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Q&As since 1989


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Adhesion between photo-resist (dry-film) and copper

I'm facing the problem of photo-resist (dry film) peeling from the copper surface in the etching process (cupric chloride etchant) of manufacturing of IC lead frame, and it causes certain wanted portion to etch off, any suggestion or advice ? any help would be appreciated.

Ken chia
- Singapore
1998

Please provide me the formulation of photo resist. I will be thankful to you.

Mohammed Tahir
- LAHORE, Pakistan
1999

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I would like to re-word Mr. Tahir's inquiry a bit, and ask that someone provide a published reference to the formulation of photo-resist, rather than the formula itself. Thanks.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1999

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1999

Dear sir,

I send you an e mail regarding to the photo resist. But I still not hear from you. Please give me the requested information. Hoping for the favorable reply.

Regards,

Mohammed Tahir
- LAHORE, Pakistan

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Hi, cousin Mohammed.

Sorry, but that's not how it works, actually. This is not a consulting service where we guarantee to answer any questions, nor where I claim to personally know the answer to all possible questions :-)

Rather, we simply post your inquiry and if any reader responds to it, we print the response as well. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1999

Was the copper surface scrubbed and cleaned properly before applying the resist? Has the resist been stored in a climate controlled atmosphere before and after application? Are you etching as soon as possible after applying the resist? Please make sure you are following the above steps as they are most likely to contribute to your problems

Rick Richardson, MSF
Dayton, Ohio
1999

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regarding the peel off of the wanted parts during etching, try subjecting first the material to stress relieving hot-water dipping (around 80 °C). This would make the edges of the patterns stress-free.

Roger
- Manila, Philippines
1999

Sir, we are in beginning of making PCB at LAB.For that we want the technique of producing photo resist as our own for students lab usage. Also I want the commercial name for photo resist thanking you stan

stan
- rec -
1999

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Roger, Stan, readers: This is not an anonymous service. We need your full names. Thanks.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1999

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1999

Dear Mr Ken,

I would recommend you this excellent book where you may find your answer :

Making Your Own Printed Circuit Boards, by Jon Varteresian. This a comprehensive 38 page guide to the basics of making your own positive printed circuit boards. Simple, easy to understand instructions include: (1)Generation of artwork, (2)Exposing and developing the resist layer, (3)Etching, (4)Tin plating, (5)Drilling and shaping PCBs are included in simple language supported by diagrams and pictures. Also explained is the "reasoning" behind what you are doing so the reader may develop an overall comprehension of the technology behind photo resist and PCB layout work. Additionally, the author includes simple plans for the reader to build his own exposure cone and exposure frame from easy to find hardware store material. At the end of the manual is a resource list detailing where various printed circuit supplies may be purchased. Finally, a two page glossary of common PCB terms is included to help the reader understand and converse about PCB fabrication.

I remembered that the formulation of photo resist was inside.

Besides I am seeking for any information about etching with alloy 42 i/o copper, could you help me ?

Thank you for your assistance, Guillaume

Guillaume Roux-Chabert
- Paris, France

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2001

It sounds like you have a surface preparation problem. I need to know are you using liquid resist or dry film?

If dry film check,

• 1. microsurface roughness (ra)
• 2. pH of surface
• 3. preheat temp
• 4. roller pressure
• 5. roller temp.

If liquid resist check,

• 1. surface pH
• 2. max temp in oven

Mark Smith
- Great Britain

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Please remember that photo resist is made up of resin, sovent and cosolvent. The ratio is important and forms a major contribution towards abnormality. Maybe you would like to check on the your fab's humidity control or rather coating process T&H conditions. One best method is to weigh the resist and check out density.

And also your surface preparation, is your adhesion temperature / set time sufficient

Ng Yam Lim
- Singapore
2004

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January 4, 2008

Am not surprised you still facing the same problem, because you don't do the process properly. First think about the right tools to endeavour the correct answer that should come inwardly from a technical consideration of the matter. Then you should survey the PVC and get it Done in a swift and proper attention.

Hope this help,
Dr Shilibrandi, pHD in Electronics

Dr Shilibrandi
- India