Nitride semiconductor wafer and method of processing nitride semiconductor wafer

OPT OpenIR > 半导体激光器专利数据库

	Nitride semiconductor wafer and method of processing nitride semiconductor wafer
其他题名	Nitride semiconductor wafer and method of processing nitride semiconductor wafer
	NAKAYAMA, MASAHIRO; MATSUMOTO, NAOKI; TAMAMURA, KOSHI; IKEDA, MASAO
专利权人	SUMITOMO ELECTRIC INDUSTRIES, LTD.
公开日期	2005-07-07
授权国家	美国
专利类型	发明申请
摘要	Nitride semiconductor wafers which are produced by epitaxially grown nitride films on a foreign undersubstrate in vapor phase have strong inner stress due to misfit between the nitride and the undersubstrate material. A GaN wafer which has made by piling GaN films upon a GaAs undersubstrate in vapor phase and eliminating the GaAs undersubstrate bends upward due to the inner stress owing to the misfit of lattice constants between GaN and GaAs. Ordinary one-surface polishing having the steps of gluing a wafer with a surface on a flat disc, bringing another surface in contact with a lower turntable, pressing the disc, rotating the disc, revolving the turntable and whetting the lower surface, cannot remedy the inherent distortion. The Distortion worsens morphology of epitaxial wafers, lowers yield of via-mask exposure and invites cracks on surfaces. Nitride crystals are rigid but fragile. Chemical/mechanical polishing has been requested in vain. Current GaN wafers have roughened bottom surfaces, which induce contamination of particles and fluctuation of thickness. Circular nitride wafers having a diameter larger than 45 mm are made and polished. Gross-polishing polishes the nitride wafers in a pressureless state with pressure less than 60 g/cm2 by lifting up the upper turntable for remedying distortion. Distortion height H at a center is reduced to H≦12 μm. Minute-polishing is a newly-contrived CMP which polishes the nitride wafers with a liquid including potassium hydroxide, potassium peroxodisulfate and powder, irradiates the potassium peroxodisulfate with ultraviolet rays. The CMP-polished top surface has roughness RMS of 0.1 nm≦RMS≦5 nm or more favorably 0.1 nm≦RMS≦0.5 nm. The CMP-polished bottom surface has roughness RMS of 0.1 nm≦RMS≦5000 nm or more favorably 0.1 nm≦RMS≦2 nm. TTV is less than 10 μm.
其他摘要	通过外延生长的氮化物膜在气相的外部下衬底上产生的氮化物半导体晶片由于氮化物和底部衬底材料之间的不匹配而具有强的内应力。通过在气相中在GaAs衬底上堆叠GaN膜并消除GaAs衬底而由于内部应力而由于GaN和GaAs之间的晶格常数的错配而向上弯曲而制成的GaN晶片。普通的单面抛光，其步骤是将带有表面的晶片粘贴在平盘上，使另一表面与下转盘接触，按压盘，旋转盘，旋转转盘并磨削下表面，不能弥补固有的扭曲。失真使外延晶片的形态恶化，降低了通孔掩模的曝光率，并引起表面裂纹。氮化物晶体是刚性但易碎的。化学/机械抛光被要求徒劳无功。目前的GaN晶片具有粗糙的底表面，其引起颗粒的污染和厚度的波动。制造并抛光直径大于45mm的圆形氮化物晶片。通过提升上部转盘以消除变形，粗抛光在压力小于60g / cm2的无压状态下抛光氮化物晶片。中心处的变形高度H减小到H≤12μm。微细抛光是一种新设计的CMP，其用含有氢氧化钾，过氧二硫酸钾和粉末的液体抛光氮化物晶片，用紫外线照射过二硫酸钾。 CMP抛光的顶表面具有0.1nm≤RMS≤5nm的粗糙度RMS或更优选地0.1nm≤RMS≤0.5nm。 CMP抛光的底表面具有0.1nm≤RMS≤5000nm的粗糙度RMS或更优选地0.1nm≤RMS≤2nm。 TTV小于10微米。
申请日期	2005-02-11
专利号	US20050145879A1
专利状态	授权
申请号	US11/055599
公开（公告）号	US20050145879A1
IPC 分类号	B24B37/00 \| C30B29/38 \| H01L21/20 \| H01L21/304 \| H01L21/306 \| H01L33/00 \| H01L21/00
专利代理人	-
代理机构	-
文献类型	专利
条目标识符	http://ir.opt.ac.cn/handle/181661/43505
专题	半导体激光器专利数据库
作者单位	SUMITOMO ELECTRIC INDUSTRIES, LTD.
推荐引用方式 GB/T 7714	NAKAYAMA, MASAHIRO,MATSUMOTO, NAOKI,TAMAMURA, KOSHI,et al. Nitride semiconductor wafer and method of processing nitride semiconductor wafer. US20050145879A1.