Composite laminate circuit structure and method of forming the same

• US 6,175,087 B1
• Filed: 12/02/1998
• Issued: 01/16/2001
• Est. Priority Date: 12/02/1998
• Status: Expired due to Term

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Markovich, Voya R., Wilson, William E., Perrino, Marybeth, Paoletti, Jim P., Keesler, Ross W.
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): NORRIS, JEREMY C
• Application Number:
  US09/204,458
• Time in Patent Office: 776 Days
• Field of Search: 174/261, 174/262, 174/263, 174/266, 174/264, 174/265, 361/794, 361/795
• US Class Current: 174/261
• CPC Class Codes: H05K 2201/09509 Blind vias, i.e. vias having one side closed
• CPC Class Codes: H05K 2201/09536 Buried plated through-holes, i.e. plated through-holes formed in a core before lamination
• CPC Class Codes: H05K 2201/096 Vertically aligned vias, holes or stacked vias
• CPC Class Codes: H05K 2201/09809 Coaxial layout reduction of cross-talk, noise or interference by printed shielding conductors for shielding around a single via or around a group of vias H05K1/0222
• CPC Class Codes: H05K 3/0023 by exposure and development of a photosensitive insulating layer
• CPC Class Codes: H05K 3/429 Plated through-holes specially for multilayer circuits, e.g. having connections to inner circuit layers
• CPC Class Codes: H05K 3/4623 the circuit boards having internal via connections between two or more circuit layers before lamination, e.g. double-sided circuit boards H05K3/462 takes precedence
• CPC Class Codes: H05K 3/4641 having integrally laminated metal sheets or special power cores

Abstract

A method forming a composite laminate structure includes providing first and second circuit board element each having circuitry on at least one face thereof and plated through holes. A voltage plane element is provided having at least one voltage plane having opposite faces with layers of partially cured photodielectric material on each face. At least one hole is photopatterned and etched through the voltage plane element but completely isolated from the voltage plane. Each through hole in the voltage plane element is aligned with a plated through hole in each of the circuit board elements to provide a surface on the voltage plane element communicating with the plated through holes. The voltage plane is laminated between the circuit board elements and the photoimageable material on the voltage plane is fully cured. The surfaces of the voltage plane element communicating with the plated through holes in the circuit board elements are plated with a conducting material to establish a connection between the circuitry on the first and second circuit board elements.

Claims

1. A composite laminate structure comprising,

first and second circuit board elements each having circuitry on at least one face thereof and plated through holes,

a voltage plane element laminated between said first and second circuit board elements, each having at least one voltage plane having opposite faces with a layer of fully cured photopatterned dielectric material on each face thereof with the at least one face of each circuit board element oriented away from said voltage plane element,

at least one hole etched through said voltage plane element without contacting said voltage plane, and at least one opening etched through each layer of photopatterned dielectric material of said voltage plane element terminating at said voltage plane to explore a portion thereof,

each through hole and each opening in said voltage plane element being aligned with a plated through hole in at least one of said circuit board elements to provide surface on said voltage plane element communicating with said plated through holes;

a unitary layer of electrically conducting material extending through each hole etched through the voltage plane and each plated through hole aligned therewith, and a unitary layer of conducting material in each of said holes etched in the voltage plane and its associated aligned platted through holes in a circuit board element and the exposed portion of the voltage plane.

2. The invention as defined in claim 1 wherein there is circuitry on each face of said circuit board elements.

3. The invention as defined in claim 1 wherein said voltage plane element has a single voltage plane.

4. The invention as defined in claim 1 wherein each circuit board element has at least one voltage plane.

5. The invention as defined in claim 4 wherein each circuit board element has plated through holes extending through said at least one voltage plane.

6. The invention as defined in claim 1 wherein at least one circuit board element has a plurality of voltage planes.

7. The invention as defined in claim 1 wherein said photopatterned dielectric material is an epoxy.

8. The invention as defined in claim 1 wherein there is circuitry on said photopatterned dielectric material on one face of said voltage plane element.