Laminate, and element comprising substrate manufactured using same

Patent metadata

Field	Value
Publication number	US-10035883-B2
Application number	US-201414422495-A
Country	US
Kind code	B2
Filing date	Apr 8, 2014
Priority date	Apr 9, 2013
Publication date	Jul 31, 2018
Grant date	Jul 31, 2018

Abstract

The present invention relates to a laminate and a device fabricated using the laminate. The laminate includes a first polyimide resin layer between a carrier substrate and a second polyimide resin layer, wherein the first polyimide resin layer has a coefficient of thermal expansion (CTE) equal to or lower than the CTE of the second polyimide-based resin layer at a temperature of 100 to 200° C., and the adhesive strength of the first resin layer to the second resin layer decreases when a physical stimulus causing no chemical changes in the first resin layer is applied to the laminate. According to the present invention, the flexible substrate can be easily separated from the carrier substrate without the need for further processing such as laser or light irradiation. Therefore, the use of the laminate facilitates the fabrication of the device having the flexible substrate. The device may be, for example, a flexible display device. In addition, the device can be prevented from deterioration of reliability and occurrence of defects caused by laser or light irradiation. This ensures improved characteristics and high reliability of the device.

First claim

The invention claimed is:

1. A laminate for cutting and peeling comprising:
a carrier substrate;
a first polyimide film disposed directly on top of at least one surface of the carrier substrate; and
a second polyimide film disposed on the first polyimide film,
wherein the first polyimide film has a coefficient of thermal expansion (CTE) equal to or lower than the CTE of the second polyimide film at a temperature of 100 to 200° C., and
wherein the adhesive strength of the first polyimide film to the second polyimide film decreases when the second polyimide film in laminate is cut to expose cross-sectional surfaces of the second polyimide film, and
wherein the second polyimide film is adapted to be peeled from the first polyimide film.

2. The laminate according to claim 1 , wherein the difference between the coefficients of thermal expansion (CTE) at a temperature of 100 to 200° C. of the first and second polyimide films is 60 ppm/° C. or less.

3. The laminate according to claim 1 , wherein the first polyimide film has an adhesive strength of at least 1 N/cm to the second polyimide film before the laminate is cut, and has a peel strength not greater than 0.3 N/cm from the second polyimide film after the laminate is cut.

4. The laminate according to claim 1 , wherein the first polyimide film comprises a first polyimide resin that has a similarity score not greater than 0.5, as calculated by Equation 1:

Similarity
⁢

⁢
score

=

α
FIT

⁡

(

k
1

×

Ls

dianhydride
,
i

+

k
2

×

Ls

diamine
,
j

)

0
k

[

Equation
⁢

⁢
1

]

where
Ls dianhydride,i =Exp[− k 3 ×Coeff i ]×V i y 0

Ls diamine,j =Exp[− k 4 ×Coeff j ]×V j y 0

k 0 =2.00,
y 0 =−1.00,
k 1 =206.67,
k 2 =124.78,
k 3 =3.20,
k 4 =5.90,
Coeff i and Coeff j are molecular asphericities calculated from the structures of dianhydride i and diamine j as monomers of the polyimide, respectively, using ADRIANA.Code (Molecular Networks GmbH),
V i and V j are McGowan volumes calculated from the structures of dianhydride i and diamine j as the monomers, respectively, using ADRIANA.Code (Molecular Networks GmbH), and
α FIT is 1.0 if exp (−4.0×|Coeff i −Coeff j |)+0.08<0.90 and is a constant from 0.1 to 0.95 if exp (−4.0×|Coeff i −Coeff j |)+0.08≥0.90.

5. The laminate according to claim 1 , wherein the first polyimide film comprises a first polyimide resin that has an imidization degree of 60% to 99% when the imidization degree is defined as the percentage of the integrated intensity of the CN bands observed at 1350 to 1400 cm −1 or 1550 to 1650 cm −1 in the IR spectrum after a composition comprising a polyamic acid resin is applied and imidized at a temperature of 200° C. or above with respect to the integrated intensity (100%) of the CN bands observed in the same wavelength range after the composition is imidized at a temperature of 500° C. or above.

6. The laminate according to claim 1 , wherein the first polyimide film comprises a first polyimide resin that has a glass transition temperature of 200° C. or above.

7. The laminate according to claim 1 , wherein the first polyimide film is formed by applying a composition including a polyimide resin or a precursor thereof on the carrier substrate and curing the composition at a temperature equal to or 0 to 200° C. lower than the curing temperature of the second polyimide film.

8. The laminate according to claim 1 , wherein the first polyimide film comprises a first polyimide resin prepared by reacting an aromatic tetracarboxylic dianhydride of Formula 1:

wherein A is a tetravalent aromatic organic group of Formula 2a or 2b:

wherein R 11 is a C 1 -C 4 alkyl or C 1 -C 4 haloalkyl group, a is an integer from 0 to 3, and b is an integer from 0 to 2,

wherein R 12 to R 14 are each independently a C 1 -C 4 alkyl or C 1 -C 4 haloalkyl group, c and e are each independently an integer from 0 to 3, d is an integer from 0 to 4, and f is an integer from 0 to 3, with an aromatic diamine compound having a linear structure to prepare a polyamic acid, and curing the polyamic acid at a temperature of 200° C. or above.

9. The laminate according to claim 8 , wherein the aromatic diamine compound is represented by Formula 4a or 4b:

wherein R 21 is a C 1 -C 10 alkyl or C 1 -C 10 haloalkyl group and 1 is an integer from 0 to 4,

wherein R 22 and R 23 are each independently a C 1 -C 10 alkyl or C 1 -C 10 haloalkyl group, X is selected from the group consisting of —O—, —CR 24 R 25 —, —C(═O)—, —C(═O)O—, —C(═O)NH—, —S—, —SO—, —SO 2 —, —O[CH 2 CH 2 O] q —, C 6 -C 18 monocyclic and polycyclic cycloalkylene groups, C 6 -C 18 monocyclic and polycyclic arylene groups, and combinations thereof, R 24 and R 25 are each independently selected from the group consisting of a hydrogen atom, C 1 -C 10 alkyl groups, and C 1 -C 10 haloalkyl groups, q is an integer of 1 or 2, m and n are each independently an integer from 0 t

Assignees

• Lg Chemical Ltd

Inventors

• Jeong Hye Won
• Kim Kyungjun
• Kim Kyoung Hoon
• Park Chan Hyo
• Shin Bora
• Lee Seung Yup
• Park Hangah
• Lee Jinho
• Im Mira

Classifications

• H10P72/7412

  the auxiliary support including means facilitating the separation of a device or wafer from the auxiliary support · CPC title

• B32B27/36

  comprising polyesters · CPC title

• B32B27/308

  comprising acrylic (co)polymers · CPC title

• B32B2457/206

  Organic displays, e.g. OLED · CPC title

• B32B7/12

  using interposed adhesives or interposed materials with bonding properties · CPC title