KR20000050186A - Method for fabricating amorphous silica filler - Google Patents

Abstract

PURPOSE: A method for manufacturing/recycling an amorphous silica filler, using pieces of quartz glass which is a waste from a semiconductor manufacturing process, is provided to recycle a waste of a melting pot for pulling a silicon monocrystal ingot as a functional material for filling. CONSTITUTION: A method for manufacturing/recycling amorphous silica filler, using pieces of quartz glass which is waste from a semiconductor manufacturing process comprises three steps. The first step is to collect pieces by selecting a kind of waste piece from a group of a waste of a melting pot for pulling a silicon monocrystal ingot and a piece of quartz glass which is a waste from a semiconductor manufacturing process. The second step is to perform a prior treatment to eliminate an impurity from the collected pieces of a waste. The third step is to smash the waste pieces into pieces having a suitable size.

Description

Method for fabricating amorphous silica filler

TECHNICAL FIELD The present invention relates to a method for producing silica filler, and more particularly, quartz glassy crucible and silicon wafer processing, which is one of the silicon single crystal ingot raising crucible wastes that are currently disposed of as simple landfills or simply reused as inexpensive side materials for refractory materials. A method for producing an amorphous silica filler using waste quartz glass jig parts waste for a wafer support during a process.

Crucibles for raising silicon single crystal ingots are common quartz glass crucibles.The reason for the use of quartz glass is that it has stable thermal properties and the same elemental components as silicon, and the mixed oxygen from the quartz glass crucible is mixed in the heat treatment process during device manufacturing. This is because of impurity fixation.

The purity of such quartz glass varies from manufacturer to manufacturer, but since most companies adjust the amount in ppb, it is possible to manufacture high purity silicon ingot.

Generally, when classifying quartz glass, there are a first kind of anhydrous quartz glass, a second kind of molten running quartz glass, a third kind of synthetic flowing quartz glass and a fourth kind of anhydrous quartz glass. Among them, first-class molten anhydrous quartz glass is mostly used as a crucible for pulling silicon single crystal ingots. The manufacturing method of this quartz glass is not published to the extent that it does not patent each other, and only the schematic degree of literature is introduced.

Therefore, the crucible waste for silicon single crystal ingot raising, which is the object of the present invention of recycling technology, can be predicted to be a first-class quartz glass as described above, and is considered to be a very high purity product.

However, since it is a waste that has been used once, the landfill is not reused in the field due to impurity residual components such as polycrystalline silicon and heat treatment history on the crucible surface.

On the other hand, many types of packaging are used to protect electronic components such as semiconductor devices, integrated circuits (ICs), and electrical components such as coils from external environments such as temperature, humidity, or shock, and to implement electrical insulation. have. In the 1950's, a package of diodes or transistors commercialized originally used ceramic materials such as metal, glass, and magnetic material. However, as the demand for semiconductors increased, the resin packaging method was developed in the late 1960s by a low pressure transfer mold method, which is now inexpensive and easy to mass produce. Is occupying.

In this resin packaging method, a material in which 50% to 90% or more of a filler is generally combined with an epoxy resin is used, but mainly crystalline silica, fused silica, alumina, or the like is used.

In particular, quartz containing few impurities (elution ions such as alkali and halogen) is often used as the filler, and fused silica and crystalline silica may be used due to necessary properties such as thermal conductivity and thermal expansion coefficient.

Technological innovations in the field of electronics and electronics are developing rapidly, and the requirements for packaging materials, as well as the requirements for fillers in these applications, are becoming more stringent. In particular, with the demand for low hygroscopicity and low stress of the packaging material, a filler capable of high filling and having a low viscosity synergistic effect even in a high filling state is required.

Resin packaging forms the mainstream of semiconductor packaging, such as LSI, and the epoxy resin packaging method by the low pressure transfer mold system is the center. Table 1 below introduces the composition of these epoxy resin packaging materials and their purpose of use.

Table 1 Composition of epoxy resin packaging material and purpose of use

Material Compound people purpose of use Compounding amount Epoxy resin Bisphenol A type epoxy resin Basic characteristics such as electrical, mechanical and thermal properties 15-40 Phenol novolac type epoxy resin Cresol novolac type epoxy resin Bisphenol A type epoxy resin Phenol novolac epoxy resin Hardener Amino 類, 無水 酸類, Phenol novolac resin Curing accelerator Nitrogen-containing compounds, Phosphine, Onium salts Promotion of hardening reaction <One Plasticizer Silicone oil, rubber Decreases the elastic modulus and thermal expansion coefficient of Resin 〈5 filling Fused Silica, Crystalline Silica, Alumina Adjustment of Resin's coefficient of thermal expansion, thermal conductivity and mechanical strength 60 to 85 coupling agent Epoxy silane, Titanate alumino-chelate, Amino silane, Zirco-aluminate Improvement of properties between resin and filler <One Flame Retardant Antimony dioxide Impart flame retardancy <One coloring agent Carbon Black, 染料 coloring <One Release agent Wax Grant of Mold Release to Molded Products <One

Packaging technology is a factor that determines the long-term reliability of semiconductors, and has played an important role in the development of miniaturization, high integration, and high performance of ICs, and thus, the required performance of packaging materials has become more strict. An important requirement has been to develop appropriate countermeasures for low hygroscopicity and low stress. In particular, an ultra-thin package having a thickness of 1 mm or less easily cracks at about 260 ° C., which is a working condition of the actual surface, even when a very small amount of moisture is absorbed in nature. Therefore, the low moisture absorption of a packaging material by high filling of a filler, improvement of the physical property of resin, etc. becomes a big subject.

Since the material constituting the semiconductor device is made of materials having different thermal expansion coefficients, internal stress due to heat is likely to occur, which causes semiconductor defects and cracks. The internal stress value by heat can be calculated according to Hooke's law,

σ (t). : Internal stress at temperature t

Tg: glass transition point

E (t): modulus of elasticity of packaging material at temperature t

α _r (t): coefficient of thermal expansion of the packaging material at temperature t

α _s (t): Coefficient of thermal expansion of the packaging material at temperature t

From this equation, it can be seen that by high-density filling of the filler, the difference in thermal expansion coefficient between the packaging material and the semiconductor element can be reduced, and the elastic modulus can be reduced by modifying the resin. Ultimately, it is possible to improve the reliability of the semiconductor.

Therefore, as the characteristics required for the packaging filler, electrical insulation, water resistance (which has low water absorption and dissolution properties), low thermal expansion coefficient, high thermal conductivity, and the like are very important. In addition, the fluidity at the time of molding does not prevent the hardening of the resin, and it is required that there are few components that emit alpha (α) rays, the price is low, and the supply and demand is easy. Does not exist.

Therefore, fillers currently commonly used are mostly silica-based fillers.

The following table 2 and 3 introduce the classification, characteristics and main uses of silica fillers for semiconductor packaging. Crystalline silica fillers produced by pulverizing natural high-purity silica are suitable for packaging power integrated circuits or bipolar devices with high thermal conductivity and high calorific value, and fused silica fillers with very low thermal expansion coefficients are used as other semiconductor packaging materials. have. The fused silica filler is obtained by melting the silica once into a quartz glass and then grinding it.

In addition, a soft error due to alpha rays emitted from the uranium (U) and thorium (Th) components contained in the high-density memory packaging material poses a problem. Therefore, synthetic fused silica having a U and Th content of 0.3 ppb or less is a problem. Is used.

Table 2 Classification and Properties of Silica Fillers for Packaging

division Quartz, crystal, crystalline silica Quartz glass, fused silica Synthetic fused silica importance 2.65 2.20 2.20 Melting Point (℃) 1.710 1,710 1,710 Thermal expansion coefficient (10 ^-7 ℃ ^-1 ) - 5.4 5.4 Thermal conductivity (10 ^-4 cal / cm · s · ℃) 120 to 300 38-48 38-48 Moh's 7 5 5 Volume resistivity (ohmcm) 10 ¹⁶ 10 ¹⁷ 10 ¹⁷ U content (ppb) 50-300 50-300 0.3 Price One 3 30

Table 3 Types and Applications of Silica Fillers for Packaging

Kinds Usage 結晶 性 silica (natural grinding) It is not necessary to reduce the thermal expansion rate and the price is cheap. For small devices (transistor, Bi-polar IC) It is not necessary to reduce thermal expansion rate and needs high thermal conductivity. For full mode of medium-sized devices (medium output transistors). Non-silica silica (synonymous with quartz glass) (processed from natural, melted, ground or spherical) Low power consumption devices that require a low thermal expansion and do not require very high conductivity: For large devices (such as various memory microprocessors represented by memory above 64K DRAM) Non-silicone silica (synthetic, ultra low U content) A memory of 64K DRAM or more, for a large-sized device having an ultra-high density, which is susceptible to malfunction due to?

On the other hand, the larger the particle size distribution of the packing material for packaging, the better the fluidity and the higher the mixing. Influence of the filler by the granulation is advantageous to the fractured phase for the expression of crack resistance of the packaging material, and to the spherical filler to improve the fluidity during molding. In addition, in accordance with efforts and demands for effectively improving the mechanical and electrical properties of packaging materials, fillers surface-coated with surface treatment agents such as epoxy silanes have been developed.

As mentioned above, the packaging filler does not satisfy all the requirements, and various kinds of mixtures are used depending on the necessary characteristics at that time.

Currently, a Japanese packaging material manufacturer develops and announces a special packaging material that reduces the absorption rate by half by improving the resin and increasing the filling rate of the filler by 20%, eliminating the need for drying before mounting the IC to the substrate. The inventors of the present invention have also been devoted to the development of ceramic packaging materials that can prevent the warping phenomenon during drying of conventional resin packaging materials, and the results are expected.

In summary, the present state of the relevant technical field shows that the waste of silicon single crystal ingot crucibles and the consumable quartz glass jig parts wastes for the wafer support during the silicon wafer processing process, which are the subjects of the present invention, can be It has been found that reuse as a crucible for single crystal pulling, which is the original use, is impossible, and if a proper pretreatment technique and an effective powder processing technique are combined, it will be possible to recycle and utilize it as a functional filler for epoxy molding compounds.

Accordingly, the present invention has been made to solve the above-mentioned problems in the related art, and the object of the present invention is to reclaim and utilize a silicon single crystal ingot raising crucible waste, which is currently landfilled, as a functional filler powder material. .

1 is a process flow diagram for explaining a method for preparing an amorphous silica filler according to an embodiment of the present invention.

2 is a graph showing the results of X-ray diffraction analysis of the amorphous silica filler prepared by the method of FIG.

3a to 3c are scanning micrographs according to the particle size of the amorphous silica filler prepared by the method of FIG.

In order to achieve the above object, a method for producing an amorphous silica filler according to one aspect of the present invention comprises a crucible waste for silicon single crystal ingot raising and a quartz glass jig fragment which is a consumable waste of semiconductor manufacturing process. Collecting the waste specimen selected from the group; A pretreatment step of removing impurities from the collected waste specimens; And powdering the waste specimen to an appropriate size.

Preferably, the pretreatment step includes ultrasonic cleaning the waste specimen and drying the cleaned specimen.

Optionally, the pretreatment step includes physically polishing the waste specimen, ultrasonically cleaning the surface polished specimen, and drying the ultrasonically cleaned specimen.

Optionally, further comprising performing a chemical and thermal treatment after the physical surface polishing treatment step.

Chemical and thermal treatments include placing the specimen in a vessel containing a water-soluble amine solution and heating the specimen to a temperature of about 80 ° C. or more for several hours.

Hereinafter, the present invention will be described in more detail with reference to the preferred preparation of the particulate amorphous silica powder filler composition according to the present invention.

(Example)

1 is a process flow diagram showing a method for preparing an amorphous silica filler according to an embodiment of the invention.

The pretreatment process is performed to effectively remove impurities adhering to the quartz glass waste, and is a technique including a physical, chemical and thermal process and a cleaning process by ultrasonic waves.

Referring to Figure 1, first, the quartz glass waste is collected (S10). Collected quartz glass waste is selectively pretreated according to the degree of contamination of the impurities (S20). Thereafter, the pretreated quartz glass waste is crushed into fine particles (S30).

The above-described pretreatment process (S20) undergoes different processes according to the degree of contamination of impurities, and when the degree of contamination is weak and easily attached impurities are attached, only simple ultrasonic cleaning treatment is performed (S112) and dried. S104).

On the other hand, when the adhesion force of impurities attached to the quartz glass waste is high and it is difficult to clean only by simple ultrasonic cleaning, the physical surface polishing treatment and the chemical and thermal treatment are selectively performed before the ultrasonic cleaning treatment. That is, the physical surface polishing treatment is first performed (S122), optionally chemical and thermal treatment (S124), ultrasonic cleaning treatment (S126), or chemical and thermal treatment first (S132), the physical surface The polishing treatment is selectively performed (S134), and the ultrasonic cleaning treatment is performed (S136).

After the ultrasonic cleaning treatment is completed, the samples are put into a grinding step after drying (S104).

The chemical and thermal treatment used here is maintained for several hours while throwing waste quartz glass shards into water-soluble amines and heating them to a temperature above 80 ° C. By the principle of oxidizing the remaining polysilicon component adhering to the surface in a SiO ₂ state, it is gradually desorbed and removed from the adhered silicon component surface.

On the other hand, this method does not act as a large defect when recycling to the final filler because it remains as crystalline silica instead of metal silicon even if it is not completely washed during the next process.

The impurity removal process by physical surface grinding treatment has the difficulty of collecting large debris as far as possible from the waste collection process, that is, the generation size of waste debris to the original size as much as possible, but the most active and perfect removal of impurities As a method, it was the main pretreatment process selected in the present invention. Grinding machines used in this process are typically portable equipment widely used for stone processing and the like.

In the ultrasonic cleaning process, the surface contamination of the collected molten glass waste collected after collection is limited to the degree of dust adhesion due to the adhesion of contaminants at the time of collection, or the waste components during the semiconductor manufacturing process (wafer during the silicon wafer processing process). Consumable jig parts for supports, etc.) were introduced into the final treatment process simply for cleaning and after the physical, chemical and thermal treatments described above were completed. The ultrasonic cleaner used at this time used a large sized cleaner specially designed and customized according to the characteristics of the waste.

Next, a step (S30) of powdering the samples of the pretreatment process is completed by the above-described method.

The quartz glass waste flakes subjected to the above-mentioned pretreatment step were subjected to granulation by conventional crushing, pulverizing and pulverizing processes. At this time, in order to prevent the mixing of impurities during grinding, the selection of interior materials for each device and other process control are carried out precisely, and before the final shipment, the particle size distribution diagram is introduced by a dry classifier after introducing the attached process technology such as magnetic screening. Precise control.

Characterization of the particulate amorphous silica powder filler composition according to the present invention obtained by the present Example was performed as follows, and the results are shown in Table 4, FIG. 2, and FIGS. 3A to 3C.

-Chemical composition analysis method and result

The analysis of the components was carried out by wet mineral chemical analysis in accordance with KS L 2101.

As shown in Table 4, as a result of the analysis, it was determined that high purity siliceous containing 99.73% of SiO ₂ as a main component, and 0.08% of alumina (Al ₂ O ₃ ) as an impurity.

Table 4 Results of Chemical Composition of Waste Quartz Glass Powder

Sample name SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ CaO MgO K ₂ O Na ₂ O TiO ₂ Total FS 99.73 0.08 Tr Tr Tr Tr Tr Tr 99.81

X-ray diffraction analysis

In general, when the quartz glass is heat-treated at 1100 ° C. or higher in an oxygen or moisture atmosphere, crystallization represented by siltu occurs. Therefore, X-ray diffraction analysis was performed to determine whether crystallization of the discarded quartz glass fragment, which is the object of the present invention, is shown in FIG.

As shown in FIG. 2, the waste debris retained the original state of the quartz glass from the point of view of the halo curve of a typical amorphous glass, and may be referred to as fused silica.

Scanning electron microscope (SEM) analysis

In order to confirm the applicability of the powder obtained as a functional filler to finely divided waste quartz glass fragments, after scanning, scanning electron microscope observation was performed for each particle size and the results are shown in FIGS. 3A to 3C.

3A shows a case in which the particle size of the particle size is about 5 μm, FIG. 3B shows a particle size of about 10 μm, and FIG. 3C shows a particle size of about 23 μm.

As shown in Figures 3a to 3c, each of the powders were represented as a typical glass closed corner, it can be seen that the even state.

-Recyclability Analysis

From the results of micronization and other analysis of waste quartz glass fragments, the objects must be high purity molten quartz glass. Therefore, to investigate the applicability to the fused quartz glass powder, the data related to the quartz glass powder were investigated.

As a result, it is considered that the present invention can be recycled as an existing packaging filler such as EMC, and can also be used as an industrial filler such as tire.

As described and demonstrated in detail above, according to the present invention, quartz glassy crucible shards and semiconductors, which are one of the silicon single crystal ingot raising crucible wastes that have been conventionally disposed of as landfills or simply reused as inexpensive side materials for refractory materials. It is possible to recycle and utilize quartz glass jig fragments, which are process consumable wastes, as high value-added functional filler materials, converting waste resources into valuable resources, protecting the environment by reducing new consumption of new natural resources, and increasing landfill years, The direct and indirect socio-economic spillover effects, such as the reduction of unproductive costs due to landfills and the recycling of more than 60 tons of waste generated per month, are very significant.

Claims (9)

Collecting at least one kind of waste specimen selected from the group consisting of a silicon single crystal ingot raising crucible waste which is being landfilled and a quartz glass jig fragment which is a consumable waste of a semiconductor manufacturing process; A pretreatment step of removing impurities from the collected waste specimens; And Method for producing an amorphous silica filler comprising the step of powdering the waste specimen to an appropriate size. The method of claim 1, wherein the pretreatment comprises ultrasonically cleaning the waste specimen and drying the washed specimen. The method of claim 1, wherein the pretreatment step includes physically polishing the waste specimen, ultrasonically cleaning the surface polished specimen, and drying the ultrasonically cleaned specimen. A method for producing an amorphous silica filler, characterized in that. 4. The method of claim 3, wherein said pretreatment step further comprises performing chemical and thermal treatments after said physical surface polishing treatment step. 5. The amorphous silica of claim 4, wherein the chemical and thermal treatment comprises introducing the specimen into a container containing a water-soluble amine solution and heating the specimen to a temperature of about 80 ° C. or more for several hours. Method of Making Fillers. 4. The method of claim 3, wherein the pretreatment step includes performing chemical and thermal treatment of the waste specimen, ultrasonically cleaning the chemically and thermally treated specimen, and drying the ultrasonically cleaned specimen. A method for producing an amorphous silica filler, characterized in that. 7. The method of claim 6, wherein the pretreatment step further comprises physically polishing the surface of the specimen after the chemical and thermal treatment steps. 8. The method of claim 6 or 7, wherein the chemical and thermal treatment comprises placing the specimen in a vessel containing a water-soluble amine solution and heating the specimen to a temperature of about 80 &lt; 0 &gt; C for several hours. Method for producing an amorphous silica filler. The method of claim 1, wherein the amorphous silica filler is used as a filler for thermosetting resin encapsulant of a semiconductor package and for manufacturing a tire.