The final mask adds the so-called layer of metallization used for all transistors and other components. In the majority of chips for this layer use aluminum, but recently began to use copper. It is explained by the best conductivity of copper in comparison with aluminum. However for universal use of copper it is necessary to solve a problem of its corrosion.
As all main producers of fans let out models as for Socket A processors (AMD), and Socket 370 (Intel) is not present sense in detail to describe each of them. Similar models (as it is visible on the example of the Golden Orb fan), will have almost identical results of tests.
Photolithographic process begins with a substrate covering a semiconductor layer with special additives, then this layer becomes covered by a photoresistive chemical composition and after that the image of a chip is projected on the surface which became now photosensitive. As a result of addition to silicon of donorny impurity the semiconductor turns out. The projector uses a special photo mask (mask) which is, some kind of, the card of this concrete layer of a chip. (The chip of the Pentium III processor contains five layers; other modern processors can have a pole and more layers. When developing the new processor it will be required to design a photo mask for each layer of a chip).
Overall performance of this cooler in comparison with other models is provided, first, with bigger weight, secondly, by that all edges are blown equally and, therefore, are used for the heat sink with the maximum efficiency.
For tests the ASUS A7V motherboard which has means for change of coefficient of multiplication of the processor and supply voltage of its kernel, and two AMD processors - Duron 600MHz and Athlon 750MHz was used. (the AMD processors delivered now have the blocked multiplication coefficient!) The system had 64Mb random access memory. As an operating system Windows 98SE was used. Measurement of temperature of the processor was carried out by means of the thermal sensor which is built in the motherboard and the ASUS Probe programs of version 1 For "warming up" of the processor Quake II in a window 640 on 480 with the greatest possible speed ("TIMEDEMO 1") was started. Fixing of value of temperature was carried out in 30 minutes after the beginning of dough.
For creation of the temperature conditions corresponding to various working frequencies and tension of a kernel dispersal was used. Remember that dispersal of the processor is violation of the rules of its operation and attracts loss of a guarantee in case of a processor exit out of operation because of an overheat.
After conclusions of a crystal were connected to contacts on the chip case, and the chip is packed, final testing is carried out. To define correctness of functioning and nominal speed. Different chips of one series often possess various speed. The special testing devices force each chip to work in different conditions (with different pressure, temperatures and clock frequencies), defining value of parameters at which correct functioning of a chip stops. Also the maximum speed is defined: after that chips are sorted by speed and is distributed on receivers: chips with close parameters get to one receiver. For example chips of Pentium 450, 500 and 550 MHz represent one chip, i.e. all of them were printed from the same photo mask, and preparations are made from same, but at the end of a production cycle were sorted by speed.
The basic chemical element used at processors is silicon, the most widespread element on the earth. It is a basic element of which coastal sand consists; however in such look it is not rather pure for production of chips.
Recently the tendency to increase in a substrate and reduction of the size of elements on a chip crystal is observed. In the name of technology the size of separately taken elements of schemes and transistors is specified.
When processing of a circular substrate comes to the end, on it the greatest possible quantity of chips will be printed. The chip usually has a form of a square or a rectangle, at the edges of a substrate there are some free sites though producers try to use each square millimeter of a surface.
In production of the Pentium III processor, until recently, the 25-micron technology was used, thus the area of a chip is equal 128 mm2, and the party of a square crystal – 11,3 mm. Now processors are made on 18-micron technology and transition to 13-micron technology is planned. It will practically allow to increase twice quantity of chips on one substrate.