AVS 47th International Symposium
    Surface Engineering Tuesday Sessions
       Session SE-TuP

Paper SE-TuP5
The Properties of the Wettability and Corrosion Resistance of Surface Preparation and PVD Coatings on Mold Steel

Tuesday, October 3, 2000, 5:30 pm, Room Exhibit Hall C & D

Session: Poster Session
Presenter: S.-M. Chiu, Metal Industries Research & Development Centre, Taiwan
Authors: S.-M. Chiu, Metal Industries Research & Development Centre, Taiwan
C.-H. Lin, Metal Industries Research & Development Centre, Taiwan
W.-C. Lo, Metal Industries Research & Development Centre, Taiwan
Y.-C. Chen, Metal Industries Research & Development Centre, Taiwan
Correspondent: Click to Email
During the production of IC components, packaging process is used for protection IC chips from harmful environments.Molding,trimming,and forming stages are three sequential works of packaging process.There are many factors affect moldability including molding die,mold condition,EMC,package design,and operator status.The function of molding die is to capsulate IC chips with thermosetting epoxy molding compound(EMC).The EMC is composed of many additives will abrade and corrode the molding die.It is important to extend the duty life of molding die for upgrading the production rate. In this study we compare several mold steels such as high-speed steel,stainless steel,tungsten carbide,and ceramics.Electrical discharging machining(EDM) and shot peening processes prepare the different surface roughness of mold steels. Some commercial surface treatment are preformed for comparing the surface characteristics of treated mold steels. There are including electroplated hard chromium,plasma nitriding,PVD coatings,and PCVD coatings.The contribution of these factors and their interactions to the contact angle,salt spray test,and wear test are determined.In the research of wettability shows,the influence of surface roughness on contact angle is to effect an increase in the contact angle from 77° to 110° as the roughness increases from an Ra value of 0.05µm to 2.0µm.The surface treatment can obviously reduce the influence of surface roughness on the contact angle.PVD Cr-based coatings show the highest contact angle value,above 120° ,even better than PTFE polymer material.PVD Cr-based coatings and plasma nitriding can effectively improve corrosion resistance of molding steels.To optimize the surface charactristics of PVD Cr-based coatings on molding die and be used in the IC packaging production lines.It shows that about 50% of production shots,comparing with electroplated hard chromium coating,before needing to clean the molding die.