Wafer reclaimed business
Reclaim wafers are an important material for wafer fabs in their manufacturing process, which can be used to monitor process parameters and the production environment, as well as reduce cost consumption, which is a key element to improve product yields and reduce costs. Therefore, as the domestic semiconductor production capacity continues to expand, the demand for reclaim wafers has also increased.
Wafer reclaim is a service in which we recycle test wafers and moniter wafers used by customers and restore their function of testing and maintaining the stabilities of the machine by using a multi-step process of removing unwanted metal and particle off the silicon surface.
Dummy wafer
The function of a dummy wafer is to maintain the stability of the machine. If the wafers of this batch are not enough to fill the empty position of the machine, a dummy wafer can be used to supplement the vacant position to maintain the stability and uniformity of the airflow, so that the reactive gas in the airflow will be evenly heated and has uniform contact with the processed silicon wafers, and a chemical-physical reaction will occur to precipitate or grow a uniform high-quality film.
Monitor wafer
Monitor wafers are the wafers to be used for monitoring the stability and reliability of the production machine during the manufacturing process.Before putting wafers into production, the monitor wafer shall be used for testing the processing to check whether the machine status is normal.During the production process, it is necessary to mix some monitor wafers with prime wafers.After the process is completed, you can use the monitor wafers to determine if the batch works properly.
Wafer reclaimed process
●The used wafers provided by the customer need to be sorted by screening the wafer surface, distinguishing between wafer types and setting geometry parameters.
●Test wafers used by customers have different levels of contamination on the wafer surface and need to be sorted to determine the next step for cleaning.
● Whether a test wafer needs to go through a stripping procedure depends on the condition of its surface. The entire procedure including hydrogen peroxide mixture, hydrofluoric acid etching and alkaline etching is performed out in an automatic batch chemical wetting tank. The process is reflected and the process is reflected in the oxidant formulation and the control of soaking time.
● After the wafer surface is eroded by chemical oxidant, a shorter process may result in unclean stripping and a longer process may lead to excessive erosion and affect recovery times. In addition, it has also to ensure that there is no cross contamination from chemical oxidizers.
● Test wafers with thick insulation layers may require grinding and removal of other film layers while ensuring rounded edges.Grinding process is similar to chemical mechanical processing, but the removal is faster and less uniform. After the grinding is completed, a more uniform and final polishing step will be performed.
● After grinding, the wafers need to be polished. The polishing can be done on one or both sides, usually through a combination of chemical reagents and machinery. Likewise, the polishing process should avoid cross-contamination of chemical reagents and pay attention to mastering the degree of polishing. Residual particles and metal contaminants may be left after polishing.
● The final cleaning process including the removal of particles left over from the polishing procedure by using oxides is completed in the immersion tank. Finally, the test wafers are dried through a surface tension dryer. The whole reclaim process involves a variety of chemicals and if the entire process cannot be fully mastered, cross contamination between machines may occur and lead to significant economic losses.
● In the final inspection stage, the reclaimed wafers are sorted according to thickness and defect detection results before shipping them back to the fab of our customers.
Indicators
Tel：0714-3291688
E-mail：info@xtek-semicon.com
Url：xtek-semicon.com
Address：No.55,Malongfan Road,Economy and Technology Development Zone,Huangshi City,Hubei Province,China
