Double-sided lapping of thin copper substrate by textured fixed-abrasive pad

摘要

Thin copper substrates with high accuracy and high surface integrity play as the extremely key components in precision physical experiments. Normally, fly cutting process is adopted to meet the requirements. However, due to the deformation of substrates caused by clamping and machining stresses, the target values cannot be achieved after disassembly. Hence, this paper presented double-sided lapping by textured fixed-abrasive pad to fabricate thin copper substrates. A flatness error compensation method was proposed to achieve high flatness taking advantage of the concave-convex surface shapes. The correlations between flatness, residual stress and subsurface defects were investigated. The results show that double-sided lapping removed the defective layer and released the residual stress induced in prior turning process. Superior to 4 μm flatness peak-to-valley (PV) was attained on both of the surfaces of Φ100 mm thin substrate by the flatness error compensation method even if the flatness PV of lapping plates were over 20 μm. The deformation layer caused by double-sided lapping was less than 2 μm.