▁Al um ina ▁is ▁very ▁hard ▁and ▁not ▁very ▁mach in able , ▁therefore ▁las ering ▁of ▁the ▁material ▁is ▁the ▁most ▁efficient ▁way ▁to ▁machine ▁it . ▁The ▁thick - film ▁process ▁is ▁also ▁a ▁process ▁of ▁mini atur ization ▁where ▁one ▁substr ates ▁normally ▁contain ▁many ▁units ▁( final ▁circ uits ), ▁with ▁the ▁las ering ▁it ▁is ▁possible ▁to ▁scri be , ▁profile ▁and ▁dr ill ▁holes . ▁S cri bing ▁is ▁a ▁las ering ▁process ▁where ▁a ▁line ▁of ▁las er ▁p uls es ▁are ▁fire ▁into ▁the ▁material ▁and ▁ 3 0 – 5 0 % ▁of ▁the ▁material ▁is ▁removed , ▁this ▁weak ens ▁the ▁substr ate , ▁after ▁all ▁other ▁process ▁are ▁done ▁to ▁build ▁the ▁thick ▁film ▁circuit ▁the ▁substr ates ▁can ▁easily ▁be ▁divided ▁into ▁single ▁units . ▁Profil ing ▁are ▁for ▁example ▁used ▁lot ▁in ▁the ▁sensor , ▁where ▁a ▁circuit ▁need ▁to ▁fit ▁round ▁tub es ▁or ▁other ▁different ▁complex ▁shapes . ▁Dr illing ▁of ▁holes , ▁provide ▁via ▁between ▁the ▁two ▁sides ▁of ▁the ▁substr ate , ▁normally ▁hole ▁sizes ▁are ▁in ▁the ▁range ▁ 0 . 1 5 – 0 . 2   mm . ▁ ▁Las ering ▁before ▁processing ▁the ▁substr ates ▁has ▁a ▁cost ▁advantage ▁to ▁las ering ▁or ▁dic ing ▁using ▁diam ond ▁saw ▁after ▁processing . ▁ ▁In k ▁prepar ation ▁In ks ▁for ▁electro des , ▁terminal s , ▁resist ors , ▁die lect ric ▁layers ▁etc . ▁are ▁commonly ▁prepared ▁by ▁mixing ▁the ▁metal