Wafer-Level Optical Proximity Sensor Packaging
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Solution Overview
Problem
Current optical proximity sensor packaging involves numerous components and complex processes, leading to high manufacturing costs, increased cycle times, and yield losses.
Innovation Solution
The processing of optical proximity sensors is performed at the wafer level, eliminating the need for a separate base substrate and integrating the light source die with the light detector die, which acts as the base, thereby reducing the bill of materials and package footprint, and using wafer level chip scale packaging for miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional packaging with separate base substrate and multiple components is used, then device functionality is achieved, but manufacturing cost increases and productivity decreases
Solution Approach 1:
The patent merges the base substrate function with the light detector die by integrating the light detector sensor areas directly into the wafer substrate. This eliminates the need for a separate base substrate and reduces the number of packaging components, directly resolving the contradiction between manufacturing efficiency and packaging complexity.
Solution Approach 2:
The wafer substrate serves multiple functions simultaneously: it acts as the base substrate, provides mechanical support, enables wafer-level processing for high-volume manufacturing, and integrates the light detector sensor areas. This multi-functionality reduces packaging complexity while maintaining manufacturing efficiency.
2Productivity
If wafer level processing is implemented, then productivity and yield improve, but manufacturing precision requirements increase
Solution Approach 1:
The patent performs light detector die attachment and encapsulant application at the wafer level before dicing. This preliminary action allows parallel processing of multiple devices simultaneously, improving throughput while the standardized wafer-level processes maintain consistent precision across all devices.
Solution Approach 2:
The wafer-level integration allows the light detector sensor areas to be directly formed on the wafer substrate without requiring separate die attachment steps. This self-integration approach simplifies the manufacturing process and reduces the cumulative precision requirements while maintaining high productivity.
3Ease of manufacture
If multiple separate components are used, then device functionality is achieved, but bill of materials cost increases
Solution Approach 1:
The patent combines multiple separate components (base substrate, light detector die, encapsulant) into an integrated wafer-level structure where the light detector sensor areas are directly formed on the wafer substrate. This merging reduces the bill of materials by eliminating separate components while maintaining all necessary functions.
Solution Approach 2:
The patent extracts the base substrate function from a separate component and integrates it directly into the wafer substrate that holds the light detector sensor areas. This extraction and integration approach reduces the total number of components and associated costs while preserving the structural and functional requirements.
Data Source
AI summary
Optoelectronic devices (e.g., optical proximity sensors), methods for fabricating optoelectronic devices, and systems including optoelectronic devices, are described herein. An optoelectronic device includes a light detector die that includes a light detector sensor area. A light source die is attached to a portion of the light detector die that does not include the light detector sensor area. An opaque barrier is formed between the light detector sensor area and the light source die, and a light transmissive material encapsulates the light detector sensor area and the light source die. Rather than requiring a separate base substrate (e.g., a PCB substrate) to which are connected a light source die and a light detector die, the light source die is connected to the light detector die, such that the light detector die acts as the base for the finished optoelectronic device. This provides for cost reductions and reduces the total package footprint.