Murata Machinery, Ltd. has developed the CDWX Bare Wafer Stocker which stores wafers during the semiconductor manufacturing process. Partial exhibits of actual systems will be exhibited at SEMICON Japan 2023 to be held from December 13, 2023, with full-scale sales beginning from the same date.

As the shift towards miniaturization and increasingly complex manufacturing processes continues in the semiconductor manufacturing industry, there has also been an increase in the number of Non-Product Wafers(NPW) which need to be stored for each process in order to manage product quality, and it is said that the total number of NPW which need to be stored exceed 30% of the total wafer in the production process. Meanwhile, there has also been an increase in wait times between processes for high variety, low volume production.

Temporary storage and management of wafers in these circumstances has generally been carried out using FOUP for storage, however the increase in the volume of wafers to be stored has spurred demand for more efficient methods.

CDWX is a high density storage system which removes wafers from FOUP and stores them in specialized cases (wafer cells). Wafer handling robots remove wafers from FOUP at load ports, and insert them one-by-one into specialized rings (cell rings) for wafer cells which are then stored on shelves on the back of the system. One set of wafer cells is composed of 25 cell rings, and innovative cell ring shapes make it possible to achieve a narrow spacing between wafers of approximately 3.7 mm while stored in wafer cells, allowing for much greater density storage than when using FOUP (which have spacing of 10 mm between wafers).

In addition, setting and removal of wafers to and from wafer cells is carried out by cell openers which open and close the wafer cells by expanding the vertical pitch of the cell ring and then restoring the pitch after the task is completed which contributes to both improve operability for wafer handling robots and reduced storage space requirements.

At Semicon Japan 2023, we will be providing semiconductor manufacturing industry customers with proposals for utilization of CDWX to achieve high density NPW storage in all processes. We will be exhibiting a production model of the cell opener, which is one of the devices which make up the CDWX system, at Muratec's booth.