Autori: Marinescu, I.D., Shoutak, A., Spanu, C.

Editorial: Abrasives Magazine, Dec-Jan, 2002.

Rezumat:

Cercetarea se refera la operatia de lepuire pe ambele fete simultan ca operatie de finisare a mono-cristalului de silicon. Articolul se concentreaza asupra operatiei de lepuire pe ambele fete simultan ca o operatie ultra-precisa in cadrul tehnologiei de prelucrare a siliconului. Lepuirea pe ambele fete simultan este una dintre operatiile critice aplicate siliconului. Operatia combina rotatia unei roti inferioare, a unui dispozitiv port-piesa si a rotii superioare, cit si a disucrilor de silicon, intr-un mediu format dintr-o emulsie abraziva continind granule diamantate ultra-fine si care produce planitati deosebite, o redusa abatere de la paralelismul fetelor, creaza o excelenta rugozitate fara ca materialul eliminat in aschii sa fie important din punct de vedere cantitativ.
Cercetari viitoare se pot axa pe inlocuirea acestui procedeu cu rectificarea pe ambele fete simultan, pe implicarea procedeului ELID si pe vibrarea ultrasonica a dispozitivului. The present research refers to the double side lapping operation as a part of the mono-crystalline silicon wafer manufacturing process. The present report focuses on the double side lapping as an ultra-precision machining operation as part of silicon wafers manufacturing procedure.
Double side lapping (DSL) is one of the most critical operations to apply to silicon wafers. This lapping operation that combines upper and lower rotating plates, carrier rotation and the rotation of the silicon pieces themselves, in an emulsion containing ultra-fine crystal grains, produces good end-surfaces flatness and parallelism planarity, reduce the waviness, creates excellent surface finish, all without important material removal rates. Discs made of silicon wafers were double side lapped using three different wheel speeds (50, 75 and 100 rpm), three different pressures (121, 242 and 484 psi) on a Melchiorre double side lapping machine from Italy. The output data were surface roughness and reduction of pieces’ dimensions. The output data were collected after 5, 10, 15, 20 and 25 minutes of DSL with the same set of input parameters.
The results proved that the surface roughness improves for increased processing times, and for high wheel speed values and high-pressure values, while the material removal rate is not significantly affected by the pressure or wheel speed values. Also, the roughness-improving trend stagnates after approximately 20 minutes. Finally, the experimental observation that the silicon can not support high pressures (484 psi) more than 15 minutes without fatally breaking was drawn.
Further research can concentrate on substituting the DSL process with a double side grinding (DSG) process, ELID employing and ultrasonic vibrating DSG.

Cuvinte cheie: lepuire, materiale ceramice, silicon // lapping, ceramics, silicon wafer

URL: http://www.abrasivesmagazine.com/DecJanE1.pdf