Production method for thermoplastic liquid crystal polymer film, circuit board and production method therefor

Patent metadata

Field	Value
Publication number	US-2016236402-A1
Application number	US-201615137343-A
Country	US
Kind code	A1
Filing date	Apr 25, 2016
Priority date	Nov 1, 2013
Publication date	Aug 18, 2016
Grant date	—

Abstract

Provided are a method for producing a thermoplastic liquid crystal polymer (TLCP) film having an improved thermo-adhesive property, a circuit board, and a method for producing the same. The production method of the TLCP film includes preparing a TLCP film as the adherend film and a TLCP film as the adhesive film;
examining each of the prepared TLCP films for a relative intensity calculated as a ratio in percentage of a sum of peak areas of C—O bond peak and COO bond peak based on the total area of C 1 s peaks in the XPS spectral profile so as to calculate a relative intensity X (%) as for the prepared adherend film and a relative intensity Y (%) as for the prepared adhesive film; and
controlling the TLCP film as the adhesive film to have a relative intensity Y by selection or activation treatment of the adhesive film so that the relative intensity X of the adherend film and the relative intensity Y of the controlled adhesive film satisfy the following formulae (1) and (2):
38< X+Y<65   (1)

−8.0< Y−X<8.0   (2).

First claim

What is claimed is:

1 . A method for producing a thermoplastic liquid crystal polymer film as an adhesive film to be thermo-bonded to an adherend body of a thermoplastic liquid crystal polymer film (hereinafter referred to as an adherend film), the method at least comprising:
preparing a thermoplastic liquid crystal polymer film as the adherend film and a thermoplastic liquid crystal polymer film as the adhesive film; examining each of the prepared thermoplastic liquid crystal polymer films for a relative intensity calculated as a ratio in percentage of a sum of peak areas of C—O bond peak and COO bond peak based on the total area of C1s peaks in the XPS spectral profile so as to calculate a relative intensity X (%) as for the prepared adherend film and a relative intensity Y (%) as for the prepared adhesive film; and controlling the thermoplastic liquid crystal polymer film as the adhesive film to have a relative intensity Y by selection or activation treatment of the adhesive film so that the relative intensity X of the adherend film and the relative intensity Y of the controlled adhesive film satisfy the following formulae (1) and (2):
38< X+Y< 65   (1)

−8.0< Y−X< 8.0   (2).

2 . The method for producing a film according to claim 1 , wherein the controlling is performed by at least one activation treatment selected from the group consisting of ultraviolet (UV) ray irradiation, plasma irradiation, and corona discharge treatment.

3 . The method for producing a film according to claim 1 , wherein the thermoplastic liquid crystal polymer film as the adhesive film is further subjected to degassing of the film before or after the controlling process of the relative intensity Y (%)
by degassing the film (i) under vacuum of 1500 Pa or lower for 30 minutes or more, by degassing the film (ii) under heating at a temperature ranging from 100° C. to 200° C., or by degassing the film under the vacuum (i) and under the heating (ii) simultaneously or separately.

4 . The method for producing a film according to claim 3 , wherein the degassing process is carried out by degassing the film under vacuum of 1500 Pa or lower while heating at a temperature ranging from 50° C. to 200° C.

5 . The method for producing a film according to claim 1 , wherein the thermoplastic liquid crystal polymer film as the adhesive film has a film thickness of 10 to 500 gm.

6 . A method for producing a circuit board comprising a thermoplastic liquid crystal polymer film as an adherend film and a thermoplastic liquid crystal polymer film as an adhesive film, the both films being laminated by thermo- bonding, the method comprising:
preparing the adherend film and the adhesive film as circuit board materials; stacking the adherend film and the adhesive film in accordance with a predetermined structure of a circuit board to obtain a stacked material, followed by conducting thermo-compression bonding of the stacked material by heating under a predetermined compression pressure; wherein the prepared circuit board materials are independently at least one member selected from the group consisting of an insulating substrate having a conductor layer on at least one surface, a bonding sheet, and a coverlay; and the adhesive film is a thermoplastic liquid crystal polymer film produced by a method recited in claim 1 .

7 . The method for producing a circuit board according to claim 6 , wherein the adherend film is an insulating substrate having a conductor circuit on at least one surface, and the adhesive film is at least one circuit board material selected from the group consisting of an insulating substrate having a conductor layer on at least one surface, a bonding sheet, and a coverlay.

8 . The method for producing a circuit board according to claim 6 , wherein the method further comprises degassing the adherend film and the adhesive film before thermo-compression bonding by degassing the film (i) under vacuum of 1500 Pa or lower for 30 minutes or more,
by degassing the film (ii) under heating at a temperature ranging from 100° C. to 200° C., or by degassing the film under the vacuum (i) and under the heating (ii) simultaneously or separately.

9 . The method for producing a circuit board according to claim 8 , wherein the degassing is carried out under vacuum at a vacuum degree of 1500 Pa or lower for 30 minutes or more at a temperature ranging from 50 to 150° C.

10 . A circuit board comprising a thermoplastic liquid crystal polymer film as an adherend film and a thermoplastic liquid crystal polymer film as an adhesive film, the both films being laminated by thermo-bonding, wherein
the adherend film has a surface portion to be adhered, the surface portion having a relative intensity X (%) calculated as a ratio in percentage of a sum of peak areas of C—O bond peak and COO bond peak relative to the total area of C1s peaks in the XPS spectral profile; the adhesive film has a surface portion to be adhered, the surface portion having a relative intensity Y (%) calculated as a ratio in percentage of a sum of peak areas of C—O bond peak and COO bond peak relative to the total area of C1s peaks in the XPS spectral profile; the relative intensities X and Y satisfy the following formulae (1) and (2):
38< X+Y< 65   (1)

−8.0< Y−X< 8.0   (2); and wherein

the circuit board shows a solder heat resistance when the circuit board is placed in a solder bath at a temperature of 290° C. for 60 seconds conforming to a method of JIS C 5012.

11 . The circuit board according to claim 10 , wherein a bonding strength between the adherend film and the adhesive film in accordance with JIS 05016- 1994 is 0.7 kN/m or higher.

12 . The circuit board according to claim 10 , wherein where there is a conductive material portion between the adherend and adhesive films, the surface area ratio of the conductive material portion existing between the adherend and adhesive films is less than 30%.

13 . The circuit board according to claim 10 , wherein difference in melting point between the adhesive film and the adherend film is 0° C. to 60° C.

Assignees

• Kuraray Co

Inventors

• Nakashima Takahiro
• Onodera Minoru
• Sunamoto Tatsuya

Classifications

• H05K2201/0141

  Liquid crystal polymer [LCP] · CPC title

• C09J5/06

  involving heating of the applied adhesive · CPC title

• C09J2467/006

  in the substrate · CPC title

• B29C66/45

  Joining of substantially the whole surface of the articles (methods or apparatus for laminating B32B37/00) · CPC title

• H05K1/032

  consisting of one material · CPC title