Sensor Topside Wirebonding Using Bumped Contact Pads
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Solution Overview
Problem
Existing optical systems for biological or chemical research face challenges in locating electrical contacts on the active surface of sensors without damaging them during fabrication, particularly in flow cells used for sequencing-by-synthesis (SBS) or cyclic-array sequencing, as processes like coating and polishing can alter the shape of top-side contact pads and be corrosive to nanowells.
Innovation Solution
A method and apparatus for enabling topside bonding to sensors on dies by forming metal bumps on electrical contacts accessible on the upper surface, which are then wire-bonded to additional contacts, preserving the integrity of the active surface and nanowells through processes like removing oxide layers, applying seed layers, and electroplating metal layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electrical contacts are located on the active surface of the sensor, then ease of manufacture and cost effectiveness are improved, but the fabrication process damages the electrical contacts
Solution Approach 1:
The patent applies preliminary action by forming a protective oxide layer on the electrical contacts before the coating and polishing processes. This oxide layer is formed in advance to protect the underlying metal contacts from damage during subsequent fabrication steps, allowing the contacts to survive the manufacturing process while maintaining their electrical functionality.
Solution Approach 2:
The patent applies preliminary anti-action by creating a protective oxide barrier that prevents harmful interactions between the fabrication processes (coating and polishing) and the electrical contacts. The oxide layer acts as a protective barrier that counteracts the damaging effects of the subsequent manufacturing steps.
2Manufacturing precision
If coating and polishing processes are applied to the sensor surface, then manufacturing precision is improved, but the electrical contacts are damaged
Solution Approach 1:
The patent applies the intermediary principle by introducing an oxide layer as a mediator between the electrical contacts and the coating/polishing processes. This oxide layer serves as a protective intermediate structure that allows the manufacturing processes to proceed with high precision while preventing direct damage to the underlying electrical contacts.
3Device complexity
If electrical contacts are positioned adjacent to the active surface, then device complexity is reduced, but wire-bonding becomes difficult
Solution Approach 1:
The patent applies preliminary action by forming protruding oxide structures on the electrical contacts before wire-bonding. These pre-formed oxide protrusions create accessible bonding surfaces that make wire-bonding feasible even when contacts are positioned adjacent to the active surface, thus maintaining low device complexity while enabling successful wire-bonding.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for efficient and reliable electrical connectivity on the top surface of sensors, maintaining the functionality of nanowells and enabling processes like SBS without the complexity of through-silicon vias, while being compatible with existing fabrication methods.
Implementation Method 1
forming a seed layer over the upper surface of the die
Implementation Method 2
electroplating a metal layer over the exposed seed layer
Data Source
AI summary
Provided herein include various examples of an apparatus, a sensor system and examples of a method for manufacturing aspects of an apparatus, a sensor system. The method may include forming bumps on a surface of one or more electrical contacts, where the one or more electrical contacts are accessible on an upper surface of a die, where the die is oriented on a substrate, and where the electrical contacts comprise bonding pads. The method may also include coupling one or more additional electrical contacts to the one or more electrical contacts, where the coupling comprises wire-bonding each additional electrical contact of the additional electrical contacts to one of the one or more electrical contacts accessible on the upper surface of the die, via a portion of the bumps on the surface of the one or more electrical contacts, thereby forming wire-bonded connections.