(Case study at Integrated Circuit Assembly Manufacturing)
Arif Rahman Hakim,
Mechanical Department of Engineering Faculty of University of Riau Kepulauan Batam
ABSTRACT
Laser marking process is one of the process step in Integrated Circuit (IC) assembly manufacturing. This process is to mark the IC unit with the device information, assembly information and product brand. One type of lead frame used for IC assembly is open end lead frame which causing the individual lead on end unit prone to damage due to hard mechanical contact. At laser mark process, the lead frame will be pushed into the laser chamber by using a solid input pusher. The existing design of input pusher will push the lead by making contact with the edge of the lead frame. Production section keep observing the damage lead problem occurred when process the open end lead frame. Damage lead was 54% of the defect occurred at laser mark process. This problem causing low yield and high rework. Team has been established to analyze the problem and found the solution.
Through investigation and analysis, team found the root cause of the problem and takes the appropriate corrective action. Design modification of input pusher from the previous design which was solid type to be U-type significantly reduces the damage lead at laser mark process. Initial observation showed that the new design able to reduce 98% of damage lead.
Key word : Design modification
Introduction
Integrated Circuit (IC) is a vital electronic component that being used widely in electronic application. This component is used in consumer product, telecommunication, computer and automotive industry. Global competition and market driven has motivated the multinational company which produce IC to sub contract the IC assembly manufacturing to the Asian country. One of the country selected by the industry to be off shore site of assembly manufacture is Batam island of Indonesia.
There is one IC assembly manufacture located in Batamindo Industrial Park Muka Kuning, Batam. This is one of top 10 IC assembly subcontractors in the world. In this factory, ICs are assembled starting from wafer chip up to the final IC component. The process step to assemble the IC is started from wafer saw process. At this process wafer will be sawn to be single chip called as die. The single die then attached to a copper lead frame using conductive epoxy glue. To strengthen the bonding, the work piece will be cured at 125oC. The next process is to connect the die to the lead frame using gold wire by ultra sonic welding. This process is called as wire bonding. All these processes are classified as front line production. Wire bonded die then goes to molding process where the work piece will be covered by using epoxy mold compound plastic that categorized as thermo set plastic. The process then continued by solder plating process where the copper lead frame will be coated by tin (Sn).For device identification, the IC package will be marked using laser process. The information written on the package contains device name, manufacturing code and product brand. After completion of laser marking process, the work piece will be trimmed and formed to be single IC unit, then the final IC component are ready to ship to the customer, the owner of the product.
In this paper, it will be elaborated the process of laser marking. At this process, work piece will be loaded into the input track of the machine then the work piece will be pushed into the laser chamber using a pusher assembly called as input pusher. Inside the laser chamber, a laser system will mark the IC package. Then finally, the marked work piece will be pushed out of the chamber and unloaded to the carrier bag. Production section observing quality issue of the product such as marking defect, package defect and lead defect. Production data showed that the lead defect contributed 54% of total defects. This quality issue is concentrated on open end lead frame type.