Etched Metallic Substrate Bumps for Fine-Pitch Interconnects
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Solution Overview
Problem
Conventional substrate manufacturing processes face challenges in achieving high density and fine gaps due to increased layers, which can lead to short circuits and thicker solder balls, making it difficult to reduce package thickness and enhance connection reliability.
Innovation Solution
A process involving a metallic substrate with conductive elements, dielectric layers, and patterned bumps formed by etching, which reduces manufacturing costs and improves connection reliability between bumps and conductive elements, using materials like reinforced carbon-carbon composite and copper for the dielectric and metallic layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of layers for the substrate is increased to meet functional requirements and enlarge the gap between contacts, then the gap between contacts is increased, but the thickness of the package cannot be reduced and the probability of short circuits increases
Solution Approach 1:
The patent transitions from using multiple substrate layers to achieve gap separation to using a three-dimensional bump structure that extends vertically from the substrate surface. This dimensional change allows contacts to be spaced closer together on the substrate plane while maintaining adequate separation through the vertical bump structure, thereby reducing package thickness while preventing short circuits.
2Reliability
If conventional solder balls with thickness of about 350 μm are used for electrical connection, then connection reliability is achieved, but the gap between solder balls must be increased to avoid short circuits, preventing high density and fine gap requirements from being met
Solution Approach 1:
The patent changes the dimensional parameters of the connection structure by creating bumps with controlled height and diameter ratios. The bumps have a height greater than their diameter, creating a vertical profile that provides electrical connection and mechanical support while occupying less horizontal space. This parameter change allows for finer gaps between contacts while maintaining connection reliability, enabling high-density contact arrangements.
3Ease of manufacture
If the body is patterned to form bumps by etching, then manufacturing cost is reduced and connection reliability is improved, but additional processing steps are required
Solution Approach 1:
The patent combines multiple functions into the bump structure formation process. The etching process that creates the bumps simultaneously defines the contact geometry, establishes electrical connection pathways, and creates the necessary mechanical support structure. This merging of functions into a single primary process reduces the need for separate manufacturing steps for each function, thereby reducing overall manufacturing cost despite the added etching step.
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
The process enables the creation of substrates with finer gaps and improved connection reliability, reducing the thickness of bumps compared to conventional solder balls and lowering manufacturing costs while minimizing the risk of short circuits.
Implementation Method 1
the body is patterned to form a plurality of bumps, and the bumps are electrically connected to the contacts by the conductive elements. The bumps are formed by etching the body
Data Source
AI summary
A process for manufacturing a substrate with bumps is provided. First, a metallic substrate having a body and a plurality of conductive elements is provided. Next, a first dielectric layer is formed on the body, and the conductive elements are covered by the first dielectric layer. Then, a plurality of circuits and a plurality of contacts are formed on a surface of the first dielectric layer, and the contacts are electrically connected to the conductive elements. Next, a second dielectric layer is formed on the surface of the first dielectric layer, and the circuits are covered by the second dielectric layer. Finally, the body is patterned to form a plurality of bumps, and the bumps are electrically connected to the contacts by the conductive elements. The bumps are formed by etching the body, so the connection reliability between bumps and conductive elements is desirable, and the manufacturing cost is reduced.