From a professional point of view, the production process of a chip is extremely complicated and tedious. But in terms of the complete IC industry chain, it is mainly divided into four parts: IC design → IC manufacturing → packaging → testing.
Chip fabrication process.
I. Chip design
Chip belongs to the small size, but great high precision products. To make a chip, design is the first link. The design needs to be done with the help of EDA tools and some IP cores, and finally made into the chip design blueprint needed for processing.
II. sand-silicon separation
All semiconductor processes start with a grain of sand. Because the silicon contained in the sand is the raw material needed to produce the silicon wafer, the "foundation" of the chip. So our first step is to separate the silicon from the sand.
III.silicon purification
After the silicon is separated out, the rest of the material is discarded. The silicon is purified in several steps to achieve the quality required for semiconductor manufacturing, which is called electronic grade silicon.
IV. Casting silicon into ingots
After purification, the silicon is cast into ingots. A single crystal of electronic grade silicon, after being cast into an ingot, weighs approximately 100 kg and has a silicon purity of 99.9999%.
V. Wafer Processing
After the silicon ingot is cast, the whole ingot has to be cut into discs, which are commonly known as wafers, and it is very thin. Subsequently, the wafers are polished until they are perfect and the surface is as smooth as a mirror.
Silicon wafers are commonly available in diameters of 8 inches (200mm) and 12 inches (300mm), the larger the diameter, the lower the final individual chip cost, but the more difficult to process.
VI. Lithography
First, three layers of material are applied to the wafer. The first layer is silicon oxide, the second layer is silicon nitride, and the last layer is photoresist. Then the completed design contains billions of circuit components of the chip blueprint into a mask, the mask can be understood as a special projection negative, containing the chip design blueprint, the next step is to transfer the blueprint to the wafer. This step is very demanding on the lithography machine.
UV light will pass through the mask to the photoresist on the silicon wafer, and the photoresist exposed to UV light during the lithography process is dissolved away, leaving a pattern consistent with that on the mask after removal. The exposed part of the wafer is dissolved with chemicals, and the remaining photoresist protects the part that should not be etched. After the etching is complete, the entire photoresist is removed to reveal a notch.
VII. Etching and ion implantation
The silicon oxide and silicon nitride exposed to the photoresist are first etched away and a layer of silicon dioxide is precipitated to insulate the transistors from each other, and then the etching technique is used to expose the bottom layer of silicon. Boron or phosphorus is then injected into the silicon structure, followed by a fill of copper to interconnect with other transistors, and then another layer of adhesive can be applied on top to make another layer of the structure. A typical chip contains dozens of layers of structure, like a densely interwoven highway.
After the above process, we get a silicon wafer covered with chips. After that, the chips are cut off the wafers with a fine cutter, soldered to the substrate, and sealed in a case. After that, after the final test session, a piece of chip is ready.
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