Introduction
Intel has several facilities in Israel, including two chip factories. We had the chance to visit Fab18, located in Kiryat Gat, which manufactures Pentium 4 chips in 90 nm process and also chipsets and flash memories. In this coverage you will have a better notion of where Intel factories are located, what is the relationship between them and, of course, how Fab18 looks like inside and how a chip manufacturing facility works.
On Figure 1 you can see where Intel fabs and development centers are distributed in the world.
click to enlarge Figure 1: Location of Intel fabs and development centers in the world.
In the so-called fabs is where the wafers are processed, i.e. the wafer enters “virgin” and exit full of chips on it. Then the wafers are sent to other facilities, called “assembly and testing”, where they are cut and the devices (processors, chipsets, etc) are packed (terminals and a body are added).
As you can see on Figure 1, Intel has fabs only in three countries: United States, Ireland and Israel. Assembly and testing facilities are found near consumer markets.
So, the final product from Fab18 is wafer, to be sent to assembly and testing facilities. That’s why you never see “Israel” on the body of any CPU but “Costa Rica”, “Malaysia” or “Philippines”, for example.
Besides the two fabs (the other one, Fab8, is located in Jerusalem and is older, established in 1985 and the first fab outside the USA), Intel has several research and development centers in Israel, as you can see on Figure 2. As we already mentioned on our IDF Tel Aviv coverage, the Haifa team is responsible for creating Pentium M CPU and all other CPUs based on its architecture, like Yonah (dual-core Pentium M) and the forthcoming Merom, Conroe and Woodcrest.
The Petach Tikva team is in charge of the development of all cell CPUs from Intel and also Wi-Max technology, after Intel bought a company called Envara in 2004. This year Intel bought a company called Oplus, located in Yokneam, which develops HDTV decoder chips. The Yakum team is a branch of the Haifa team and also develops CPUs and chipsets for mobile platform.
click to enlarge Figure 2: Intel fabs and development centers in Israel.
Intel history in Israel is very old. The Haifa development facility was established in 1974 (just five years after Intel was established) with five engineers headed by Dov Frohman, the man that created the EPROM chip.
Now that you have an overall look about Intel’s activities in Israel, let’s go to Fab18.
Intel Fab18
Fab18 was established in 1999 and at that time produced Pentium III wafers. It was upgraded to the 90 nm process and now it produces wafers for Pentium 4 CPUs, chipsets and flash memories. There are 3,700 people working there.
click to enlarge Figure 3: Intel Fab18 in Kiryat Gat, Israel.
Before continuing, we’d suggest you to read our tutorial How Chips are Manufactured, for a better understanding of what we are going to talk from now on.
Due to its huge size – Fab18 has the size of two soccer courts – and to the very high cost of building and maintaining a clean room, instead of the entire factory being a huge clean room, only the parts needed to be operated under a clean environment use clean rooms. So the factory has several clean rooms. The area behind the clean rooms are called “chase”, and is where the process tools, electricity, exhaust, etc are located.
The floor of the clean rooms and the chases isn’t solid. It uses a mesh for allowing the air to circulate. The air is totally replaced every four minutes. Also, below the fab is where tanks with the chemical products necessary for the manufacturing process are located.
On Figure 4 you can see one of the clean rooms. Pay attention to the floor. Of course inside the clean rooms everybody must wear the so-called “bunny suits” to prevent contamination of the wafers (since the transistors created on the wafer are microscopic even the smallest particle of dust can destroy the chip being manufactured).
click to enlarge Figure 4: One of the clean rooms.
On this picture you can a technician handling a black box (called “lot”), which has wafers inside. He is putting the lot inside one machine, or processing tool. Only the “entrance” of the processing tool is located inside the clean room; its body is located in the chase, for cost reductions, as we mentioned.
Intel Fab18 (Cont’d)
On Figure 5 you can see a chase (pay attention on the floor). These are the machines that process the wafers and where the technician is putting the lot on Figure 4.
click to enlarge Figure 5: A chase.
The number of clean rooms and machines is impressive, because of the number of steps necessary to manufacture a CPU wafer. A Pentium 4 CPU uses 26 photolithographic masks. For each mask it may be necessary several steps to process it, plus the doping and metal layer stages. Thus the CPU manufacturing process can have hundreds of steps.
Just to give an example to clarify, for processing the first chip layer using the example we posted on our How Chips are Manufactured tutorial, the following steps would be necessary:
- Grow silicon dioxide on the wafer.
- Apply a layer of photoresist.
- Apply the first mask.
- Expose the wafer to ultraviolet light.
- Remove the “soft” part of the photoresist layer using solvent.
- Remove the exposed parts of silicon dioxide (etching process).
- Remove the rest of the photoresist material.
As you can see, in this example for processing the first layer it would be necessary seven steps, each one occurring in a different place and using different machinery. On real chips more steps may be necessary. So imagine a CPU like Pentium 4 that has 26 masks.
On the steps where ultraviolet light is being applied, the clean room uses orange light, not white light like the other clean rooms, as you can see on Figure 6, because the photoresist layer is sensitive to white light.
click to enlarge Figure 6: Clean room running a photolithographic process (the light bulbs are orange).
Intel Fab18 (Cont’d)
As we mentioned, the technicians don’t handle the wafers directly. The wafers are located in squared boxes called lots, which holds 25 wafers each. On Intel fab, lots carrying wafers using aluminum on their metal layers are black, while wafers using copper on their metal layers are orange.
click to enlarge Figure 7: A lot (this is an older lot model and was located on the small Fab18 museum).
When the technician inserts the lot in the processing tool, the machine will open it, take each wafer, process it and then put the processed wafers back in the lot.
From one clean room to the other the lots are carried automatically by a set of tracks. On Figure 6 you can see a track (like a monorail train track) on the ceiling. That is where the lots are carried.
In some cases the track system brings the lot directly inside a machine, not needing an employee to put the lot inside it.
For each machine there is a screen where the technician can see what the machine is doing and which wafers are being processed.
As we mentioned, the final product from Fab18 is not ready-to-use CPUs, but wafers containing several chips. These wafers after being manufactured are sent to test and assembly factories located in other countries like Malaysia, Costa Rica and Philippines, where they cut the wafer, put terminals and a body on the chips, test them, label them and then ship to the market.
