Resistive Contact Pad Structure That Eliminates External Resistors
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Solution Overview
Problem
The design of integrated circuit contact pads often requires external surface mount resistors, which increase the circuit area and cost, as they need to be coupled in series with the contact pads.
Innovation Solution
The integration of a resistive contact pad structure with a high resistance layer within the contact pad itself, eliminating the need for external resistors by forming a resistive contact pad with a lower and upper conductive layer and a resistor layer in between, which can be coupled to interconnect components like solder bumps or balls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external surface mount resistors are used with contact pads, then the required resistance levels are achieved, but the circuit area and cost increase
Solution Approach 1:
The patent combines the contact pad and resistor into a single integrated structure. The resistive contact pad structure includes a conductive layer forming the contact pad and a resistive layer formed over portions of the conductive layer, creating an inline resistor that is integrated with the contact pad itself. This eliminates the need for separate external resistors and reduces circuit area.
Solution Approach 2:
The contact pad structure is designed to serve multiple functions: it acts as both a contact pad for electrical connection and as a resistor with specific resistance values. The resistive layer is configured to provide the required resistance while the conductive layer provides the contact interface, allowing one structure to fulfill both roles that previously required separate components.
2Reliability
If external surface mount resistors are used with contact pads, then the required resistance levels are achieved, but the manufacturing cost increases
Solution Approach 1:
The patent combines the contact pad and resistor into a single integrated structure. The resistive contact pad structure includes a conductive layer forming the contact pad and a resistive layer formed over portions of the conductive layer, creating an inline resistor that is integrated with the contact pad itself. This eliminates the need for separate external resistors and reduces circuit area.
Solution Approach 2:
The resistance value is controlled by adjusting parameters of the resistive layer such as its thickness, material composition, and lateral dimensions. By modifying these parameters during the fabrication process, different resistance values can be achieved within the same integrated structure, providing manufacturing flexibility without requiring different external components.
Data Source
AI summary
An integrated circuit structure includes (i) a first layer including a first metal, (ii) a second layer above and in contact with the first layer, the second layer including a resistive material, and (iii) a third layer above and in contact with the second layer, the third layer including a second metal. In an example, the resistive material is different from one or both the first metal and the second metal. An interconnect component is above and in contact with the second layer. In an example, the interconnect component is a solder bump or a solder ball. In an example, a resistivity of the resistive material of the second layer is at least 20%, or at least 50% greater than a resistivity of each of the first and third layers. In an example, the resistive material includes a third metal different from the first and second metals and/or a metalloid.