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Ceramic substrate manufacturers share the ten design principles of ceramic substrate metal sealing structure

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  When the ceramic substrate manufacturer is in the ceramic metal package, it is first carried out after planning the completion of the metal package structure. So, how is the ceramic metal package structure planned? What are the criteria for planning?

Ceramic substrate

  1, ceramic substrate metal sealing structure - linear expansion coefficient matching criteria ceramic - metal seal inoculated metal parts and ceramic parts of the first expansion coefficient stress is consistent or close, in the entire area from room temperature to welding temperature, the phase difference should be Within the range of 7% to 10%.

  2, ceramic substrate metal sealing structure - low modulus of elasticity, low yield limit criteria, in the non-matching sealing, because of the large difference in thermal expansion, should choose a low modulus of elasticity. Metal materials with low yield limits are used as parts, such as oxygen-free copper.

  3, ceramic substrate metal sealing structure - compressive stress criterion Because the tensile strength of ceramic is about one of the compressive strength, therefore, when planning the sealing parts, the porcelain parts should be subjected to compressive stress. For example, stainless steels with high strength and high coefficient of linear expansion should be jacketed. ,

  4, ceramic substrate metal sealing structure - thermal conductivity approach criteria When selecting the lover's data, in addition to the thermal expansion should match, the thermal conductivity of the two is relatively close, the thermal stress on the small sealing member is favorable.

  5, ceramic substrate metal sealing structure - reduce the stress criterion Under the premise of ensuring the strength of the butt joint is sufficient, the thickness of the metal on the sealing surface should be as thin as possible to release part of the pressure. For example, the thickness of the metal on the sealing surface is usually 0.5 to 1.0 mm, and the tubular thin tube is better than the strength needle.

  6, ceramic substrate metal sealing structure - stress accumulation guidelines

  Stress gathering is very detrimental in the seal, often resulting in poor reliability or even catastrophic results. For example, input window seals should use circular windows as much as possible to prevent the application of rectangular or square windows.

  7, ceramic substrate metal sealing structure - excessive sealing criteria In the sealing process, especially in the needle sealing structure, excessive sealing should be used to reduce stress. For example, Mo, kovable needle is greater than or equal to 1mm, and should not be sealed directly with a solid needle, but should be replaced with a transition seal.

  8, ceramic substrate metal sealing structure - knife edge sealing criteria Knife sealing in the last ten years, a lot of choices, the main reason is: parts processing is simple. The cost is reduced; the parts are cooperative and easy to assemble, and it is easy to plan and produce; the sealing stress is small, which is beneficial to the improvement of product quality and reliability. In the case of the organization's mediation, it should be sealed with a knife edge.

  9, flexible structure criteria In addition to the above-mentioned reduction in the thickness of the metal parts can reduce the stress, the flexible structure can also reach the same intention, so the planning should be as long as possible to lengthen the gap between the seals, reduce the amount of solder, No solid or "dead" can be formed during welding.

  10, ceramic substrate metal sealing structure - solder preferred guidelines When selecting solder, try to use the plastic material and do not form a hidden compound with the parent material during welding, in the shape, the choice of silk is appropriate. In the same situation, the filament solder is 20% to 35% higher than the sheet-like sealing strength, and solder with a low soldering temperature is used as much as possible.

  The above are the ten planning guidelines for the ceramic metal package structure of ceramic substrates as described in the small series. If you have any questions about the sealing of ceramic substrates, you can consult Xiaobian.
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