Yao Ting from Shengmei Semiconductor: The market prospects for front-end electroplating equipment are broad

On October 24, the 2021 Beijing International Microelectronics Symposium and IC WORLD Conference was held in Beijing. At the "Breakthrough and Innovation of Integrated Circuit Equipment" forum in the morning, Yao Ting, process manager of ACM Semiconductor Equipment (Shanghai) Co., Ltd., delivered a keynote speech on "The Application of Copper Interconnection Process in Integrated Circuits".

As the application driver chip technology develops towards smaller critical dimensions (CD), greater density, and lower unit device cost, it is necessary to introduce metal copper as an interconnect conductive material because metal copper can reduce chip energy consumption, bring higher packaging density, excellent anti-electromigration performance, and relatively fewer process steps.

According to Yao Ting, metallic copper is used as the conductive material in the dual Damascus process of integrated circuits, advanced packaging and three-dimensional stacking 3D TSV process.

The preparation of copper interconnects mainly uses the method of electrochemical plating (ECP), which usually fixes the silicon wafer on the fixture with the front side facing down, conducts electricity through the fixture, immerses the silicon wafer as a cathode in the plating solution, and deposits metal copper on the seed layer on the surface of the silicon wafer under the action of the electric field. However, when the chip process technology node enters 14nm and below, the process encounters major challenges.

Yao Ting said that the reduction in metal line width and the improvement in anti-reflection pose great challenges to electroplating bottom up (a filling method). For this reason, at the 14nm node and below, the copper content of the electroplating solution must be reduced, that is, 40g/L copper is replaced with 5g/L or even a lower 2.5g/L. In this way, in the initial stage of electroplating, the nucleation of copper electrodeposition can be better controlled, which is conducive to defect-free bottom up of electroplated copper. If it reaches 7nm and below, cobalt electroplating solution will be introduced. "Compared with copper, although the resistivity of cobalt is higher, after comprehensively considering the process requirements, cobalt has many advantages."

Yao Ting believes that by selecting appropriate additives, system concentrations and optimized current control, defect-free bottom up filling of cobalt can be achieved through the coordination of mass transfer and electrochemical reactions.

ACM Semiconductor has accumulated many years of experience in electroplating technology and started its layout in 1998. It has 67 patents and 182 patents pending. Its main core technologies include in-cavity flow field control, multi-anode power supply output control, system impedance control, silicon wafer clamps, etc.

In response to the above-mentioned electroplating process applications, ACM has developed four types of electroplating equipment, including dual Damascus plating equipment, three-dimensional stacking electroplating equipment, advanced packaging electroplating equipment (including two equipment models with and without gold plating), and third-generation semiconductor electroplating equipment.

Yao Ting made a prediction about the prospects of the global electroplating equipment market: as the number of 3D stacking and advanced packaging applications increases, the demand for front-end IC electroplating process equipment increases, and the overall size of the equipment market will increase to US$700 million.

In the domestic market, although it still mainly relies on foreign imports, the market share of domestic manufacturers is steadily increasing. In 2019, the sales of ACM's entire copper electroplating equipment was US$7 million, which increased to US$13 million in 2020, an increase of 85%. Yao Ting said: "In the future, ACM will continue to increase its market share and do its utmost for the development of domestic equipment."

It is worth mentioning that ACM Semiconductor brought its full range of products to the exhibition this time, and explained in detail its world-first SAPS, TEBO megasonic cleaning technology and Tahoe single-wafer tank combination cleaning technology, and demonstrated single-wafer back-side cleaning equipment, tank-type automatic cleaning equipment, single-wafer brush cleaning equipment and other cleaning equipment, as well as electroplating equipment, vertical furnace tubes and other series of classic best-selling products and many new products in 2021.