Phil, For aluminium wedge bonders try K&S, Palomar, or Delvotek. Wedge bonding to nickel, immersion gold is a reasonable process. I have not tried it over three layers of photo imagable dielectric though, but can see no fundermental reason why it shouldn't work. Bonding takes place at room temperature, so the Tg of the material isn't so important for bonding. A three layer built up board is going to limit your choice of suppliers at the moment, but you may be able to find one who can give you a gold bondable surface. Single and multi chip BGA substrates, for example can be gold wire bondable. This may get round the need for new equipment and a slower bonding process. Some suppliers may be able to produce a board with fewer built up layers, depending on their technology. There are many alternative ways of solving the problem and you need to look at the whole picture. If you do go to wedge bonding there are some things to consider. One major difference with wedge bonding is that the tool must be kept in line with the wire, unlike a capillary, which can bond at any angle. The two approaches to achieving this are either to rotate the bonding head, or to rotate the substrate. This need for rotation is the main reason for the slower throughput of wedge bonding, compared with ball. The choice of machine will depend on which part, the head, or the substrate, is the easier and quicker to rotate. If the substrates are always going to be small, 1.5 x 1.5" is fine, then pick a bonder with a rotating workholder as these can be faster. If the substrates are bigger, or are going to be panalised several up, then you will need a bonder with a rotating head. The layout of the bond wires and attach pads on the board may need to be modified compared with a ball bonded design. Wedge bonds tend to be narrower than ball bonds, but are long. Problems can occur at fine pitches if the wires are at extreme angles. regards, Jeremy Drake --------------------------------------------------------------------------------------------------------------------------------------------------------------- Please respond to Phil Hersey <[log in to unmask]> To: [log in to unmask] cc: (bcc: Jeremy J Drake/HQ/CUK/Celestica) Subject: [TN] seeking aluminum wedge bonding advice I just found out that I can replace a $120 LTCC substrate with a $1.95 microvia PCB. Trouble is the PCB comes with nickel/flash gold so cannot be wire bonded using our gold ball bonding equipment. Evidently it can be bonded using ultrasonic aluminum wedge. This MCM has over 700 wires in a 1.5"x1.5" area (one of the ASIC's has 220 wires itself)- military application. Does anyone have experience with al. wedge on such boards? Construction is 175C Tg FR4 core with 3 layers of photovia on top (photoimageable epoxy plated up with copper). Will it work? Who makes the best bonder? Phil Hersey, Hytek Microsystems ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################ ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################