Dennis Yee

Inner‐layer copper reliability of electroless copper processes

Purpose – The purpose of this paper is to present an overview of the alternative testing approaches that may be used to assess interconnect quality and their application to laminate material and plated‐through‐hole (PTH) process control.Design/methodology/approach – The paper introduces the importance of inner‐layer copper reliability and how to evaluate it. It reviews and discusses the effects of all factors involved, including laminate material, panel design, and chemical controls, on interconnect defects (ICDs).Findings – The best possible reliability can only be achieved by implementation of process controls ranging from incoming laminate material inspection to drilling parameters and finally chemical controls within the electroless copper process.Research limitations/implications – This paper focuses on through‐hole multilayer reliability. Although blind via reliability shares some aspects with through‐hole reliability, there are other factors that only apply to blind vias. This area will be the subj...

Next generation Copper electroplating for HDI micro-via filling and through hole plating

A novel DC blind micro via filling process was formulated for high volume HDI and substrate core layer metallization production. The process yields high quality results over a wide current density range. The process will be commercialized and it is anticipated that there will be substantial future growth in adoption of this technology to fill blind micro vias. This new chemistry in combination with optimized plating conditions and plating equipment can fill blind micro vias of various geometries. The plated copper has excellent physical and mechanical properties with a mirror bright surface. This formulation is intended to be used with either vertical or horizontal in-line jet impingement equipment in both panel and pattern modes. All organic additives can be easily monitored and controlled by conventional CVS analysis techniques.

Next generation electrolytic copper plating process for HDI applications

Copper electroplating is a critical step in the fabrication of reliable High Density Interconnect (HDI) substrates intended for use as core layers in build-up applications. HDI substrates may contain vias and through holes having several different dimensions that make it challenging to meet via filling and hole throwing power (TP) requirements. A next generation Electrolytic Copper plating process was developed to fill blind micro vias and provide good TP in through holes to meet the demands of this market. Void-free bottom-up fill in via features with higher throwing power in through holes is achieved with this novel Direct Current (DC) copper electroplating product. The copper via fill plating bath is formulated with novel additives to operate over a wide range of operating conditions.

CIRCUPOSIT™ 6530 catalyst process for electroless copper metallization

This paper describes the development of a new ionic palladium catalyst, CIRCUPOSIT™6530 Catalyst, along with a tartrate-based horizontal electroless copper bath, CIRCUPOSIT™6550, to meet the performance demands of high-density-interconnect (HDI) and packaging (PKG) substrates in horizontal electroless copper plating. Implementation of the new ionic catalyst process is demonstrated through excellent coverage and reliability performance of through holes and microvias on HDI and PKG substrates following processing in horizontal equipment, as well as peel strength on low profile dielectric materials in the semi-additive process. Results also showed that the new CIRCUPOSIT™6530 Catalyst demonstrated stable performance during customer qualification.

High performances PPR copper plating for high aspect ratio boards

Multilayer boards, which are widely used in professional electronics such as sever, communication, medical and military equipments, trend to increase layer counts (up to more than 56 layers) and aspect ratio (up to more than 25:1). Accordingly, it becomes more and more difficult to plate copper into the through holes with an acceptable deposit. To meet these demands, a new generation of high performances periodic pulse reverse (PPR) copper plating process has been developed. It is designed for use with soluble anodes and simple rectangle waveforms in vertical application. The new PPR chemistry demonstrates an excellent and stable throwing power up to a tested bath life of more than 200 AH/L. Neither a continuous carbon polish nor the frequent carbon treatment is required during operation. Meanwhile, it is easy to restart after idling with no need for a long dummy process. Effects of substrate, waveform on throwing power performance, the process capability to pattern and blind vias plating are also discussed in this article.

A novel and green electroless copper

Glyoxylic acid (GA) has been reported to be a promising autocatalytic reducing agent in electroless copper for more than 26 years, which can eliminate the environmental hazards, health and safety concerns associated with formaldehyde. This paper will introduce a novel and environmental-friendly electroless copper process with GA and tartrate as autocatalytic reducing agent and chelatant respectively. It had comparable plating performance with those conventional formaldehyde baths and the decomposition of GA can be suppressed. This novel GA electroless copper bath can potentially be applied in both vertical and horizontal equipment.