The quality of Ultra-pure water is an important factor for yield rate and profitability in nanoelectronics manufacturing.
The highest grade (Type 1) of Ultrapure water (UPW) is used in the manufacturing process of nanoelectronic components. The components are built by assembling thousands of integrated circuits. The components must be cleaned after each step of manufacture, which means that it is rinsed in UPW a hundred times or more to remove all chemicals and reaction products that have been used in the manufacturing process. Removing these contaminants is critical to commercial viability. Any contaminant that is left may cause short circuit or malfunction which will cause the component to be scrapped in the final quality test. Having many components scrapped is characterized as low yield rate and is a major threat to profitability. A consistent supply of pure water is necessary in order to keep reject rates (scrapping) down.
Disclaimer: This article is in Swedish.
XZERO has developed proprietary technology for the manufacture and recycle of UPW that removes all contaminants efficiently, even the smallest (sub-20 nano) nanoparticles.
The equipment is called LastRinse and will reduce scrapping and increase yield rates.
As a general guideline 30 – 40 litres of UPW are used to wash every component (chip). One factory may use up to 10 million litres of UPW per day. The use in the nanoelectronics (semiconductor) industry worldwide is several billion litres per day. The total number of semiconductor manufacturing companies worldwide are a few hundred. Each one may have several factories at different locations.
LastRinse offers the following advantages
The starting point is a wafer (a round thin disk, usually of silicon). After cleaning and rinsing the wafer meticulously, several hundreds of separate microelectronic components (chips) are built step by step, layer on layer on the wafer. At each step of this process, the wafer is tested with specially designed equipment under computer control.
When the process is completed, all the chips on a wafer are individually tested again. Those that pass the rigorous electrical tests are then cut from the wafer with high-speed, water-cooled, diamond cutting saws and mounted in metal or plastic packages, called modules. These modules are then tested again.
The primary building blocks on the wafer are the transistors, i.e. tiny switches that by being off or on signal 0 or 1 – the basis of all digital systems. The next level building block is the integrated circuit (IC). An IC is composed of several components of various types – transistors, diodes, resistors, and capacitors. These are wired into a specific circuit having a specific function. An IC can consist of as few as two components up to hundreds of billions of components. Soon the technology for making ICs will probably be able to put hundreds of trillions of components in one IC. As the components get smaller, the demand on the purity of the rinsing water increases.
To obtain purest water possible, the nanoelectronics industry adopts most of the major established water purification technologies in sequential steps where one step removes a set of particular contaminants but may also introduces other contaminants which have to be removed by a subsequent step. 15-20 purification steps or more in sequence will generally be required.
LastRinse only distinguishes between two types of contamination. Volatile and non-volatile. LastRinse first removes volatiles from the feed water by degassing. Pure water is then extracted from the remaining feed in molecular form. The feed is turned into a concentrated brine. A part of the brine is continuously tapped and concentrated to solid waste by evaporation.
Xzero is about one year delayed in its core project partly because of general technical delays and partly because of delays from lock downed suppliers. The technical problems are now solved and the project speeds ahead although at a slow pace because Corona has created back-logs that still delay deliveries from foreign suppliers of tools and components.
These delays have caused economical strain. In order to counteract potential financial problems, Xzero is making a subscription to its existing shareholders for 700 000 € in January 2021.
Xzero also expects to receive the last payment of 130 000 € from the Horizon grant in March 2021 after handing in the final report in February 2021.
From experience with our customers, we also have realised that we need substantial finance to be able to launch the four products that we now have developed to be market ready in 2021. Therefore, we will need a substantial inflow of equity capital. To become attractive for a needed equity investment, we believe that it is important for the company to have a positive cash flow, or at least substantial incomes from sales