China Needs to Produce More of Certain Wet Electronic Chemicals for Itself

By Quan Meizi, Zhu Datong, China Electronics Materials Industry Association

In the late 1960s, China began to develop electronic-grade high purity special chemical reagents for the manufacture of integrated circuits, used in removing photoresist after photolithographic processing, in wet processes like cleaning, etching, doping and developing, in wafer surface treatments, and in removing film for the front working procedure production. They are called wet electronic chemicals or ultra-pure chemicals. The wet electronic chemicals sector was thus created.
Wet electronic chemicals must meet high requirements for quality, use in production, environmental cleanliness and rapid product upgradability. The national government places great importance on development of this sector. In October 2014, the “Action Plan for Innovation and Development in New Display Industry during 2014-2016”, jointly developed by the Ministry of Industry and Information Technology of China (MIIT) and the National Development and Reform Commission (NDRC) put forward a policy position on “the promotion of the development and industrialization of high-purity (over 99.999%) ammonia, silane, chlorine and titanium tetrafluoride gas, as well as electronic chemicals such as developers, etching solutions and acidic chemical reagents” .
Wet electronic chemicals are divided into general-purpose wet electronic chemicals and functional wet electronic chemicals, according to their composition and technological application. The main general-purpose wet electronic chemicals are hydrogen peroxide, hydrofluoric acid, sulfuric acid, phosphoric acid, hydrochloric acid, nitric acid, ammonia, ammonium hydroxide, ammonium fluoride, potassium hydroxide and acetic acid. The main functional wet electronic chemicals are developer, stripping liquid, cleaning liquid and etching solution.

Explosive increase of capacity

China’s research on ultra-pure reagents (including wet electronic chemicals) started in the mid 1970s. During 2006-2009, China's wet electronic chemicals sector changed dramatically in the distribution of enterprises and the market pattern. Some established enterprises and research institutes (being mainly distributed in northern China) withdrew from the ranks of the sector. At the same time, industrial clusters for the production of wet electronic chemicals gradually formed in Jiangyin and Suzhou, and a number of new private enterprises and joint ventures emerged. Since the end of 2009, demand for wet electronic chemicals in new markets (flat panel displays, solar cells, etc.) has expanded rapidly, production capacity has grown quickly, and output has increased explosively.
At present, China hosts more than 40 wet electronic chemicals producers, of which more than 20 have considerable production scale. The proportion of exclusively foreign-funded enterprises is very small – most producers are domestic enterprises or joint ventures.
China’s actual output of wet electronic chemicals increased from less than 5 kt in the early 21st century to 46 kt in 2008. During 2009-2014, due to the growth of demand for new types of products such as solar cells and flat panel displays, the production capacity of China’s wet electronic chemicals sector has grown rapidly.
In 2014, the demand for general-purpose wet electronic chemicals accounted for 88% of all domestic demand for wet electronic chemicals. Hydrogen peroxide and high-purity sulfuric acid were most in demand, accounting for around 32% of all wet electronic chemical consumption.
Demand for functional wet electronic chemicals accounted for the remaining 12% of wet electronic chemicals demand. In recent years, stripping liquids for flat panel displays and metal etching solutions have increased significantly in their share of the functional wet electronic chemicals market.

Liquid crystal displays promote the development of demand

By 2018, China’s total demand for wet electronic chemicals will likely reach 730 kt, and the demand in making semiconductors, liquid crystal panels, crystalline silicon solar cells – three large applications – will be 193 kt, 383 kt and 154 kt, respectively. In the next few years, rapid development of the liquid crystal display sector will promote rapid growth of demand for wet electronic chemicals in the manufacture of LCD panels, China’s self-sufficiency in this field will also improve greatly, so the proportion of wet electronic chemicals demand in this application market will increase significantly, promoting the overall growth of demand for wet electronic chemicals.
In domestic semiconductor wafer processing, the main in-demand wet electronic chemicals are sulfuric acid (accounting for 32.8% of demand), hydrogen peroxide (28.1%), ammonia (8.3%), developer (6.0%) and hydrofluoric acid (5.9%). The first four are used mainly in wet-cleaning wafers. China’s self-sufficiency for wet electronic chemicals used for cleaning wafers of six inches or less (generally 0.8-1.2μm and 0.5-0.6μm) is around 80%, but for wafers of eight inches or more, it is only 10%.
In liquid crystal panel processing, the main in-demand wet electronic chemicals are phosphoric acid (accounting for 41.3% of demand), nitric acid (24.06%), polar solutions like MEA (15.8%) and acetic acid (9.59%). Consumption of new acid molybdenum aluminum etching solution (commonly called aluminum etching solution) is the largest. The wet electronic chemicals being used in the liquid crystal panel field are mostly high-purity mixed (or composite) solutions such as array developer, ITO etching solution, Al etching solution, Cu etching solution and stripping liquid.
In the domestic crystalline silicon solar cell chip processing field, the main in-demand wet electronic chemicals are hydrofluoric acid (accounting for 31.39% of demand), nitric acid (21.17%), potassium hydroxide (24.06%) and hydrochloric acid (11.04%). These are all used mainly to process and clean crystalline silicon solar cell chips. Domestic enterprises control over 98% of this market.
China needs to further develop independent innovation for the technology, supporting technology, and environmental protection, recycling and reuse technology for wet electronic chemicals.