Bonding structure and flexible device
A bonding structure comprising a contact pad, an anisotropic conductive film (ACF) and a contact structure is provided. The contact pad includes at least one recess, wherein a thickness of the contact pad is T, and a width of the at least one recess is B, The ACF is disposed on the contact pad and includes a plurality of conductive particles; each of the conductive particles is disposed in the at least one recess. A diameter of the conductive particles is A, and A is larger than B and T and satisfies B≦2(AT−T 2 ) 1/2 . The contact structure is disposed on the ACF and electrically connected to the contact pad via the conductive particles. The disclosure also provides a flexible device including a substrate, a patterned insulating layer, at least one contact pad, ACF, and a contact structure.
1. A bonding structure, comprising:
a contact pad, comprising at least one recess, wherein a thickness of the contact pad is T and a width of the at least one recess is B;
an anisotropic conductive film, disposed on the contact pad and comprising a plurality of conductive particles, each of the conductive particles is disposed in the at least one recess, wherein a diameter of each of the conductive particles is A, and A is larger than B and T, and satisfies B≦2(AT−T 2 ) 1/2 ; and
a contact structure, disposed on the anisotropic conductive film and electrically connected to the contact pad via the conductive particles.
2. The bonding structure according to claim 1 , wherein the anisotropic conductive film further comprises an insulator, the plurality of conductive particles are disposed within the insulator.
3. The bonding structure according to claim 1 , wherein the at least one recess has an aperture pattern.
4. The bonding structure according to claim 3 , wherein the aperture pattern is a round aperture, a triangular aperture or a polygonal aperture.
5. The bonding structure according to claim 3 , wherein the aperture pattern is arranged in an array on the contact pad.
6. The bonding structure according to claim 3 , wherein the aperture pattern is distributed irregularly on the contact pad.
7. The bonding structure according to claim 1 , wherein the at least one recess has a striped pattern.
8. The bonding structure according to claim 1 , wherein the at least one recess is a through hole structure or a blind via structure.
9. A flexible device, comprising:
a substrate, comprising a bonding region and a wire region;
a patterned insulating layer, disposed on the substrate and located in the bonding region;
at least one contact pad, covering the patterned insulating layer such that a surface of the at least one contact pad comprises at least one recess;
an anisotropic conductive film, disposed on the at least one contact pad and comprising a plurality of conductive particles, each of the conductive particles disposed in the at least one recess, wherein a thickness of the contact pad is T, a width of the at least one recess is B, and a diameter of each of the conductive particles is A, wherein A is larger than B and T and satisfies B≦2(AT−T 2 ) 1/2 ; and
a contact structure, disposed on the anisotropic conductive film and connected to the contact pad via the conductive particles.
10. The flexible device according to claim 9 , wherein the anisotropic conductive film further comprises an insulator, the plurality of conductive particles are disposed within the insulator.
11. The flexible device according to claim 9 , wherein the patterned insulating layer comprises a 3D mesh pattern.
12. The flexible device according to claim 11 , wherein the 3D mesh pattern comprises a plurality of vertical portions and a plurality of horizontal portions, the vertical portions and the horizontal portions are staggered to constitute the 3D mesh pattern.
13. The flexible device according to claim 11 , wherein the patterned insulating layer is further extended into the wire region.
14. The flexible device according to claim 11 , wherein a material of the 3D mesh pattern comprises a photoresist material or an oxide material.