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Adhesive Dispense Equipment

Chris

#18008

Adhesive Dispense Equipment | 26 October, 2001

I am looking for opinions on inline adhesive dispense equipment. I am considering Creative Automation, GPD, Asymtek, and Camalot. I will be dispensing dots of conductive adhesive about .010" in diameter.

Thanks,

Chris

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#18011

Adhesive Dispense Equipment | 26 October, 2001

Consider a stencil printer [ie, MPM, DEK, Ekra, Minami] to print your adhesive.

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#18013

Adhesive Dispense Equipment | 27 October, 2001

Most of the machine suppliers Fuji, Siemens, Universal and Panasonic did regret that they were building glue machines. Applying adhesive compared to placing a component looks so simple, but it is not and the defect rate is higher than placing 1206 components. There are two basic differences in the methods of glue machines. Air pressure or pump. Asymtek bought the patent rights from Nordson of a high pressure piston pump, which is somewhat different from the first two methods. All methods have in common that they cannot cope with air bubbles, which may be entrapped in the syringes. The adhesive manufacturer have to make sure that any air bubbles are removed with centrifugal force after filling the cartridges. Make sure, you get the conductive adhesive in the syringe size used by the machine supplier. The second problem is glue stringing. Strings often occur when the spacer is not the right match of the needle diameter, or if the glue viscosity changed. Ideally the glue dot looks like a Hershey Kiss with a base to height ratio of 2-3 to 1. This means that the variation of glue dot sizes with one needle diameter is pretty small. This also means that if the spacer hits a landing the space is higher than on board level and strings are possible. Another possible defect is caused by so called satellites. When the glue dot is applied and the needle lifts up, the pile of glue will form an hour glass shape with one pile on the board and a drop hanging on the needle. We assume that the glue string breaks in the middle. But sometimes it breaks in two pieces with a small satellite in the middle. If you don�t allow for settling time and move the glue head to the next position the satellite or a small glue dot may land anywhere on the board. The process is very sensitive to temperature and moisture, which change the viscosity of the adhesive. If you really decide to apply glue dots with a machine rather than with a stencil, I would put my money on the spindle pump.

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flynhi34

#18016

Adhesive Dispense Equipment | 28 October, 2001

Thanks for the info on the printers. I have printed conductive epoxy on Dek 265 with great success in the past. The issue I have is that I need to attach with both epoxy and solder on the same side of the PCB. I could double print. Print conductive epoxy first and then print solder. Solder stencil would have to have pockets half etched into the board side of the screen. Actually this would be the fastest method to produce the product. However, if dispensing would work well, it would give me a lot of flexibility at the cost of speed. I will soon be doing some 3D population and dispensing sounds more attractive. Although, I could probably stencil print too. Not sure which way to go. Conductive epoxy printing is nothing like solder paste printing. Material changes really affect print quality. I will give it some more thought.

Thanks,

Chris

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#18017

Adhesive Dispense Equipment | 29 October, 2001

If you can half-way justify the cost delta, go with the dispenser.

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#18018

Adhesive Dispense Equipment | 29 October, 2001

If you are doing this in a high volume, you could concider using a pin transfer method. Apply solder paste first. Have a plate made with retractable pins in the location you want to have the adhesive dots. Dip the pins into a lake of adhesive. Align plate with board and print all dots at once. May I ask, why you are using conductive adhesive and solder paste on the same board ?

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Hugh Martin

#18020

Adhesive Stencils | 29 October, 2001

We have made a number of step up adhesive stencils using a new material called Cirlex. This material demonstrates excellent release characteristics and is easly cleaned. Typically the glue printing is after the solder printing. The stencil is all laser cut including the relief pockets for the solder pads. If you would like more information on this unique product please contact me. hmartin@kjmarketing.com

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Chris

#18021

Adhesive Dispense Equipment | 29 October, 2001

I am attaching bare die using conductive epoxy.

Thanks,

Chris

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#18029

Adhesive Dispense Equipment | 30 October, 2001

Chris, I should have read your request more carefully. .010" glue dot diameter would require at least .005" needle diameter. No way you can do it with the above mentioned machines. You are already stretching the capability of glue machines for 0402 components. Again, I would look into a custom solution by using test pins dipped in glue.

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Sean D

#18033

Adhesive Dispense Equipment | 30 October, 2001

Hello Chris,

If you could humor me, what are the limiting factors forcing your dot size to .010"?

What is the die size that you are placing? What are the accuracy tolerances?

Was eutectic die attach never an option for this bare die?

Have you determined 100% which epoxy you plan to use or are you open to suggestions?

Have you discussed this process with the applications departments of any of the affore mentioned companies? I would mention your tolerances to them and be ready to provide samples for quantitative data analysis should any of them buy into the process and claim capability. If none of these suppliers will claim capability they may offer viable alternatives for you to further examine.

By placing the burden on the apps departments to provide quantifiable data to support claims you can best benefit in choosing an appropriate process and supplier. Just be ready to absorb some custom tooling costs should you wish to run your own parts for evaluation.

Good Luck, Sean

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#18037

Adhesive Dispense Equipment | 30 October, 2001

I haven�t read this, but maybe you can do a report for us. Look at: �Achieving Ultra-Fine Dot Solder Paste Dispensing� http://www.uic.com/wcms/WCMS.nsf/index/Material_Dispensing_0.html

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flynhi34

#18041

Adhesive Dispense Equipment | 30 October, 2001

I have not looked into eutectic die attach. My dies are about .012" square and could get smaller. Currently using a Epoxytech conductive adhesive. I am going to go out and look at equipment and build samples. Some vendores state they can do .010" dots. Will also investigate epoxy stamping or pin transfer. I have a lot of experience printing conductive epoxies for gold bump flip chip attach. Have attached flip chips with pitches below .008" using conductive epoxy. I know printing will work but would love the 3D capability provided with dispense equipment. Luckily this dispense equipment does not have to dispense anything smaller than .010" diameter and these .010" dots are spaced far from one another.

Thanks,

Chris

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CAL

#18083

Adhesive Dispense Equipment | 2 November, 2001

You may want to also try MRSI. They have awsome machines for bridging the gap between Semiconductor and SMT. They have an excellent research group and can answer a mojority of your questions. http://www.mrsigroup.com they are located in Mass, USA. Dan Crowley (VP Sales)is a contact person and can help you with you problem.

If you talk to Dan Tell him Cal Driscoll hooked you up.

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