The Forming Process Researched in Sandblasting Separation of Masked Silicon Wafers

• Main Authors: V. V. Zhukov, A. A. Gornichev, S. A. Stepanov
• Format: Article
• Language: Russian
• Published: MGTU im. N.È. Baumana 2016-01-01
• Series: Nauka i Obrazovanie
• Subjects: microwave diode; silicon plate; disc-crystal; sandblasting cutting; abrasive material; masking material
• Online Access: http://technomag.edu.ru/jour/article/view/51

<p>The object of study is a semiconductor silicon disc-crystal currently used in the design of semiconductor diodes. The disc-crystal is manufactured by the sandblasting separation of a premasked silicon wafer into individual elements. The crystal has frustum-of-a-cone shape with its top diameter determined by a protective masking disc diameter and the bottom one defined by the features of the forming process. The apex angle of the cone 2α or a half-angle α between the lateral surface of the cone and the normal drawn to its base is used as a reference value.</p><p>The work has studied the influence a thickness of the separated wafer and a width of the gap between the masked discs on the crystal shape. The masking cover is a set of square protective elements (3x3 mm), spaced at 0.6; 0.7; 0.8 and 0.9 mm. The mask material is a self-adhesive PVC-film with thickness of 200 microns. Pilot-plant semi-automatic sandblasting equipment was used to for separation.</p><p>After processing of results (the angle 2α at the top of the cone) the following conclusions have been made:</p><p>- with increasing thickness of the silicon wafers the gap between the protective discs of mask must be increased;</p><p>- in case a range of the minimum gaps between the protective discs is within 0.35 - 1.20 mm the half-angle α, which defines the shape of the cut surface, can be considered to be constant and equal to 12º ... 14º.</p>