MXPA00002296A - A fluorometric method for increasing the efficiency of the rinsing and water recovery process in the manufacture of semiconductor chips - Google Patents

Abstract

A method for determining wafer cleanliness by fluorometric monitoring of the impurities in the semiconductor wafer chip rinse solution. A clean chip is indicated by a leveling off or increased concentration of impurities as the rinsing of the chip progresses. A method for optimizing reuse or recycling of the water discharged from the rinse process which accurately measures the contaminants in that water.

Description

A FLUOROMETRIC METHOD TO INCREASE THE EFFICIENCY OF THE PROCESS OF RINSING AND RECOVERY OF WATER IN THE PREPARATION OF MICROCIRCUITS OR CHIPS -3EMIOCM) OCESES FIELD OF THE INVENTION A method for determining the purity of the discs by fluorometric monitoring of the impurities in the rinsing solution of the semiconductor chip disc. A clean chip is indicated by a leveling of the increase in the concentration of the impurities as the rinsing of the progress of the chip. A method to optimize the reuse or recycling of water discharged from the rinse processes, which exactly measures the contaminants in such water.

BACKGROUND OF THE INVENTION Semiconductor devices, whether of the integrated circuit type or individual element, are universally fabricated from monocrystalline material in the form of a slice. Each slice provides a large number of devices. The semiconductor discs are obtained from the onocrystalline semiconductor rods by means of the REF .: 032715 cut of the rods in sections. The discs are then attached to the polishing plates with, for example, beeswax, a synthetic wax or other adhesive and polished using a polishing agent. The polished discs are contaminated with the adhesive, traces or traces of the polishing agent, and with other impurities. Since even small amounts of impurities can cause considerable variation in the electrical parameters of the finished structural elements, the discs have been vigorously cleaned to remove the impurities. The cleaning of the polished discs is usually carried out in two essentially different successive operations: first, a washing operation involving dissolution and rinsing operations and, second, a mechanical cleaning operation to remove the last traces or traces of impurities from of the surface of the disc. The washing stage, as it is done in a general manner, involves a number of separate operations. The remaining wax, cement or other adhesive is first removed by the solution in a suitable solvent, which is suitable in an ultrasonic tank or a steam vessel. An example of such a solvent is trichlorethylene. The discs are then washed with acetone to remove any remnants of trichlorethylene, after which they are rinsed with water. They are then immersed in concentrated nitric acid and again rinsed with water. The discs are usually then submerged in hydrofluoric acid so that they provide their hydrophobic surfaces, and once again they are rinsed with water. Then the mechanical cleaning stage continues, which consists mainly of cleaning or rubbing with a suitable cloth. It is apparent that the washing operation is complicated, time consuming and expensive. The recently cut, bent or sprayed silicon discs are extremely dirty compared to the subsequent manufacturing requirements and may be cleaned, if the subsequent manufacturing process of the electronic device is successful. Among the dirt components of the discs are spindle oil or extra light oil; hand cream, silicon particles; silicon powder; coolant solution, which includes wetting agents; benders and sand grains for polishing or polishing; epoxy cast compounds; impressions of human fingers; colloidal silicon dioxide; sodium dichloroisocyanurate and its reaction products with sodium carbonate; sodium carbonate; amorphous silicon dioxide; other metal impurities deposited on silicon surfaces from components for slurries or slurries, and possibly other materials. If this dirt is not removed from the discs, the subsequent processing steps are adversely affected. The need for clean and smooth surfaces of damage-free semiconductor discs has become increasingly important. Smooth surfaces, polished are obtained by the use of slurries or slurries polishing pastes. The silica polisher is an example of a typical polishing process. In the silica polishing process, a slurry or slurry polishing paste is used which includes a colloidal silicon dioxide abrasive, sodium dichloroisocyanurate as the oxidizing agent and sodium carbonate as a base. The pH of the polishing slurry or slurry is below 10. After polishing, it is necessary to clean the polished surface to remove the slurry or polishing paste and other surface contaminants with minimal chemical or mechanical damage to the surface. .

Fine particles that adhere to a silicon semiconductor surface can reduce the performance or efficiency of the discs as you can well imagine. These particles will adhere to each other, creating agglomerates called large particles. The origins of the particles are literally numerous to list: dust, pollen, scales of human skin, oxides, etc., as well as remnants of slicing and slicing operations. The primary holding or gripping forces are van der aals and electrostatic forces. The chemical bond may also prevail. Up to now, numerous methods to reduce or purge the particles have been proposed: the filtration of the air with the ease of production, personal meticulousness, lateral rotation of the discs to centrifuge the particles, immersion of the discs in a liquid to reduce adhesion, and so on. The immersion, however, can introduce another force, mainly, capillary attraction after the removal of the water from the immersion bath. The above is discussed in more detail in an article entitled, An Analysis of the Adhesion of Particles in Semiconductor Surfaces "(for its abbreviations in English" An Analysis of Particle Adhesion on Semiconductor Surfaces ") R. Alien Bowling in SOLID-STATE SCIENCE AND TECHNOLOGY, September 1985, presenting the last conclusion it emphasizes, which should be replaced in the prevention of particle placement in the first place, instead of the dependence on a subsequent elimination effort.The article by R. Alien Bowling takes into account an early investigation of the cleaning detergent, whether aqueous or non-aqueous, as a means of eliminating the particles, but this technique does not alter the conclusion of the author, in fact, the critically anguished author of the size of the detergent molecules, which could be small enough to squeeze between the harmful particles and the silicon surface, suggests that effective removal by detergents could involve the relationships between the size of the harmful particle and the size of the detergent molecule. The detergents are organic in nature: many are of a polar nature and they tend to chemically bond to the discs as noted in a recent article, "Cleaning Techniques for Disk Surfaces" (for its acronym in English "Cleaning Techniques for Wafer Surfaces "(Semi-International, 1987) This same article uses ultrasonic and megasonic stresses or stresses as auxiliary in chemical cleaning, considered especially beneficial in the loosening of polar bonds such as those which can be reached from the use of peroxides, for example, peroxide-ammonium hydroxide solutions that are used to break the strong bonds of electric particles The 1987 article concludes by means of updated chemical cleaning, also known as liquid chemistry. the mechanical complexes used for liquid chemistry (immersion bath equipment, Centrifugal spray equipment, and so on). A few details of the chemistry are discussed, only generalities of the greater part, such as "acids", "oxygen plasmas", "choline chemistry" and "RCA chemistry". Choline chemistry, due to its foul odor, presents a management problem. Therefore, it is contraryly accepted, to provide for the adoption of a closed system. The so-called "RCA chemistry" involves two aqueous systems applied in sequence, namely a treatment with NH4OH / H202 followed by a treatment with HC1 / H202. The solutions are volatile, giving harmful vapors which, if mixed, result in a settling of NH4C1 particles. Other problems are discussed. The processing of the discs by methods described above depends on great convenience if the disc is a fresh slice or slice from the rod of the crystals in which they grow or if it is a disc which has undergone subsequent IC manufacture. such as heavy duty covers, photolithography, insertion of the conductor pins and so on. Thus, one can compare the description in the North American Patent Application No. 4,159,619 which is directed to the prefabrication of the surface activating cleaning of fresh slices, polished discs and in the description in the US Patent No. 4,276,186 where it is an effort to purge an IC module of solder fluids residues and remove the so-called upper sealing material from the chip. When many chemicals are used, they themselves tend to objectively discolor and etch the surface of the disc; Here more care is concerned. Disc discoloration is perceived by the electronics industry as a possible source of electrical problems. As it is evident from the previous discussion, it is very important that the chip is clean. Still, how to determine if the chip is clean ?. A method for determining the purity of the disc is described in U.S. Pat. No. 4,156,619, an essay to clean. As a means of determining the purity of the discs, one may immerse a cotton swab in methylene chloride and brush through the disc. The disc can only be considered clean if the scourer has a clean appearance after brushing the disc. This is a visual technique which will not result in the precise and highly accurate determination of whether or certain contaminants, invisible to the naked eye, are still on the chip. It is considered a method for determining the concentration of an active agent containing residues or fingerprints in non-aqueous solutions of the active agent in cleaning solutions for the food processing industry, as well as for the industrial cleaning of cleaners through flow, in German Patent DE 4234466, there are no samples of direct impurity monitoring in the manufacturing process of the semiconductor chip, or for the monitoring of cleaning solutions in the manufacturing process of the driver chip. Accordingly, it is an object of this invention to provide a fast and accurate method for determining the purity of the semiconductor chip either by directly monitoring the impurities, or indirectly monitoring the cleaning solution associated with the cleaning process of the semiconductor chip.

Brief Description of the Invention A method for determining the purity of the discs by fluorometric monitoring of the impurities in the rinsing solution of the semiconductor chip disc. A clean chip is indicated by a leveling of the increased concentration of the impurities like the rinsing of the progress of the chip. A method to optimize the reuse or recycling of water discharged from the rinsing process in which the contaminants in such water are exactly measured.

Description of the Invention To quantify the fluorescent characteristics of a target species indicator, a variety of fluorescent analysis methods are available to be used individually or in combination. Such fluorescent analysis techniques include, without limitation, techniques that measure and / or indicate: 1. The appearance or disappearance of fluorescence; 2. A change in the excitation and / or emission of the fluorescence wavelengths; 3. Rapid fluorescent cooling (by a specific substance) or elimination of rapid cooling; 4. Fluorescence changes based on specific light absorbance changes (increase or decrease); 5. A well-defined temperature dependency of the fluorescence; 6. A well-defined pH dependency or other condition of fluorescence dependence; and 7. Exploiting a temperature dependency and / or pH dependency of the fluorescence to see or increase the effects of techniques 1 to 4.

The detection and quantification of specific substances by fluorescence emission spectroscopy are found in the proportionality between the amount of light emitted and the amount of a fluorescent substance present. When the energy in the form of light, including ultra violet and visible light is directed in a cellular sample, the fluorescent substances there, will absorb the energy and emit such light energy that it has a long wavelength of light absorbed. A fluorescent molecule absorbs a photon that results in the promotion of an electron from the state of energy connected to ground to an excited state. When the state of the excited electron is relaxed from a state of higher energy vibrationally excited to the state of vibrationally excited lower energy, the energy is lost in the form of heat. When the electron relaxes to the electronic state connected to earth, the light is emitted at a lower energy than that absorbed due to the loss of energy in the form of heat, and thus at a wavelength greater than absorption. The amount of light emitted is determined by a photodetector. In practice, the light is directed in the cellular sample through an optical light filter so that the transmitted light is of a known wavelength, which is referred to as the excitation of the wavelength and reported in a manner general in nanometers ("nm"). The cell sample is designed to optimize the fluorescent response for the analyte, depending on the analysis of the chosen method. The emitted light is similarly selected through a filter, so that the amount of light emitted is measured at a known wavelength or a spectrum of wavelengths, which refer to the emission of the wavelength and of the wavelength. general way also reported in nanometers. When the measurement of the fluorescent intensity of the specific substances or categories of substances at low concentrations is desired or required, as is frequently the case with the processes of the present invention, the filters are placed by a specific combination of excitation and emission of the wavelengths, selected for low measurements of substantially optimal level. In general, the concentration of a target species indicator or fluorescent trace or trace can be determined from a comparison of a sample emission intensity to a calibration curve of the target species indicator or trace concentration or trace against the emission, by the same set of excitation wavelength / emission wavelengths. Such a method of concentration by comparison, whereby the sent emissions are converted to an equivalent concentration, is preferably used to determine the concentrations of a target species indicator or tracer that is within the concentration range over which a response is observed. of linear emission, and this concentration range is referred to herein as the "linear emission response concentration range". The range of linear emission response concentration is for some, extension dependent on the specific target species indicator, tracer, cell path length and configuration, and the excitation wavelength / emission wavelength set is used. In the indicator of target species or upper tracer concentrations of a fluorescent target species indicator or linear emission response concentration range of the given tracer, there is a negative deviation from the ideal (linear) behavior, the degree of emission for a given concentration it is less than that predicted by a linear extrapolation. In such examples, the sample can be diluted by known factors up to the concentration of the species indicator of the fluorescent target or tracer that falls within the range of linear emission response concentration. Two other correction techniques are available when the concentration is greater than the linear emission response concentration range when the linear response range is defined within ten percent + of the perfectly linear response. Since the range of linear emission response concentration is for some, extension dependent on the excitation wavelength / emission wavelength set, a set of excitation wavelength / alternate emission wavelength may be used . The use of cell samples with short path lengths for excitation / light emission will also correct or alleviate the problem. If the indicator or species tracker of the fluorescent target is present in the sample at only exceptionally low concentrations, there are techniques for concentrating the target species indicator or tracer by known factors until their concentration falls within the emission response concentration range linear or is otherwise more easily measured, for example, by liquid-liquid extraction. However, preferably a calibration curve over the range of linear emission response concentration can be prepared or obtained before using a species indicator or tracker of the given objective. Preferably, the indicator or species tracer of the target, respectively, will be selected or added to the water treatment agent in an amount sufficient to provide a concentration of the target species indicator or tracer in an amount sufficient to provide a concentration of the indicator or tracer of target species in the sample that is within the range of linear emission response concentration. In general, the linear emission response concentration range of an indicator or species tracer of the fluorescent target is broad enough to easily determine the amount of target species indicator or tracer that will be sufficient for this purpose. A range of linear emission response concentration for an unmodified sample and typical standard equipment, will offer more extension through a concentration range from a concentration of "m" to a concentration of at least 2,000 m. When "extended" operation techniques are used, for example simple dilution, an optimum alternate excitation wavelength array is used, and / or the use of optimal small cell trajectory lengths is used., can range from a range of linear emission response concentration from m to 10,000,000 and more. An example of a measurable range of operation (ranging from m to 10,000,000m) is approximately 1 part per billion (designated as m in this example) to approximately 10,000 parts per million (designated 10,000,000 m in this example).

A determination of the concentration of an indicator or tracer of target species in a system can be made when the concentration of the indicator or tracer of target species in the water system is as low as several parts per million (ppm), or parts per billion (ppb), and on time as low as parts per trillion (ppt). In a preferred embodiment, the amount of a fluorescent tracer added to the water treatment agent feeder should be sufficient to provide a tracer concentration in the water system sample of about 50 ppt to about 10 ppm. The ability to measure very low levels is a huge advantage. Such fluorescence analyzes (measurements of light emitted in response to light transmitted to the water system sample) can be made at one site, preferably almost instantly and on a continuous basis, with simple portable equipment. As mentioned above, it may sometimes be desired to monitor a plurality of indicators or species tracers of the fluorescent target. For example, it may be desired to monitor more than one target species, or an indicator and tracer of target species for each of one or more water treatment agents, or indicators of different target species by more than one water treatment agent. Water. In some examples, it may be desired to use a plurality of indicators and / or tracers of target species, only for a single water treatment agent, for example, to confirm that an indicator or tracer of target species is not subject to any selective loss Such indicators or tracers of different target species can all be detected and quantified in a sample of an individual water system because they are all fluorescent substances if their respective wavelengths of emission do not interfere with each other. Thus, current analyzes for multiple objective species indicators or plotters are possible by the selection of indicators or plotters of target species that have appropriate spectral characteristics. Preferably, the separated wavelengths of the radiation should be used to excite each of the indicators or tracers of the target species, and their fluorescent emissions should be observed and measured at separate emission wavelengths. A calibration curve of separate concentration can be prepared or obtained for each indicator or tracer of target species. In other words, more than one indicator or tracer of target species can be used, and then the presence and / or concentration can be determined from each of the indicators or tracers of the target species in the water system, using analytical parameters (particularly the excitation / emission wavelengths) effective for each of said indicators or tracers of the target species, in which the analytical parameters are preferably sufficiently different to differentiate between the measurements. Since a plurality of indicators of target species or tracers may be separately, but monitored concomitantly, the present invention does not exclude the use of one or more additional target species indicators or tracers for the preferred purposes of the present invention. invention, nor does it exclude the concomitant use of an indicator or tracer of target species for purposes of the present invention and for some other purposes.

Fluorescent emission spectroscopy on a substantially continuous basis, at least over a given period of time, is one of the preferred analytical techniques for the process of the present invention. It is one of the preferred analysis techniques for the quantification and determination of the concentration of the indicator or tracer of the target species in a system for the regulation of water treatment agents., and this analysis technique has significant advantages. A monochromatic dual spectrofluorometer can be used for a fiuorometric analysis conducted on an intermittent basis and for continuous and / or in-line fluorescent regulation. Portable or compact fluorometers, equipped with appropriate excitation and emission filters and the flow of quartz through the cells are commercially available, for example from Turner Designs (Sunnyvale, Calif.) In general, for more fluorescent emission spectroscopy methods that have a reasonable degree of practicability, it is preferable to perform the analysis without the isolation of some form of the indicator or tracer of the target species. Thus, there may be some degrees of fluorescence background in the water system, in which the fluorescence analysis is conducted, in which the fluorescence background may come from chemical compounds in the water system that are not related to the present invention. . In the example where the fluorescence background is low, the relative intensities (measured against a standard fluorescent compound at a standard concentration, and assigned to a relative intensity, for example a relative intensity of 100) of the fluorescence of the indicator or species tracer of the target against the background can be very high, for example at a ratio of 100/10 or 100/2, when certain combinations of the excitation and emission wavelengths are still employed at concentrations of indicators or tracers of low target species , and such proportions should be representative of relative relization (under similar conditions) of respectively 10 and 50. In a preferred embodiment, the excitation / emission wavelengths and / or the indicators or species plotters of the target are selected to provide a relative fluorescence of at least about 5 or 10 for the anticipated background fluorescence background. For example, for more water system backgrounds, a compound having a relative embodiment of at least about 5 at a reasonable concentration is very suitable as an indicator or tracer of target species. When there is or can be a specific chemical species of highly reasonable fluorescence in the background, the indicator or species tracer of the target and / or the emission wavelengths can often be selected to nullify or at least minimize any interference of the Tracer measurements caused by the presence of such species. A method for the continuous continuous monitoring of chemicals, by means of fluorescent emission spectroscopy and other methods of analysis, is described in U.S. Pat. No. 4,992,380 and U.S. Patent No. 5,435,969, descriptions of which are incorporated herein by reference. When the target species indicator is not fluorescent and the incipient reagent is fluorescent, a fluorescent analysis technique, such as that described above, will be directed to the focus or focused on the fluorescence of the incipient reagent. The measurement of the target species will be the loss of the incipient reagent, as consumed in the formation of the target species indicator, as manifested by the change in its fluorescence intensity and / or the excitation / emission characteristics of the target. wave. Similarly, if both the target species and the incipient reagent indicators are fluorescent, but have different fluorescent characteristics, for example between maximum emission wavelengths, the fluorescence analysis technique could focus on the loss of light emitted at the wavelength of the incipient reagent of the maximum emission, or instead of the increase of the light emitted at the wavelength of the target species indicator, as a function of the formation of the target species indicator from the interaction between the incipient reagent and the target species. The colorimetry, chemiluminescence or spectrophotometry, with or without chemometric analysis, can be used to detect and / or quantify a chemical tracer. Colorimetry is a determination of a chemical species based on its ability to absorb ultraviolet or visible light. A colorimetric analysis technique is a visual comparison of a bleaching or standard solution (containing a known concentration of the tracer species) with that of a sample of the fluid to be monitored. Another colorimetric method is the spectrophotometric method wherein the ratio of the incident intensities and the transmitted light beams are measured at a specified wavelength by means of a detector such as a photocell or photomultiplier tube. Using a co-diode probe, a fiber optic (dual) probe, such as a Brinkman PC-80 probe (570 nm filter), a sample solution is admitted to a cell flow in which the probe is immersed. An optical fiber cable shines or reflects the incident light through the sample liquid in a mirror inside the cell and the reflected light is transmitted again through the sample liquid in a fiber optic cable and then to the analyzer unit co-calorimeter, which contains a colorimeter, on the other cable. The colorimeter has a transducer that develops an electrical signal analogous to the reflected light characteristics of the concentration of the tracer. The voltage emitted by the transducer activates a dial indicator and a continuous printed cash register output unit. A voltage point monitor set can be used to monitor or feel constantly the analog voltage generated by the colorimeter, and after the detection of a trace signal, a response signal can be transmitted for a power line response of treatment agent to start or alter the proportion of food. Such a colorimetric analysis technique and the equipment that may be employed therefore, are described in US Patent No. 4,992,380, incorporated herein by reference. The chemical tracers suitable for use in conjunction with a coiorimetric technique, include transition metals and substances which show absorbance of light which is detectable from that of the other species present in the fluid system or substances which react with reactants color formers to produce the absorbance of light ia which is detectable from that of the other species present in the fluid system. An ion selective electrode can be used to determine the concentration of an inert chemical tracer through the potentiometric measurement of specific ion tracers in aqueous systems. These electrodes respond only to selected ionic materials and gases dissolved in liquids, and here such tracers may be ionized (or dissolved gases) in the environment in which they are being determined. Ion-selective electrodes depend on a potential development between a thin membrane by the difference in ion (or gas) concentrations to be measured on each side of the ionically conducting thin layer. The concentration inside the electrode is fixed and the power varies with the concentration of ions (or gas). By calibration (the potential or current against concentration), the ion concentration (or gas) in the electrode sample can be indexed to a standard or reference electrode that is insensitive to the tracer ion. To provide continuous monitoring of the tracer, the electrodes can be immersed directly in a stream of one of the fluids (which collectively comprise a cellular flux), or the monitored fluid is passed through an external cellular flux in which they have the reference and selective electrodes have been inserted into the ion. A technique and monitoring equipment of the ion selective electrode tracer therefore, is described in US Patent No. 4,992,380, incorporated herein by reference. The present invention in a broad manner, does not preclude the use of such other techniques for the monitoring of a target species indicator, particularly when the target species indicator is the species of the target itself, particularly when such an alternative method can be performed. without undue interference, and quickly enough for purposes of terminating system consumption for the target species. Analytical techniques for the quantification of the presence and / or concentration of a chemical species without isolation are therefore within an enveloping technology, and the previous study of analytical techniques to be used in the monitoring of a species indicator or tracer of the objective in the process of the present invention may not yet be exhaustive, and the most similar techniques equivalent to the foregoing for the purposes of the invention will be developed in the future. In the manufacturing process of the semiconductor chip, the fluorescence of the impurity can be monitored directly as an indicator of the purity of the chip or re-usable of the water of the rinsing process. However, an inert tracer material can be added for direct monitoring of impurities as above. Such an inert tracer can be added to the rinsing solution directly, or in a side stream to a different point in the manufacturing process of the semiconductor chip. The invention is a method for improving the purity efficiency of the semiconductor chip, during the manufacture of the semiconductor chip comprising the steps of: a) cleaning the semiconductor chip by means of a rinsing process to remove the impurities from the surface of the chip by means of the Submerging the chip repeatedly in an aqueous rinse solution; b) fluorometrically monitor the rinse solution for the fluorescent impurities while the immersion of the chip determines said concentration of impurities in said rinse solution; c) correlating the fluorometric values for said impurities in concentration amounts of said impurities; d) observing an increase in the concentration of the impurities during the rinsing process as determined in step c) and; e) determine that the chip is clean, as the termination of the rinsing process is indicated when the concentration of the impurities in the rinsing solution ceases the increase of step d) and becomes constant. In this way, as it happens cleaning and washing of impurities from the chip, it is expected that the amount of impurity in the cleaning solution will increase. However, at a point where no more impurities can be removed, the amount of impurity will be a constant value (the increase stops). This indicates that the cleaning process is complete. For practicing some aspect of the invention, the fluorometric detection can be a fluorescent technique, and can be monitored by at least one fluorescent emission value. Furthermore, for the practice of some aspect of this invention, cleaning may occur subsequent to the polishing process of the semiconductor chip processing. The chip can be successively submerged in a series of said rinsing solutions. It is within the field of view of this invention, that any single impurity can be monitored, or more than one impurity can be monitored at the same time. Another aspect of the invention is a method for improving the efficiency of the cleaning of the semiconductor chip during the manufacturing of the semiconductor chip comprising the steps of: a) cleaning the semiconductor chip by means of a rinsing process to remove the impurities from the surface of the chip by atomizing the chip repeatedly with an aqueous rinse solution; b) collect the spent rinsing solution that is washed from the chip; c) monitoring the solution fluorometrically consumed by fluorescent impurities, in order to determine said concentration of impurities in said consumed rinse solution; d) correlating the fluorometric values of said impurities to concentration amounts of said impurities; e) observing an increase in the concentration of the impurities during the rinsing process as determined in step d); and f) determining which chip is clean, as the termination of the rinsing process is indicated when the concentration of the impurities in the rinsing solution ceases the increase of step e) and becomes constant. Another aspect of this invention is a method for increasing the efficiency of the semiconductor chip cleaning process during the manufacture of the semiconductor chip, comprising the steps of: a) cleaning the semiconductor chip by a rinsing process to remove impurities from the surface of the chip; chip by repeatedly immersing the chip in an aqueous rinse solution; b) monitoring said fluorometric solution of rinsing by fluorescent impurities; c) correlating the fluorometric values of said impurities to the concentration amounts of said impurities; and d) determining whether said rinse solution contains said impurities in a concentration above or below a predetermined minimum acceptable concentration of said impurities; e) again using said rinsing solution if the concentration of the impurities is below the minimum acceptable concentration; and f) discharging said rinse solution if the concentration of the impurities is above the minimum acceptable concentration. Yet another aspect of this invention is a method for increasing the efficiency of the semiconductor chip cleaning process during the manufacture of the semiconductor chip, comprising the steps of: a) cleaning the semiconductor chip by a rinsing process to remove the impurities from the chip surface by spraying or spraying the chip repeatedly in an aqueous rinse solution; b) collect the spent rinsing solution that is washed from the chip; c) monitoring said fluorometric solution of rinsing by fluorescent impurities, to determine said concentration of impurities in the spent rinsing solution; d) correlating the fiuorometric values for said impurities to concentration amounts of said impurities; e) determining whether the spent rinsing solution contains said impurities in a concentration above or below a predetermined acceptable minimum concentration of said impurities; and f) again use the rinsing solution if the concentration of the impurities is below the minimum acceptable concentration; g) discharge the rinsing solution if the concentration of the impurities is above said minimum acceptable concentration. A further aspect of this invention is a method for improving the efficiency of semiconductor chip production, comprising the steps of; a) clean the semiconductor chip by means of a rinsing process to remove the impurities from the surface of the chip with an aqueous rinse solution; b) monitoring said fluorometric solution of rinsing to obtain a fluorometric performance by fluorescent impurities; c) determining from said reading, the identity of said impurities; and d) adjust production in accordance with the decrease or decrease in impurities. This method can be advantageous in two ways. The first is that the technique could be used to monitor the presence of an impurity not normally in the rinsing stream. The presence of this impurity could indicate a malfunction somewhere up the line in the manufacturing process. This could serve as an early indicator of a problem with production which requires adjustment. The second advantage of such a technique could be that certain impurities could be expected by products of the manufacturing process. They could be present routinely within a certain acceptable range. When the detection method indicates the presence of impurities to a degree greater than the expected amount, it could be indicated that the part of the manufacturing process which originates the presence of such impurity needs adjustment. Using the techniques described above, the following organic solutions for rinsing the semiconductor chip can be monitored, among others: acetone; butylacetate; ethoxyethyl acetate; ethyl benzene; ethylene glycol; isopropanol; methylethyl ketone; n-methyl pylorridone; tetramethyl ammonium hydroxide; xylene; sulfonates; carboxylates; phosphates; polyglycides of hills; poly (oxyethylene) alcohols; betaines; and dioctyl phthalates. This list is not exhaustive, as any fluorescent impurity can be adequately analyzed by this technique. The following examples are presented to describe the preferred embodiments and utilities of the invention and do not suggest limiting the invention unless stated otherwise in the claims appended thereto.

Example 1 A fluorometer could be placed to measure certain organics in the rinse bath. The disks have a stage of process to realize them, and are then rinsed in ultra-pure water baths. The rinses are to remove the impurities (some of these are organic in the attached list) of the previous stages before moving them in the next stage of the process. Normally, the disks (chips) remain in the rinsing tank for a predetermined amount of time, but the optimization of this time does not occur to any great extent. It is expected that as the rinse removes a particular impurity from a chip, as long as the quantities of such impurity allow the chip to go into the spent rinsing solution. By measuring the increase of organics in the bath, and determining the point at which no more organics are removed in the bath, as indicated by a leveling, or the constant concentration of the impurity monitoring process could be accelerated, reducing the manufacturing cycle time.

Example 2 A fluorometer could measure certain organics in the water discharged from the baths. The fluorometer signal could be monitored, and when a certain level is exceeded, it could cause activated valves to fill the water in the bath, with water having an acceptably low concentration of the harmful organics.

Example 3 The water could flow through a fluorometer on a current basis. When the signal exceeds a certain level, the valves could be activated to direct the water to a process to reduce the organic content to an acceptable level. This method could also be used downstream of the elimination process also as a control.

Example 4 The fluorometer could be used to monitor the presence of certain impurities. When the specific impurity monitored (which could be a known product of a certain specific portion of the manufacturing process) is present in the rinse water above a certain (usual) level, it could be an indication that the countercurrent process in the chip manufacturing results in the presence of impurity being complete, and needs adjustment. This countercurrent process can then be adjusted in response to the unusual increase in a particular process per product. Thus, the described method could be used as an indicator to turn the manufacturing process very well.

Changes made in the composition, operation and arrangement of the method of the present invention are described herein without departing from the concept and scope of the present invention as defined in the following claims.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, the content of the following is claimed as property.

Claims (10)

1. A method for improving the cleaning efficiency of the microcircuit or semiconductor, during the manufacture of the semiconductor chip, characterized in that it comprises the steps of: a) cleaning the semiconductor chip by means of a rinsing process to remove the impurities from the surface of the chip by submerging of the chip repeatedly, in an aqueous rinse solution; b) fluorometrically monitor the rinse solution for the fluorescent impurities while the immersion of the chip determines said concentration of impurities in said rinse solution; c) correlating the fluorometric values for said impurities in concentration amounts of said impurities; d) observing an increase in the concentration of the impurities during the rinsing process as determined in step c) and; e) determine that the chip is clean, as the termination of the rinsing process is indicated when the concentration of the impurities in the rinsing solution ceases the increase of step d) and becomes constant.

2. The method of claim 1, characterized in that said fluorometric detection is a fluorescent technique, and the monitoring is at least one fluorescent emission value.

3. The method of claim 1, characterized in that said cleaning occurs subsequent to the polishing process of the manufacture of the semiconductor chip.

4. The method of claim 1, characterized in that the chip is repeatedly submerged in a series of said solution solutions.

5. A method for improving the efficiency of the cleaning of the semiconductor chip during the manufacture of the semiconductor chip, characterized in that it comprises the steps of: a) cleaning the semiconductor chip by means of a rinsing process to remove the impurities from the surface of the chip by atomization to the chip repeatedly with an aqueous rinse solution; b) collect the spent rinsing solution that is washed from the chip; c) monitoring the solution consumed fiuorometrically by fluorescent impurities, to determine said concentration of impurities in said consumed rinse solution; d) correlating the fluorometric values of said impurities to concentration amounts of said impurities; e) observing an increase in the concentration of the impurities during the rinsing process as determined in step d); and f) determining which chip is clean, as termination of the rinsing process is indicated when the concentration of the impurities in the rinsing solution ceases the increase of step e) and becomes constant.

6. The method of claim 5, characterized in that said fluorometric detection is a fluorescent technique, and the monitoring is at least one fluorescent emission value.

7. The method of claim 5, characterized in that said cleaning occurs subsequent to the polishing process of the manufacture of the semiconductor chip.

8. A method to increase the efficiency of the semiconductor chip cleaning process during the manufacture of the semiconductor chip, characterized in that it comprises the steps of: a) cleaning the semiconductor chip by a rinsing process to remove the impurities from the surface of the chip by immersing the chip. chip, repeatedly, in an aqueous rinse solution; b) monitoring said fluorometric solution of rinsing by fluorescent impurities; c) correlating the fluorometric values of said impurities to the concentration amounts of said impurities; and d) determining whether said rinse solution contains said impurities in a concentration above or below a predetermined minimum acceptable concentration of said impurities; e) again using said rinsing solution if the concentration of the impurities is below the minimum acceptable concentration; and f) discharging said rinsing solution if the concentration of the impurities is above the minimum acceptable concentration.

9. A method for increasing the efficiency of the cleaning process of the semiconductor chip during the manufacture of the semiconductor chip, characterized in that it comprises the steps of: a) cleaning the semiconductor chip by means of a rinsing process to remove the impurities from the surface of the chip by atomization or spraying the chip repeatedly, in an aqueous rinse solution; b) collect the spent rinsing solution that is washed from the chip; c) monitoring said flushing solution fiuorometrically by fluorescent impurities, to determine said concentration of impurities in the flushing solution consumed; d) correlating the fluorometric values for said impurities to concentration amounts of said impurities; e) determining whether the spent rinsing solution contains said impurities in a concentration above or below a predetermined minimum acceptable concentration of said impurities; and f) again use the rinsing solution if the concentration of the impurities is below the minimum acceptable concentration; g) discharge the rinsing solution if the concentration of the impurities is above said minimum acceptable concentration.

10. A method for improving the efficiency of the production of the semiconductor chip, comprises the steps of: a) cleaning the semiconductor chip by means of a rinsing process to remove the impurities from the surface of the chip with an aqueous rinsing solution; b) monitoring said fluorometric solution of rinsing to obtain a fluorometric performance by fluorescent impurities; c) determining from said reading, the identity of said impurities; and d) adjust production according to the decrease or decrease of impurities.