Vacuum substrates made of aluminum oxide ceramics

Vacuum substrates made of aluminum oxide ceramics
24 марта 2022

Vacuum substrates made of aluminum oxide ceramics

Ceramic substrates made of aluminum oxide Al2O3 are the basis for the creation of hybrid integrated circuits (GIS), ceramic capacitors, resistors, heaters, various semiconductor elements and electrical products. Aluminum oxide itself has a second name - corundum. Therefore, it is not uncommon to find the names "corundum ceramics". The abbreviation VK is vacuum-dense corundum (some decipher vacuum-dense ceramics).
There are several main types of corundum ceramics. VK94 (pink), VK96 (white), VK100, polycor (international name: luxalox), sapphire.

What is the difference between these materials? As a standard, ceramics with the abbreviation VK have an X-ray amorphous or fine-crystalline structure. The ceramic itself is opaque, and its color depends on the impurities that make up its composition, and varies from bright pink to snow-white.

VK100 ceramics are corundum ceramics with a maximum degree of purification close to 100%, maximum theoretical density, opaque white color, which can be polished to a surface roughness of Ra 0.05, not inferior in this parameter to crystal analogues.

Polycor is a ceramic with the international name lukalox, from the name polycrystalline corundum. The key difference between this ceramic and traditional VC is the crystal structure. Due to crystallization, a higher theoretical density is achieved, the substrates become translucent with a white sheen. At the same time, the degree of purity corresponds to VK100 ceramics.

Sapphire is a single crystal of aluminum oxide. It has an even higher theoretical density than that of polycor, maximum transparency and minimum amount of impurities among all analogues. Sometimes you can find ceramics with the name sapphirite – this is one of the names of polycrystalline alumina ceramics.

The different crystal structure cannot but affect the further processing of the substrates. Transparent ceramics do not lend themselves well to laser scribing (additional manipulations are required) and lend themselves well to disk cutting.

properties 

VK94-ДН

VK96-ДН

VK100-ДН

Sapphire

VK96 polycor

VK100 polycor

 Al2O3, %, no less

94,4

96,0

99,6

100,0

96,0

99,7

Density, г/см3, no less

3,60

3,70

3,90

3,98

3,70

3,96

Flexural strength, МПа, не менее

280

350

500

450 ~ 895

310

313

ТКЛР, ·10-6/°С
(при 20…900 °C)

6,5 ~ 7,5

6,5 ~ 8,0

6,2 ~ 8,2

5,0 ~ 6,7*

7,9

8,0

Dielectric constant (при 20 °C)

9,0 ~ 10,0

9,0 ~ 10,0

10,0

9,3 ~ 11,5*

9,0 ~ 9,4

9,45 ~ 9,95

The tangent of the dielectric loss angle, ·10-4

4

2

2

1

4

1

Roughness of the polished surface Ra, мкм

-

≤ 0,032

≤ 0,05

0,007-0,010

-

0,025

Roughness of the polished surface Ra, мкм

0,63

0,63

0,10

-

1,60

1,60


*depends on the orientation of the crystal


Unlike transparent and translucent analogues, VK ceramics lends itself well not only to disk cutting, but also to laser scribing, which is a cheaper and more productive cutting method compared to disk. However, without additional adaptation of the technology, problems may arise when breaking it into frames, since there is an "undirected fracture".


 The company "Dzhienaxel" is a reliable supplier of ceramic substrates VK100-DN TU23.43.10-004-34576770-2017, which can be used as an equivalent to substrates VK100 TU 6366-000-07593894-2013 "Polycor".


Advantages:

  • full reproducibility of all characteristics from batch to batch;
  • high-quality polishing of the sides for microstrip metallization, thin-film filters and resistors;
  • the material is suitable for laser scribing, as it does not have transparency;
  • the material can be cut by disc cutting without chipping;
  • suitable for use in microwave devices;
  • prompt launch of products into production, the ability to work with both large-scale projects and small-scale batches;
  • deliveries within the framework of electronic bidding for 44FZ and 223FZ

All products undergo quality control. In case of problems or difficulties with the processing of substrates VK100-DN TU23.43.10-004-34576770-2017, our technologists are ready to advise and help with the adaptation of the machining technology.


References

1. Lucalox ceramic / . - Text : direct // Ceramics - Lucalox Tubing. - 1981. - No. Catalog 7730. - p. 1-

2. Sapphire. - Text: electronic // JSC "Monocrystal": [website]. - URL: https://www.monocrystal.ru/catalog/sapphire / (accessed: 03/23/2022).

3. Substrates. - Text: electronic // JSC "Polikor": [website]. - URL: https://www.polikor.net/katalog/podlozhki.html (date of application: 03/23/2022).

4. Ceramic substrates. - Text: electronic // Jianaxel LLC: [website]. - URL: https://gnelectronics.ru/produktsiya/keramicheskie-podlozhki / (accessed: 03/23/2022).



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