Wet BATCHSPRAY Power Device Manufacturing
As history tells us, before a solution can be found, a problem must first arise that needs to be solved. The history of Siconnex began when a power device manufacturer was faced with this challenge and since then many new applications and solutions have been enabled throughout the semiconductor industry, including power, LED, analog/mixed signal, MEMS, and many more.
Optimization of a Standard Power Process: Al(Si) – Freckle or Ti/TiN Etch and Resist Strip
One of the most common processes within the power industry is Al etch followed by barrier or freckle etch and resist strip. This process sequence opened up the door to success for Siconnex at a European customer’s site 12 years ago. The main issue faced by the customer was that this process sequence requires a large number of different wet benches full of chemicals, which at that time were mainly manually operated. This procedure involved wasting huge amounts of cleanroom space, exhaust gas, chemicals, and operator time. In addition, the result was barely sufficient in terms of particles and uniformity.
In standard production conditions, nobody wants to change an existing process or system. It’s good to maintain a healthy skepticism when it comes to amending processes, but the possibility for improvement will eventually be exhausted. In this case, it was the sheer number of factors which were far from the optimum level that led to the decision being made to change the process.
At this stage, Siconnex introduced the Siconnex BATCHSPRAY technology. The system used was equipped with three chemical tanks and the option of using ozone in the process. With the Siconnex BATCHSPRAY solution, all the chemicals, water, ozone, and other gases are channeled to a process chamber, where they are sprayed onto a rotating batch or batches of wafers.
This principle enhances chemical exchange significantly. Furthermore, drying can also be performed inline in the process chamber. With this solution, the customer combined the whole process sequence into one system with a 2.2 m2 footprint and on a dry in–dry out basis.
As a further benefit, uniformity dropped to below 2% as a result of the high chemical exchange. This was achieved for “within wafer," “wafer to wafer," and even “batch to batch" uniformity thanks to the in-situ, automated end point detection system.
Throughput saw a significant improvement too once the whole sequence was processed without interruption and intermediate drying. With operators not having to carry the wafers from one wet bench to another, the throughput was more than doubled.
One of the most important benefits was the use of ozone, which made it possible to replace the solvent chemical entirely. This is a huge benefit in terms of cost, since only O2 is needed to generate O3. Additionally, this is an advantage for the operators. Since most solvents are hazardous chemicals and replacing them with what is basically air leads to a much better working environment.
When all the benefits of this optimized process technology are summarized together, the real cost-saving potential is revealed:
Combination of four processes:
Resist strip (up to five processes are possible in total)
Simultaneous processing of 50 wafers
Average process: 45 min
Average throughput: 67 wph
No solvent required
Taking all of this into account, the typical time for return on investment (ROI) is close to one year, depending on the existing process.
This process with the Siconnex BATCHSPRAY technology has been implemented at 16 plants around the world and continues to be in high demand among existing and new customers alike even after 12 years.
State-of-the-Art Technology, Processing of SiC, and GaN for High-End Technology
One of the changing factors within the power device industry is the wafer material used. For high frequency, high power, high temperature, or low leakage current, compound semiconductor substrates are used to ensure that the increasing requirements are met. The two materials most commonly in use at the moment are SiC and GaN.
For these materials, Siconnex has developed, and is still developing, processes so as to put itself in a position to provide state-of-the-art equipment.
The focus of these investigations is to provide cleaning technologies for new materials, as well as the possibility to perform uniform etching.
Siconnex Batchspray® Acid
300 mm Semiconductor Manufacturing
Although the current power market is focused predominantly on 200 mm or below, Siconnex is already one step ahead, providing its BATCHSPRAY platform–fully automated and ready for full integration in state-of-the-art 300 mm fabrication plants–for all semiconductor sectors.
In this case, two BATCHSPRAY process chambers share one robot. Each chamber is able to process 25 wafers with a diameter of 300 mm simultaneously.
The results for 300 mm wafers are the same as or even better than the results achieved for 200 mm, meaning that uniformity values below 2% are standard.
The Siconnex BATCHSPRAY system is the method of choice for high-volume, low-cost production.
Siconnex is looking forward as technology progresses, seeing every challenge as a possibility to provide the ideal solution. A future step within the power sector is going to be keeping an eye on the evolution of emerging materials like AlN, diamond or Ga2O3 and developing the solutions the industry needs. Besides the power sector, Siconnex also provides solutions for markets such as LED, MEMS, analog/mixed signal, and many more.
Our goal is to replace wet benches with the Siconnex BATCHSPRAY technology to help our customers save resources and money, while also achieving better process results. For this reason, Siconnex is constantly looking into new applications within existing and new markets. In the Siconnex laboratory, new processes are developed and existing processes continually optimized.
The Siconnex equipment development team works closely with the process team to guarantee that the rising demands placed on Siconnex systems are fulfilled and that our systems are at the cutting edge of technology.