Low-cost, high throughput, large area meniscus coating for MCM-D and MCM-L substrates

The electronics industry is driven toward product miniaturization with higher functionality at reduced costs. This trend is expected to grow in all products sectors, including flat panel displays and portable consumer devices. Material deposition techniques can be a significant contributor to the overall manufacturing costs. We have investigated meniscus coating as a low-cost tool for large area polymer deposition. Meniscus coating has the following advantages over conventional spin coating: (i) minimal material waste; (ii) higher throughput; (iii) higher planarity; (iv) minimal defect density; and (v) thickness uniformity over a large area. All these factors help reduce the overall manufacturing costs. The objective of our efforts is to develop, install, and qualify an automated low-cost, high-throughput polymer deposition method for large-area MCM-D and MCM-L substrates. This paper reports materials and process optimization for 12 inch x 12 inch substrates that is scalable to 24 inch x 24 inch substrates. A variety of polymer photoresists, dielectrics, and composites are used for thick film coating on 12 inch PWB and glass substrates. For each material, the deposition process is optimized to the desired film thickness. For higher throughput and lower manufacturing costs, an automated coating workcell is designed. The proposed coating workcell includes a robotic material handling and convection drying of coated films with automated loading/unloading capability. Design and fabrication of the integrated workcell, coating throughput, uniformity of coating, and analysis of defects on the deposited films are addressed in this paper.