Planarized Integration Structure for Warped Packaging Substrates
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Solution Overview
Problem
Non-planar bonding mismatches and dimensional distortions occur when integrating circuit dies with warped packaging substrates, due to the substrate's convex shape causing uneven surfaces and making it difficult to achieve reliable electrical connections.
Innovation Solution
A method involving the formation of conductive pillars on a warped packaging substrate, placement of bridging dies with conductive interconnects between pillars, and a cover layer to planarize the features, followed by attaching top dies using conductive bonding contacts, ensuring all surfaces are coplanar for uniform electrical bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a warped packaging substrate with convex meniscus shape is used, then the substrate can accommodate thermal expansion and provide structural support, but non-planar bonding mismatches and dimensional distortions occur when integrating circuit dies
Solution Approach 1:
The patent applies preliminary action by forming a planarization layer over the warped packaging substrate before integrating the circuit dies. This planarization layer is deposited in advance to create a flat bonding surface, preventing non-planar bonding mismatches and dimensional distortions that would otherwise occur due to the substrate's convex meniscus shape. The bridging dies are also strategically placed beforehand to establish a planar reference surface.
Solution Approach 2:
The patent uses an intermediary approach by introducing a planarization layer as a mediator between the warped packaging substrate and the circuit dies. This intermediate layer compensates for the substrate's non-planarity, allowing precise bonding alignment while maintaining the substrate's structural support capabilities. The bridging dies serve as additional intermediaries to establish coplanar bonding surfaces.
2Reliability
If conductive pillars are formed directly on the warped substrate surface, then electrical connections can be established, but uneven surfaces make it difficult to achieve reliable electrical connections
Solution Approach 1:
The patent applies preliminary action by forming a planarization layer over the conductive pillars before placing the bridging dies. This planarization step creates uniform coplanar surfaces for all conductive features, ensuring reliable electrical connections. The conductive pillars are formed first, then planarized, allowing subsequent dies to bond reliably to all features at the same elevation.
3Adaptability or versatility
If bridging dies are placed between conductive pillars on a non-planar surface, then electrical interconnections can be established, but dimensional mismatches and distortions occur during integration
Solution Approach 1:
The patent applies preliminary action by strategically placing bridging dies between conductive pillars before forming the planarization layer. These bridging dies serve as reference elements that help establish a planar bonding surface. The planarization layer is then formed over all features, ensuring that the bridging dies and conductive pillars are at the same elevation, thereby preventing dimensional mismatches and distortions during subsequent die integration.
4Stability of the object's composition
If the substrate surface is left in its original convex shape, then the substrate maintains its thermal expansion properties, but coplanarity of bonding surfaces cannot be achieved
Solution Approach 1:
The patent applies preliminary action by forming a planarization layer over the warped substrate surface before integrating circuit dies. This planarization layer is deposited in advance to create a flat bonding surface, achieving coplanarity of all bonding features while allowing the underlying substrate to maintain its convex shape and thermal expansion accommodation properties.
Solution Approach 2:
The patent applies dimensionality change by adding a planarization layer in the vertical dimension to compensate for the substrate's surface warpage. This additional layer provides a coplanar bonding surface without altering the substrate's original shape or its ability to accommodate thermal expansion. The solution moves from trying to flatten the substrate to creating a flat surface above it.
Data Source
AI summary
A method of forming a planarized integration structure is provided. The method includes forming at least two conductive pillars on a packaging substrate, wherein the packaging substrate has a positive or convex meniscus shape. The method further includes placing a bridging die on the packaging substrate between an adjacent pair of the at least two conductive pillars, wherein the bridging die includes one or more conductive interconnects. The method further includes forming a cover layer on the substrate over the at least two conductive pillars and the bridging die, and planarizing the conductive pillars and the one or more conductive interconnects.