CN1189787A - On-site preparation of ultra-high-purity hydrochloric acid for semiconductor processing - Google Patents

Abstract

Highly purified HCl for semiconductor manufacturing is prepared on-site using the following steps: HCl vapor (12) is extracted from a liquid HCl reservoir (11) and the filtered vapor is washed in a water-containing scrubber (17) at a low pH (15).

Description

On-site preparation of ultra-high-purity hydrochloric acid for semiconductor processing

Background and overview of the invention

The present invention relates to systems and methods for providing ultra-high purity hydrochloric acid for semiconductor manufacturing.

Contamination is generally a top priority concern in integrated circuit fabrication. Most steps in modern integrated circuit fabrication are cleaning steps of one kind or another; these cleaning steps may be required to remove organic contaminants, metallic contaminants, photoresists (or their inorganic residues), etch by-products , native oxides, etc.

According to 1995 data, the cost of a set of pre-production equipment (integrated circuit chip manufacturing plants) is usually more than 1 billion US dollars, most of which are used for particle control, cleaning and pollution control measures.

A significant source of contamination is impurities in process chemicals. Because cleaning is so frequent and important, contamination due to cleaning chemistry is highly undesirable.

One of the longstanding process changes in semiconductor processing is the change (and attempts to make) between dry and wet processing. In dry processing, only gaseous or plasma phase reactants come into contact with the wafer. In wet processing, various liquid reagents are used for different purposes, such as etching silicon dioxide or removing native oxide layers, removing organic matter or trace organic pollutants, removing metals or trace organic pollutants, etching nitrogen silicon, etching silicon.

Although plasma etching has many attractive capabilities, it is not suitable for cleaning. There are no readily available chemical methods for removing some of the most undesirable impurities, such as gold. Therefore, wet cleaning is important to modern semiconductor processing; and likely to remain so for the foreseeable future.

Plasma etching is performed using a photoresist in place and cannot be directly followed by a high temperature step. Otherwise, the etchant is stripped and cleaning is necessary.

Substances that cleaning must remove may include: photoresist residues (organic polymers); sodium; alkaline earth metals such as calcium or magnesium; and heavy metals such as gold. Many of these species cannot form volatile halides, so plasma etching cannot remove them. Cleaning with wet chemical methods is required.

As a result, the purity of the process chemicals is less critical during plasma etching, since the plasma etch step is always followed by a cleaning step before the high temperature step, which removes these contaminants from the surface before the high temperature step acts on them. to remove these harmful pollutants. However, the purity of the liquid chemicals is much more important because the collision rate on semiconductor surfaces is typically a million times higher than in plasma etching, and because the liquid cleaning step is directly followed by a high temperature step.

However, wet processing has a major disadvantage, namely ionic contamination. Integrated circuit structures use only a few dopant species (boron, arsenic, phosphorus, and sometimes antimony) to form the desired p-type and n-type doped regions. However, many other species are also electronically active dopants, which are highly undesirable contaminants. Many of these pollutants may have harmful effects, such as high junction leakage currents at concentrations below 10 ¹³ /cm ³ , and some less desirable pollutants will melt into silicon; that is, in silicon In the case of contact with an aqueous solution, the equilibrium concentration of the contaminant is higher in the silicon than in the solution. Also, some of the less desirable contaminants have such high diffusion coefficients that introduction of such dopants into any part of a silicon wafer tends to diffuse these contaminants throughout the wafer, including semiconductors where these contaminants would cause electrical leakage Knot.

Therefore, all liquid solutions used on semiconductor wafers preferably have extremely low levels of all metal ions. Preferably, the concentration of all metals combined should be less than 300ppt (trillion); and for any one metal, the concentration should be less than 10ppt, and the lower the better. Furthermore, contamination by both anions and cations must be controlled. (Some anions may have bad effects, for example, complexing metal ions can reduce the mobility of metal atoms or ions in the silicon lattice.)

Front-end manufacturing facilities often include an on-site purification system that produces high-purity water, known as "DI" water, or deionized water. However, obtaining process chemicals in the required purity is more difficult.

The parent application discloses a method of producing ultra-high purity ammonia in an on-site system at a semiconductor wafer production site: pumping ammonia vapor from a liquid ammonia reservoir; passing the ammonia vapor through a microfilter; and purifying water with a high pH (preferably deionized water, which has been equilibrated with the ammonia stream) to scrub the filtered vapor. The discovery could enable the conversion of commercial-grade ammonia to ammonia of sufficiently high purity for high-precision manufacturing without the need for traditional distillation columns. Ammonia vapor is withdrawn from the feed accumulator itself and is used as a single stage distillation to remove non-volatile impurities and high boiling impurities such as oxides, carbonates and hydrides of alkali and alkaline earth metals, halogenation of transition metals compounds and hydrides, as well as high boiling hydrocarbons and halocarbons. Reactive volatile impurities previously thought to be found in commercial grade ammonia, such as certain transition metal halides, Group III metal hydrides and halides, certain Group IV metal hydrides and halides, and halogens required are removed by distillation, and it has now been found that they can be removed by scrubbing to a degree suitable for high precision operations. This is a very unusual finding, since the scrubbing process is traditionally used to remove macroscopic impurities, not trace impurities.

The extremely pure levels required for semiconductor manufacturing are rare or unique to various industrial processes. At such extremely pure levels, handling of the chemicals would have been undesirable (although, of course, this cannot be completely avoided). Exposure of ultrapure chemicals to the air (especially where workers are also present) must be minimized. Such exposure risks introducing particulate matter, which creates pollution. Shipment of ultrapure chemicals in closed containers is also undesirable due to the inherently high risk of contamination, either at the manufacturer or at the user. Furthermore, undetected contamination can damage large numbers of expensive wafers.

Because there are often many corrosive and/or toxic chemicals used in semiconductor processing, reagent supplies are often separated from pre-production worker locations. The construction and maintenance of pipeline systems for ultra-high-purity gases and liquids is well understood in the semiconductor industry so that most gases and liquids can be transported from anywhere in the same building (or even the same location) to the wafer fabrication site .

The present application discloses systems and methods for preparing ultrapure chemicals on-site at a semiconductor fabrication facility so that they can be piped directly to the point of use. The disclosed systems are such compact devices that they can be in the same building (or in an adjacent building) as pre-production so that handling can be avoided.

hydrochloric acid

An important class of chemicals used in semiconductor processing is HCl in gaseous and aqueous forms. Liquid hydrochloric acid is also widely used in the acid cleaning portion of standard RCA cleaning.

As noted above, the parent application discloses methods and systems for producing ultra-high purity ammonia. Modifications of these methods and systems have now been found to be useful in the preparation of ultrapure HCl.

The starting material was commercial grade anhydrous HCl. The first purification step is provided by simple vaporization. (The vapor pressure of HCl is 613 ^psi at 70°F and ¹¹⁸⁵ psi at 124.5°F, so this vapor pressure always provides sufficient delivery pressure for pumping from bulk storage tanks.) Preferred HCl vapor is drawn directly from the storage tank. (In another embodiment, liquid HCl is transferred in batches from a large storage tank and vaporized in a vaporization chamber at controlled temperature and pressure.)

Preparation of hydrochloric acid

The purified gaseous HCl can now be dissolved in water to produce concentrated hydrochloric acid.

On-site preparation of ultrapure hybrid cleaning solutions

The present application discloses the preparation of mixed cleaning solutions, such as RCA acid cleaning solutions and RCA alkaline cleaning solutions, at the wafer fabrication plant site from components that have themselves been ultra-purified at the same site.

RCA cleaning consists of: 1) solvent wash to remove all organics - with perchlorethylene or similar solvent; 2) base clean - NH ₄ OH + H ₂ O ₂ + H ₂ O; and 3) acid clean - HCl + H ₂ O ₂ +H ₂ O. See W. Runyan and K. Bean, Semiconductor Integrated Circuit Fabrication Technology (1990), incorporated herein by reference. For semiconductor manufacturing, such cleaning reagents are often purchased as packages. However, this means that some handling of the solutions in these packages is required at the manufacturer's plant and at the point of use. As noted above, such handling is always undesirable for ultra-high purity chemicals.

Various other cleaning chemistries have been proposed. For example, a Shiraki clean is an aggressive pre-epitaxy clean that adds a nitric acid step to the clean sequence, using slightly higher temperatures and concentrations. See Ishizaki and Shiraki, "Low Temperature Surface Cleaning of Silicon and Its Application to Silicon MBE", 133, J. ELECTROCHEM. Soc. 666 (1986), incorporated herein by reference.

The RCA acid cleaning solution is usually HCl+H ₂ O ₂ +H ₂ O, the ratio of which is 1:1:6 or 1:2:8. According to one of the innovations disclosed herein, an RCA acid cleaning solution (or similar cleaning solution) is prepared in situ at the wafer fabrication facility by mixing in situ purified ultrapure HCl with in situ purified ultrapure hydrogen peroxide. Purity is thereby increased while the risk of undetected accidental contamination is reduced.

Brief description of the drawings

The disclosed invention will now be described with reference to the accompanying drawings, which illustrate important exemplary embodiments of the invention, which are hereby incorporated by reference herein, in which:

Figure 1 is a process flow diagram of an embodiment of a device for preparing ultrapure hydrochloric acid.

FIG. 2 is a block diagram of a semiconductor manufacturing line that may include the purification apparatus of FIG. 1 .

FIG. 3 is a block diagram of a semiconductor cleaning section in a wafer fabrication facility, which may include the hydrochloric acid purification of FIG. 1 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The many innovative aspects of this application will be described with particular reference to a presently preferred embodiment (which embodiment is given as an example of the invention and not as a limitation of the invention), wherein:

Purification of HCl

According to the invention, HCl vapor is first withdrawn from the vapor space of the liquid HCl feed reservoir. In this way the vapor is drawn off as a single stage distillation, leaving some solid impurities and high boiling impurities in the liquid phase. The feed reservoir can be any conventional feed storage tank or other reservoir suitable for holding HCl, which can be in anhydrous or aqueous form (preferably anhydrous). The accumulator can be maintained at atmospheric pressure, or if it is desired to increase the flow rate of HCl through the system, it can also be maintained at a pressure higher than atmospheric pressure. The accumulator is preferably temperature controlled such that the temperature is maintained in the range of about 10 to about 50°C, preferably about 15 to about 35°C, most preferably about 20 to about 25°C.

Impurities that can be removed by withdrawing HCl vapor from the vapor phase include metals of Groups I and II of the Periodic Table, as well as complexed forms of impurities resulting from their contact with HCl. Also removes oxides and carbonates of these metals, and hydrides such as beryllium hydride and magnesium hydride; group III elements and their oxides, and adducts of hydrides and halides of these elements; transition metal hydrides and heavy hydrocarbons and halocarbons such as pump oils.

The HCl drawn from the reservoir is passed through a filter unit to remove any solid matter entrained by the vapor. Microfiltration and ultrafiltration devices and membranes are commercially available and used. The brand and type of filter can be selected according to needs. The presently preferred embodiment uses a coarse filter followed by a 0.1 micron filter before the ion purifier with no further filtration after the ion purifier.

The filtered vapor then passes through a scrubber where the vapor is scrubbed with low pH pure water, preferably deionized water. The low pH water is preferably aqueous HCl, which is circulated through the scrubber to increase the concentration to saturation. The scrubber is easily operated as a conventional countercurrent scrubber. Although the operating temperature is not critical, the scrubber is preferably operated at about 10 to about 50°C, preferably about 15 to about 35°C. Likewise, the operating pressure is not critical, although it is preferred to operate at a pressure from about atmospheric pressure to about ³⁰ psig above atmospheric pressure. The scrubber is usually equipped with traditional column packing to allow sufficient contact between liquid and gas, and preferably has a demisting section.

In a presently preferred embodiment, the column packing height is about 3 feet (0.9 meters) and the internal diameter is about 7 inches (18 centimeters), resulting in a packing volume of 0.84 cubic feet (24 liters) and a pressure drop of about 0.3 inches of water. (0.075 kPa) and less than 10% flooding, the circulation flow rate under normal conditions is about 2.5 gallons per minute (0.16 liters per second) and 5 gallons per minute (0.32 liters per second) at 20 percent flooding ), the gas inlet is below the packing, and the liquid inlet is above the packing, but below the defogging section. For the column of this description, the preferred packing is one having a nominal size less than one-eighth of the column diameter. The defogging section of the tower has similar or denser packing, otherwise there is a conventional structure. It should be understood that all specifications and dimensions in this paragraph are examples only. Each system parameter is variable.

In a typical operation, deionized water is first saturated with HCl, creating a wash medium that is used as the starting point. During the operation of the scrubber, a small amount of liquid in the tower kettle is periodically removed to remove accumulated impurities.

Examples of impurities removed with scrubbers include reactive volatile species such as metal halides; phosphorus, arsenic, and antimony halides and hydrides; transition metal halides; and group III and VI metal halides and hydrides thing.

The apparatus described here can be operated in batch, continuous or semi-continuous mode. Continuous or semi-continuous operation is preferred. The volumetric processing rate of the HCl purification system is not critical and can vary widely. However, in most operations used in the present invention, the flow rate of HCl through the system is in the range of about 200 ml/hr to thousands of liters/hr.

Optionally, the HCl exiting the scrubber may be further purified prior to use, depending on the particular type of manufacturing process in which the HCl is purified. For example, in some cases it is advantageous to have dehydration and distillation units in the system. Distillation columns can also be operated in batch mode, continuous mode or semi-continuous mode. In batch operation, typical operating pressures are 300 ^psig (2068 kPa) and batch sizes of 100 psi (45.4 kg). In this example, the column has a diameter of 8 inches (20 cm), a height of 72 inches (183 cm), is operating at 30% flooding, and has a vapor velocity of 0.00221 ft/s (0.00067 m/s), equivalent to Based on a theoretical board height of 1.5 inches (3.8 cm), 48 theoretical boards. In this example, the size of the reboiler (boiler) is about 18 inches (45.7 cm) in diameter and 27 inches (68.6 cm) long, with a reflux ratio of 0.5, a circulating cooling water inlet temperature of 60 °F (15.6 °C), and an outlet temperature of 90°F (32.2°C). Again, this is only an example and distillation columns can be used in a wide variety of configurations and operating parameters.

Depending on its use, with or without a distillation step, purified HCl can be used as a purified gas or as an aqueous solution, in this latter case the purified HCl is dissolved in pure water (preferably deionized water) . Proportions and methods of mixing are conventional.

A flow diagram illustrating an example of an HCl purification apparatus according to the present invention is shown in FIG. 1 . Liquid HCl is stored in reservoir 11. HCl vapor is extracted 12 from the vapor space of the accumulator, then passes through a shut-off valve 13, a filter 14. The flow rate of the filtered HCl vapor 15 is controlled by a pressure regulator 16 and the vapor 15 is sent to a scrubber 17 equipped with a packing section 18 and a demisting plug 19 . The saturated aqueous HCl20 flows downward, while the HCl vapor flows upward, the liquid is circulated by the circulating pump 21, and the liquid level is controlled by the liquid level sensor 22. The waste liquid 23 is periodically extracted from the residual liquid at the bottom of the scrubber. Deionized water 24 is sent to scrubber 17, and pump 25 is used to maintain high pressure. The washed HCl26 is sent to one of three alternative processes. These are: (1) Distillation column 27 where the HCl is further purified. The resulting distilled HCl28 is then sent to the point of use. (2) Dissolving unit 29, where HCl is mixed with deionized water 30 to obtain an aqueous solution 31, which is sent to the point of use. For plant operations with multiple points of use, the aqueous solution may be collected in a storage tank from which HCl is drawn to lines for multiple points of use in the same plant. (3) Delivery line 32, which delivers HCl in gaseous form to the point of use.

Of these alternative schemes, the second and third schemes, which do not use the distillation column 27, are suitable for producing HCl with less than 100 ppt of any metallic impurities. However, for some applications, having distillation column 27 is preferred. In this case, the distillation column will remove non-condensable gases such as oxygen and nitrogen that may interfere with the purge. Furthermore, since the HCl leaving scrubber 17 is saturated with water, as an option, a dehydration unit may be added in the system between scrubber 17 and distillation column 27, depending on the characteristics and efficiency of the distillation column.

For any of these alternative processes, the resulting gaseous HCl or aqueous solution stream can be divided into two or more branch streams, each of which is sent to a different point of use, so that the purified HCl is simultaneously to many points of use.

Experimental summary

Two separate HCl cylinders obtained from Matheson Gas Products were used for this study. Note the difference in impurity composition in the two cylinders, which may reflect changes in the general HCl source. The purpose of this study was to develop a purification method for virtually any feed, not to optimize the method for a particular batch.

The entire experimental procedure was carried out in a ventilated fume hood without controlling the room atmosphere. The floor was untreated concrete, so it is likely that the Ca, K and Na results were higher than would be obtained in an actual point-of-use system with environmental controls.

Sampling devices manufactured by CGA have 1/4 inch pipe fittings and bellows seal valves with 1/4 inch pipe connections, both constructed of stainless steel. The outlet of the valve is connected to a 1/4 inch tetrafluoroethylene stub so that liquid or vapor can enter the vial directly. In this way, aqueous HCl samples can be prepared directly in vials without the need for liquid transfer in an uncontrolled environment.

Vials were prepared by rinsing thoroughly with DI and emptying 4 times before adding approximately 100 ml of DI and capping the vial. Samples were prepared by bubbling HCl from the source and method of choice into DI prefilled into vials. In most cases, the addition of HCl was continued until the solution in the vial was saturated, as evidenced by HCl passing through the solution and venting to the fume hood exhaust. At saturation, the sample solution feels hot to the touch, and the vial becomes partially dented when capped tightly and cooled.

The simulated ion purifier ("IP") system was fabricated from 1 inch tetrafluoroethylene tubing. One end of the connecting tubing is welded to the cap tight section of tubing about 1 foot high. The other part of the tubing is capped with a cap with two 1/4" holes. Insert 1/4" tetrafluoroethylene tubing into these two tight-fitting holes, one going down to the bottom of the unit and the other just through the top. The lower 4" section of the assembly is fitted with Raschig rings cut from 1/4" thin wall tetrafluoroethylene tubing. During the experiment, this simulated IP was loaded with approximately 100 mL of DI. HCl gas is fed through the bottom tube to obtain a gas/liquid interface. Although this component is nowhere near as efficient as a well-designed IP with a packed column, worst-case IP performance can be estimated. The bottom sample of this IP requires additional handling to transfer the bottom sample to vials for laboratory experiments. For this reason, IP bottom samples may measure higher due to contamination from the environment.

A liquid HCl sample was taken from each cylinder by inverting the cylinder and draining the liquid into a pre-prepared sample container. Measured impurities are truly the worst case, as this liquid sampling technique often also leaves samples with more particles, and additional handling exposes samples to room air for extended periods of time. The ICP results for the liquids withdrawn from the two cylinders are listed in Table 1. These results have been normalized to 37.25% HCl, which is the nominal specification for aqueous HCl derived from the HCl point-of-use system. The significant excess of Fe and other contaminants obviated the need for more sensitive ICP/MS testing; therefore, the actual amounts of less significant contaminants were unknown. However, as long as these impurities can be reduced to acceptable levels in the product, the exact amount is only of technical interest. Fortunately, all of these impurities can be removed using distillation and/or IP techniques.

The following elements were found in one or both cylinders analyzed: Al, B, Ba, Cr, Cu, Fe, K and Na. Contamination concentrations and removal techniques are discussed in the following sections.

A number of experiments have been performed in order to demonstrate this rationale for the purification of HCl. For brevity and clarity, similar experiments are described in groups.

Measurement of Liquid Anhydrous HCl

Anhydrous liquid HCl is measured by inverting the cylinder and absorbing the anhydrous liquid HCl directly in water. This represents a worst case scenario, since solid impurities may also get into the solvent. The samples were then sent for ICP analysis for metals. (Cylinder 1: Sample No. 062993602, Cylinder 2: Sample No. 062993605).

Measurement of Vapor Anhydrous HCl

In these experiments, the cylinder was supported by the top outlet line. Anhydrous HCl vapor was distilled from the liquid and dissolved in a small sample of ultrapure water through a spray tube. This method represents traditional single-stage distillation. Use these data to compare with purifier experiments. (Cylinder 1: Sample No. 071293601, Cylinder 2: Sample No. 062993603).

Ion Purifier Measurements

These laboratory-scale experiments were performed with equipment described previously. After loading the ultrapure water into the simulated purifier and connecting the outlet of the purifier to another part of ultrapure water, slowly send HCl gas into the experimental device. There is a considerable exotherm with the absorption of HCl into the first stage purifier, increasing the temperature and concentration in the purifier until the boiling point of the system is reached. Upon reaching the boiling point of the system, HCl gas is no longer absorbed in the purifier, but is bubbled through the liquid along the tortuous path provided by the Raschig ring packing. In this method, the vapor is scrubbed by an aqueous medium. Metallic impurities that have a greater affinity for aqueous solutions than for the vapor state will remain in the liquid phase. The purified gas is then absorbed in the next stage to form hydrochloric acid. Both the liquid remaining in the purifier ("bottom" sample) and the "washed" product sample ("product") were then sent for analysis by ICP/MS methods. Both cylinders were used in several experiments and are listed in the remainder of Table 1.

Experimental summary

A comparison of the liquid obtained from each cylinder with the vapor distilled from that liquid illustrates the purification achievable by simple distillation (liquid from cylinder 1 to vapor from cylinder 1, liquid from cylinder 2 to vapor from cylinder 2) and shows that there is Good purification with a separation factor of 10-5000. However, levels of many species still exceed 1 ppb. Adding sequential or multi-stage distillation capabilities, while further improving purity, adds significant expense and complexity. However, the impurity content of the outlet product of the purifier is significantly lower than that of the simple distillation scheme. Furthermore, for any given element, the bottoms sample was much higher than the product stream in any one experiment, illustrating the separation effectiveness of this technique. Purifiers are much simpler and less expensive to manufacture and operate than multistage distillation systems.

Cylinder 2IP Analog-I

Experimental work: open the storage tank valve, no leakage. Open the sample valve, a lot of bubbling and liquid is carried out to waste. Close the sample valve with some suck back. Reopen at an appropriate rate. Some HCl gas was discarded a few seconds before injecting into DI. The DI sample was still transparent and the bottom of the IP turned quite yellow. Remove the sample injection tube and cap with the HClS product sample. Remove the sample tube to IP from the sample valve and close the sample valve. Pour the IP bottom sample into the sample container.

Sample number: IP bottom 063093501, HClS product 063093502.

Cylinder 1IP Simulation

Experimental Work: Open the valve to get a good flow of HCl to the IP. When saturated, HCl gas was passed through IP. After a few seconds to achieve line clean, introduce the product line into the vial. Remove the product line when the sample is saturated. It was observed that leaking from the vent in the valve, premature suction and water washout would corrode the hole in the bellows seal. Samples were recovered from IP storage tanks.

Sample number: IP product 071293603, IP bottom sample 071293602

Cylinder-2IP test

Experimental Work: Same setup and procedure as previous experiments, but without (NH ₄ ) ₂ S.

Sample number: IP bottom sample 071493603, IP product 071493604

Sample Analysis Form

The following three-part table presents the results of the tests involving each of the above samples:

HCl laboratory scale test results: sample number 062993602 062993603 062993605 063093601 063093602 Id: 93-7239 93-07240 93-07242 93-07338 93-07339 sample cylinder 1 liquid Cylinder 2 Vapor Cylinder 2 liquid Cylinder 2IP Cylinder 2IP bottom sample product analyze 6.10 17.31 6.80 34.55 15.34 Ag <2.15 al ＜136.18 16.89 164.34 191.91 <54.15 Au <2.15 ＜24.04 <54.15 B 2070.12 4.41 745.00 410.77 ＜27.20 Ba 36.64 <2.15 <12.60 <2.48 <5.59 be <1.83 <0.65 <1.64 <0.32 <0.73 Bi ＜678.44 <2.15 ＜608.60 < ＜269.78 Ca <7.33 <2.58 8.44 <1.29 < Cd ＜14.05 <2.15 <12.60 < <5.59 co ＜136.18 <2.15 <122.16 < <54.15 sample number 062993602 062993603 062993605 063093601 063093602 Id: 93-7239 93-07240 93-07242 93-07338 93-07339 sample cylinder 1 liquid Cylinder 2 Vapor Cylinder 2 liquid Cylinder 2IP Cylinder 2IP bottom sample product Cr 775.53 ＜24.10 ＜61.35 27276.06 ＜27.20 Cu 1337.34 2.71 ＜61.35 354.71 ＜27.20 Fe 144225 29.22 129696 84865.31 ＜27.20 Ga ＜678.44 ＜239.08 ＜608.60 ＜269.78 Ge ＜678.44 ＜239.08 ＜608.60 ＜119.78 In <2.15 K <1801.43 2.39 3.62 La <2.15 Li ＜14.05 <2.15 <12.60 <2.48 <5.59 Mg <1.83 <0.65 <1.64 <0.32 <0.73 mn ＜14.05 <4.95 <12.60 2043.09 <5.59 Mo ＜183.20 2.71 ＜61.35 414.01 ＜27.20 Na 293.11 0.97 <0.55 ＜47.98 ＜108.06 Ni ＜271.74 <95.76 ＜243.77 14402.97 ＜108.06 P ＜136.18 <47.99 <122.16 ＜24.04 <54.15 Pb <2.15 PD ＜678.44 <2.15 ＜608.60 ＜119.78 ＜269.78 Pt ＜678.44 <2.15 ＜608.60 ＜119.78 ＜269.78 Sb ＜678.44 <2.15 ＜608.60 ＜119.78 ＜269.78 sn ＜339.52 <2.15 ＜304.57 <59.95 <135.01 Sr ＜68.39 <2.15 ＜61.35 ＜12.08 ＜27.20 sample number 062993602 062993603 062993605 063093601 063093602 Id: 93-7239 93-07240 93-07242 93-07338 93-07339 sample cylinder 1 liquid Cylinder 2 Vapor Cylinder 2 liquid Cylinder 2 IP Cylinder 2 IP bottom sample product Ta ＜678.44 <2.15 ＜608.60 ＜119.78 Ti ＜136.18 <47.99 <122.16 ＜24.04 <54.15 Tl <2.15 V ＜68.39 ＜24.10 ＜61.35 ＜12.08 ＜27.20 W <2.15 Zn ＜68.39 ＜24.10 ＜61.35 152.02 ＜27.20 Zr ＜189.30 <2.15 <122.16 ＜24.04 <54.15 sample number 070193601 070193602 071293601 ID 93-07388 93-07389 93-07890 sample Cylinder 2 IP Cylinder 2 IP Cylinder 1 Vapor bottom sample product analyze 33.92 14.42 18.49 Ag 0.00 <2.58 ＜44.93 Al ＜24.49 2.40 Au 0.00 <2.58 B <12.30 3.93 ＜22.56 Ba <2.53 <2.58 8.06 be <0.33 <2.58 <0.60 Bi <122.01 <2.58 ＜223.82 Ca 0.00 <3.10 <2.42 sample number 070193601 070193602 071293601 ID 93-07388 93-07389 93-07890 sample Cylinder 2 IP Cylinder 2 IP Cylinder 1 Vapor bottom sample product Cd <2.53 <2.58 <2.62 co ＜24.49 <2.58 ＜44.93 Cr <12.30 <2.58 ＜22.56 Cu <12.30 <2.58 ＜22.56 Fe 124.09 3.69 ＜22.56 Ga <122.01 <0.00 ＜223.82 Ge 0.00 <0.00 ＜223.82 In 0.00 <2.58 K 0.00 7.17 La 0.00 <2.58 Li <2.53 <2.58 <4.63 Mg <0.33 <2.58 <0.60 mn 91.15 0.00 <4.63 Mo <12.30 <2.58 ＜22.56 Na ＜48.87 11.47 ＜89.65 Ni ＜48.87 0.00 ＜89.65 P ＜24.49 0.00 ＜44.93 Pb 0.00 <2.58 PD <122.01 <2.58 ＜223.82 Pt <122.01 <2.58 ＜223.82 Sb <122.01 <2.58 ＜223.82 sample number 070193601 070193602 071293601 ID 93-07388 93-07389 93-07890 sample Cylinder 2 IP Cylinder 2 IP Cylinder 1 Vapor bottom sample product sn ＜61.06 <2.58 <112.01 Sr <12.30 <2.58 ＜22.56 Ta 0.00 <2.58 ＜223.82 Ti ＜24.49 0.00 ＜44.93 Tl 0.00 <2.58 V <12.30 0.00 ＜22.56 W 0.00 <2.58 Zn <12.30 0.00 ＜22.56 Zr ＜24.49 <2.58 ＜44.93 sample number 071293602 071293603 071493603 071493604 ID 93-07891 93-07892 93-07974 93-07975 sample Cylinder 1 IP Cylinder 1 IP Cylinder 1 IP Cylinder 1 IP bottom sample product bottom sample product analyze 33.33 16.67 35.08 14.49 Ag ＜24.92 ＜49.83 7.33 <2.57 A1 0.00 0.00 3.57 0.67 Au 0.00 0.00 <1.06 <2.57 B <12.52 <25.03 19.64 <2.57 Ba 5.59 <5.14 <1.06 <2.57 be <0.34 <0.67 <1.06 <2.57 Bi ＜124.17 ＜248.26 <1.06 <2.57 Ca <1.34 <2.68 19.76 1.90 Cd <1.45 <2.90 <1.06 <2.57 co ＜24.92 ＜49.83 2.34 <2.57 Cr <12.52 <25.03 0.00 0 00 Cu <12.52 <25.03 21.02 <2.57 Fe 62.59 <25.03 0.00 1.75 Ga ＜124.17 ＜248.26 0.00 0.00 Ge ＜124.17 ＜248.26 0.00 0.00 In 0.00 0.00 <1.06 <2.57 K 0.00 0.00 0.00 2.08 La 0.00 0.00 <1.06 <2.57 Li <2.57 <5.14 <1.06 <2.57 Mg <0.34 <0.67 11.79 <2.57 sample number 071293602 071293603 071493603 071493604 ID 93-07891 93-07892 93-07974 93-07975 sample Cylinder 1 IP Cylinder 1 IP Cylinder 1 IP Cylinder 1 IP bottom sample product bottom sample product mn <2.57 <5.14 0.00 0.00 Mo <12.52 <25.03 29.63 <2.57 Na ＜49.73 <99.44 1.71 4.19 Ni ＜49.73 <99.44 0.00 0.00 P ＜24.92 ＜49.83 0.00 0.00 Pb 0.00 0.00 <1.06 <2.57 PD ＜124.17 ＜248.26 <1.06 <2.57 Pt ＜124.17 ＜248.26 <1.06 <2.57 Sb ＜124.17 ＜248.26 <1.06 <2.57 sn ＜62.14 ＜124.24 <1.06 <2.57 Sr <12.52 <25.03 <1.06 <2.57 Ta ＜124.17 ＜248.26 <1.06 <2.57 Ti ＜24.92 ＜49.83 0.00 0.00 Tl 0.00 0.00 <1.06 <2.57 V <12.52 <25.03 0.00 0.00 W 0.00 0.00 <1.06 <2.57 Zn 40.23 <25.03 0.00 0.00 Zr ＜24.92 ＜49.83 <1.06 <2.57

Improvements and Workarounds

As those skilled in the art realize, the innovative basic principles disclosed in this application are capable of modification and variation over a wide range of applications, and thus the scope of the claimed protection is limited by the specific illustrative disclosure given. limits.

For example, the disclosed innovative technology is not strictly limited to the fabrication of integrated circuits, but can also be used to fabricate discrete semiconductor components, such as optoelectronic devices and power devices.

As another example, the disclosed innovative technology can also be used in other process manufacturing that adopts integrated circuit manufacturing methods, such as thin film magnetic heads and active matrix liquid crystal displays; but the main application is in integrated circuit manufacturing, and the disclosed technology is in other fields The application is secondary.

As another example, the use of a scrubber for liquid-gas contacting is not strictly required; a bubbler can be used in place of the scrubber, although this replacement is preferred due to the lower efficiency of the gas/liquid contact of the bubbler. Not very hopeful.

Optionally, other filtration or filtration stages may be used in conjunction with the disclosed purification apparatus.

It should also be noted that additives can be added to the purified water if desired, although this is not done in the presently preferred embodiment.

As mentioned above, the main embodiment is an in situ purification system. On the other hand, in a less preferred class of embodiments, the disclosed purification system may also be adapted for use as part of a manufacturing unit that produces ultra-high-purity chemicals for shipment; however, this alternative embodiment cannot The advantages of in situ purification as discussed above are obtained. An inherent risk encountered with such applications is the handling of ultra-high-purity chemicals as discussed above; The initial purity achievable by other techniques provides a path. Furthermore, in such applications, a drying section can also be used after the ion purifier.

As mentioned above, the main embodiment involves providing the ultrapure aqueous chemicals that are most important to semiconductor manufacturing. However, the disclosed system and method embodiments can also be used to provide purified gas streams. (In many cases it is appropriate to use a dryer downstream of the purifier).

It should also be noted that ultrapure chemical piping in semiconductor prefabrication facilities may include in-line or pressurized reservoirs. Thus "direct" piping in the claims does not exclude the use of such reservoirs, but they must not be exposed to uncontrolled atmospheres.

Claims (38)

1. on-the-spot assistant system that the superhigh-purity reagent that contains HCl is provided for the semiconductor manufacturing operation in semiconductor equipment manufacturing works, this system comprises: one is connected to liquid HCl source and provides the source vaporize of HCl steam flow by it; Described HCl steam flow is connected to pass through the ion purification devices, and it makes the high purity water circular flow that contains concentrated hydrochloric acid contact with described HCl steam flow; And the preparation facilities of a connection, it receives the described HCl steam flow from described purification devices, and makes described HCl steam and liquid, aqueous merging, makes the ultrapure aqueous solution that contains HCl; And a piping, it delivers to respectively using a little of semiconductor equipment manufacturing works with described aqueous solution.

2. according to the system of claim 1, wherein between described source vaporize and described purification devices, also has particulate filter.

3. according to the system of claim 1, wherein said liquid HCl is made up of anhydrous HCl in the source.

4. according to the system of claim 1, wherein said circulation high purity water does not contain any additives.

5. according to the system of claim 1, wherein said liquid HCl has only normal business level purity in the source.

6. according to the system of claim 1, wherein said vaporizer is a big basin.

7. according to the system of claim 1, wherein said vaporizer is operated under controlled temperature, and it is connected to receive the liquid HCl of arrogant basin.

8. on-the-spot assistant system that the superhigh-purity reagent that contains HCl is provided for the semiconductor manufacturing operation in semiconductor equipment manufacturing works, this system comprises: one is connected to receive liquid HCl and to provide the source vaporize of HCl steam flow by it; Described HCl steam flow is connected to pass through the ion purification devices, and it makes the high purity water circular flow that contains concentrated hydrochloric acid contact with described HCl steam flow; And the preparation facilities of a connection, it receives the described HCl steam flow from described purification devices, and makes described HCl steam and liquid, aqueous merging, makes the ultrapure aqueous solution that contains HCl; Thereby described ultrapure aqueous solution can use in semiconductor equipment manufacturing works, and does not need to carry in a large number or liquid surface is exposed in any environment.

9. system according to Claim 8 wherein is provided with particulate filter between described source vaporize and described purification devices.

10. system according to Claim 8, wherein said liquid HCl is made up of anhydrous HCl in the source.

11. system according to Claim 8, the high-purity current of wherein said circulation do not contain any additives.

12. system according to Claim 8, wherein said liquid HCl has only normal business level purity in the source.

13. system according to Claim 8, wherein said vaporizer are big basin.

14. system according to Claim 8, wherein said vaporizer is operated under controlled temperature, and is connected to receive the liquid HCl of arrogant basin.

15. the on-the-spot assistant system that ultra-pure HCl is provided for the semiconductor manufacturing operation in described factory in semiconductor equipment manufacturing works, this system comprises: one is connected to receive liquid HCl and to provide the source vaporize of HCl steam flow by it; Described HCl steam flow is connected to pass through the ion purification devices, it makes the high-purity water circular flow that contains concentrated hydrochloric acid contact with described HCl steam flow, and the drier device of a connection, it receives the described HCl steam flow from described purifier, and dry described HCl steam; And a piping, it delivers to respectively using a little of semiconductor equipment manufacturing works with described aqueous solution.

16., wherein between described source vaporize and described purification devices, be provided with particulate filter according to the system of claim 15.

17. according to the system of claim 15, wherein said liquid HCl is made up of anhydrous HCl in the source.

18. according to the system of claim 15, wherein said high purity water circular flow does not contain any additives.

19. according to the system of claim 15, wherein said liquid HCl has only normal business level purity in the source.

20. according to the system of claim 15, wherein said vaporizer is big basin.

21. according to the system of claim 15, wherein said vaporizer is operated under controlled temperature, and is connected to receive the liquid HCl of arrogant basin.

22. a system for preparing ultra-pure HCl, described system comprises:

(a) reservoir that the liquid HCl of vapor space is arranged on storage liquid;

(b) extract the connecting line that contains the HCl steam out from described vapor space;

(c) from the steam of extraction like this, remove the particulate filtration film; And

(d) liquid-vapor interface contact chamber, the steam that filters by described filter membrane contact with the HCl aqueous solution in deionized water therein, is the HCl gas of purifying through the steam that washs like this.

23. according to the system of claim 22, wherein also comprise a destilling tower, be used to distill steam from described scrubber.

24. a system of making high-accuracy electronic component, described system comprises:

(a) one contains the production line that carries out the work station of various steps on many wafers that are used for containing semi-conducting material in the electronic component manufacturing, and at least one uses gaseous state HCl as the gas source of handling described workpiece in the described work station;

(b) the purifying servicing unit that links to each other with described work station by pipeline, so that the HCl of described ultra-high purity form to be provided, described servicing unit comprises:

(i) liquid HCl reservoir that vapor space is arranged above storage liquid HCl;

(ii) extract the connecting line that contains the HCl steam out from described vapor space for one;

(iii) from the steam of extraction like this, remove the particulate filtration film for one; And

(iv) a scrubber is used for making the steam that filters by described filter membrane to contact at the aqueous solution of deionized water with HCl, and so the steam of washing is the HCl gas of purifying;

(c) described purification devices links to each other with described work station by pipeline, so that the HCl of described ultra-high purity form to be provided.

25. according to the system of claim 24, wherein said servicing unit also comprises the destilling tower that is used to distill from the steam of described scrubber.

26. according to the system of claim 24, wherein said servicing unit also comprises described purified HCl gas and purified water is merged to make the equipment of the HCl aqueous solution.

27., wherein leave described servicing unit in the place that is positioned within about 30 centimetres of described equipment, so that the product of step (b) is directly used in described workpiece with the HCl of described servicing unit purifying according to the system of claim 24.

28. according to the system of claim 24, the size of wherein said servicing unit can be produced described purified HCl gas to about 200 liters/hour speed with about 2.

29. according to the system of claim 24, (ii), the (iii) and (iv) part of wherein arranging described servicing unit is to be used for continuous or semicontinuous stream.

30. one kind for the work station of making in the high-accuracy electronic element production line provides high-purity HCl compositions and methods, described method comprises:

(a) from the reservoir that contains HCl, extract HCl gas out in the vapor space of liquid HCl top;

(b) make described HCl gas by filter membrane, therefrom to remove particle greater than 0.005 micron;

(c) make described HCl gas pass through scrubber, thereby described HCl gas is contacted with the aqueous solution of HCl in deionized water through filtration like this; And

(d) retrieve described HCl gas, and described HCl gas is delivered to described work station from described scrubber.

31. according to the method for claim 30, wherein also be included in described HCl gas delivered to before the described work station, will be dissolved in the purified water from the described HCl gas of described scrubber.

32. according to the method for claim 30, wherein also be included in described HCl gas delivered to before the described work station, with described HCl gas by destilling tower so that be further purified.

33. method according to claim 30, wherein also comprise another step: (b ') delivering to described HCl gas before the described work station, will be from the described HCl gas of described scrubber by destilling tower so that be further purified, and will be dissolved in the pure water from the described HCl gas of described destilling tower.

34. according to the method for claim 30, wherein step (b) is carried out to about 50 ℃ temperature range about 10.

35. according to the method for claim 30, wherein step (b) is carried out to about 35 ℃ temperature range about 15.

36. according to the method for claim 33, wherein step (b) and (b ') carry out to about 35 ℃ temperature range about 15.

37. according to the method for claim 30, wherein step (b) about 15 to about 35 ℃ temperature range and at about normal pressure to being higher than about 30 pounds/inch of atmospheric pressure ²Pressure under carry out.

38. according to the method for claim 33, wherein step (b) and (b ') about 15 to about 35 ℃ temperature range and at about normal pressure to being higher than about 30 pounds/inch of atmospheric pressure ²Pressure under carry out.

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