3D IC Backside Power Delivery Network Fabrication
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Solution Overview
Problem
The fabrication of complex mobile application devices faces control issues during backside processing due to their small form factor, particularly in thinning semiconductor substrates, which is challenging and inefficient, especially with the increased number of interconnect levels required for modern electronic devices.
Innovation Solution
A 3D IC device integration method that avoids backside grinding by using a material separation layer and a temporary carrier wafer, enabling precise control of the front side thickness through a layer-transfer process, and forming a backside power delivery network before the front side process, thus eliminating the need for an etch stop layer and reducing thermal damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If backside grinding is used to thin semiconductor substrates, then substrate thickness is reduced, but manufacturing precision and control are compromised
Solution Approach 1:
The patent applies preliminary action by forming the material separation layer at a predetermined depth within the substrate before any thinning operations. This pre-positioned layer serves as a reference marker that enables precise thickness control during subsequent processing steps, allowing the substrate to be thinned to the exact desired thickness without compromising manufacturing precision.
Solution Approach 2:
The patent introduces a material separation layer as an intermediary element between the substrate and the thinning process. This layer acts as a mediator that facilitates precise thickness measurement and control, enabling accurate substrate thinning while maintaining manufacturing precision. The layer's known position and properties provide a reference framework for controlling the thinning operation.
2Manufacturing precision
If etch stop layer is used in substrate thinning, then thickness control is improved, but device complexity increases
Solution Approach 1:
The material separation layer performs multiple functions simultaneously: it serves as a depth reference marker, a separation plane for dicing operations, and a guide for thickness control during thinning. By consolidating these multiple functions into a single layer, the patent reduces fabrication process complexity while maintaining manufacturing precision, eliminating the need for separate etch stop layers and associated processing steps.
Solution Approach 2:
The patent applies local quality by creating a material separation layer with distinct properties at a specific location within the substrate. This localized layer has different material characteristics from the surrounding substrate, enabling it to serve as a unique reference point for thickness control and separation operations without affecting the overall substrate properties or requiring additional complex processes.
3Ease of manufacture
If conventional backside processing is used, then power delivery network can be formed, but thermal damage occurs to sensitive devices
Solution Approach 1:
The patent applies segmentation by separating the substrate processing into distinct stages: first forming the material separation layer and power delivery network structures, then using this layer as a protection barrier during subsequent thinning and processing operations. This segmentation allows the power delivery network to be formed and protected simultaneously, enabling manufacturing while preventing thermal damage to sensitive devices through the separation layer's protective function.
Data Source
AI summary
An integrated circuit (IC) package is described. The IC package includes a power delivery network. The IC package also includes a first die having a first surface and a second surface, opposite the first surface. The second surface is on a first surface of the power delivery network. The IC package further includes a second die having a first surface on the first surface of the first die. The IC package also includes package bumps on a second surface of the power delivery network, opposite the first surface of the power delivery network. The package bumps are coupled to contact pads of the power delivery network.