DuPont CB100. conductive via plug paste. Potential Cause/Solution. thick boards.

Transcription

1 DuPont CB100 conductive via plug paste Trouble Shooting Guide Problem Delamination in the center of the board Plating popping off the top/bottom of the vias Delamination and break at knee of the via Delamination for some other reason than mentioned above Large voids in centers of vias Plating difficulties over CB100 Potential Cause/Solution Verify Dry/Cure schedule. Possible trapped solvent especially in thick boards. CB100 cannot be exposed to desmear of plasma etch chemistries. Permanganate from the desmear process will attack CB100. If button plating, the button must not be sanded down to the foil when planarizing the via. This will cause stress during subsequent high temperature processing. Check lamination time/temperature and board type. CB100 cannot withstand the lamination cycle of PTFE/Teflon materials. The epoxy in CB100 will degrade when exposed to extended time above 200 C Filling in multiple passes using vacuum. If vias cannot be filled in one pass with vacuum assist, then fill without vacuum using multiple passes. Do not fill via from both sides. This is more of a cosmetic issue than a reliability issue. Surface contaminated. High pressure water rinse after planarization. Possible resist residue over vias. Dry/Cure Delamination Improper Dry/Cure Cycle: Either the drying/curing steps were not adequate to remove solvent and/or cure the epoxy properly, or the drying temperature was too high and the epoxy started to cure before the solvent could be removed. Bake Cycle Guidelines (Based on Panel Thickness) Since other variables can affect the dry and cure rate, such as board density, via diameter, oven air flow and oven load, this is meant to be a starting point to help board shops ensure fully dried and cured plugged vias. Panel Thickness Dry Schedule Cure Schedule < C/60 min 160 C/60 min C/90 min 160 C/90 min C/2 hrs 160 C/2 hrs C/3 hrs 160 C/3 hrs > C/4 hrs 160 C/4 hrs

2 Weak Knee Following are examples of delamination caused by a weak knee. Delamination due to a weak knee can be caused by improper planarization. Do not remove the Button Plating down to the Foil Copper when planarizing DuPont CB100 via plug paste. Weak Knee During subsequent high temperature processing differences in TCE of the various materials cause stress which may result in separation/delamination between the plating and the foil. 2

3 Exposure to De-Smear or Plasma Etch Process Delamination Exposure to de-smear or plasma etch processes should be avoided since it aggressively attacks DuPont CB100 conductive via plug paste. Underfilled Via Dimpled/Underfilled Via The squeegee tip can deflect into the via and scoop out paste during printing. Squeegee Squeegee CB100 Option for ensuring the CB100 fill will be above the top of the via Plating Resist (Button Plating) can be used as a mask for printing. The resist can be removed after CB100 has been dried and cured. 3

4 Underfilled Via (continued) A stencil (2 3 mils thick) can be used to fill the vias, as an option for ensuring CB100 fill will be above the top of the via. Voids in the Fill Voids can be created in CB100 by using multiple squeegee passes with a continuous vacuum. Example Voids can also be created in CB100 by filling the via from both sides. Example Void 4

5 Exposure to Excessive Heat Delamination Over heating CB100 during laser drilling of blind vias in the layer above may damage the fill. The epoxy in CB100 will degrade when exposed to temperatures above 200 C for extended periods of time. Plating Difficulties Ensure that CB100 is free from contamination and residue. CB100 Filled Hole After Plating 5

6 For more information on DuPont CB100 conductive via plug paste or other DuPont Microcircuit Materials products, please contact your local representative: Americas DuPont Microcircuit Materials 14 T.W. Alexander Drive Research Triangle Park, NC Tel: Europe DuPont (UK) Limited Coldharbour Lane Bristol BS16 1QD United Kingdom Tel: Asia DuPont Kabushiki Kaisha Sanno Park Tower, 11-1 Nagata-cho 2-chome Chiyoda-ku, Tokyo Japan Tel: DuPont Taiwan, Ltd. 45 Hsing-Pont Road Taoyuan, Taiwan 330 Tel: DuPont China Holding Co. Ltd Bldg 11, 399 Keyuan Rd. Zhangji Hi-Tech Park Pudong New District Shanghai , China Tel: ext DuPont Korea Inc. 3~5th Floor, Asia tower #726 Yeoksam-dong, Gangnam-gu Seoul , Korea Tel: E.I. DuPont India Private Limited 7th Floor, Tower C, DLF Cyber Greens Sector-25A, DLF City, Phase-III Gurgaon Haryana, India Tel: DuPont Company (Singapore) Pte Ltd 1 Harbour Front Place, #11-01 Harbour Frong Tower One, Singapore Tel: Copyright 2010 DuPont or its affiliates. All rights reserved. The DuPont Oval, DuPont, The miracles of science, Kapton and all products or words denoted with or are registered trademarks or trademarks of E.I. du Pont de Nemours and Company or its affiliates ( DuPont ). NO PART OF THIS MATERIAL MAY BE REPRODUCED, STORED IN A RETRIEVAL SYSTEM OR TRANSMITTED IN ANY FORM OR BY ANY MEANS ELECTRONIC, MECHANICAL, PHOTOCOPYING, RECORDING OR OTHERWISE WITHOUT THE PRIOR WRITTEN PERMISSION OF DUPONT. Caution: Do not use in medical applications involving implantation in the human body or contact with internal body fluids or tissue unless the product is provided by DuPont under a formal written contract consistent with the DuPont Policy Regarding Medical Applications of DuPont Materials H ( Medical Applications Policy ) and which expressly acknowledges the contemplated use. For additional information, please request a copy of DuPont Medical Caution Statement H and the DuPont Medical Applications Policy. The information provided herein is offered for the product user s consideration and examination. While the information is based on data believed to be reliable, DuPont makes no warranties, expressed or implied as to the data s accuracy or reliability and assumes no liability arising out of its use. The data shown are the result of DuPont laboratory experiments and are intended to illustrate potential product performance within a given experimental design under specific, controlled laboratory conditions. While the data provided herein falls within anticipated normal range of product properties based on such experiments, it should not be used to establish specification limits or used alone as the basis of design. It is the product user s responsibility to satisfy itself that the product is suitable for the user s intended use. Because DuPont neither controls nor can anticipate the many different end-uses and end-use and processing conditions under which this information and/or the product described herein may be used, DuPont does not guarantee the usefulness of the information or the suitability of its products in any given application. Users should conduct their own tests to determine the appropriateness of the products for their particular purpose. The product user must decide what measures are necessary to safely use the product, either alone or in combination with other products, also taking into consideration the conditions of its facilities, processes, operations, and its environmental, health and safety compliance obligations under any applicable laws. This information may be subject to revision as new knowledge and experience become available. This publication is not to be taken as a license to operate under, or recommendation to infringe any patent. This information may be subject to revision as new knowledge and experience become available. K /10 6