Sensor Package Dummy Tracks for Overmoulding Pressure Protection
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Solution Overview
Problem
Existing sensor packaging methods are prone to errors and damage during the overmoulding process, particularly affecting conductive lines and protective layers, leading to signal degradation and increased production costs due to the pressure exerted by moulding inserts.
Innovation Solution
Incorporating dummy tracks on the sensor package that raise the surface level to match or exceed the height of conductive lines, distributing pressure from moulding inserts and preventing moulding compound ingress, while allowing conductive lines to remain undamaged and protected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If moulding compound is applied to encapsulate the sensor substrate, then the electronics are protected, but the conductive lines and protective layers may be damaged due to pressure from the moulding insert
Solution Approach 1:
Dummy tracks are added to the sensor substrate before the moulding process to pre-position pressure reception areas. These dummy tracks are strategically placed to intercept and absorb the pressure from the moulding insert before it can reach and damage the conductive lines and protective layers, thereby preventing mechanical damage while maintaining connection reliability
Solution Approach 2:
The dummy tracks serve as an intermediary element between the moulding insert and the conductive lines. They act as a buffer that receives and distributes the mechanical pressure from the moulding insert, protecting the vulnerable conductive lines and protective layers from direct contact with the pressurizing insert during the moulding process
2Adaptability or versatility
If the sensing element is exposed to receive stimulation, then the sensor function is maintained, but the conductive lines are vulnerable to damage during moulding
Solution Approach 1:
The sensor substrate surface is segmented into functional zones: exposed sensing areas that maintain sensing capability and protected areas where dummy tracks are positioned to receive moulding pressure. This segmentation allows the sensing element to remain exposed for proper stimulation reception while the dummy tracks provide localized protection for conductive lines in specific high-pressure zones
Solution Approach 2:
Dummy tracks are positioned as intermediary structures between the moulding insert and the conductive lines in regions where the sensing element must remain exposed. These dummy tracks intercept pressure in a controlled manner, allowing the sensing areas to stay accessible while protecting the underlying conductive infrastructure
3Productivity
If additional protection structures are added to protect conductive lines, then manufacturing yield improves, but device complexity increases
Solution Approach 1:
The dummy tracks are merged with the existing conductive line structure and can be formed using the same metallization processes. By combining the protective dummy tracks with the functional conductive elements in a single integrated substrate structure, the solution improves production yield without significantly increasing device complexity or requiring additional manufacturing steps
Data Source
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AI summary
A sensor package comprises an active element with a first region and an opposite second region. The first region includes a sensing structure. The second region comprises at least one contact pad. A moulding compound encapsulates the second region and not the first region. The active element comprises at least one conductive line for routing signals from the sensing structure to the contact pad. The projection of the conductive line over the active element corresponds to a portion of the external surface of the active element. The active element comprises at least one dummy track providing a protrusion thereby raising a portion of the surface of the active element to at least the same height as the portion corresponding to the conductive line. These protrusions can receive mechanical pressure from a moulding insert applied during manufacture, relieving pressure over the portion of the surface including the conductive lines.