Printed circuit board with tin pads

• US 8,077,472 B2
• Filed: 09/15/2008
• Issued: 12/13/2011
• Est. Priority Date: 06/05/2008
• Status: Expired due to Fees

• Current Assignee: Hon Hai Precision Industry Co., Ltd.
• Original Assignee: Hon Hai Precision Industry Co., Ltd.
• Inventors: Liu, Shu-Tzu
• Primary Examiner(s): PAPE, ZACHARY
• Application Number:
  US12/211,035
• Publication Number:
  US 20090301768A1
• Time in Patent Office: 1,184 Days
• Field of Search: 174250-268, 361748-803
• US Class Current: 361/753
• CPC Class Codes: H05K 1/0215 Grounding of printed circuits by connection to external grounding means
• CPC Class Codes: H05K 1/05 Insulated conductive substrates, e.g. insulated metal substrate
• CPC Class Codes: H05K 1/116 Lands, clearance holes or other lay-out details concerning the surrounding of a via
• CPC Class Codes: H05K 2201/099 Coating over pads, e.g. solder resist partly over pads
• CPC Class Codes: H05K 2201/09909 Special local insulating pattern, e.g. as dam around component
• CPC Class Codes: H05K 2201/10409 Screws
• CPC Class Codes: H05K 2203/043 Reflowing of solder coated conductors, not during connection of components, e.g. reflowing solder paste
• CPC Class Codes: H05K 3/0094 Filling or covering plated through-holes or blind plated vias, e.g. for masking or for mechanical reinforcement
• CPC Class Codes: H05K 3/3452 Solder masks
• CPC Class Codes: H05K 3/3485 Applying solder paste, slurry or powder thick film methods for applying conductive paste or ink patterns H05K3/12

Abstract

A printed circuit board of the present disclosure includes a main body, a tin layer, and a solder mask. The main body defines a through hole configured for being connected to a grounding component. The tin layer is formed on a surface of the main body around the through hole. The tin layer contacts the grounding component. The solder mask is formed between a periphery of the through hole and the tin layer. The solder mask is configured to prevent tin cream of the tin layer from flowing into the through hole.

Claims

1. A printed circuit board, comprising:

a main body defining a through hole configured for being connected to a grounding component, wherein a fixing member is passed through the through hole of the printed circuit board, and engages with the grounding component, the main body includes a first copper layer, a first steel layer, a grounding layer, a second steel layer, and a second copper layer, arranged in that order, a plurality of first tin pads are positioned on the first steel layer, and protrude out of the first copper layer, a head portion of the fixing member abuts the first tin pads, the fixing member is electrically connected with the grounding layer, and a plurality of second tin pads are positioned on the second steel layer, and protrude out of the second copper layer;

a tin layer formed on a surface of the main body around the through hole for contacting the grounding component, wherein the tin layer covers the second tin pads; and

a solder mask formed between a periphery of the through hole and the tin layer, wherein the solder mask prevents tin cream of the tin layer from flowing into the through hole.

2. The printed circuit board as claimed in claim 1, wherein the tin layer comprises four fan-shaped portions substantially evenly arranged around the through hole, wherein the solder mask is formed between adjacent fan-shaped portions of the tin layer.

3. The printed circuit board as claimed in claim 1, wherein the tin layer and the solder mask are coated on the second copper layer.

4. The printed circuit board as claimed in claim 1, wherein the main body defines a plurality of conductive vias for providing an electrical connection between the first copper layer, the second copper layer and the first steel layer, the grounding layer, the second steel layer.

5. A printed circuit board, comprising:

a main body defining a through hole configured for being connected to a grounding component, wherein a fixing member is passed through the through hole of the printed circuit board, and engages with the grounding component, the main body includes a first copper layer, a first steel layer, a grounding layer, a second steel layer, and a second copper layer, arranged in that order, a plurality of first tin pads are positioned on the first steel layer, and protrude out of the first copper layer, a head portion of the fixing member abuts the first tin pads, the fixing member is electrically connected with the grounding layer, and a plurality of second tin pads are positioned on the second steel layer, and protrude out of the second copper layer;

a tin layer formed on a surface of the main body around the through hole, the tin layer comprising a plurality of portions and contacting the grounding component, wherein the tin layer covers the second tin pads; and

a solder mask configured for preventing tin cream of the tin layer from flowing into the through hole, wherein a first portion of the solder mask is formed between a periphery of the through hole and the tin layer, and a second portion of the solder mask is formed between adjacent portions of the tin layer.

6. The printed circuit board as claimed in claim 5, wherein the tin layer and the solder mask are coated on the second copper layer.

7. The printed circuit board as claimed in claim 5, wherein the main body defines a plurality of conductive vias for providing an electrical connection between the first copper layer, the second copper layer and the first steel layer, the grounding layer, the second steel layer.

8. A printed circuit board, comprising:

a main body defining a through hole configured for being connected to a grounding component, wherein a fixing member is passed through the through hole of the printed circuit board and engages with the grounding component, wherein the main body includes a first copper layer, a first steel layer, a grounding layer, a second steel layer, and a second copper layer, arranged in that order, a plurality of first tin pads are positioned on the first steel layer, and protrude out of the first copper layer, a plurality of second tin pads are positioned on the second steel layer, and protrude out of the second copper layer;

a tin layer formed on a surface of the main body around the through hole for contacting the grounding component, wherein the tin layer covers the second tin pads; and

a solder mask formed between a periphery of the through hole and the tin layer, wherein the solder mask prevents tin cream of the tin layer from flowing into the through hole.