Steve, I have tried to access Steve Gregory web site for posting with no luck. I will have to rely on text exchange. I agree that a picture is worth a thousand words. The Bonding measurements are: Left Side: .00035 micro inches ( .35 mils ) Right Side: .00245 micro inches ( 2.45 mils ) victor, -----Original Message----- From: Creswick, Steven [mailto:[log in to unmask]] Sent: Thursday, August 29, 2002 4:01 AM To: [log in to unmask] Subject: Re: [TN] Die attach/bonding material Victor, Is it possible to share what you have observed? Specifically, what is the bond line thickness and what amount of lack of planarity, or skewness, do you see? We (collectively) can at least give you a sense of whether you are needlessly concerned (maybe :-) ) Steve -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] Sent: Wednesday, August 28, 2002 3:11 PM To: [log in to unmask]; Creswick, Steven Subject: RE: [TN] Die attach/bonding material Steven, and other TechNetters: The die size is .156" x.098" (156x98 mils). I known NOTHING of the Assembly Process and Equipment. I only have results from a cross section I conducted. Is this observation worth perusing as an Assembly Process Capability Issue and/or Concern stand point. In a previous life with big blue this was worth high lighting to the vendor. I would rather arm myself with industry requirements/guidelines before asking the vendor what their process should yield. I don't want the FOX guarding the HEN house. victor, -----Original Message----- From: Creswick, Steven [mailto:[log in to unmask]] Sent: Wednesday, August 28, 2002 11:48 AM To: [log in to unmask] Subject: Re: [TN] Die attach/bonding material Victor, I ditto the comments made by Bill (below). With respect to polymeric attachments - the cured bondline thickness (adhesive thickness beneath the device) is somewhat determined by device size, equipment set-up, and material requirements. With most 'normal' die attach adhesives, you will get something like 0.5-1.5 mils (0.0005-0.0015") of bondline thickness for die in the size range of 8-50 mils per side. Larger die usually result in greater bondline thicknesses - partially by design (to better absorb stresses). For a device 0.250" square, I would expect a bondline thickness of around 2-2.5 mils (unless, by design, or material requirement, I was seeking something different). Some low-stress die attach materials actually seek bond lines in excess of 3 mils. Check with your polymer supplier for their specific process recommendations Your placement equipment has a role in the process too. If you go and try to place a 10 mil square device with a whopping 300-400 grams of placement force, you can count on your bondline thickness being on the low side (and or a crushed device or pick up tool). Now then, if you were to place it with a more reasonable 15-30 grams, you may find my numbers to be more realistic. Everthing is relative to your set-up and materials choices - no one can second guess from a distance. With respect to fillets - If you want to maximize heat transfer out of the chip, keep your fillets up. How high?? Personnally, if you are 50% up the side of the chip you are high enough! Why risk buggering up the wire bonding process with adhesive resins which may wick up the side and over the top of the chip. If you do not have the realestate to create larger fillets - your design is your limiting factor. Generally, fillets improve die shear strength (by effectively increasing the contact area). If you have a 'normal' 18-20 mil thick device, and you have fillets 5-8 mils up the sides - that should look nice! IF you had a 4 mil thick LED and you have fillets that tall, you just rendered the chip non-usable!! THere goes "its all relative" thing again. With respect to skew - How much skew can your wire bonder accept before the pattern recognition systems fails to capture the image? 5°? 10°? If you have wires crossing where they should not be - you have too much skew, otherwise "too much" is somewhat established by your design. Hope this helps a little bit (more/too) Steve Creswick - Gentex Corporation -----Original Message----- From: Bill Christoffel [mailto:[log in to unmask]] Sent: Wednesday, August 28, 2002 8:34 AM To: [log in to unmask] Subject: Re: [TN] Die attach/bonding material IMHO, some of the best information regarding die attach (alloy or polymeric) can be found in good old MIL-STD 883 (Method 2017 section 3.1.2, Element Attach) Note: a lot depends on the specific type of component due to defining active circuit area. If you have specifics feel free, this has been my area for over 20 years. Bill C. Advanced Manufacturing Engineer NorLux Corp. -----Original Message----- From: Victor Hernandez [mailto:[log in to unmask]] Sent: Tuesday, August 27, 2002 1:22 PM To: [log in to unmask] Subject: Re: [TN] Die attach/bonding material Importance: High Mr. MoonMan & Fellow TechNetters Can you please direct me to some literature/Requirement for die attach/bonding material thickness. Min and Max thickness. How far up the thickness of the die can the bonding material cover. Along that same line what is the skew aloud. victor, ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------