The changeover to 12-inch wafers has caused problems, though, as a pod of 8-inch wafers only weighed five kilograms, whereas the new 12-inch wafers weigh in at a whopping 9kg per pod.
The new size and weight of wafers at the 12-inch plant has forced TSMC to experiment with its equipment in order to achieve the same productivity as 8-inch plants enjoy. The company is also using more robotic equipment to carry the pods through each step in the manufacturing process, since the wafers inside are getting too bulky.
Cost of production
One major headache Hung has been trying to tackle in the pilot line is getting the cost of production to equal, then surpass that of the older technology, 8-inch silicon wafers.
"Is the cost equal? No, right now, the cost is not equal," said Tsai Nun-sian (
The major issue is speed, getting a heavier silicon wafer through the equipment at the same rate or faster than an 8-inch wafer.
On an 8-inch wafer, it usually it takes 30 days from start to finish to get through the entire manufacturing process. And Tsai says TSMC won't be able to achieve this kind of speed in 12-inch wafers until late next year. Of course, in the transition to the new technology, this was anticipated.
The pilot line is a learning tool for the company and a place to try out equipment made by different semiconductor tool manufacturers.
"Once we select the right equipment, we continue to work with the supplier and help upgrade the performance of the tools," said Tsai.
So to make a semiconductor, one of the first steps in the process is to polish the 12-inch wafers and prepare it for photographing. Long before this step, however, a "mask" must be made.
The semiconductor design (also called an IC or integrated circuit design) must be carved into a "mask" made of quartz crystal. This quartz crystal mask will then be placed on top of each 12-inch wafer inside an ion imprinting machine, where the quartz crystal mask shows the ion imprinter where to paint the semiconductor design. Although "painting" is the term used in this article, it is more like exposing a photograph. Exposure chemicals are used and the wafer has to go through a developing process.
After imprinting the design, as the silicon wafer is passed along the manufacturing process, the design is already on the wafer and other machines actually carve out the semiconductor design.
"The mask defines the circuit pattern, that is all that needs to be changed to run the design of a new company through the process," said Hung, explaining how designs are changed quickly in a semiconductor foundry.
When changing to a new technology, companies like TSMC depend on semiconductor equipment makers to create user-friendly machines. Sometimes, the vendor will simply make the equipment bigger to accommodate the new size of the wafer, in this case 12 inches. Other firms will redesign tools and software and the customer has to decide which company to buy from.
RSS