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Electrochemical Deposition of Copper
As the miniaturization of interconnection technologies requires reduced geometrical and increased electrical demands on the signal path, the variety of applications and the increased demands on electrochemical deposited copper became more challenging.
But integrating electrodeposited copper for wafer level packaging provides several advantages, as there are: Fine pitch application, effective signal transmission material and thermal stability.
Chemistry
The copper deposition process for redistribution layer (RDL) is a high precision pattern plating process for fine line and pad geometries within photo resists structures. Moderate deposition speeds fill these structures up to 15µm of thickness. Major criteria is the within wafer and die uniformity of less then 10% surface deviation.
The thickness for copper pillar or stud structures is usually estimated with 65µm. Therefore the highest applicable deposition speed is providing the advantage of increased productivity. Here the Atotech copper deposition process is designed as high speed pattern plating process.
Equipment
Atotech's electrolytic copper deposition processes can be used on both major semiconductor equipment concepts – the fountain tool concept and the vertical processing concept. Corresponding information on the best know process conditions are the fundaments during the qualification and implementation at customer scale.
Advantages
The copper deposition process with Atotech’s specific organic and inorganic set up is providing the advantages of:
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Advanced geometry filling with optimized organic additives | |
Available for inert and soluble anode technology | | Superiour filling performance in DC plating mode |
| Advanced surface distribution for wide current density range |
| Global presence of Atotech |
| The Atotech Spherolyte™ RDL and Spherolyte™ Pillar processes are providing for various aspect ratio and deposition speed conditions the best known method, in order to achieve the industry targets on electrolytic deposited copper quality. |
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RDL structure
(Copper pad and interconnect) |
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| Copper Pillar Area Array |
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