成果報告書詳細
管理番号20140000000680
タイトル*平成24年度中間年報 太陽エネルギー技術研究開発 太陽光発電システム次世代高性能技術の開発 マルチワイヤーソーによるシリコンウエハ切断技術の研究開発
公開日2015/2/19
報告書年度2012 - 2012
委託先名株式会社コベルコ科研
プロジェクト番号P07015
部署名新エネルギー部
和文要約
英文要約Title:High performance PV generation system for the future. Development of slicing technology of Si wafer by multi wire saw system. (FY2010-FY2014) FY2012 Annual Report

The target of this development is to get high quality Si wafers with minimum kerf loss. Combination of resin coated steel saw wire (R-wire) and diamond loose abrasive is employed in this development. In FY2012, the first three year’s targets of the development are completed. We have achieved kerf loss of less than 120μm, depth of damaged layer of less than 5μm, surface roughness of less than 0.5μm, and slicing speed of 0.3mm/min with 120x20mm Si wafers by optimization of slicing conditions, coolant, and abrasives. The second multi wire saw that enables the slicing with very fine saw wire of less than 100μm diameter was introduced in FY2012. The test slice was started on October. At the beginning of the test slice, erosion of resin of R-wire was occurred and it took about four month to overcome this trouble. Optimization of slurry supply method was effective to prevent the erosion of the resin. Finally, the kerf loss of 95μm is achieved with 90μm diameter R-wire at the second multi wire saw. Substantial size Si wafers, 125 and 156mm square,  are prepared with 130μm diameter R-wire and supply them to several solar cell manufacturers to evaluate the merit of the small damaged layer of R-wire slicing. A detailed investigation of depth of damages layer is done. The depth of damaged layer is measured by etching method and the depth of dislocation pits is recognized as the depth of damaged layer. Sometimes, no dislocation pit is observed at the wafer sliced by R-wire, and the depth of slicing grooves is recognized as the depth of damaged layer. On the other hand, the depth of dislocation is about 0.3μm by TEM observation. The effect of dislocation and slicing groove on efficiency of solar cell or life time of the wafer will discuss in next two years. In next two fiscal years, to make clear the relationship between the depth of damaged layer and the efficiency of solar cell is planned at a special conference of NEDO project members and R-wire is one of the important subject at the conference. Improvement of the slicing speed more than 0.3mm/min is investigated and that of 0.57mm/min is obtained with 130μm diameter R-wire. It is made clear that slicing speed of R-wire depends on the speed of the wire. To feed Si ingot when the R-wire becomes the maximum speed, we call this method Feed Synchronization, is very effective to improve the slicing speed. A trial calculation of variable cost of slicing process is done. The variable cost of R-wire shows almost the same or a little bit lower than that of diamond wire. It becomes more clear that R-wore is expected to decrease the cost of Si wafers for solar cells by small kerf loss and small damaged layer.
ダウンロード成果報告書データベース(ユーザ登録必須)から、ダウンロードしてください。

▲トップに戻る