Sputtering targets can be simply clamped to the sputter source cathode inside the sputter depositing system. However, this procedure can prove costly due to cracking, warping or other damage to the target in use caused by inadequate cooling. Wherever possible, it is good practice to bond the sputter target to a strong, compatible backing plate.
Target Bonding is a critical process and the exact fabricating method employed can vary depending on the choice of the sputtering target material. A properly bonded sputtering target will normally give a longer working life than a non-bonded target, may enable the use of a higher power input to achieve faster sputtering rates and will enable thin film process parameters to be consistently repeated. Shear stresses that develop between the target and backing plate, due to heating during sputtering, can be a cause of bonding failure when the backing plate and sputtering materials do not have compatible coefficients of thermal expansion. Depending on the dimensional tolerances allowed, the bond thickness can be adjusted to help compensate for these stresses.