Grantee Research Project Results
Final Report: Development of Thermal Spray Circuit Board (TSCB) Technology To Replace Electroplating and "Print-and-Etch" Circuit Board Fabrication Techniques
EPA Contract Number: 68D99072Title: Development of Thermal Spray Circuit Board (TSCB) Technology To Replace Electroplating and "Print-and-Etch" Circuit Board Fabrication Techniques
Investigators: Lenling, William J.
Small Business: Thermal Spray Technologies Inc.
EPA Contact:
Phase: I
Project Period: September 1, 1999 through March 1, 2000
Project Amount: $66,627
RFA: Small Business Innovation Research (SBIR) - Phase I (1999) RFA Text | Recipients Lists
Research Category: SBIR - Pollution Prevention , Pollution Prevention/Sustainable Development , Small Business Innovation Research (SBIR)
Description:
The purpose of the research is to develop a method of reducing the oxidation that occurs in thermal sprayed copper during processing. Thermal sprayed copper is used in a proprietary method of manufacturing circuit boards, dubbed the Thermal Spray Circuit Board (TSCB) process. This environmentally-friendly TSCB process, when compared to conventional circuit board fabrication techniques, conserves energy, greatly reduces water consumption, eliminates nearly all process chemicals, and possesses the ability to recycle all copper material. Unfortunately, the copper in the TSCB process has a high electrical resistivity which stems from oxidation that occurs during its processing. By eliminating the oxidation, the electrical resistivity of the copper will decrease and the TSCB should theoretically perform as well as the conventional copper.Techniques to reduce oxidation in the thermal sprayed copper were to flow along two avenues of research. The first avenue was through the development of a shroud that encapsulates the spray plume protecting the molten copper from the oxidizing atmosphere. The second avenue was to investigate dopants that will reduce the degree at which the copper is able to oxidize when exposed to oxygen.
Summary/Accomplishments (Outputs/Outcomes):
Two generations of shrouds were completed and a third was being built by the completion of the phase-I research. These prototype shroud were able to demonstrate that it is possible to reduce the amount of copper oxidation during processing using this concept. However, the shroud by itself was unable to eliminate all of the oxidation from occurring and as a result the electrical resistivity of the copper was still well above pure copper.After a thorough literature search and careful screening of processes used to created dopant powder it was decided that casting was the most economical way. Powders of copper and dopant elements (boron, magnesium, and aluminum) were combined, melted, and cast into ingots. These ingots were then to be atomized to create doped powder. The powder was then to be thermal sprayed to create doped copper coatings. These coatings were then to be electrically tested and their results compared to shrouded copper and conventional copper. Unfortunately, time ran out in phase-I and the ingots are still waiting to be atomized into powder.
Conclusions:
With help from FORESIGHT SCIENCE & TECHNOLOGY, a commercialization strategy was outlined. Because there exists a strong desire in the circuit board prototyping industry for a quicker fabrication method, we began here. Initially it was unclear what disadvantages, other than the high resistivity, the TSCB process had compared to conventional circuit board prototyping methods. Unfortunately it was uncovered that the trace density of the TSCB was lower. Because both electrical conductivity and trace density are critical to circuit boards in the prototyping market, it has been suggested that TST take a hard look at what the TSCB technology can do and to redirect it towards a commercially viable opportunity that requires those capabilities.Supplemental Keywords:
Circuit Boards, Prototyping, Thermal Spray, Copper, Electrical Resistivity, Dopants., Economic, Social, & Behavioral Science Research Program, Scientific Discipline, Waste, Sustainable Industry/Business, cleaner production/pollution prevention, Technology for Sustainable Environment, New/Innovative technologies, Engineering, Hazardous, Market mechanisms, Economics & Decision Making, carbon bond formation, electroplating, printed circuit boards, circuit board manufacturing, electronics industry, recycling, innovative technology, coating formulations, thermal spray circuit board (TSCB) technology, pollution prevention, cost effective, innovative technologies, metal recyclingThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.