Sensor Package Ground-Window Layout for Stronger Die Adhesion
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Solution Overview
Problem
The adhesion strength between a metalized-and-plated surface and die-attached epoxy in existing substrate-based electronic packages is affected by metal surface characteristics, and the thickness of the solder mask in optical sensor packages complicates design and manufacturing, increasing costs.
Innovation Solution
A sensor packaging method that includes forming windows in the upper protection layer of a substrate for ground electrodes, applying adhesive material, and attaching a sensor die to the substrate through this layer, enhancing adhesion strength by using non-conductive and conductive adhesive materials, and exposing the core material layer for additional adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sensor is directly attached to the metalized-and-plated surface, then the adhesion strength is affected by metal surface characteristics, but the design and manufacturing complexity increases due to solder mask thickness considerations
Solution Approach 1:
The patent introduces a non-conductive layer (solder mask or protective layer) as an intermediary between the sensor die and the substrate. This layer serves as a mediator that eliminates the direct dependency on metal surface characteristics for adhesion, while also simplifying design by providing a uniform attachment surface that doesn't require precise thickness considerations in the optical path.
Solution Approach 2:
The patent segments the attachment function from the electrical function by using a non-conductive layer for mechanical adhesion while maintaining separate ground electrode pathways. This segmentation allows the adhesion mechanism to be independent of the metalized surface properties, resolving the contradiction between adhesion strength and design complexity.
2Ease of manufacture
If the sensor is directly attached to the metalized-and-plated surface, then the attachment process is simplified, but the adhesion strength becomes dependent on metal surface characteristics
Solution Approach 1:
The non-conductive layer acts as an intermediary that provides a consistent, controllable surface for adhesive attachment. This mediator layer decouples the adhesion process from the variable metal surface characteristics, allowing for reliable attachment without being constrained by metal surface preparation requirements.
Solution Approach 2:
The patent changes the surface property parameter from metal surface characteristics to non-conductive layer surface characteristics. This parameter change enables more predictable and controllable adhesion behavior, as the non-conductive layer can be engineered to provide optimal surface properties for adhesive bonding independent of the underlying metal surface.
Data Source
AI summary
A sensor packaging method and a sensor package are provided. The method includes: providing a substrate having upper and lower board surfaces, in which the upper board surface has a die-bonding region. The substrate includes a core material layer, an upper metal layer, and an upper protection layer, a first window is formed to penetrate the upper protection layer and located at a periphery of the die-bonding region, and the first window is opened for a first ground electrode connected to a first ground portion. The method further includes: performing a dispensing step to apply an adhesive material on the upper board surface in at least a portion of the die-bonding region; and attaching a sensor die to the substrate through the adhesive material, in which the sensor die is disposed in the die-bonding region and has a first ground pin electrically connected to the first ground electrode.