JPH05508517A - Polypropylene wafer carrier - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Polypropylene wafer carrier This invention transports silicon wafers to be processed into integrated circuit chips (+hipp ing). Learn more This invention relates to the properties of polypropylene used in such shipping containers. do.

[Background of the invention]

The above-mentioned containers, known as zippers, have been used for a long time and are polypropylene. Molded from pyrene. The polypropylene that has been used so far has It was chosen because of its high level of transparency. Polyps that have been used so far Lopyrene is considered to be very clean based on the total amount of volatiles evaporated. It was getting worse. The total amount of volatile substances at this time was A (order Pbiladelph, order Pann571!n) of the American species Atty for Testing and -7 Territorials (American 5 ociet7 lot Testing IndMaterials) by Published Annual Book of NST-M Standards (Annual Book of ASTM Sth nda+dsl 15.0 It is determined by the well-known test method described in Volume 3 F1227.

However, users of these zippers have found that traditional polypropylene zippers contain organic impurities. Outgas (ou1ga+) L, this organic impurity adheres to the sea urchin/%- I understand. Typically, if there are no organic impurities on the surface of these wafers, In some cases, the wafer's oxide layer is very hydrophilic and deionized (DI) water is No water droplets are formed on the wafer. All this Housed within a traditional zipper formed from polypropylene that has been used in Ueno 1- is an organic contamination fo+ resulting from exposure to the zipper's polypropylene. It can be seen that it becomes hydrophobic due to ganic c++ lamination). ing.

The polypropylene used in conventional zippers, which produces this hydrophobic property, is A string from Wilmington, Lauea (Wilmingfon 5Del!vue) Ninnisny Incorporated 01imont Il, S, A , Inc. ) random copolymer. Random copolymer is Polymerize monomers to which a high activity (high acji polymer 1 ty) catalyst has been added. After mixing, add a clarifying agent (clui17ing Bent) and calcium stearate. is added as a flow enhancer, and phosphorous acid Added antioxidants such as salt and hindered phenols. Ta. The catalyst is also an atactic material (g + 1c Itel material produced during polymerization). Even the polypropylene is not removed before being used to mold the zipper. There wasn't.

The exact characteristics of the polypropylene component are generally kept as trade secrets and therefore The characteristics of the ingredients used in other zippers on the market are not publicly available. I don't know, I don't understand.

Also, double deixed polypropylene Ren has been known for a long time, but it includes silicon and gallium arsenide wafers, A memory disk made of magnetic material is stored (+to+e) for transportation. This polypropylene has never been used for zippers or containers. . These traditional double-deashed polypropylenes are made with clarifying agents and flow It uses a large amount of enhancers and some types of hindered enzymes with large molecular weights. Nor-based antioxidant/ozone cracking inhibitor (xnliotonanl) is also used. It's here. All of these, if used in wafer zippers, can cause significant outgassing. Polymers that occur in large amounts and contaminate the stored sea urchins to an unacceptable degree. Becomes propylene. As a result, the wafer becomes unacceptably hydrophobic. sand In other words, it needs to be cleaned before use.

Hydrophobicity is best measured by simply wetting the wafer surface with DI water. Common. If the water does not spread over the wafer and becomes water droplets, the wafer becomes contaminated. and immediately know that it must be cleaned before use.

Of course, cleaning requires an extra step in wafer processing, which can be costly. will also generate more particles that will further contaminate the wafer surface. For the sake of possibility, it's not a good thing. Wafer manufacturers also avoid hydrophobic contamination. I also take care. Because contamination can affect the wafer in other ways It is from.

The zippers are hydrophobic on the wafers carried by these polypropylene zippers. A somewhat harsh and rough process is needed to determine whether Tests have been conducted. The conventional methods are very subjective (Sυbie However, the magnitude of the hydrophobicity that occurs on the wafer is This shows that different pyrenes result in different results. The conventional test method The wafer was placed inside such a polypropylene zipper in the open at 50°C. This includes a 24-hour storage step. After 24 hours of storage, the wafer Remove from zipper, wet with DI water, and tilt to vertical position. After 10 seconds, Record the percentage of wafers that are not hydrophobic.

[Summary of the invention]

It is an object of this invention to prevent organic contamination and its related effects on wafers contained within the zipper. Polypropylene with properties that minimize the possibility of causing hydrophobicity A storage device formed from pyrene suitable for storing and transporting wafers. manufacturing containers.

Another object of the present invention is to provide a zipper with a zipper made of polypropylene. by providing an improved method for checking hydrophobicity occurring in wafers. Ru.

A feature of this invention is that silicon wafers and other similar wafers as well as magnetic devices can be A polypropylene container specifically used for storing and transporting discs.

This polypropylene container is used to store the products stored inside the container. Outgassing onto the recon wafer, resulting in contamination or hydrophobicity of the wafer Materials such as atactic polypropylene and oligomers that can cause Molded from polypropylene. Preferred polypropylene is a clarifying agent and Old style catalysts containing as little antioxidants and flow enhancers as possible consists of a doubly deashed random copolymer polymerized with inside the zipper Such polypropylene minimizes the outgassing of organic contaminants and is Keep silicon wafers clean when performing storage. Therefore, Copy Unino 1- There is no need to wash the sea urchins after they are stored in the container and before further processing. It disappears. Obtained from a polymerization process using highly active catalysts and containing the aforementioned additives Polypropylene can contaminate the wafer surface and make the wafer surface hydrophobic. This could be used if the material that causes it is removed.

Constructed from double deashed polypropylene, this container is impact resistant and It is also transparent enough to allow the stored wafers to be opened in closed containers. It can be visually inspected without any need for inspection.

Eliminating clarifying agents from double deashed polypropylene is often This is not a problem if the This is because the thin cross-section makes the container panels sufficiently transparent. This is because it is clear and necessary inspections can be performed.

The preferred polypropylene used to form containers is Low ethylene content for transparency and impact resistance, important properties for antennas. We use as little random copolymer as possible. Transparent in polypropylene It is important to keep the amount of brightening agent as low as possible. Because the container part Random copolymers themselves are sufficiently transparent unless they have a particularly thin cross section. This is because they do not have . Transparency means that in normal use it is adequately transparent and required to be able to inspect the silicon wafer housed inside the antenna. be.

Unlike this, polypropylene is made with minimal antioxidants/antiozonants. Consists of a double deashed homopolymer with added low enhancer. It's okay. Usually, homopolymers do not have added clarifying agents. From homopolymer This double deashed polypropylene is used in some panel areas. If molded into a very thin cross-section, it will have appropriate transparency. From homopolymer Polypropylene made of random copolymers has high impact resistance. Although it may not be impact resistant, it has adequate impact resistance in most cases.

This is because the polypropylene range tube on which the wafer is mounted is This is because ~- is expensive and is therefore treated with great care. homopolymer polypropylene The main difference between the two is the elimination of ethylene from the monomer. random copo Lima contains ethylene.

For polypropylene, antioxidants/antiozonants help break the polymer chains. This is important to prevent the material from becoming brittle. Preferably, use The antioxidant used is Ethanox 7, (Efhanox) 330, It is a hindered phenol compound that has the property of producing little gas. this is Reduce the hydrophobicity that occurs in stored wafers.

Polypropylene mold filling (mol dlit! fng) and to improve ejection characteristics. It is important to minimize the amount of flow enhancer in the polypropylene. Ru.

Polypropylene to remove oligomers, atactic polypropylene, and polymerization catalysts. It is believed that it is important to double de-ash the pyrene. double deer Wash polypropylene with solvent cleaning agent (+olven+vxshingl) By double-passing the molded container into the Uni-No- outgasses the amount of organic contaminants that need to be cleaned again after storage. It includes steps to ensure that this does not happen.

The double deashed material has some volatiles from the solvent detergent in it. However, these compounds have sufficiently small molecular weights and are sufficiently volatile to Because it is rich, it recondenses on the wafer (τeeon+1ense) and becomes hydrophobic. There is no such thing as causing sex. Also double deashed polypropy Len is a trace amount of gold that is thought to become a contaminant if it accumulates on the surface of Unino. It is also important that the level of trxce metal is low.

Whenever we use the word wafer, we are referring to silicon that is processed into circuit chips. various types of disks and disks formed from gallium arsenide and gallium arsenide; Any object such as a wafer, a disk processed into a memory disk, or a magnetic medium. shall be included, without any special limitation.

Another feature of this invention is that silicon urinary oxides can be contaminated to cause hydrophobicity. Determine the suitability of polypropylene for use in zippers without ine). Organic for sample sea urchin/'- The material must be washed first so that the resulting hydrophobicity can be seen later. . After properly cleaning the wafer, this Unino 1- is also pre-cleaned of organic contaminants. stored in washed jars and then at a temperature of e.g. 50° C. for about 20 hours. Store with polypropylene resin in a sealed clean jar. We When storing wafers inside zippers, wafers are stored at high temperatures of 50°C. be exposed to. After storage and exposure, Cecil drop contact angle measurement is performed. The hydrophobicity of a wafer is measured by a method called hydrophobicity. Cecil drop (+ es+ile d+op) contact angle measurement method is effective when organic contamination is very small. Unless the surface of the roller or wafer is very hydrophilic, Can be measured accurately. Preferably the jar and its cover, the wafer and the inside of the jar. Support the wafer on an aluminum stand and using an oxygen plasma cleaning device. Washing is preferred. Oxygen plasma cleaning equipment is commercially available and It is well known to engineers. Otherwise, add Nochromix (H) in sulfuric acid. Place the jar in a strong acid such as concentrated sulfuric acid with hromixl additive or chromium trioxide. Clean by soaking. After cleaning with these acids, rinse the jars with DI water. and dry on an open frame (Ilimel).The wafer will turn red. Prepare wafers or wafers by heating them on an open frame until Cleaning organic contaminants from aluminum stands for supporting the housing. this Unlike other products, you can use UV ozone cleaners to clean jars, stands, and wafers. However, it is preferred to use oxygen plasma cleaning.

Utilizing Cecil Drop Contact Angle Method to Determine Hydrophobicity of Wafer Surface When using a microsyringe, pour a small drop of DI water onto the sea urchin/X- wear. When the water droplet stops spreading, the surface of the wafer and the base of the water droplet (bx measure the angle between the tangent to se). This is the advancing angle (advxncing It is called 'alley'. Tilt the wafer or pour water until the water drops move. By pulling back to the microsyringe, the retraction angle (+eceding a ngle) is also measured. When the end of the water droplet starts to retreat, water removal (vatξr umoval) and calculate the angle between the surface of the wafer and the tangent to the base of the droplet. Measure. Retraction angles are very difficult to measure when the angles are very small.

However, a small angle means that the surface is highly hydrophilic and hydrophobic. It shows that there is no

[Brief explanation of the drawing]

Figure 1 shows a polypropylene container for transporting silicon wafers according to the present invention. FIG.

Figure 2 shows the polypropylene used in molding the polypropylene shipping container of Figure 1. 2 is a flowchart showing polymerization and washing of polymer.

Figure 3 shows that the surface is cleaned and hydrophilic, and deionized water spreads over the surface. FIG. 2 is a perspective view showing one of the silicon wafers.

Figure 4 is a side elevational view of the silicon wafer of Figure 3, showing that the wafer is highly hydrophilic. It shows deionized water spread evenly over the surface.

Figure 5 shows that deionized water droplets are formed on a surface that is at least partially hydrophobic. 1 is a perspective view of a silicon wafer having a surface that looks like

FIG. 6 is an elevational view of the wafer of FIG. 5 with water droplets forming on the surface of the wafer. It shows water.

Figure 7 shows an oxygen plasma cleaning device useful for cleaning sample wafers and a polypropylene Others used in an improved method to check the hydrophobic effects of pyrene resins FIG.

Figure 8 determines the hydrophobic impact of resin on stored wafers A closed cage used to expose the wafer to polypropylene resin Figure 2 shows a lean jar.

Figure 9 shows the effect of hydrophobicity of polypropylene on silicon wafers. Cecil Drop Contact Angle Measurement Used for Improved Method for FIG.

[Detailed explanation]

The wafer storage device 9 has an outer container made of polypropylene for transporting wafers. It has a tena 10. Important parts of the outer container: beam septacle 11 and cover 12 It is. Receptacle 11 and cover 12 are firmly aligned at joint 13. engaged with the body. The joint 13 is sealed by tape with adhesive on it. The inside of the container is sealed and isolated from the surrounding conditions outside the container. It is. Alternatively, the cover 12 can be attached to the receptacle 11 using a latching mechanism. May be held on top. The container 10 is made entirely of polypropylene by injection molding. It is formed from Polypropylene is very transparent and therefore inside the container The objects in the container are visible through the walls of the container.

Container 10 contains an inner container or wafer carrier 14.

The wafer carrier 14 includes a large number, typically 25, silicon wafer carriers. 5 is stored. Wafer carrier 14 and container 10 are then formed. It is molded from the same polypropylene as the original. Other similar wafer carriers 14 is Teflon PFA or perfluoroalkoxy molded from other materials such as polyethylene or polyethylene. may be used, but is probably not used for polypropylene containers10. Will.

The individual wafers are placed side by side in alignment with each other. wafer are separated from each other by a plurality of separating teeth or webs 16. web 16 is formed integrally with the wafer carrier 14 on the side wall of the wafer carrier 14. has been done. Teeth or webs 16 allow each wafer 15 to engage an adjacent wafer. This minimizes wafer movement within the carrier.

The wafer carrier 14 is provided with a web 16, which is moved by the robot. It is easier to handle the rear. The upper part 17 of the wafer carrier 14 is open. wafer insertion or removal when the carrier is removed from the shipping container 10. makes it easy to take out. The bottom part 18 is also open, and the bottom part 18 is open to the wafer 15. Processing liquid can be flowed through. Generally, the side walls 19 of the carrier are also coated with wafers. Slots are provided to allow liquid or gas to flow during processing. .

Wafer carrier 14 is described in U.S. Pat. No. 4.949.1148 or 3.96. 1.877 or other similar commercially available carriers. It has a ya-like structure.

The lower part or receptacle 11 and cover 12 are completely closed and the container This prevents liquid or gas from flowing into or out of the na 10. It should be noted that there are

When the wafer 15 is stored, the inner surface of the wafer beam receptacle 11 is exposed. outgassing occurs from the container walls. The transport container has cover 12 The cover 12 has a cushioning device formed in the cover 12 or attached to the cover 12.

The cushion device 20 engages with the wafer 15 and presses it downward, and the wafer is held in a wafer carrier 14.

Preferred materials for forming container 10 and wafer carrier 14 are Diashed antioxidant/antiozonant and fluorene/tamensa , preferably a random copolymer polypropylene that also contains a clarifying agent. this Unlike , antioxidants/ozone inhibitors and fluorocarbons are used as materials. A doubly deashed homopolymer may also be used.

Double deashed random copolymer polypropylene or double deashed random copolymer polypropylene It is known that it is the least likely to cause aqueous reactions. random copolymer polypropylene is naturally transparent and has impact resistance. These properties are suitable for shipping containers. That's important. These characteristics are due to homogeneous materials, which are less solid, less transparent, and have less impact resistance. It is considered to be considerably superior to polymers, but in many cases it is not decisive. It's not important.

Random copolymer is a polypropylene basic structure (random to backbone) It has an ethylene monomer polymerized to Random copolymers consist of the following repeating units: It has a unique position (uni).

Here, "X" has more than 90% links. Etile of random copolymer resin The content is between 2.2 and 2.8%.

Double deashed polypropylene is one of the clearest polypropylene resins. It is thought that there is one. This process removes oligomers and attaches. The polymerization catalyst is removed and the isotactic polypropylene is This is because the desired propylene, known as carbon, remains. isotactic polyp Lopyrene has the following steric configuration (iteric orienlxlion) have

The oligomers that are removed are compounds with almost no monomeric units. Should I remove it? The sticky polypropylene produced is a very soft and sticky material. Used for adhesives. Atactic polypropylene is as follows Contains monomer units with a specific steric configuration.

In both of the configurations described above for polypropylene, R is a group of CH, It represents the The polymerization catalyst is also removed by the deash treatment. This touch The medium is a recently developed high-activity polymer used when polymerizing certain types of polypropylene. It is an old style catalyst compared to the sexual catalyst. Highly active catalyst polypropylene After the synthesis, undesirable catalysts, atactic materials, and outgassing It may be possible to use it if it is washed to remove other materials such as oligomers that cause unknown.

Double deashed random copolymer polypropylene used here contain volatiles from solvent detergents to some extent; Since the compound has a sufficiently small molecular weight and is sufficiently volatile, it is - not recondensed on top to create hydrophobicity. Washing the polymer removes the Because the medium is useless (ol +or++) oxidized metal ash (xsh) , deashing (called dcashingl) Polypropylene that is polymerized Due to the high ash content and atactic content when producing It is necessary to perform ashing. Double deashing washed polypropylene It has a double pass step in the process. Deashed polypropylene is In addition to low levels of hydrophobic compounds, there are also low levels of trace metals. Metal is a semiconductor This is beneficial since it is considered a pollutant in the industrial industry.

Although fairly transparent, random copolymers are transparent enough to be used in this situation. Therefore, it is necessary to use a clarifying agent in the polypropylene molded into the container 10. It is hoped that Clarifying agents crystallize polypropylene and make it optically clear. .

The clarifying agent is preferably a sorbitol-based material, which is a basic sugar Structure and benzaldehyde derivative (derinttve 1ppendxfe) have

The clarifying agent is preferably known as Mtlsui NC4. stomach. Mitsui NC4 is a very transparent material. Clarifying agents should be used at very low levels. It is preferable to use 1.5o (lpp is preferred. The clarifying agent is thus added to the lowest possible filling level (iosdi11!1 polypropylene on stored wafers. It is thought that this can contribute to reducing the influence of hydrophobicity of Ren. Clearing agent filling level The bell is loo~3. Although it is in the range of QOOppl++, the level is usually Considering that is 2.500 ppm, it is understood that this filling level is small. can.

The structure of the material Mitsui NC4 is as follows.

Derivative Sorbitol Sugar - basic structure Antioxidants/antiozonants (hereinafter referred to as antioxidants) are added to polypropylene. This prevents the polymer chains from breaking and making the material brittle.

Although there are many antioxidants to choose from, the preferred antioxidant is ethyl. Manufactured by Corporation (!1byI Corps, riHonl) It is Ethanox (E [huoz) 330. Technically, Eternoc The step 330 includes 1, 3. 5-) Listyl-2,4,6-) Listile (3,5-G Consists of benzine (tert-butyl-4-hydroxybenzyl) Ru. This antioxidant is a high molecular weight hindered phenolic compound and is Contains no salt. Phosphorus is a strong dopant in semiconductors, and it is difficult to get out on the wafer. Eliminating phosphites is a highly undesirable antioxidant by-product. is desirable. The preferred loading level of antioxidant is about 1.000 ppm plasma. This is a minus 15%. This level is used as an antioxidant in the production of polypropylene. This is the minimum range of filling levels for In some cases the filling level is 250P Generally, acid The inhibitor is loaded at levels ranging from 1,000 ppm to 2,500 ppm.

Other antioxidants that can be used, although not preferred, include Ciba Geigi (C Irganox (Irgino) manufactured by Hibs Geigg There is x>1010. This antioxidant is technically Tetrakis (methylene) [3,5-di-tert-butyl-4-hydroxy cyhydrocinnamate)] methane It is expressed as The polypropylene used to form the container 10 is mostly Contains flow enhancer additives as well as polypropylene. The most common floe Calcium stearate is used in polypropylene container 10. has been done. Filling level in polypropylene of this invention for container lO The color is set to about 1100pp plus or minus 15%, and it is polypropylene. while minimizing the potential for contamination of materials outgassed from – giving characteristics. This filling level is about 250 ppm, which is the general filling level. Yes, otherwise the filling level is 1. Floae range up to HOpp Considering that it is a 3D filter, it can be seen that it is very small. steer Calcium phosphate is a flow enhancer in the polypropylene compounds of this invention. This is considered to be the preferred form.

Other additives added to polypropylene are not used in polypropylene in container 10. Preferably not. These other additives are UV stabilizers and thermal stabilizers. and extend the service life of materials exposed to ultraviolet light. most one Common sources of UV irradiation are the sun and fluorescent lights, which do not include UV stabilizers. Transparent or translucent polypropylene should not be exposed to ultraviolet light for long periods of time. It becomes brittle when exposed to stress. This use of container 10 is not intended and must be followed. Avoid additives that may cause contamination.

When producing homopolymer polyprohin, a polymerization reactor (po17 + uri zation reacted). but , all the process steps shown in Figure 2 were followed except that no clarifying agent was added. I will do it. The amounts are the same as those shown for the random copolymer polypropylene. It is the same.

In summary, hydrophobic properties for wafers stored in polypropylene containers Until now, polypropylene, which has a very low impact on was not used. In addition, this polypropylene is different from other conventional polypropylenes. It's much improved compared to that. This requires very little clarifying agent or flow enhancer. The surface of the wafers stored in the container must be In order to improve the hydrophilicity and suppress the hydrophobicity, the new resin uses Ethanox 330. This is because it is used.

FIG. 2 shows a port used when forming a zipper or shipping container 10. General processes for polymerization, deashing, drying and pelletizing of polypropylene It shows the process. Ethylene and propane are used as catalysts and propane as solvents. A monomer containing pyrene is placed in a polymerization reactor 25. In the polymerization reactor 25, Lima is suspended in a solvent. Remove the polymer suspended in propane from the reactor. After taking out (drew ofil), flush propane at 26 (flash oll). For deashing, a solvent, preferably hebutane, is flushed. The polymer solids are placed in a deashing device 27. suspended in a solvent The deashed solids are taken out from the deashing device 27 and filtered. It will lead you to 28. That is, it is first guided to the bag filter, then to the drum filter. The liquid is separated from the solids. Atactic polypropylene and catalyst , oligomers and other undesirable substances can cause What is removed along with the solvent separated from the solids consisting of , in this filter. Isotactic polypropylene flakes It is fed to a second stage 29 of deashing or cleaning. At this stage, for example A solvent such as butane is added. Take out the solvent containing the polymer flakes again and , leads to filter 30.

That is, it is first led to the bag filter and then to the drum filter. This fill Separates liquids and solids, and removes atactic polypropylene, catalysts, oligomers, etc. Remove solvent containing undesirable materials. Extract the polymer flakes from the filter 30. The sample is taken out and supplied to the oven 31. Oven 31 turns the remaining solvent into polymer flakes. Remove and tumble the flakes! , to finish the drying process. do. Next, when feeding the flakes into the extruder and pellet apparatus 32 Additives such as antioxidants, clarifying agents, and flow enhancers are added to dried polymer resins. Add to the tank to complete the process. Pellets are suitable for use in containers 10 Molding machine 3 from pellets made of polypropylene and manufactured as described above. 3.

Molding shipping containers made from all the different types of polypropylene you can think of. caused by transporting containers made of polypropylene without the need to An improved method for measuring hydrophobicity on silicon wafers has been developed.

Typically placed in a covered glass jar, washed to eliminate organic contaminants. Install the silicon wafer made. Jars are also free of organic contamination, at least on the inside. Cleaned free of staining substances. The wafers are made of aluminum in a jar. Preferably, it is supported on a stand. Aluminum stands also have organic contamination The substance has been cleaned. Put the polypropylene resin in the jar, as shown in Figure 1. The temperature to which the wafers are exposed during transportation and storage in the container 10 stored at a temperature for a period of time. Once the exposure is complete, remove the wafer from the jar. Remove and place a palm drop of deionized water onto the wafer surface. forward movement of water droplets Measure the contact angle and retracted contact angle. These angles are at the wafer surface shows hydrophobicity. When the contact angle is large, the hydrophobic property is large and the hydrophilic property is large. When the contact angle is small, it is less hydrophobic and more hydrophilic. It shows that is large.

Next, of the polypropylenes tested, the one with the least hydrophobicity on the wafer surface was selected. Formed into a shipping container and used as a container.

More specifically, a system such as the wafer 35 depicted in FIGS. Recon wafers and glass jars 36 all with their covers 37 and aluminum Along with the stand 38, a commercially available plastic plug of the type designated by the reference numeral 39 in FIG. Oxygen plasma cleaning in a Zuma cleaner. The plasma cleaner has reference number 40 a vacuum for evacuating the RF oscillator and process chamber 42, represented by It has a pump 41. wafer 35, glass jar 36 and cover 37 When installed separately with the aluminum stand 38 against the Organic contaminants on the surface are cleaned. After cleaning the wafer in this way, A quantity of deionized water is placed on the surface of the wafer 35. Then, this deionized water is 3 and 4, a thin sheet or film is deposited on the surface of the wafer 35. It becomes Lum 43 and expands.

After cleaning the wafer, I installed a clean wafer 35 without getting it wet. A clean aluminum stand 38 is placed inside the glass jar 36 and a quantity of After putting the polypropylene resin into the lower part of the jar, cover it with the cover 37.

The closed jar is then kept at a temperature of about 50°C for a suitable period of time, e.g. 20 hours. The wafer 35 and the resin 44 are then stored in the container 1o. Exposure to the general environment in which it is stored. The resin 44 in the jar generates outgas. Similarly, organic contaminants are deposited on the surface of the wafer 35, which has a hydrophobic property (an affinity for water). (lack of sexuality).

After exposing the wafer 35 to the polypropylene resin for a certain amount of time, the wafer 35 Once removed from the glass jar 36, add one or more drops of deionized water. 45 onto the surface of wafer 35. If the wafer surface is hydrophobic, Figure 5 and the water collects to form water droplets as shown in FIG. Then Cecil Drop Measure the contact angle of the tap. The contact angle in forward and backward conditions is It directly represents the hydrophobicity on the wafer surface.

Measuring the contact angle of a Cecil drop is generally well known in the past. and can be implemented in a number of ways. The contact angle is The angle that the shape of the droplet at its edge makes with the surface it rests on. Ru. The advancing contact angle is the angle at which the water drop moves or advances over the wafer surface. is the contact angle at the droplet end. The movement or advancement of a water droplet is The size of the droplet increases and the edge of the water droplet begins to move outward, or the droplet is placed on top of the When a wafer is tilted, the effect of gravity causes water droplets to move across the surface. I wake up when I wake up. The receding angle means that the amount of water droplets decreases and moves toward the inside of the wafer. , when the wafer is tilted and the water droplets follow (roll). It is the contact angle of the water droplet. In Figure 9, the water droplet 45 is greatly enlarged. Ru. A tangent line 46 is tangent to the droplet 45 at the advancing end of the droplet to the surface of the wafer 35. There is. The forward contact angle is designated by reference numeral 47. Retraction contact angle Degree 48 is after a certain amount of liquid is removed from the water droplet by microsyringe 50. is represented by an arrow between tangents 49 of the water droplet 45a. Retraction contact angle 4 8 is when the volume of the water droplet decreases and the shape of the water droplet becomes 45a shown by the dotted line in Fig. 9. , measured when the edge of the droplet just begins to move inward over the wafer surface. do.

The contact angle can be determined using an optical comparator with a macro lens or a cover. It can be easily measured by Mela. Macro lenses magnify water droplets and The takt angle can be measured.

In other cases, the contact angle may project an image of the water drop or a goniometer Measured using a telescope with an eyepiece. Also, the contact angle is It can also be measured by measuring its size, i.e. its diameter and height. of course, When measuring the advancing or receding contact angle, use a water droplet shaker. Movement and deformation must be avoided.

Cecil drops of DI water on silicon wafers exposed to various polypropylene The results of measuring the contact angle of the tap are shown in Table 1 below.

Material Advance angle Retraction angle (degrees) (degrees) AA (preferred) 10.0 0.6 A (homopolymer) 9.9 1.0 F 17.0 1.0 Cecil drop condensation of water on silicon wafers after exposure to these various substances. When measuring the tact angle, all the materials have a fairly small hydrophobicity on Unino 1-. , indicating considerable hydrophilicity. Container 10 is preferred in this specification. It is made of material AA, which is considered to be a desirable material. Material AA is old style It is a random copolymer that is doubly de-ashed using a catalyst. This copoly Ma contains 2.2 to 2.8% ethylene. Approximately 1 ethanolox 330 ．． It was used as an antioxidant/antiozonant at a loading level of 1,000 ppm.

The clarifying agents described above were used at the 1.500 pp-level. flow enhancer Calcium stearate was used at a loading level of IOQppm. This preference Polypropylene, which is made from a thin material, performs significantly better than other materials tested. Ta.

Material A is a homopolymer material, with polyplasts that are stiffer and more brittle than random copolymer materials. Formed into lopyrene. This homopolymer is double de-ashed and antioxidant/ 1.000 ppm of hindered phenol was used as an antiozonant.

Approximately 1100 pp of calcium stearate was added as a flow enhancer.

Material F in Table 1 is a random copolymer material. This random copolymer material is approximately 2 , SOQppm sorbitol clarifying agent, antioxidant / antiozonant The l.

QOG ppm of hindered phenols and estimated loading level of 2511 ppm. using an additive called calcium stearate as a flow enhancer. It is double deashed.

This invention aims to minimize the hydrophobicity generated on stored sea urchins. Improved conveying compound for silicone unino 1- made of polypropylene. Let's find out something about Tena. This invention features a cap made from polypropylene. Hydrophobic influence of polypropylene on silicon wafers stored in rear Concerning an improved way to check.

This invention may be embodied in other forms without departing from its spirit or essence. can. Accordingly, the embodiments described above are merely illustrative and do not limit the invention. do not have. For the scope of this invention, please refer to the appended claims rather than the embodiments described above. should be looked into.

FIG.8 summary This is a shipping container for silicon wafers. This container holds ethylene. Minimize it as much as possible, and use it as an antioxidant/antiozonant. The amount of high molecular weight hindered phenol should be minimized, and the amount of clarifying agent and Double deashed lander with as little flow enhancer as possible It is formed from polypropylene, which is a mucopolymer. semiconductors in storage A test method for measuring the hydrophobic effect of polypropylene on wafers includes , clean the organic contamination from the sample wafer and clean the inside of the glass jar and the inside of the glass jar. A step of cleaning organic contamination from the cover and the stand holding the wafer; - exposed to polypropylene at high temperature for a certain period of time in a jar, and various other steps. of DI water on the surface of a silicon wafer exposed to polypropylene. and measuring the droplet contact angle, and the minimum water droplet contact angle is It shows the hydrophobic influence of polypropylene on the wafer.

international search report

Claims (25)

[Claims] 1. a container for accommodating wafers, said container having at least one wafer therein; It has a device for holding the wafers and the container is double deashed. It is molded from polypropylene, and the polypropylene is coated with antioxidant/ozone. Wafer storage device with added anti-crack agent and flow enhancer. 2. The double deashed polypropylene is a random copolymer polypropylene. The wafer storage device of claim 1 comprising pyrene. 3. The double deashed polypropylene is homopolymer polypropylene A wafer storage device according to claim 1, comprising: 4. The double de-ashed polypropylene is also added with a clarifying agent. Wafer storage according to claim 1, consisting of a random copolymer polypropylene. Device. 5. A wafer in which the device for holding the wafer is molded from polypropylene. - has a carrier part, and the polypropylene contains an antioxidant/antiozonant and Made from double deashed polypropylene with added flow enhancer. A wafer storage device according to claim 1. 6. The double deashed random copolymer is passed through a washing process twice. A wafer storage device according to claim 1. 7. The random copolymer has an ethylene content in the range of 2.2% to 2.8%. A wafer storage device according to claim 1. 8. The polypropylene is polymerized using an old type of catalyst and then The wafer storage device according to claim 1, wherein the wafer storage device is de-ashed. 9. The clarifying agent is a sorbitol-based material, and this material is a sugar-based material. The wafer according to claim 4, which has this structure and has a benzaldehyde derivative. Storage device. 10. Claim 9, wherein said clarifying agent has a loading level of about 1,500 ppm. The wafer storage device described in Section 1. 11. The antioxidant/antiozonant is a high molecular weight hindered phenol. The wafer storage device according to claim 1, wherein the wafer storage device is a compound. 12. The antioxidant/antiozonant has a loading level of about 1,000 ppm. A wafer storage device according to claim 11. 13. The antioxidant/antiozonant is Ethanox 3. 30. The wafer storage device according to claim 1, wherein the wafer storage device is 30. 14. Claim 1, wherein the flow enhancer is calcium stearate. The wafer storage device described. 15. Claims wherein said flow enhancer has a fill level of about 100 ppm. 15. The wafer storage device according to item 14. 16. A closed solid outer container part that can be opened and a an inner container portion housed therein, said inner container portion having a small amount therein; holding at least one silicon wafer, said outer container portion and said inner container portion; The container part is molded from polypropylene made of polypropylene monomer, and Polypropylene monomer is polymerized using a catalyst and the resulting polymer is then The wafers are cleaned twice, producing harmful catalysts and outgassing, and contaminating the wafers and making them hydrophobic. The resulting polypropylene is freed from antioxidants and other materials are removed. Enhancers are also added to prevent contamination of wafers stored in containers. For wafers that have as little as possible Shippa. 17. The polypropylene monomer is random polypropylene added with ethylene. polypropylene, and a clarifying agent is further added to this polypropylene. The sipper for wafers according to item 16. 18. Claim 1, wherein the polypropylene monomer comprises homopolypropylene. The sipper for wafers described in item 6. 19. An improved method for measuring hydrophobicity on silicon wafers, comprising: The method includes the step of performing a Cecil drop angle measurement on the wafer surface. The steps involved are placing deionized water on the surface of the wafer and discharging some of the water droplets onto the wafer. The water droplets are moved forward on the surface of the wafer, and just before some of the water droplets begin to advance, the water droplets are - forms a forward contact angle to the wafer surface at the point of contact with the surface and the contact angle representing hydrophobicity on the wafer surface. and measuring the skin. 20. The step of advancing a portion of the water droplet onto the wafer surface may include moving a certain amount of water onto the wafer surface. 20. The method of claim 19, further comprising the step of adding water to settle the water droplets. 21. The second portion of the water droplet is moved away from the end of the water droplet that is in contact with the wafer surface. immediately before this part starts to retreat with respect to the second part of the water droplet. forming a receding contact angle with the wafer surface at the end of the water droplet. In addition, the regression condenser is used as a quantity representing the hydrophobicity of the wafer surface. 20. The method of claim 19, wherein the takt angle is measured. 22. A polypropylene resin molded into a closed container is placed inside said container. A modification to measure the effect of hydrophobicity on silicon wafers stored in It is an improved method, A step of cleaning organic contamination from the surface portion of the sample silicon wafer and Cleaning organic contamination from the inside of a glass jar and the jar closure that can contain and the step of Insert polypropylene resin particles into the jar and place the wafer in the polypropylene resin. a step of keeping the resin particles free in the jar and closing the jar; Then, the wafer and polypropylene resin particles are heated for a certain period of time and then closed. A step of simulating the storage condition of the wafer in the antenna, and then on the wafer as a quantity expressing the hydrophobic influence of polypropylene on For the advancing and receding contact angles of the deionized water droplet, and performing a drop angle measurement. 23. The step of measuring the Cecil drop contact angle is performed on the surface of the wafer. placing a drop of deionized water on the wafer surface and at the point where the drop makes contact with the wafer surface. The forward and backward contact angles that a water droplet makes with the wafer surface are measuring the point at which the portion of the water droplet begins to move on the wafer portion; 23. The method according to claim 22. 24. cleaning organic contamination from the wafer surface and the jar and closure; 23. The method of claim 22, including the step of oxygen plasma cleaning. 25. The step of cleaning organic contamination from the silicon wafer includes heating the wafer. 19. The method of claim 18, comprising the step of: