Optoelectronic Chip Packaging With Spacer-Defined Integrated Optics
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Solution Overview
Problem
Existing optoelectronic semiconductor devices require large external lenses for desired optical characteristics, leading to bulkiness and increased manufacturing costs, especially in chip-scale packages (CSPs) for applications like floor illumination and time-of-flight (ToF) sensors.
Innovation Solution
A method involving the use of a temporal spacer to protect the light-exit face of optoelectronic semiconductor chips, followed by forming a reflector that extends beyond the chip, and integrating a space-saving optical element such as a meta lens or micro lens array, allowing for miniaturization and simplified manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large external lenses are used to achieve desired optical characteristics, then optical performance is improved, but device size and bulkiness increase
Solution Approach 1:
The optical element is integrated directly into the chip-scale package structure, with the reflector extending beyond the chip and the optical element positioned above it. This nested arrangement allows the optical components to be contained within the compact CSP footprint rather than requiring separate external lenses, thereby achieving desired optical characteristics without increasing overall device volume.
Solution Approach 2:
The reflector is designed to extend beyond the chip in a lateral direction, creating a three-dimensional structure that allows the optical element to be positioned in a gap above the chip surface. This vertical dimensionality change enables compact optical integration without increasing the lateral footprint of the device.
2Reliability
If large external lenses are used, then optical characteristics are achieved, but manufacturing complexity and costs increase
Solution Approach 1:
The reflector and optical element are integrated as part of the chip-scale package structure itself, merging multiple functions (light reflection, light shaping, and protection) into a single compact unit. This eliminates the need for separate external lens assemblies and their associated mounting and alignment procedures, thereby simplifying manufacturing while achieving the desired optical characteristics.
Solution Approach 2:
The reflector serves multiple functions: it reflects light from the chip, provides a mounting structure for the optical element, and when combined with the temporal spacer, creates a protective framework during manufacturing. This multi-functionality reduces the number of separate components needed, simplifying the overall manufacturing process.
3Volume of moving object
If temporal spacer is applied and reflector is formed extending beyond chip, then space-saving optical integration is achieved, but manufacturing process complexity increases
Solution Approach 1:
The temporal spacer is applied to the chip surface before the reflector is formed. This preliminary action establishes the precise geometry and positioning framework for the subsequent reflector formation process, ensuring that the reflector extends beyond the chip in the correct configuration. This pre-positioning simplifies later manufacturing steps by providing built-in alignment references.
Solution Approach 2:
The temporal spacer acts as an intermediary element during manufacturing, serving as a temporary structure that defines the gap height and provides alignment references for forming the reflector and positioning the optical element. After the reflector is formed, the temporal spacer is removed, having fulfilled its mediating role in achieving precise geometric relationships without requiring complex external alignment procedures.
Data Source
AI summary
In an embodiment, a method for producing optoelectronic semiconductor devices includes applying a temporal spacer to protect a light-exit face of an optoelectronic semiconductor chip by applying a photoresist onto a first carrier, subsequently developing the photoresist in places thereby forming the temporal spacer and subsequently mounting the optoelectronic semiconductor chip onto a side of the temporal spacer facing away from the first carrier, forming a reflector in a lateral direction directly around the optoelectronic semiconductor chip and around the temporal spacer, subsequently removing the temporal spacer so that the reflector extends beyond the light-exit face and applying an optical element onto the reflector so that a gap exists between the light-exit face and a light-entrance face of the optical element.