KR0173179B1 - Method of manufacturing lead-aluminosilicate glass by sol-gel method - Google Patents

Abstract

The present invention relates to a method for producing lead aluminosilicate glass which can be used for semiconductor surface protection by the sol-gel method.

In the method for producing lead aluminosilicate glass using the sol-gel method of the present invention, a lead-based raw material, an aluminum-based raw material and deionized water are mixed and stirred to dilute a mixed aqueous solution and a silicon-based raw material to alcohols to form an alkoxide solution, respectively. Step 1; Stirring and mixing the alkoxide solution with stirring the mixed aqueous solution, followed by two steps of pouring ammonia water to react; Three steps of stirring until the treatment is uniform; Leaving the treated material to precipitate and then removing the clear solution at the top to obtain a glass gel solution; And it comprises a five steps of drying the glass gel solution, heat drying in an oxygen atmosphere.

According to this method, lead aluminosilicate-based glass for semiconductor bonding protection can be produced economically high purity and finer than conventional commercial glass powder.

Description

Method for producing lead aluminosilicate glass by sol-gel method

The present invention relates to a method for producing lead aluminosilicate glass by the sol-gel method, and more particularly to a method for producing lead aluminosilicate glass which can be used for protecting the semiconductor surface by the sol-gel method. .

Generally, glass is manufactured using the melting method which mix-melts and cools a raw material. However, since the melting process of the raw material is carried out in the crucible, a large amount of impurities are likely to be mixed, and a high cost melting process and a long time grinding process are required in the crushing and pulverizing of the cooled glass lumps. It takes a lot.

Therefore, the present inventors attempted to produce lead aluminate-based glass by using a sol-gel method which has the following advantages over the melting method.

The sol-gel method has the following advantages over the melting method.

First, incorporation of impurities can be minimized to produce high purity glass.

Second, the fine powder of the glass can be easily made. Dry heat treatment of the glass gel produced by the sol-gel reaction results in agglomeration of fine particles, which can be finely powdered by a short grinding process.

Third, the process is simple.

The main metal elements of the glass for semiconductor junction protection to be dealt with in the present invention are Pb, Al, and Si, and passivation glass currently produced in Japan, USA, Germany, etc., that is, the main metal elements are Pb, Si, B, or Zn, It is different from those of Si and B.

After all, an object of the present invention is to provide a technique for producing a lead aluminosilicate-based glass for semiconductor junction protection by the sol-gel method that requires high reliability and high purity.

The method for producing lead aluminum silicate glass by the sol-gel method for achieving the object of the present invention, by mixing and stirring lead-based raw materials, aluminum-based raw materials and deionized water, dilution of the mixed aqueous solution, silicon-based raw materials in alcohols 1 step of making each alkoxide solution; Stirring and mixing the alkoxide solution with stirring the mixed aqueous solution, followed by two steps of pouring ammonia water to react; Three steps of stirring until the treatment is uniform; Leaving the treated material to precipitate and then removing the clear solution at the top to obtain a glass gel solution; And it is characterized by having the five steps of drying the glass gel solution, heat drying in an oxygen atmosphere.

1 is a thermogravimetric analysis graph of the glass gel according to the present invention.

2 is a graph of infrared absorption analysis of glass gel.

Figure 3 is a microstructure photograph after the reaction of the glass gel at 750 ℃.

4 is a graph of zeta potential characteristics of lead aluminosilicate glass.

5 is a graph showing the average particle size of the lead aluminosilicate-based glass dispersion particles.

6 is a graph showing the degree of densification of lead aluminosilicate-based glass according to firing temperature.

7 is a graph showing the flow-down characteristics of the lead aluminosilicate-based glass according to the firing temperature.

8 is a graph comparing X-ray diffraction characteristics of lead aluminosilicate-based glass after heat treatment at 850 ° C. and 1020 ° C. FIG.

In the present invention, lead-based, aluminum-based and silicon-based raw materials used as starting materials are used in a weight ratio of 10 to 30: 6 to 14: 55 to 67, and the mixed aqueous solution is Pb (NO ₃ ) ₂ and Al (NO _3). ) _{3 ·} 9H ₂ O is mixed at a weight ratio of 1: 1 to 1.5, and the alkoxide solution is usually prepared by diluting tetraethylorthosilicate (TEOS) in methanol.

In addition, after step 4, ammonia water is poured into the treated material, followed by stirring and precipitation to remove the clear solution at the upper part, which may be repeated a plurality of times. In step 5, the first dry gel is heated to 750 ± 5 ° C. to 2˜. The reaction is carried out for 3 hours to prepare lead aluminosilicate glass of the present invention.

The present invention will be described in more detail as follows.

First, Pb (NO ₃ ) ₂ and Al (NO ₃ ) _{3 ·} 9H ₂ O are dissolved in deionized water, and the mixed aqueous solution is mixed with TEOS in ethanol to form an alkoxide solution. The two solutions are first mixed and hydrolyzed while slowly adding ammonia water while stirring, removing clear portions of the hydrolyzed solution, adding deionized water and stirring several times to finally dry the remaining portion of the solution. As described above, when the glass produced by using the method for producing glass by the sol-gel method proposed in the present invention is powdered, a predetermined fine glass powder can be obtained.

Using the method of the present invention, the glass composition is 45.5% SiO ₂ , 10.2% Al ₂ O ₃ and 44.3% PbO (molar ratio of SiO ₂ 71.8%, Al ₂ O ₃ 9.4%, PbO 18.8%) by weight. The glass composition was prepared by weight ratio of SiO ₂ 40%, Al ₂ O ₃ 10%, PbO 50%, SiO ₂ 50%, Al ₂ O ₃ 10%, PbO 40%, and the glass composition was SiO ₂ by weight. Thermogravimetric analysis was performed while heating at 3 ° C / min for 40%, 10% Al ₂ O ₃ and 50% PbO.

Figure 1 shows the thermogravimetric analysis using the dried gel specimens, it can be seen that the weight loss of about 82% occurred at a temperature of 100 ~ 160 ℃. An additional 8% weight loss occurred up to 400 ° C, with only 10% of the original weight remaining after the solid phase reaction at 750 ° C. Even when PbO and SiO ₂ amounts were changed, the thermogravimetric analysis was the same as that of the basic composition.

In order to investigate the cause of the weight loss due to the temperature rise, infrared absorption spectrometry (FTIR) was performed on the specimens heat-treated at 120, 200, 400 and 750 ° C. Figure 2 shows the infrared transmittance at each wavelength by irradiating infrared rays to the glass gel specimen heat-treated at each temperature. The main absorption band is represented by ^{2500㎝ -1, 1640㎝ -1, 1400㎝ -1} , 9600~1280㎝ -1 in each of which a hydrogen-bonded H ₂ O, a water molecule, CH, asymmetric Si-O-Si . First, in ^{120 ℃ 3500㎝ -1, 1640㎝ -1,} 1400㎝ -1, appears both in 9600~1280㎝ ^-1 are four absorption bands, by the temperature when viewed in conjunction with this, the thermogravimetric analysis of the sol- It can be seen that the bond between ethanol and water used in the gel method is almost intact.

Since this tendency is repeated at 200 ° C., it can be seen that ethanol and water were not completely removed even if the weight loss was 82%. At 400 ℃, the 1400 cm ^-1 absorption band does not appear and the 9600 to 1280 cm ^-1 absorption band is also very weak, indicating that the CH bonds, that is, the alcohol components, have been completely removed, and the Si-O-Si bonds have most of the inorganic properties. As can be seen, it can be seen that H ₂ O still remains. When it reaches 750 ℃, it can be confirmed that the special absorption zone disappears and is completely inorganic. It is preferable to carry out the solid-phase reaction of the glass gel manufactured by the sol-gel method at 750 degreeC in view of this, since the organic component in a glass gel can be completely removed and it can be made into oxide glass.

The lead aluminosilicate glass powder whose solid phase reaction was completed at 750 ° C. was dry pulverized for 30 minutes in an attrition mill, and then observed under an electron microscope, and the microstructure thereof is shown in FIG. 3. The microstructure shows that the glass particles prepared by the sol-gel method and reacted at a high temperature have an average particle diameter of about 5 μm or less.

Furthermore, a closer look at the individual particles reveals that one particle is a mass in which small pieces are bound together. Compared with the glass powder currently commercially available, it can be seen that the particle size is fine and further refinement is possible through additional grinding in consideration of the mass of small pieces. Therefore, the glass powder produced in the present invention is advantageous in this regard because the fineness of the glass powder is a factor that determines not only the efficiency of use of the glass particles for semiconductor bonding protection but also the aging stability of the dispersion.

In order to examine the zeta potential characteristics, which are the main factors for using the glass produced in the present invention for semiconductor bonding protection, as compared with commercial glass, commercial glass powder is dispersed in ethanol and an electrolyte is added to change the time in the friction mill. After milling, the zeta potential and particle size of the dispersion were measured and compared. HNO ₃ was added to the electrolyte from the solid-phase reacted glass to obtain a suspension, and then the milling times in the friction mill were changed to 10, 30, 60, 120 and 300 minutes. After the dispersion was finished, the dispersion was precipitated for 10 minutes, and then the zeta potential and the particle size distribution of the dispersion were investigated using a Zeta master apparatus, which is shown in FIG. 4.

As shown in FIG. 4, the zeta potential according to the milling time of the lead aluminosilicate-based glass was found to be positively charged by adding HNO ₃ to the electrolyte as a whole, and the zeta potential was about 40 mA after 10 minutes of milling. When the milling time was increased to minutes, 60 minutes, and 120 minutes, the zeta potential increased to 47-4 ㎷, but when it was increased to 300 minutes, the zeta potential decreased to about 42 mV. As a result, the zeta potential of the lead aluminosilicate-based glass manufactured in the present invention is very high, and thus, it can be seen that the charging ability is excellent, thereby maximizing electrodeposition efficiency as the semiconductor bonding protection glass.

FIG. 5 is a graph showing the results of investigating the particle size distribution of the dispersion solution after settling for 10 minutes after milling the lead aluminosilicate glass. In the case of milling for 30 to 60 minutes, it can be seen that the particles in the dispersion became finer than those for 10 minutes.

Next, densification behavior and viscous flow phenomena of lead aluminosilicate-based glass applied during the firing process at a high temperature were applied as conditions for carrying out the process to protect the semiconductor junction. To this end, about 1.5 g of glass powder was molded into discs and sintered in an oxygen atmosphere. The molded specimens were 12.5 mm in diameter and 5.4 mm in height, and were placed on a silicon single crystal plate and maintained at 850, 920, 975, 1025 and 1075 ° C. for 15 minutes. The temperature increase rate was 5 ° C / min, the cooling was cooled by turning off the power of the electric furnace, and oxygen was flowed by 5 L per minute.

6 shows the densification behavior of the lead aluminosilicate-based glass according to the sintering temperature. According to the results, it can be seen that the sinter density is lower at higher temperatures than 850 ° C.

FIG. 7 compares the flatness (base / height) indicating the flow-down characteristics of glass according to the calcination temperature. According to this result, it can be seen that as the temperature rises, the glass flows down well. Such a result is the same as or similar to that of the current commercial glass.

In order to investigate the crystallization of the lead aluminosilicate-based glass at high temperature, molded glass specimens were placed on a silicon plate as in commercial glass, and heat-treated at each temperature, and then subjected to X-ray diffraction. The area where X-ray diffraction occurred was the closest to the glass-silicon interface and was expected to show the crystallization behavior that may occur at the glass-silicon interface during high temperature firing. The lead aluminosilicate glass was found to have no crystallization in the entire temperature range of 850 to 1075 ° C. unlike commercial glass.

FIG. 8 shows the results of X-ray diffraction of lead aluminosilicate glass after heat treatment at 850 and 1075 ° C. FIG. The same result is shown at other temperatures. This result is consistent with the general result that Pb-based passivation glass is not crystallized, suggesting that at least the passivation with lead aluminum silicate-based glass is not limited to crystallization with temperature in the firing step.

As can be seen from the above results, according to the method of the present invention, the lead aluminosilicate-based glass for semiconductor junction protection has a glass powder by using the sol-gel method while sufficiently having an effect as a conventional semiconductor junction protection glass. It can be further miniaturized and has the effect of reducing the manufacturing cost.

Claims (6)

Mixing and stirring lead-based raw materials, aluminum-based raw materials, and deionized water to dilute the mixed aqueous solution, and dilute the silicon-based raw materials with alcohols to form an alkoxide solution, respectively; Stirring and mixing the alkoxide solution with stirring the mixed aqueous solution, followed by two steps of pouring ammonia water to react; Three steps of stirring until the treatment is uniform; Leaving the treated material to precipitate and then removing the clear solution at the top to obtain a glass gel solution; And a step of drying the glass gel solution and heating and drying it under an oxygen atmosphere to prepare lead aluminosilicate glass using the sol-gel method. The lead aluminosilicate-based glass using the sol-gel method according to claim 1, wherein the ammonia water is poured into the treated material after 4 steps, and the stirring and precipitation are carried out to remove the clear solution of the upper part. Method of preparation. The lead-based aluminosilicate-based glass of the sol-gel method according to claim 1, wherein the starting material of lead-based, aluminum-based and silicon-based raw materials is used in a weight ratio of 10 to 30: 6 to 14: 55 to 67. Manufacturing method. The lead alumina using the sol-gel method according to claim 1, wherein the mixed aqueous solution is made by mixing Pb (NO ₃ ) ₂ and Al (NO ₃ ) ₃ .9H ₂ O in a weight ratio of 1: 1 to 1.5. Method for producing nosilicate glass. The method for producing lead aluminosilicate-based glass according to claim 1, wherein the alkoxide solution is prepared by diluting tetraethylorthosilicate (TEOS) in methanol. The method for producing lead aluminosilicate-based glass using the sol-gel method according to claim 1, wherein the drying gel is heated to 750 ± 5 ° C. for 2 to 3 hours in a 4 step.