Vertical CSP Light-Emitting Unit With Exposed Chip Surfaces
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Solution Overview
Problem
The LED industry lacks a solution to manufacture vertical chips in Chip Scale Package (CSP) form and apply them flexibly to light-emitting devices due to limitations imposed by wire bonding positions in conventional CSP manufacturing processes.
Innovation Solution
A light-emitting unit with a light-emitting chip surrounded by an optical encapsulant, where the top and bottom surfaces are exposed, allowing die-bonding to a substrate via a connection pad and wire bonding to another circuit via a conductive wire, while the side surface is encapsulated, enhancing yield and light emission performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional CSP manufacturing process is used with flip-chip technology, then five sides of the flip chip can be encapsulated, but vertical chips cannot be manufactured due to wire bonding position limitations
Solution Approach 1:
The patent inverts the conventional encapsulation approach by exposing the top and bottom surfaces of the light-emitting chip while encapsulating only the surrounding side surface. This inversion allows wire bonding to be performed on the exposed top surface while maintaining the structural benefits of encapsulation, thereby enabling vertical chip configuration in CSP form factor.
Solution Approach 2:
The patent segments the encapsulation coverage to selectively expose specific surfaces (top and bottom) while encapsulating others (side surface). This selective segmentation allows the wire bonding point on the top surface to remain accessible for electrical connection, resolving the conflict between encapsulation and wire bonding requirements.
2Reliability
If the light-emitting chip is fully encapsulated, then protection is improved, but wire bonding and light extraction are hindered
Solution Approach 1:
The patent applies local quality by providing different encapsulation coverage to different surfaces of the light-emitting chip. The side surface receives full encapsulation for protection, while the top and bottom surfaces remain exposed to allow wire bonding and light extraction, respectively. This localized differentiation resolves the contradiction between protection and operational accessibility.
3Reliability
If the top surface of the light-emitting chip is covered by encapsulant, then protection is improved, but light extraction efficiency decreases
Solution Approach 1:
The patent applies local quality by providing different encapsulation coverage to different surfaces of the light-emitting chip. The side surface receives full encapsulation for protection, while the top and bottom surfaces remain exposed to allow wire bonding and light extraction, respectively. This localized differentiation resolves the contradiction between protection and operational accessibility.
Data Source
AI summary
A light-emitting unit and a light-emitting device are provided. The light-emitting unit includes a light-emitting chip and an optical encapsulant. The light-emitting unit has a top surface and a bottom surface opposite to each other in the thickness direction, and a surrounding side surface. The top surface and the bottom surface are surrounded by the surrounding side surface, and the light-emitting chip includes a connection pad located on the bottom surface and a wire bonding point that is located on the top surface. The surrounding side surface of the light-emitting chip is surrounded by the optical encapsulant, and the top surface and the bottom surface of the light-emitting chip are exposed outside of the optical encapsulant.