Weekend sharing: Wafer production process

Copyright Statement: This article is reproduced from Tyco Tianrun. If you feel it is inappropriate, please contact us, thank you!

Engineers have all seen chips, and many engineers have also seen wafers, but do you know the specific production process of wafers? Please follow the editor's steps to take a closer look.

Generally speaking, wafer production includes two major steps: ingot manufacturing and chip manufacturing, which can be further divided into the following main processes (ingot manufacturing only includes the first process below, and the rest all belong to chip manufacturing, so they are sometimes collectively referred to as post-processing processes for crystal column slicing):

Ingot growth -- Ingot cutting and inspection -- Outer diameter grinding -- Slicing -- Round edge -- Surface grinding -- Etching -- Defect removal -- Polishing -- Cleaning -- Inspection -- Packaging

1. Crystal rod growth process: It can be divided into:

1) Melt Down : Place the block of high-purity polycrystalline silicon in a quartz crucible and heat it to above its melting point of 1420 ° C to completely melt it.

2) Neck Growth : After the temperature of the silicon slurry stabilizes, slowly insert the seed crystal in the < 1.0.0 > direction into it, and then slowly lift the seed crystal upward to reduce its diameter to a certain size (generally about 6mm ), maintain this diameter and stretch it 100-200mm to eliminate the difference in grain arrangement orientation within the seed crystal.

3) Crown Growth : After the neck growth is completed, slowly reduce the lifting speed and temperature to gradually increase the neck diameter to the required size (such as 5 , 6 , 8 , 12 inches, etc.).

4) Crystal Body Growth : Continuously adjust the lifting speed and melting temperature to maintain a fixed crystal rod diameter until the crystal rod length reaches the predetermined value.

5) Tail Growth : When the length of the crystal rod reaches the predetermined value, the lifting speed is gradually increased and the melting temperature is raised to gradually reduce the diameter of the crystal rod to avoid displacement and slippage caused by thermal stress, and finally the crystal rod is completely separated from the liquid surface. At this point, a complete crystal rod is obtained.

2. Cutting & Inspection :

The head and tail parts of the grown crystal rod with smaller diameters are removed, and the size is tested to determine the process parameters for the next processing step.

3. Surface Grinding & Shaping :

Since the outer diameter and roundness of the crystal rod have certain deviations during its growth process, and its outer cylindrical surface is also uneven, the outer diameter must be trimmed and ground so that its size and shape errors are less than the allowable deviation.

4. Wire Saw Slicing :

Since silicon is very hard, in this process, a ring-shaped thin saw blade with diamond particles embedded on the inner edge is used to cut the crystal rod into thin slices.

5. Edge Profiling ​

Since the outer edge of the freshly cut chip is very sharp and silicon single crystal is a brittle material, in order to avoid edge cracking that affects the chip strength, destroys the chip surface finish and brings contamination particles to subsequent processes, dedicated computer-controlled equipment must be used to automatically trim the chip edge shape and outer diameter.

6. Lapping : ​

The purpose of grinding is to remove the saw marks and damage on the chip surface caused by cutting, so that the chip surface reaches the required smoothness.

7. Etching ​ ​

Use chemical etching to remove the damaged layer on the chip surface caused by processing stress after the previous processing steps.

8. Gettering : ​

Use sandblasting to remove defects and flaws on the chip to the lower layer to facilitate subsequent processing.

9. Polishing ​ ​

The edges and surfaces of the chip are polished to further remove particles attached to the chip and to obtain excellent surface flatness to facilitate the wafer processing steps to be discussed later.

10. Cleaning : ​

The processed chips are finally cleaned thoroughly and air-dried.

11. Inspection ​ ​

Carry out a final comprehensive inspection to ensure that the product finally meets the specified technical indicators such as size, shape, surface finish, flatness, etc.

12. Packing : ​

The finished products are separated, wrapped and packed with flexible materials, ready to be sent to the following chip manufacturing workshops or shipped out of the factory to ordering customers.

[About reprinting]: Reprinting is limited to full text reprinting and the title and content of the article must be completely retained. No deletion or addition of content is allowed to circumvent the original protection, and the beginning of the article must indicate: Reprinted from the WeChat public account "Semiconductor Industry Observation icbank". Thank you for your cooperation!

【About submission】: Semiconductor elites are welcome to submit articles. Once accepted, they will be published with your name and rewarded with a red envelope! Please indicate "Submission" in the title of the manuscript email, and indicate your name, phone number, unit and position in the manuscript. Welcome to add my personal WeChat account MooreRen001 or send an email to jyzhang@moore.ren

Click to read the original text and join the Moore Elite