CMP

Depending on who you talk to, this is a chemical mechanical polisher or a chemical mechanical planarization tool. Used for polishing substances such as silicon dioxide, tantalum and tungsten off of silicon wafers. The method of operation is as follows:

1. A cassette of wafers is placed on the load station.
2. A small arm comes over and removes one wafer from the load station. The load station elevator then moves down one space.
3. The small arm moves back to its original position, and transfers the wafer to the carrier arm. The carrier arm holds the wafer in place with a vacuum.
4. The carrier arm takes the wafer over to the first platen. The arm forcibly presses the wafer against the spinning platen, which is coated with slurry. At this stage, oxide or whatever substance is on the wafer is erode eroded away, as the result of both the chemical reaction caused by contact with the slurry, and the grinding force caused by the friction between the wafer and the platen.
5. The wafer may or may not be polished again using a different slurry on the final platen. In our case, we just put DI water on the second platen to rinse and even off the erosion.
6. Next, the wafer is carried to the rinse station, a small tank of DI water in which the wafer is spun for a few minutes to make sure all the slurry is rinsed off.
7. Finally, the wafer is carried over to the unload station where it is dropped off onto a small platform, and carried by a stream of water to the unload cassette. The unload elevator then moves down one space in anticipation of the next wafer.
8. The machine returns to 2, and repeats the process for the next wafer.

The one I deal with regularly is made by IPEC, model 372M. It's also about 10 years old and craps out constantly. I occasionally do stupid things and wind up breaking parts of it. I had no idea that a stupid little piece consisting primarily of two fiber-optic cables could cost $400. Supply and demand, I guess.

An opcode for the 6502 processor. This one involves a comparison operation. However, a compare operation sets flags (in the register) as if a subtraction had been carried out. If the value in the accumulator is equal or greater than the compared value, the Carry will be set. The equal (Z) and sign (S) flags will be set based on equality or lack thereof and the sign (i.e. A>=$80) of the accumulator.

Back to the 6502 opcodes metanode

In Perl, a comparison operator for strings, similar to the numeric comparison operator '<=>'.

<=> and cmp return:

• -1 if left operand less than right operand
• 0 if operands are equal
• 1 if left operand greater than right operand

These returns are the same as strcmp in C.

A chip multiprocessor. CMPs place several processors on one die and can be potentially faster than other SMP techniques because the processors sit on a fast internal bus and share L2 cache. IBM's Power4 processor is a CMP.

CMP is also a 6502 instruction that does a subtraction A - N, throwing away the result but updating the flags as if the instruction were SBC. Often used for comparisons.

• Function: A - N => bit bucket
• Updates flags: S . . . . . Z C
• Opcode numbers:

  (d,x) $C1
  dp    $C5
  imm   $C9
  abs   $CD
  (d),y $D1
  d,x   $D5
  a,y   $D9
  a,x   $DD
  

Similar: CPX | CPY | SBC
See also: 6502 instructions | 6502 addressing modes