JPS6148774B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel glass for semiconductor packaging. More specifically, the present invention relates to a glass for semiconductor passivation that directly coats the surface of a joint portion of a semiconductor element to stabilize the surface. Conventionally, PbO, B ₂ O ₃ , Al ₂ O ₃ and SiO ₂ have been used to stabilize the joint surface of silicon semiconductor devices.
lead glass or ZnO, B ₂ O ₃ ,
Zinc glass whose main components are Al ₂ O ₃ and SiO ₂ is used as a glass for semiconductor packaging. In order to prevent the coating glass from cracking and to reduce the residual stress imparted to the semiconductor elements, it is necessary to use glass with a composition range close to the thermal expansion coefficient of silicon, and therefore the thermal expansion coefficient is close to that of silicon. The coefficient is 35×10 ^-7 ~
Limited to glass compositions in the range of 50×10 ^-7 °C ^-1 . Therefore, it is inevitable that the baking temperature of glass as mentioned above will exceed 600℃, and stabilizing with glass coating after electrode formation in the semiconductor manufacturing process will result in a thicker alloy layer of aluminum and silicon for the electrode. , is not possible as it will adversely affect the joints. On the other hand, from the requirements of manufacturing technology for semiconductor devices, if it is possible to stabilize the surface by glass baking at a temperature as low as possible below the alloying temperature of aluminum and silicon (approximately 570°C) after forming the electrodes of the device, Part of the mask forming process using photolithography can be omitted, simplifying the manufacturing process.
It is believed that it is possible to reduce element costs. Therefore, as a result of intensive research in order to eliminate the above-mentioned drawbacks and achieve the above-mentioned purpose, the present inventor found that PbO65~
90% (wt%, same below) and _{B2O3 10-35} %
A filler-added glass made by adding at least one powder of 1 to 10μ selected from the group consisting of aluminum titanate and zirconium phosphate as a filler to the low melting point glass in an amount of 25 to 50% based on the low melting point glass. The present inventors have discovered the fact that when used as a device, the above-mentioned drawbacks can be eliminated and the above object can be achieved, and the present invention has been completed. In other words, in order to meet the above-mentioned demands in semiconductor device manufacturing technology, the present invention can coat the surface of the joint of a semiconductor device at a low temperature below the alloying temperature of aluminum and silicon (approximately 570°C), and It is an object of the present invention to provide a glass for passivation that can be stabilized. In the present invention, two of the PbO and B ₂ O ₃
A low melting point glass consisting of three components may be used, or a low melting point glass consisting of three components in which SiO ₂ is further added may be used. When the low melting point glass used in the present invention is composed of two components, PbO and B ₂ O ₃ , PbO is 65 to
The low melting point glass is blended with B ₂ O ₃ in a range of 90%, and the low melting point glass is blended with PbO, B ₂ O ₃ and SiO _2.
When consisting of components, PbO65-90% and
_B2O3 consisting _of 10-35% plus _SiO2
It is blended in a range of 1.5 to 6.0%. The components constituting the low melting point glass are blended in the composition ratios described above and then melted by a normal glass melting method. The low melting point glass cullet thus obtained is ground to 325 mesh passes of powdered glass and then mixed with filler. The filler used in the present invention includes at least one member selected from the group consisting of aluminum titanate (Al ₂ O ₃ .TiO ₂ ) and zirconium phosphate (2ZrO ₂ .P ₂ O ₅ ); 1-10
It is added to the powdered glass in the form of a powder of μ. When the particle size of the filler is smaller than the above range, the chemical activity of the surface becomes large, and the interaction between the glass and the filler material becomes active, making it impossible to obtain a glass film having the desired coefficient of thermal expansion. Moreover, when it exceeds the above range, it becomes difficult to control the necessary film thickness, which is not preferable. The amount of filler added to the glass powder is 25 to 50% based on the total amount of glass powder used. The filler-added glass powder prepared in this manner is applied to the bonding surface of silicon semiconductor devices using conventionally known glass bonding techniques such as centrifugal sedimentation, electrophoresis, doctor blading, and printing. It is applied to a thickness of several microns to several tens of microns and baked onto the bonded surface at a firing temperature of about 400 to 560°C. The coated glass thus obtained has a coefficient of thermal expansion within the range of 45×10 ^-7 to 55×10 ^-7 °C ^-1 and is suitably used as a glass for semiconductor packaging. The coefficient of thermal expansion of silicon semiconductor is 28
×10 ^-7 to 35 × 10 ^-7 °C ^-1 . As described in detail above, the semiconductor passivation glass of the present invention has a higher glass coating temperature (baking temperature) than the passivation glass used for conventional silicon semiconductor device surface stabilization.
By significantly lowering the temperature, it is possible to perform glass bonding at a temperature below the alloying temperature of aluminum and silicon, which can greatly contribute to the simplification of semiconductor manufacturing processes. Next, the glass for semiconductor packaging of the present invention will be explained with reference to Examples. Example 1 Glass components: PbO 174g (87%), B ₂ O ₃ 26
g (13%) to produce glass cullet using a normal glass melting method, and then crushing this,
Obtained 325 mesh powder glass. To this powdered glass, 133g of aluminum titanate (Al ₂ O ₃ TiO ₂ ) having a particle size of 1 to 10μ (40% to the powdered glass) was added and mixed until sufficiently homogeneous to form filler-added glass. was prepared. The obtained filler-added glass is coated to the required thickness using a conventionally known semiconductor surface coating method.
Baked at 450°C for 10-30 minutes. The coefficient of thermal expansion of the obtained coated glass was 54×10 ^-7 °C ^-1 . Examples 2 to 6 and Comparative Examples 1 to 3 Each coated glass was obtained in the same manner as in Example 1, except that glass components and fillers shown in the following table were used and fired at the respective firing temperatures shown in the table. These test conditions and test results are shown in the following table together with the test conditions and test results of Example 1.

[Table] Good results were obtained in Examples 1 to 6, but when the amount of filler was too large as in Comparative Example 1, pinholes and bubbles formed in the glass coating. When the amount of filler is too small, as in Ai, the thermal expansion coefficient does not approach that of silicon, and cracks occur in the formed glass film, making it impossible to achieve the goal of stabilizing the semiconductor surface. Furthermore, as in the case of Comparative Example 3, the SiO ₂ content is
When the temperature increases to 17.6%, the softening point of the glass increases, and good results were obtained at 620°C, but it was impossible to form a glass film at a temperature lower than about 570°C, where an alloy of aluminum and silicon is formed.

Claims (1)

[Claims] 1 PbO 65-90% by weight and B ₂ O ₃ 10-35% by weight
A semiconductor assembly made by adding at least one powder of 1 to 10 μm selected from the group consisting of aluminum titanate and zirconium phosphate as a filler to a low melting point glass in an amount of 25 to 50% by weight based on the low melting point glass. glass. 2 PbO65-90% by weight and _{B2O3 10-35} % by weight
A low melting point glass made by adding 1.5 to 6.0% by weight of SiO ₂ to a low melting point glass, and at least one powder of 1 to 10 μm selected from the group consisting of aluminum titanate and zirconium phosphate as a filler. Glass for semiconductor packaging made by adding 25 to 50% by weight to glass.