Printed circuit board, method of producing the same, and electronic unit

• US 20070187136A1
• Filed: 09/20/2005
• Published: 08/16/2007
• Est. Priority Date: 09/29/2004
• Status: Abandoned Application

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Higashiguchi, Masahiro, Tan, Kunihiro
• Application Number:
  US11/230,965
• Publication Number:
  US 20070187136A1
• Time in Patent Office: Days
• US Class Current: 174/250
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 23/24 solid or gel at the normal operating temperature of the device H01L23/3135 takes precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• CPC Class Codes: H05K 2203/0585 Second resist used as mask for selective stripping of first resist
• CPC Class Codes: H05K 2203/0588 Second resist used as pattern over first resist
• CPC Class Codes: H05K 2203/0594 Insulating resist or coating with special shaped edges
• CPC Class Codes: H05K 3/284 for encapsulating mounted components H05K1/185 takes precedence

Abstract

A printed circuit board is disclosed that is able to prevent outflow of a potting resin out of a sealing region. The printed circuit board includes a conductive pattern formed on an insulating substrate, an electrode for connecting an electronic part to the conductive pattern, and a stripe-like resin-outflow-prevention dam arranged in a periphery of a resin-sealing region covering the electronic part. An outer side surface and an upper surface of the resin-outflow-prevention dam subtend an acute angle.

Claims

1. A printed circuit board, comprising:

a conductive pattern formed on an insulating substrate;

an electrode for connecting an electronic part to the conductive pattern; and

a stripe-like resin-outflow-prevention dam arranged in a periphery of a resin-sealing region covering the electronic part;

wherein an outer side surface of the resin-outflow-prevention dam and an upper surface of the resin-outflow-prevention dam subtend an acute angle.

2. The printed circuit board as claimed in claim 1, wherein

the resin-outflow-prevention dam has a quadrilateral cross section;

and

a width of the upper surface of the resin-outflow-prevention dam is greater than a width of a lower surface of the resin-outflow-prevention dam.

3. The printed circuit board as claimed in claim 2, wherein the resin-outflow-prevention dam has approximately an inverse trapezoidal cross section.

4. The printed circuit board as claimed in claim 1, wherein

an insulating material layer is formed on the printed circuit board and at least has an opening in a region where the electrode is formed, and

the resin-outflow-prevention dam is formed on the insulating material layer.

5. The printed circuit board as claimed in claim 1, wherein

an insulating material layer is formed on the printed circuit board and at least has an opening in a region where the electrode is formed, and

the resin-outflow-prevention dam is formed from the insulating material.

6. An electronic unit, comprising:

a printed circuit board having a conductive pattern formed on an insulating substrate, an electrode, and a stripe-like resin-outflow-prevention dam; and

an electronic part that is connected to the conductive pattern through the electrode to mount the electronic part on the printed circuit board;

wherein

the resin-outflow-prevention dam is arranged in a periphery of a resin-sealing region covering the electronic part, and

a resin for sealing is applied in the resin-sealing region to cover the upper surface of the resin-outflow-prevention dam.

7. A method of producing a printed circuit board including a conductive pattern formed on an insulating substrate, and an electrode for connecting an electronic part to the conductive pattern;

and a resin-outflow-prevention dam arranged in a periphery of a resin-sealing region covering the electronic part,

said method comprising the steps;

depositing a material layer on the insulating substrate for forming the resin-outflow-prevention dam;

forming an etching mask pattern on the material layer in an area where the resin-outflow-prevention dam is to be formed;

etching the material layer selectively by dry etching with the etching mask pattern as a mask to selectively remove the material layer; and

over-etching the material layer to form the resin-outflow-prevention dam having approximately an inverse trapezoidal cross section.

8. A method of producing a printed circuit board including a conductive pattern formed on an insulating substrate, and an electrode for connecting an electronic part to the conductive pattern;

and a resin-outflow-prevention dam arranged in a periphery of a resin-sealing region covering the electronic part,

said method comprising the steps;

depositing a positive photosensitive material layer on the insulating substrate for forming the resin-outflow-prevention dam;

arranging a light-shielding mask on the photosensitive material layer in an area where the resin-outflow-prevention dam is to be formed;

over-exposing the photo-sensitive material layer by using the light-shielding mask; and

developing the photosensitive material layer to form the resin-outflow-prevention dam having approximately an inverse trapezoidal cross section.