Optoelectronic device chip having a composite spacer structure and method making same
An optoelectronic device chip, and a method for making the chip, are disclosed. The chip comprises a device substrate, an optically transparent upper substrate, and a composite spacer layer which includes an adhesive material and a plurality of particles dispersed in said adhesive material. The distance between the device substrate and the upper substrate is controlled by the thickness of the composite spacer layer so that the variation is within the depth of focus of optical system.
1. A method for making an optoelectronic device chip, comprising:
providing an upper package layer;
providing a composite material at predetermined locations on the bottom surface of said upper package layer;
providing a device substrate, on which an optoelectronic device has been made;
bonding said upper package layer with said device substrate; and
transforming said composite material to become a solid structure,
wherein said composite material includes an adhesive material and a plurality of particles dispersed in said adhesive material, and wherein the distance between the bottom surface of said upper package layer and the top surface of said device substrate is defined by the diameter of one of said particles.
2. The method as claimed in claim 1 , wherein the distance between the bottom surface of said upper package layer and the top surface of said device substrate is in a range at a target distance plus or minus the depth of focus of an associated optical system.
3. The method as claimed in claim 1 , wherein said adhesive material comprises a photopolymer material curable under ultra-violate light, and said particles are made of glass, polymers or resins.
4. The method as claimed in claim 1 , wherein said solid structure is anisotropic conductive.
5. The method as claimed in claim 4 , wherein adhesive material is an insulating adhesive material, and said particles are conductive.
6. The method as claimed in claim 4 , further comprising:
providing a through-hole in said upper package layer; and
forming a conductive layer at least in said through-hole, to electrically connect with said solid structure.
7. The method as claimed in claim 6 , further comprising; providing a conductive pad between said composite material and the bottom surface of said upper package layer, and wherein said conductive layer electrically connects with said solid structure via said conductive pad.