This report presents a profile of the printed wiring board (PWB) industry, and defines and describes the typical manufacturing steps or "use clusters" in the manufacture of multilayer rigid PWBs.
PWBs serve to interconnect the devices and components in the vast majority of electronic products. Without this critical component, most electronic products either could not function or would be significantly more expensive if constructed with other interconnect technologies. PWBs play a crucial role in the advancement of electronic packaging and interconnections because improvements in PWBs reduce the size and cost of electronic devices while boosting performance. Progress in PWB technology and manufacturing drives U.S. competitiveness in both existing products and new technologies. The U.S. Department of Defense (DoD), the U.S. Department of Commerce (DoC), the Japanese Ministry of International Trade and Industry (MITI), and the European Community (EC) all include electronic systems and components on their critical technology lists.
A March 1993 report published by MCC (the Microelectronics and Computer Technology Corporation) entitled, Environmental Consciousness: A Strategic Competitiveness Issue for the Electronics and Computer Industry, identified key environmental technology needs in electronics systems manufacturing. The study concluded that effective collaboration between government, industry, academia, and the public is vital for developing and implementing environmentally conscious products and processes. Industry and government programs in environmental technology should encourage such collaboration and focus on specific pilot projects.
The study effort stimulated a collaborative effort to develop a roadmap for the electronics industry. The final roadmap document, released in December of 1994, was produced through a collaborative process that collectively involved more than 100 organizations, including the Advanced Research Projects Agency (ARPA), DoE and the Environmental Protection Agency (EPA), and several prominent trade associations. The Institute for Interconnecting and Packaging Electronic Circuits (IPC) was instrumental in developing the information on PWBs through its Environment, Health, and Safety Committee. The EPA Design for the Environment PWB Project was stimulated in part by both of these activities.
DESIGN FOR THE ENVIRONMENT PROJECT
This profile report was prepared in support of the U.S. EPA Design for the Environment PWB Project. The Project is a cooperative effort between the EPA, IPC, MCC, industry, research institutions, and public interest stakeholders to identify and assess environmentally safer substitute materials, processes, and technologies for the PWB industry. This report a profile of the industry (Part 1) and description of the major industry processes (Part 2) is one step in the overall assessment. The information contained in this report contributes to the selection of specific materials, processes, and technologies to be investigated further.
PART 1: INDUSTRY PROFILE
The total world market for all PWBs is approximately $21 billion, of which U.S. production accounts for about one quarter (>$5 billion). U.S. domination of this world market eroded from 1980 to 1990, but has come back slightly in recent years. However, like a commodity industry, the PWB industry is characterized by highly competitive global sourcing with very low profit margins.
There are approximately 700 to 750 independent PWB manufacturing facilities in the U.S. In addition, there are approximately 70 captive printed wiring board facilities. The states with the highest number of PWB manufacturing facilities are California, Minnesota, Texas, Illinois, Massachusetts, and Arizona. However, there are PWB manufacturing facilities in virtually all 50 states and territories. In sheer numbers, the vast majority of PWB manufacturers are small to medium enterprises with annual sales under $10 million. In the U.S., the majority of PWBs (>75%) are produced by independent manufacturers. Many original equipment manufacturers (OEMs) have shut down their PWB operations and now buy their PWBs from independent manufacturers.
Since 1980, rigid multilayer PWBs have grown to dominate the domestic production value of all PWBs. Rigid multilayer boards now account for approximately 66% of the domestic market. One-quarter of the market is double-sided rigid boards, and the remainder are single-sided and flexible circuits. The market for multilayer boards has grown from approximately $700 million in 1980, to almost $3.4 billion in 1993. The PWB industry directly employs approximately 75,000 people. Of this number, about 68% of employment is concentrated in production jobs the highest ratio of production jobs for U.S. electronic manufacturing.
IPC estimates that a minimum of 2% of PWB revenues in 1991 went to pay for pollution controls. In comparison, the average net profit for the PWB industry in 1991 was about 2.2% of sales. The cost of waste treatment (estimated at over $140 million in 1990 for major merchant PWB manufacturers) and the additional regulatory burdens of recordkeeping, manifesting, and inventory reporting constitute a significant cost to the PWB manufacturers in this country. The fundamental processes, however, have remained the same and many pollution prevention efforts have reached their cost-effective limits. Part 2 of this document will describe the PWB manufacturing process and identify alternative technologies that may be evaluated in a design for the environment effort, thereby decreasing cost and environmental impact simultaneously.
PART 2: USE CLUSTER PROFILE
PWB manufacturing is a highly technical, complicated operation requiring large equipment investments and over fifty processes. The manufacturing processes described in Part 2 are organized and described in "use clusters." A use cluster is a set of chemicals, processes, and technologies that can substitute for one another to perform a specific function. A use cluster profile of the industry, therefore, describes alternate chemicals, processes, or technologies that may be used to complete each step or function in the entire PWB manufacturing process.
This PWB use-cluster profile describes the fabrication processes for the largest product segment of the industry, the rigid multilayer PWB. The use cluster profile is intended to aid in the selection of a use cluster for assessment in a DfE project. The profile identifies different processes in the PWB industry (e.g., laminating, making holes conductive) and steps within those processes (e.g., imaging, etching, plating). The process steps are described in flow chart form with a description of each step. Next, the chemicals, processes, and technologies used in each step are briefly described. The profile may also mention commonly accepted alternatives to these practices and areas that are recognized to have especially high environmental impacts. Information on the risk and releases of these materials can then be investigated to target areas for further work but is not within the scope of this report.