US 6,606,792 B1Granted

Process to manufacturing tight tolerance embedded elements for printed circuit boards

AssigneeOak-Mitsui, Inc.

InventorJohn A. Andresakis

Life of this patent

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Abstract

A process for forming printed circuit substrates incorporating impedance elements in which a pattern of impedance elements and a conductor pattern are incorporated on an insulating support. The process involves depositing a layer of an impedance material on a first surface of a sheet of an electrically highly conductive material and attaching a second surface of the sheet of highly conductive material to a support. Then one applies a layer of a photoresist material onto the layer of impedance material with imagewise exposure and development. After etching away the portion of the impedance layer material underlying the removed nonimage areas of the photoresist material, a pattern of impedance elements remain on the sheet of highly conductive material. Thus printed circuit board with impedance elements can be manufactured to a high degree of electrical tolerance.

Claims31

Dependent claims

A process for forming a printed circuit substrate with impedance elements comprising performing step (a) or (b):

(a) depositing a layer of an impedance material on a first surface of a sheet of an electrically highly conductive material and attaching a second surface of the sheet of electrically highly conductive material to a support;
then;
(b) attaching a second surface of a sheet of electrically highly conductive material to a support and depositing a layer of an impedance material on a first surface of the sheet of electrically highly conductive material;
then
(c) applying a layer of a photoresist material onto the layer of impedance material;
(d) imagewise exposing the photoresist material thus forming image areas and nonimage areas, and then removing the nonimage areas while retaining the image areas;
(e) etching away a portion of the impedance layer material underlying the removed nonimage areas of the photoresist material, and then optionally removing the image areas of the photoresist material thus leaving a pattern of impedance elements on the sheet of electrically highly conductive material,
(f) forming a plurality of target holes through the sheet of electrically highly conductive material;
(g) attaching one side of a sheet of insulating material to the sheet of electrically highly conductive material such that the impedance elements are between the sheet of insulating material and the sheet of electrically highly conductive material;
(h) removing the support from the sheet of electrically highly conductive material;
(i) applying an additional layer of a photoresist material onto the second surface of the sheet of electrically highly conductive material;
(j) imagewise exposing the additional layer of photoresist material thus forming image and nonimage areas, and then removing the nonimage areas while retaining the image areas;
(k) etching away the portion of the sheet of electrically highly conductive material underlying the removed nonimage areas of the photoresist material, and then optionally removing the image areas of the photoresist material thus leaving a pattern of conductive lines of the highly conductive material such that at least some of the conductive lines contact at least some of the impedance elements.

10 more elements

A process for forming a printed circuit substrate with impedance elements comprising performing step (a) or (b):

(a) depositing a pattern of impedance elements on a first surface of a sheet of electrically highly conductive material and attaching a second surface of the sheet of electrically highly conductive material to a support;
(b) attaching a second surface of a sheet of electrically highly conductive material to a support and depositing a pattern of impedance elements on a first surface of the sheet of electrically highly conductive material;
(c) forming a plurality of target holes through the sheet of electrically highly conductive material;
(d) attaching one side of a sheet of an insulating material to the sheet of electrically highly conductive material such that the impedance elements are between the sheet of insulating material and the sheet of electrically highly conductive material;
(e) removing the support from the sheet of electrically highly conductive material;
(f) applying a layer of a photoresist material onto the second surface of the sheet of electrically highly conductive material;
(g) imagewise exposing the layer of photoresist material thus forming image and nonimage areas, and then removing the nonimage areas while retaining the image areas;
(h) etching away the portion of the sheet of electrically highly conductive material underlying the removed nonimage areas of the photoresist material, and then optionally removing the image areas of the photoresist material thus leaving a pattern of conductive lines of the electrically highly conductive material such that at least some of the conductive lines contact at least some of the impedance elements.

5 more elements

A process for forming a printed circuit substrate with impedance elements comprising performing step (a) or (b):

(a) depositing a layer of a photosensitive impedance material on a first surface of a sheet of an electrically highly conductive material attaching a second surface of the sheet of electrically highly conductive material to a support;
then
(b) attaching a second surface of a sheet of electrically highly conductive material to a support and depositing a layer of a photosensitive impedance material on a first surface of the sheet of electrically highly conductive material;
then
(c) imagewise exposing the photosensitive impedance material thus forming image and nonimage areas, and then removing the nonimage areas while retaining the image areas thus leaving a pattern of impedance elements on the sheet of electrically highly conductive material;
(d) forming a plurality of target holes through the sheet of electrically highly conductive material;
(e) attaching one side of a sheet of an insulating material to the sheet of electrically highly conductive material such that the impedance elements are between the sheet of insulating material and the sheet of electrically highly conductive material;
(f) removing the support from the sheet of electrically highly conductive material;
(g) applying a layer of a photoresist material onto the second surface of the sheet of electrically highly conductive material;
(h) imagewise exposing the layer of photoresist material thus forming image and nonimage areas, and then removing the nonimage areas while retaining the image areas;
(i) etching away the portion of the sheet of electrically highly conductive material underlying the removed nonimage areas of the photoresist material, and then optionally removing the image areas of the photoresist material thus leaving a pattern of conductive lines of the electrically highly conductive material such that at least some of the conductive lines contact at least some of the impedance elements.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/578,424Filed 25 May 2000
Granted: 19 Aug 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification16 codes

H05K 1/167
Incorporating printed electric components, e.g. printed resistors, capacitors or inductors: incorporating printed resistors
H05K 1/162
Incorporating printed electric components, e.g. printed resistors, capacitors or inductors: incorporating printed capacitors
H05K 3/002
Etching of the substrate by chemical or physical means: by liquid chemical etching
H05K 3/0023
Etching of the substrate by chemical or physical means: by exposure and development of a photosensitive insulating layer