Microfiber dielectrics which facilitate laser via drilling

• US 6,224,965 B1
• Filed: 06/25/1999
• Issued: 05/01/2001
• Est. Priority Date: 06/25/1999
• Status: Expired due to Fees

• Current Assignee: Alliedsignal Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: McAuliffe, Mavyn, Xu, Chengzeng, Haas, David R.
• Primary Examiner(s): LAM, CATHY FONG FONG
• Application Number:
  US09/344,038
• Time in Patent Office: 676 Days
• Field of Search: 442/60, 442/65, 442/117, 442/152, 442/164, 442/172, 428/209
• US Class Current: 428/209
• CPC Class Codes: H05K 1/0373 containing additives, e.g. fillers H05K1/036 takes precedence
• CPC Class Codes: H05K 2201/0209 Inorganic, non-metallic particles
• CPC Class Codes: H05K 2201/0251 Non-conductive microfibers relatively short elongated particles H05K2201/0248
• CPC Class Codes: H05K 3/0032 of organic insulating material
• CPC Class Codes: H05K 3/0035 of blind holes, i.e. having a metal layer at the bottom
• CPC Class Codes: H05K 3/0038 combined with laser drilling through a metal layer
• CPC Class Codes: H05K 3/4644 by building the multilayer layer by layer, i.e. build-up multilayer circuits making via holes in the insulating layers H05K3/0011; special circuit boards as base or core whereon the multilayer is built H05K3/4602
• CPC Class Codes: H05K 3/4652 Adding a circuit layer by laminating a metal foil or a preformed metal foil pattern H05K3/4647 takes precedence
• CPC Class Codes: H05K 3/4655 by using a laminate characterized by the insulating layer general-purpose insulating materials H05K1/03, H05K3/4673
• CPC Class Codes: H05K 3/4673 Application methods or materials of intermediate insulating layers not specially adapted to any one of the previous methods of adding a circuit layer similar methods for protective coatings H05K3/28
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/49126 Assembling bases
• CPC Class Codes: Y10T 29/49139 by inserting component lead or terminal into base aperture
• CPC Class Codes: Y10T 29/49156 with selective destruction of conductive paths
• CPC Class Codes: Y10T 29/49165 by forming conductive walled aperture in base
• CPC Class Codes: Y10T 428/24917 including metal layer
• CPC Class Codes: Y10T 428/24926 including ceramic, glass, porcelain or quartz layer
• CPC Class Codes: Y10T 442/2008 Fabric composed of a fiber or strand which is of specific structural definition
• CPC Class Codes: Y10T 442/2049 Each major face of the fabric has at least one coating or impregnation
• CPC Class Codes: Y10T 442/2475 Coating or impregnation is electrical insulation-providing, -improving, or -increasing, or conductivity-reducing
• CPC Class Codes: Y10T 442/2762 : Coated or impregnated natural fiber fabric [e.g., cotton, wool, silk, linen, etc.]
• CPC Class Codes: Y10T 442/2861 : Coated or impregnated synthetic organic fiber fabric
• CPC Class Codes: Y10T 442/2926 : Coated or impregnated inorganic fiber fabric

Abstract

This invention concerns electronic substrates comprising a non-woven filler material and a resin material. The present invention also includes electronic products manufactured from the electronic substrates of this invention including, but not limited to prepregs, metal clad laminates, and printed wiring boards with and without lased via holes. The present invention further includes a method of manufacturing printed built-up wiring boards including the steps of forming a prepreg and forming at least one via in the prepreg.

Claims

1. A lasable prepreg for use in fabrication of build-up multilayer printed wiring boards comprising:

a. a non-woven matrix of glass micro-fibers, in which the glass micro-fibers have a diameter of less than about two microns; and

b. a partially cured polymer.

2. The prepreg of claim 1 wherein the non-woven reinforcing material includes less than 40 wt % of a supplemental reinforcing material selected from organic fiber, organic pulp and mixtures thereof.

3. The prepreg of claim 1 wherein the polymer is selected from a thermoplastic polymer, a thermosetting resin and mixtures thereof.

4. The prepreg of claim 1 including from about 5 to about 45 wt % of non-woven reinforcing material and from about 55 to about 95 wt % polymer.

5. The prepreg of claim 1 wherein at least 80% of the micro-fiber glass has a diameter of less than about 1 micron.

6. The prepreg of claim 1 wherein the polymer is a thermosetting resin that is cured from between 10 and 50% of full cure.

7. The prepreg of claim 1 wherein the prepreg includes a first surface and a second surface wherein a copper foil is adhered to at least one prepreg surface.