GE ULTEM* films in electrical and electronic appllications
Publication Date: 2004-Oct-27
The IP.com Prior Art Database
GE ULTEMTM Films in Electrical & Electronic Applications
Flexible Printed Circuitry
General Electric ULTEMTM polyetherimide film can be utilized in a number of electronic applications for rigid and flexible electronic constructions. Ultem film can be processed as a high temperature flex substrate core, high temperature multi-layer circuit, high temperature coverlay material, and a rigid stiffener for second level assembly operations. ULTEM polyetherimide film is available in a thickness range of 25 to 750 micron. The ability to mold and thermally form ULTEM materials give it advantages over traditional polyimides.
High resolution flexible circuit processes established using ULTEM polyetherimide materials have shown ULTEM resin to have excellent electrical properties including low dielectric constant and dissipation factor. Adhesiveless single and double sided flexible circuits have been fabricated and tested for performance (electrical, mechanical, thermal) and reliability (thermal cycling, tear propagation, flexural endurance, and solderability). Critical flex circuit fabrication processes such as metal adhesion, micro-via formation, lamination, photolithography, and module singulation have been evaluated.
Ø ULTEM film can be metallized utilizing a number of traditional processes such as direct metal sputtering, electrodeposition, electroless deposition, direct lamination, and lamination with adhesive.
Metal adhesion in excess of 10lbs/in. was achieved using a sputtered metal process to ULTEM polyimide film. The data in table 1 was produced from a sputtered seed metal with 0.3um of sputtered copper. Copper was then electrodeposited to 25um . Metal stripes were patterned on the Ultem film and a 90 degree peel test was performed. The samples were then subjected to an 18hr. water boil and the peel test was repeated.
Ø Via interconnect processes have been demonstrated using GE Ultem polyetherimide film include; mechanical drilling, chemical etching, laser drilling (as well as ablation and profiling).
Via Interconnect processing was tested using a via string pattern which incorporated Ultem polyimide lamination adhesiveless processing with laser via drilling. Subsequent metal deposition and subtractive pattern transfer resulted in the test circuit design. The process of lamination, drill, and metal can be repeated for multi-layer circuit fabrication. Similar processes have also been evaluated using Ultem polyimide with acrylic adhesive for lower temperature single to multi-layer flex constructions. Ultem processing has been demonstrated in rigid and non-rigidized formats (in addition to flex constructions Ultem has been built on rigid substrates such as glass, silicon, ceramic, etc.).
Via Interconnect Cross-sectional Process Flow
Ø Dielectric properties of Ultem films have been characterized to 10GHz. Ultem as used in ...