Solder mask thickness specifications by fabricators are: * Wet mask: 0.0002 ~ 0.0004� on trace * LPI mask: 0.0002 ~ 0.0008� on trace
Liquids usually range between 10 to 13 um (0.00039 to 0.00051") when dried. Liquid resist processes I have seen are putting down 8-10 um (about 0.4 thou) of resist.
SM-840C - Qualification & Performance Of Permanent Solder Mask describes the require performance of solder masks.
Common LPI solder mask materials are: * Coates ImageCure XV501T & XV501TSM * Coates ImageFlex (Flexible Solder Mask) SV 601T * Enthone DSR 3241 and DSR 3241 GM * Rogers RFlex 8080 LP1 & RFlex 8080 LP3 (Flexible) * Shipley OPSR 5600, OPSR 5700, and OPSR 5900 * Shipley EPIC SP 200 * Taiyo PSR 4000 BN and 4000 AUS5 * Taiyo PSR 9000 (Flexible) * Vantico's Probimer 77 LPI Solder Mask
LPI solder mask can be applied with screen-printing, roll coating or spray coating. LPI solder mask application equipment suppliers are: * Teledyne Halco Hudson, NH * Circuit Automation Irvine, CA
Solder mask application service bureaus are: * Mask Technology 2601 South Oak St Santa Ana, CA 92707 714-557-3383 Fax 4778 * SolderMask 17905 Metzler Lane Huntington Beach, CA 92647 (714) 842-1987 Fax (714) 847-0244
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