイテッド | Method for fabricating a group III nitride device and the device so fabricated |
-
2006
- 2006-03-10 CN CNB2006100245841A patent/CN100450714C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101954617B (en) * | 2009-07-20 | 2013-02-06 | 上海半导体照明工程技术研究中心 | Method for performing chemical mechanical polishing on lithium aluminate wafer |
| CN102263024A (en) * | 2011-07-18 | 2011-11-30 | 北京通美晶体技术有限公司 | Back side anticorrosion method of single side polishing wafer |
| CN108081117A (en) * | 2017-11-29 | 2018-05-29 | 浙江工业大学 | A kind of lithium tantalate polishing method based on mild abrasives fixation grinding tool |
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| Publication number | Publication date |
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| CN100450714C (en) | 2009-01-14 |
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Granted publication date: 20090114 Termination date: 20120310 |