Surface Leveling Tool With Anisotropic Copper Etching for TGV Planarization
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Solution Overview
Problem
The challenge in semiconductor manufacturing is to effectively planarize copper surfaces on glass cores with high aspect ratio through glass vias (TGVs) without causing over-etching, which is crucial for preventing reliability risks and reducing the need for costly chemical mechanical polishing.
Innovation Solution
An anisotropic etching tool with modules that use etch inhibitors and angled nozzles to selectively remove copper from recessed areas, preventing over-etching into the TGVs and maintaining the integrity of the glass core surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional isotropic copper etching approaches are used to remove copper recesses and planarize the surface, then copper removal is achieved, but significant etching into the TGVs occurs causing reliability risks
Solution Approach 1:
The patent applies different etching characteristics to different regions of the substrate. By making the etching process anisotropic (direction-dependent), copper is selectively removed from recessed areas while TGVs are protected from etching. This local differentiation in etching behavior allows surface planarization without compromising TGV integrity
Solution Approach 2:
The patent changes the fundamental parameter of etching anisotropy from isotropic to anisotropic. This parameter change transforms the etching process from one that uniformly attacks all exposed copper surfaces to one that selectively removes copper only in specific orientations, thereby planarizing the surface while preserving TGV structures
2Manufacturing precision
If significant copper is plated onto the glass core surface to fill high aspect ratio TGVs, then adequate TGV filling is achieved, but significant copper recesses form around the TGVs
Solution Approach 1:
The patent changes the etching anisotropy parameter to selectively remove the problematic copper recesses that formed during TGV filling. The anisotropic etching process targets copper in specific geometric configurations (recesses) while leaving other copper structures (TGV fills) intact, thereby correcting the shape defect without compromising the filling adequacy
3Manufacturing precision
If chemical mechanical polishing is used to planarize the copper surface, then surface flattening is achieved, but manufacturing cost increases significantly
Solution Approach 1:
The patent replaces the mechanical polishing process with a chemical etching process. Instead of using mechanical abrasion to remove material, the invention uses anisotropic chemical etching to selectively dissolve copper from recessed areas. This substitution eliminates the need for costly CMP equipment and processes while achieving the same surface planarization goal
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 solution effectively planarizes copper surfaces, reduces the risk of TGV cracking, and minimizes the need for chemical mechanical polishing, enabling reliable and cost-effective manufacturing of semiconductor packages with high aspect ratio TGVs.
Implementation Method 1
It is therefore important to have anisotropic copper etching solutions that can effectively flatten the recesses and remove copper on the surface
Implementation Method 2
discharging a chemical etchant at an acute angle towards the target to perform selective removal of the metal layer
Data Source
AI summary
The present disclosure is directed to a planarization tool having at least one module with a target holder for supporting a target with a metal layer, at least one of a plurality of etch inhibitor dispensers for discharging an etch inhibitor toward the target, and a plurality of nozzles for discharging a chemical etchant at an angle towards the target to perform selective removal of the metal layer for planarization of the target. In an aspect, the plurality of etch inhibitor dispensers and the plurality of nozzles may be combined as a single unit to discharge the chemical etchant and the etch inhibitor together. In another aspect, the plurality of etch inhibitor dispensers and the plurality of nozzles may be configured in a single module or separate modules.