Sensor Chip Protection via Inverted Mounting and Through-Silicon Vias
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Solution Overview
Problem
The handling of sensor chips during processing is challenging due to the exposure of both sides containing sensitive elements, making them difficult to manage and increasing the risk of damage, especially when the sensing element needs to be protected from contact with supports during manufacturing and operation.
Innovation Solution
A sensor chip design featuring a substrate with a sensing element and conductors on the front side and contact pads on the back side, with through-silicon vias for electrical connection, and a spacer on the front side to protect the sensing element during manufacturing and operation, allowing the chip to be flipped and mounted with its back side facing the support, thus preventing direct contact and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor chip is mounted with the sensing element facing the circuit board, then electrical connection is achieved, but the sensing element cannot access the measurement environment and may be damaged
Solution Approach 1:
The sensor chip is inverted during mounting so that the back side with contact pads faces the circuit board while the sensing element on the front side faces the measurement environment. This inversion resolves the contradiction by allowing both electrical connection and environmental access simultaneously
Solution Approach 2:
Through-silicon vias act as intermediaries to conduct electrical signals from the sensing element on the front side through the substrate to the contact pads on the back side, enabling electrical connection without requiring the sensing element to contact the circuit board directly
2Ease of operation
If through-silicon vias are used to mount the sensor chip with the back side facing the circuit board, then the sensing element can access the measurement environment, but both sides of the chip contain exposed elements making handling difficult
Solution Approach 1:
The front side of the substrate is selectively modified by removing material in specific regions to create recesses that expose only the sensing element, while the back side contact pads remain exposed for electrical connection. This localized differentiation allows the chip to be held by the spacer without exposing the sensing element to damage
3Ease of operation
If the front side of the substrate is removed to expose the sensing element, then the sensing element can be accessed, but the sensing element becomes vulnerable to damage during handling
Solution Approach 1:
A spacer is deposited on the front side of the substrate beforehand to provide mechanical support and protection. During handling, the chip is held by the spacer rather than the exposed sensing element, preventing damage while maintaining environmental access
Data Source
Figure 1a~1g
Figure 2a~2h
Figure 2i~2l
AI summary
In a method for manufacturing a sensor chip a spacer (3) is arranged at the front side (11) of a substrate (1) at which front side (11) a sensing element (2) is arranged, too. Holes (14) are etched for building vias (15) extending through the substrate (1) between the front side (11) of the substrate (1) and its back side (12). After etching, the holes (14) are filled with conductive material to complete the vias (15). The spacer (3) provides protection to the sensing element (2) and the sensing chip throughout the manufacturing process.