JP2006007052A - Method and apparatus for cleaning of electronic part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for cleaning electronic parts by the use of radical active species, with the capability of cleaning organic matter or inorganic particulates improved by increasing the concentration of the hydroxyl radical and the concentration of the hydrogen radical produced. <P>SOLUTION: A carrying roller 109 carries a substrate 101 flatly in the direction of the arrow A, and a mixed solution 104 comprising a first ozone-containing cleaning solution and a second hydrogen-containing cleaning solution is supplied onto the substrate 101 from a supply nozzle 102 for the mixed solution arranged above the substrate 101 in the carrying passage. Then, UV light 105 from a UV-irradiating device 103 is cast onto the mixed solution 104 supplied on the substrate 101 to generate hydroxyl and hydrogen radicals which clean the substrate 101. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cleaning method and a cleaning apparatus for cleaning a surface of a precision substrate such as an electronic material, in particular, a liquid crystal glass substrate, a semiconductor substrate, a metal substrate, a quartz glass substrate, a mask blank substrate, a photomask substrate, and an optical disk substrate. is there.

  Conventionally, a cleaning method using an RCA cleaning method has been used for a semiconductor silicon substrate, a liquid crystal glass substrate, and the like. This is a cleaning method using a high-temperature concentrated chemical solution (sulfuric acid + hydrogen peroxide solution, hydrochloric acid + hydrogen peroxide solution + water, ammonia + hydrogen peroxide solution + water) based on hydrogen peroxide. In these methods, rinsing water containing a chemical solution such as acid, treatment equipment for treating volatile components, acid gas, and the like generated from the cleaning device are separately required. Further, there is a cost for processing the waste liquid generated by the processing. Furthermore, in recent years, the size of the mother substrate of a semiconductor wafer or a liquid crystal panel tends to increase, and accordingly, the amount of chemical liquid used and the amount of waste liquid generated in the cleaning process also increase. Increase is a problem.

  In addition, a method of using an acidic surfactant as an alternative to a concentrated chemical solution is also used, but the surfactant may also be changed to an environmental hormone, and problems with biodegradability in the environment have been pointed out. . Furthermore, although the waste liquid treatment cost is reduced compared to the method using concentrated chemicals, it is difficult to remove particles and foreign substances contained in the surfactant, and measures such as installing filters and monitoring with a particle counter are required. It becomes.

  On the other hand, the design rules for semiconductors and liquid crystals are continually miniaturized, and in the situation where liquid crystals are approaching the sub-micron level, and semiconductors are approaching the level of 0.1 micron or less, photo used as an exposure substrate. There is an increasing demand for cleaning the mask substrate. The photomask substrate is obtained by laminating a metal thin film of chromium or the like on a quartz glass substrate by vapor deposition or sputtering to form a mask blank substrate, applying a resist or the like to this, exposing it, etching it, and patterning the surface. In order to obtain a clean photomask substrate from the viewpoint of improving the yield of semiconductors and liquid crystal panels, highly purified substrates are required from the stage of quartz glass substrate and mask blank substrate. In addition, liquid crystal glass substrates and optical disk substrates are required to have a high degree of cleanliness similar to photomask substrates. Therefore, it is necessary to completely remove impurities in the cleaning process of these precision substrates, and improvement of the cleaning power in the cleaning process is an important issue.

  While solving the above conflicting requirements, as a cleaning means to escape from conventional cleaning methods using concentrated chemicals and surfactants, or cleaning methods that rely on physical forces such as water flow, water components, that is, oxygen atoms and A cleaning method using radical active species composed of hydrogen atoms has been proposed. Examples of radical active species composed of oxygen atoms and hydrogen atoms include hydrogen radicals, oxygen radicals (atomic oxygen), hydroxyl radicals, and superoxide anion radicals.

  For example, when water molecules are irradiated with energy such as radiation, two radical active species, hydrogen radical [• H] and hydroxyl radical [• OH], are generated. A hydrogen radical consists of one proton [H +] and one unpaired electron [•], and is a hydrogen atom itself. On the other hand, a hydroxyl radical is also called a hydroxy radical and is a kind of active oxygen. Further, when water molecules are irradiated with radiation, electrons are knocked out of the water molecules by radiation in addition to the breaking of the O—H bond. One type of superoxide anion radical is generated.

  The hydroxyl radical has an action of breaking organic bonds by its strong oxidizing power, and the hydrogen radical has an action of reducing metal oxides and the like by its strong reducing power. The characteristics of these radically active species are extremely high in reactivity and instantaneously change to water, hydrogen, oxygen, etc. by reaction with the reactive species, so there is almost no burden on the environment, and even at a concentration of several tens of ppm It has a sufficient cleaning effect.

  As a cleaning technique using this radical reaction, for example, Patent Document 1 discloses a cleaning method for removing fine particles using hydrogen radicals generated by applying ultrasonic waves to hydrogen water. On the other hand, Patent Document 2 discloses a method in which ozone water cleaning, which uses the oxidizing power of ozone in ozone water, is combined with hydrogen water cleaning, as a cleaning method for removing organic substances on a substrate simultaneously with the removal of fine particles. ing. The method for generating hydrogen radicals is the same ultrasonic wave as in Patent Document 1. The cleaning ability of fine particles using hydrogen radicals depends on the concentration of hydrogen radicals, but since hydrogen radicals are generated by the reaction between hydroxyl radicals and water molecules, ultrasonic waves were used in the cleaning methods of Patent Documents 1 and 2. Hydrogen radicals are generated by reacting hydrogen radicals generated by the cleavage of water molecules with hydrogen, and the cleaning ability depends on the output of ultrasonic waves, which are means for generating hydroxyl radicals.

However, in the above hydrogen radical generation method, for example, for a hydrogen concentration of 1.2 ppm, hydrogen used for hydrogen radical generation is only about 1/10 of the contained hydrogen. Furthermore, when hydrogen water having a hydrogen concentration of 1.2 ppm or more is used, there is a problem that the ultrasonic wave propagation efficiency is lowered, and the hydrogen radical concentration is lowered to reduce the cleaning ability. There is a certain limit to the amount of radicals produced. Therefore, it has been difficult for the methods of Patent Documents 1 and 2 to further improve the cleaning ability.
JP 2000-117208 A JP 2001-96241 A

  In view of the above problems, the present invention is directed to cleaning organic substances and inorganic fine particles by increasing the concentration of hydroxyl radicals and also increasing the concentration of hydrogen radicals in cleaning electronic components that use radical active species to remove impurities. It is an object of the present invention to provide a cleaning method and a cleaning apparatus for an electronic component capable of improving performance.

  In order to achieve the above object, the present invention provides an electronic component comprising a step of supplying a first cleaning liquid containing ozone onto the electronic component, and a step of irradiating the first cleaning liquid on the electronic component with ultraviolet light. It is characterized by being a cleaning method.

  The present invention also includes a step of mixing a first cleaning solution containing ozone and a second cleaning solution containing hydrogen and supplying the mixture onto the electronic component, and mixing the first and second cleaning solutions on the electronic component. And a step of irradiating the liquid with ultraviolet light.

  The present invention also includes a step of separately supplying a first cleaning liquid containing ozone and a second cleaning liquid containing hydrogen onto the electronic component, and the first and second mixed on the electronic component. And a step of irradiating the cleaning liquid with ultraviolet light.

  According to the present invention, in the electronic component cleaning method configured as described above, the first cleaning liquid includes anode water.

  According to the present invention, in the electronic component cleaning method configured as described above, the second cleaning liquid contains cathode water.

  According to the present invention, in the electronic component cleaning method having the above-described structure, a light source including ultraviolet light having a wavelength of 300 nm or less is used as the ultraviolet light source.

  According to the present invention, in the electronic component cleaning method having the above-described configuration, the ozone concentration of the first cleaning liquid is 5 ppm or more and 60 ppm or less.

  According to the present invention, in the electronic component cleaning method having the above-described configuration, the hydrogen concentration of the second cleaning liquid is set to 0.1 ppm or more and 2 ppm or less.

  According to the present invention, in the electronic component cleaning method having the above-described configuration, the molar concentration of ozone in the mixed solution is 0.5 times or more the molar concentration of hydrogen.

  According to the present invention, in the electronic component cleaning method having the above-described configuration, the molar concentration of hydrogen in the liquid mixture is set to be twice or more the molar concentration of ozone.

  According to the present invention, in the electronic component cleaning method configured as described above, the electronic component is any one of a liquid crystal glass substrate, a semiconductor substrate, a metal substrate, a quartz glass substrate, a mask blank substrate, a photomask substrate, and an optical disk substrate. It is characterized by that.

  According to another aspect of the present invention, there is provided a cleaning apparatus for cleaning an electronic component by the cleaning method having the above-described configuration, the first supply nozzle supplying the first cleaning liquid onto the electronic component, and the first supply nozzle on the electronic component. And an ultraviolet light irradiation device for irradiating the cleaning liquid with ultraviolet light.

  Further, the present invention is a cleaning apparatus for cleaning an electronic component by the cleaning method having the above-described configuration, and a liquid mixture supply nozzle for supplying the liquid mixture onto the electronic component, and ultraviolet light on the liquid mixture on the electronic component And an ultraviolet light irradiation device for irradiation.

  According to another aspect of the present invention, there is provided a cleaning apparatus for cleaning an electronic component by the cleaning method configured as described above, wherein the first supply nozzle supplies the first cleaning liquid onto the electronic component, and the second cleaning liquid is supplied to the electronic component. It is characterized by comprising a second supply nozzle for supplying upward, and an ultraviolet light irradiation device for irradiating ultraviolet light at a position where the first and second cleaning liquids are mixed on the electronic component.

  The present invention is also a cleaning apparatus for cleaning an electronic component by the cleaning method having the above-described configuration. As the ultraviolet light irradiation apparatus, a low pressure mercury lamp, a high pressure mercury lamp, an excimer ultraviolet lamp, a vacuum ultraviolet lamp, a halogen lamp, an excimer Any one of a laser, an ultraviolet laser, and an ultraviolet light emitting diode is used.

  According to the first configuration of the present invention, the cleaning liquid containing ozone is supplied onto the electronic component, and the cleaning liquid is irradiated with ultraviolet light on the electronic component to generate a high concentration of hydroxyl radicals on the electronic component. The attached resist residue, organic matter, and the like can be effectively cleaned.

  Further, according to the second configuration of the present invention, the first cleaning liquid containing ozone and the second cleaning liquid containing hydrogen are mixed and supplied onto the electronic component, and the mixed liquid is applied to the ultraviolet on the electronic component. By irradiating with light, it is possible to effectively wash inorganic fine particles such as resist residues, organic substances, and metal oxides that are generated on the electronic component by generating high-concentration hydrogen radicals and hydroxyl radicals.

  According to the third configuration of the present invention, the first cleaning liquid containing ozone and the second cleaning liquid containing hydrogen are separately supplied onto the electronic component and mixed on the electronic component. By irradiating the cleaning liquid with ultraviolet light, it is possible to prevent ozone and hydrogen contained in each cleaning liquid from reacting before the cleaning to lower the concentration, and to generate hydrogen radicals and hydroxyl radicals more efficiently.

  According to the fourth configuration of the present invention, in the electronic component cleaning method according to any one of the first to third configurations, the first cleaning liquid is obtained using anode water that is easily obtained by electrolysis of water. Can be prepared.

  According to the fifth aspect of the present invention, in the electronic component cleaning method according to any one of the second to fourth aspects, the second cleaning liquid is obtained using cathode water that is easily obtained by electrolysis of water. Can be prepared.

  According to the sixth configuration of the present invention, in the electronic component cleaning method according to any one of the first to fifth configurations, a light source including ultraviolet light having a wavelength of 300 nm or less is used as the ultraviolet light source. Thus, it is possible to efficiently decompose ozone in the cleaning liquid by irradiating ultraviolet light in the vicinity of the absorption wavelength of ozone, and to further increase the concentration of hydroxyl radicals.

  According to the seventh configuration of the present invention, in the electronic component cleaning method according to any one of the first to sixth configurations, the ozone concentration of the first cleaning solution is 5 ppm or more and 60 ppm or less. The ozone concentration in the inside can be made as high as possible and below the saturation concentration, while preventing the ozone from being re-released as bubbles while ensuring the ozone concentration during cleaning, preventing the deterioration of the wetting performance of electronic components it can.

  According to the eighth configuration of the invention, in the electronic component cleaning method according to any one of the second to seventh configurations, the hydrogen concentration of the second cleaning liquid is set to 0.1 ppm or more and 2 ppm or less. The hydrogen concentration in the cleaning liquid can be made as high as possible and below the saturation concentration, ensuring the cleaning ability and preventing the deterioration of the wetting performance of the electronic component.

  According to the ninth configuration of the present invention, in the electronic component cleaning method according to any one of the second to eighth configurations, the molar concentration of ozone in the mixed solution is set to 0.5 molar concentration of hydrogen. By setting the number to twice or more, the cleaning conditions can be appropriately set from a cleaning condition in which organic substance removal and fine particle removal are used together to a condition specialized for organic substance removal.

  According to the tenth configuration of the present invention, in the electronic component cleaning method according to any one of the second to eighth configurations, the molar concentration of hydrogen in the mixed solution is at least twice the molar concentration of ozone. As a result, the cleaning conditions can be appropriately set from a cleaning condition using both organic substance removal and fine particle removal to a condition specialized for fine particle removal.

  According to an eleventh configuration of the present invention, in the electronic component cleaning method according to any one of the first to tenth configurations, the electronic component is a liquid crystal glass substrate, a semiconductor substrate, a metal substrate, a quartz glass substrate, Since it is one of the mask blank substrate, photomask substrate, and optical disk substrate, it is possible to achieve complete removal of impurities on the substrate in the cleaning process without increasing the processing cost and increasing the environmental load. In addition, it is possible to manufacture a precision substrate that is indispensable for manufacturing semiconductors and liquid crystals with fine design rules.

  According to the twelfth configuration of the present invention, in the cleaning device that cleans the electronic component by the cleaning method of the first configuration, the first supply nozzle that supplies the first cleaning liquid onto the electronic component; By providing an ultraviolet light irradiation device that irradiates the first cleaning liquid with ultraviolet light on the electronic component, a highly reactive hydroxyl radical can be generated following the cleaning operation on the electronic component. Resist residues and organic substances adhering to the substrate can be efficiently removed.

  According to the thirteenth configuration of the present invention, in the cleaning apparatus that cleans the electronic component by the cleaning method of the second configuration, the mixed solution supply nozzle that supplies the mixed solution onto the electronic component, and the electronic component By providing an ultraviolet light irradiation device for irradiating the mixed liquid with ultraviolet light, highly reactive hydroxyl radicals and hydrogen radicals can be generated on the electronic component following the cleaning operation. Impurities such as adhering resist residues, organic substances, and inorganic fine particles can be efficiently removed.

  According to the fourteenth configuration of the present invention, in the cleaning device that cleans the electronic component by the cleaning method of the third configuration, the first supply nozzle that supplies the first cleaning liquid onto the electronic component; By including a second supply nozzle that supplies the second cleaning liquid onto the electronic component, and an ultraviolet light irradiation device that irradiates the position where the first and second cleaning liquids are mixed on the electronic component. In addition, it is possible to provide a cleaning apparatus that prevents ozone and hydrogen contained in each cleaning solution from reacting and reducing the concentration before cleaning, and more efficiently generates hydrogen radicals and hydroxyl radicals.

  According to the fifteenth configuration of the present invention, in the cleaning device having any one of the twelfth to fourteenth configurations, as the ultraviolet light irradiation device, a low pressure mercury lamp, a high pressure mercury lamp, an excimer ultraviolet lamp, or a vacuum ultraviolet lamp. By using any one of a halogen lamp, an excimer laser, an ultraviolet laser, and an ultraviolet light-emitting diode, the ozone decomposition efficiency is improved by irradiating light containing a lot of ultraviolet light of 254 nm which is the absorption wavelength of ozone. It can be set as the washing | cleaning apparatus which further improved the production | generation effect.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing the configuration of the cleaning apparatus of the present invention. Reference numeral 101 denotes a substrate such as a semiconductor or a liquid crystal panel, which is to be cleaned by the cleaning method of the present invention. Examples of the substrate 101 mainly include a liquid crystal glass substrate, a semiconductor substrate, a metal substrate, a quartz glass substrate, a mask blank substrate, a photomask substrate, and an optical disk substrate. Here, only the substrate 101 is illustrated as an object to be cleaned, but is not limited thereto, and includes a wide range including various parts of precision instruments. In FIG. 1, a case where the substrate 101 is a liquid crystal glass substrate and applied to a so-called flat-flow cleaning apparatus will be described.

  The cleaning method of the present invention is intended to remove contamination on the surface of the substrate 101, and both organic contamination and inorganic contamination can be targeted for removal. Specifically, when the substrate 101 is a semiconductor substrate or a liquid crystal substrate, the organic contamination can include organic thin films such as resist remaining in the masking peeling process and contamination from other organic substances. Examples of the contamination include oxide film fragments scattered during etching, metal oxide particles adhering in a film forming process such as sputtering or CVD, and other metal oxide particle contamination. In the present invention, it is possible to remove submicron-sized inorganic contaminants with high cleanliness, and organic contaminants can be effectively removed at the same time. It is characterized in that contamination can be effectively removed with high cleanliness regardless of the type.

  In the present invention, electronic components are cleaned using radically active species. Hydrogen and ozone are used as the raw material molecules for the radical active species, and a cleaning solution in which these are dissolved in an appropriate solvent is supplied onto the electronic component. The first cleaning liquid containing ozone and the second cleaning liquid containing hydrogen are generated by separately dissolving hydrogen and ozone in separate solvents by an ozone solution generation unit and a hydrogen solution generation unit separately installed. The first and second cleaning liquids are generated by a film dissolution method or an electrolysis method in each generation unit.

When water is energized and electrolyzed, water molecules [H ₂ O] are divided into hydrogen ions [H ⁺ ], oxygen molecules [O ₂ ], and electrons on the anode side, and hydrogen ions and oxygen molecules increase and water is increased. Oxygen molecules that dissolve in the water also increase. At this time, ozone, oxygen radicals and the like are also generated. On the other hand, on the cathode side, electrons act on water molecules to increase hydroxy ions [OH ⁻ ] and hydrogen molecules [H ₂ ], and hydrogen molecules dissolved in water also increase. That is, if the anode side and the cathode side are separated by a suitable diaphragm, ozone will be contained in the electrolytic cathode water on the anode side, and hydrogen will be contained in the electrolytic anode water on the cathode side. Similar effects can be obtained even when used as the first and second cleaning liquids. The first and second cleaning liquids are supplied into the mixed liquid supply nozzle 102 according to arrows B and C on the first supply line 106 and the second supply line 107, respectively.

  The solvent used in the present invention is not limited as long as it can dissolve hydrogen or ozone, and water or various organic solvents can be used. However, since radically active species generated from raw material molecules react and disappear easily with impurities contained in the solvent, it is preferable that the solvent does not contain such impurities, and also considers environmental load issues. Then, it is preferable to use water instead of an organic solvent. Therefore, a particularly preferable solvent used in the present invention is water, and it is preferable that such water is purified, but it may contain unavoidable impurities that do not cause a decrease in the concentration of radical active species. There is no.

  Reference numeral 103 denotes an ultraviolet light irradiation device that irradiates the mixed liquid 104 on the substrate 101 with ultraviolet light 105 guided in accordance with an arrow D through an ultraviolet light waveguide line 108 from a light source (not shown). The ultraviolet light waveguide line 108 is composed of an optical fiber cable made of quartz or the like. The ultraviolet light 105 decomposes ozone in the mixed liquid 104 containing ozone, and effectively generates hydroxyl radicals. For this reason, as the ultraviolet light 105, it is preferable to use light containing a large amount of light at 254 nm, which is a wavelength with high light absorption ability of ozone.

  Specifically, low-pressure mercury lamps, high-pressure mercury lamps, vacuum ultraviolet lamps, xenon lamps, excimer UV lamps, etc., lamps containing light in the ultraviolet region with a wavelength of 300 nm or less, excimer lasers, ultraviolet lasers, X-rays, radiation, etc. Any light source capable of decomposing ozone and generating hydroxyl radicals can be used. However, since the irradiation intensity of the ultraviolet light 105 greatly affects the radical generation concentration, a light source with a small change in irradiation intensity, a long emission lifetime, and a low running cost is more desirable. Therefore, a particularly suitable light source is a low-pressure mercury lamp, and it is more preferable that light other than the light having a wavelength of about 254 nm is shielded by the filter.

The light intensity of the ultraviolet light source is expressed by the following formula (1).
E = (5 × 10 ¹² × h × NA × Q × C) / (48 × λ × P) (1)
However,
E [W]: intensity of irradiated light at the absorption wavelength of ozone,
Q [L / min]: ozone solution flow rate,
C [ppm]: ozone solution concentration,
NA: Avogadro's number,
h: Planck's constant,
λ [nm]: absorption wavelength of ozone,
P: photon yield of hydroxyl radical generation,
It is.

Therefore, for example, assuming that the flow rate is 5 [L / min], the ozone solution concentration is 5 [ppm], the absorption wavelength of ozone is 254 [nm], and the photon yield of hydroxyl radical generation is 0.5, the absorption wavelength of ozone. The irradiation light intensity in is 5 × 10 ¹² × (6.63 × 10 ⁻³⁴ ) × (6.02 × 10 ²³ ) × 5 × 5 / (48 × 254 × 0.5) ≈8 [W]. . When a low-pressure mercury lamp is used as the light source, the total output is usually four times the output at 254 nm. In this example, ozone can be completely radicalized by using a 32 W low-pressure mercury lamp.

  Reference numeral 109 denotes a transport roller for transporting the substrate 101. The substrate 101 is transported in the direction of arrow A by the substrate transport roller 109, and a cleaning unit comprising the mixed liquid supply nozzle 102 and the ultraviolet light irradiation device 103 installed in the middle of transport. The cleaning process is performed sequentially. The cleaning method of the present invention is a cleaning method characterized by having energy saving, cost reduction, and high cleaning ability, and shows the greatest effect particularly when applied to a cleaning process of a liquid crystal glass substrate having a large cleaning area. be able to.

  In recent years, liquid crystal glass substrates have been remarkably increased in size, and flat-flow cleaning is becoming the mainstream for the purpose of reducing uniformity and tact time. However, the effect of the present invention is not limited to the flat-flow cleaning method. The showering method in which the cleaning liquid is poured in a shower or the like, the spin cleaning method in which the cleaning liquid is supplied onto the rotating substrate, and the substrate containing the cleaning liquid. It is possible to apply to any conventionally known cleaning means using a cleaning liquid, such as an immersion cleaning method for immersing in a batch type immersion tank and a combination thereof, and the same cleaning power improvement effect is obtained for any cleaning means. Obtainable.

  In the case of the immersion cleaning method, if the depth of the cleaning liquid existing between the light source and the substrate is large, the ultraviolet light from the light source will not easily reach the substrate surface, and the concentration of radicals generated on the substrate surface will be low. Can be considered. For this reason, it is necessary to appropriately set the liquid depth of the immersion tank according to the absorption coefficient and concentration of ozone, the type of the light source to be used, and the like, and it is desirable to set it to several tens of mm or less under normal conditions. In addition, the cleaning efficiency can be further improved by combining the above-described cleaning methods with physical cleaning using ultrasonic irradiation or a sponge.

Next, the principle of the cleaning method of the present invention will be described. In the cleaning method of the present invention, the first and second cleaning liquids containing ozone and hydrogen, which are the above-mentioned radical generating raw material molecules, are mixed and supplied to the surface of the substrate 101, and further, the ultraviolet light irradiation apparatus is applied to the supplied mixed liquid 104. The surface of the substrate 101 is washed with hydrogen radicals and hydroxyl radicals generated by ultraviolet light 105 irradiated from 103. The radical generation mechanism will be described using the following reaction formulas (I) to (III).

In the radical generation mechanism in this cleaning method, first, by irradiating ultraviolet light, ozone in the liquid mixture is photoexcited as shown in the reaction formula (I). Photoexcited ozone splits into excited oxygen atoms and oxygen molecules. Since oxygen molecules are stable, they are dissolved in water or saturated and released into the air. On the other hand, since the excited oxygen atoms are in a highly active state, they react with surrounding water molecules as shown in the reaction formula (II) to generate hydroxyl radicals. This hydroxyl radical is also very reactive, and the reaction proceeds with surrounding water molecules and hydroxyl radicals, and finally changes to water and oxygen.

  However, since the mixed solution contains hydrogen, the hydroxyl radical also reacts with hydrogen as shown in reaction formula (III). By this mechanism, hydrogen radicals are generated. Hydroxyl radicals generated by the mechanism described above are effective in cleaning resist residues and other organic substances on the substrate due to their oxidizing power, and even the hydrocarbon carbon-carbon bonds are decomposed. And is broken down into carbon dioxide. In addition, the generated hydrogen radicals are effective for removing fine particles derived from inorganic metal oxides attached on the substrate by the reducing power. This is because the highly reactive hydrogen radical acts on the fine particle adhesion bond formed by the bond between the fine particle and the dangling bond on the surface of the substrate, thereby cutting the adhesion force of the fine particle, cleaning, This is considered to be due to the effect of acting on dangling bonds having no surface bonding to form hydrogen terminations and suppressing recombination between the fine particles and the substrate.

Further, in the cleaning method of the present invention, cleaning specialized to the cleaning object can be performed by changing the molar concentration ratio of ozone and hydrogen in the mixed liquid of the first and second cleaning liquids. As shown in reaction formulas (I) to (III), hydroxyl radicals are generated approximately twice as much as ozone concentration. Therefore, when the molar ratio of hydrogen to ozone is 2: 1, hydroxyl radicals are completely produced. Is consumed to generate hydrogen radicals. Therefore, for example, when the ozone concentration ratio is higher than this, since hydroxyl radicals are generated excessively, it is possible to remove organic contamination on the substrate simultaneously with the removal of the fine particles.

  However, since the hydroxyl radical and the hydrogen radical are both highly reactive, the side reaction easily proceeds to generate water. Therefore, when the ozone concentration is increased from the above ratio, the production amount of hydrogen radicals decreases and the particulate removal ability tends to decrease. In addition, when the hydrogen concentration ratio is increased from the above concentration ratio, hydrogen is not completely radicalized, so that the amount of hydrogen radicals generated is decreased. On the other hand, the concentration of hydroxyl radicals is also decreased. As a result, the consumption of hydrogen radicals due to this side reaction decreases, and the concentration of hydrogen radicals actually increases and the particulate removal ability improves.

  From the above tendency, if the molar concentration of ozone is set to 0.5 times or more of the molar concentration of hydrogen, the cleaning condition is specialized for organic matter removal, and the molar concentration of hydrogen should be set to more than twice the molar concentration of ozone. For example, the cleaning conditions are specialized for removing inorganic fine particles. In other words, cleaning is performed by setting the molar concentration of hydrogen and ozone as appropriate, so that the cleaning condition specialized for fine particle cleaning is changed to the cleaning condition specialized for organic substance removal through the cleaning condition combining organic substance removal and fine particle removal. It becomes possible to set freely.

  In addition, the cleaning performance improves as the concentration of hydrogen and ozone increases. However, if the concentration of hydrogen and ozone exceeds the saturation concentration, they are re-emitted as bubbles during cleaning, so these bubbles mix with the substrate. The wetting performance with the liquid is reduced, and the cleaning effect is reduced. Therefore, it is preferable to use a solution having a saturation concentration or less for hydrogen and ozone. Specifically, when the solvent of the first and second cleaning liquids is water, it is preferable to use the ozone concentration in the range of 5 to 60 ppm and the hydrogen concentration in the range of 0.1 to 2 ppm. As described above, since hydrogen and ozone have different saturation concentrations with respect to the solvent, the molar concentration ratio of hydrogen and ozone in the mixed liquid can be appropriately set by adjusting the mixing ratio of the first and second cleaning liquids. it can.

  Here, a mixed liquid obtained by mixing a first cleaning liquid containing ozone and a second cleaning liquid containing hydrogen is supplied onto the substrate 101, and the mixed liquid is irradiated with ultraviolet light, whereby hydroxyl radicals and hydrogen radicals are generated. Although the cleaning method to be generated has been described, in the case where the contamination of the electronic component is limited to resist residue or organic matter, only the hydroxyl radical is only supplied by supplying only the first cleaning liquid containing ozone and irradiating ultraviolet light. It is also possible to perform cleaning by generating Even in such a case, the ozone concentration is preferably 5 to 60 ppm in order to prevent a decrease in the wetting performance between the substrate and the mixed solution.

  Next, FIG. 2 shows a side view of the cleaning device when the cleaning device of FIG. 1 is viewed from the direction of arrow E, and the first embodiment of the present invention will be described using this. Portions common to FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. The transport roller 109 flows and transports the substrate 101 in the direction of the arrow A, and the first cleaning liquid containing ozone and the first cleaning liquid containing hydrogen are supplied from the mixed liquid supply nozzle 102 provided above the substrate 101 in the middle of the transport path. A mixed liquid 104 obtained by mixing the two cleaning liquids is supplied onto the substrate 101.

  Next, the mixed solution 104 supplied onto the substrate 101 is irradiated with ultraviolet light 105 from the ultraviolet light irradiation device 103, whereby hydroxyl radicals and hydrogen radicals are generated by the above-described mechanism, and the substrate 101 is cleaned. it can. Since hydrogen and ozone are reactive, the first cleaning liquid and the second cleaning liquid are separately supplied from the first supply line 106 and the second supply line 107, and then in the mixed liquid supply nozzle 102. The mixed liquid 104 is produced | generated by mixing.

  The ultraviolet light 105 is introduced into the ultraviolet light irradiation device 103 from a remote light source such as a low-pressure mercury lamp through the ultraviolet light waveguide line 108, and on the substrate 101 using an optical member (not shown) such as a beam splitter. The mixed liquid 104 is uniformly irradiated. Due to the hydroxyl radicals and hydrogen radicals generated by the irradiation with the ultraviolet light 105, the impurities 110 adhering to the substrate 101 are sequentially removed as the carrier roller 109 performs the flat flow.

  Next, a second embodiment of the present invention will be described with reference to FIG. Portions common to those in FIG. 2 are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, only the first cleaning liquid 113 containing ozone is supplied onto the substrate 101 from the first nozzle 111 provided above the substrate 101 in the middle of the transport path. Further, at the supply point, the substrate 101 is cleaned by generating hydroxyl radicals by irradiating the ultraviolet light 105 from the ultraviolet light irradiation device 103. Thereby, when the impurity 110 adhering to the substrate 101 is limited to a resist residue or an organic substance, the impurity 110 can be efficiently removed with a simpler structure than in the first embodiment.

  Next, a third embodiment of the present invention will be described with reference to FIG. Portions common to those in FIG. 2 are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, the first cleaning liquid 113 containing ozone from the first nozzle 111 provided above the substrate 101 in the middle of the transport path is provided adjacent to the first nozzle 111. A second cleaning liquid 114 containing hydrogen is supplied onto the substrate 101 from the nozzle 112. The respective cleaning liquids 113 and 114 supplied onto the substrate 101 are mixed on the surface of the substrate 101 by a water flow. Furthermore, by irradiating ultraviolet light 105 from the ultraviolet light irradiation device 103 at the mixing point, hydroxyl radicals and hydrogen radicals are generated by the mechanism described above, and the substrate 101 is cleaned.

  Since ozone and hydrogen are reactive, the first cleaning liquid 113 is supplied to the first nozzle 111 via the first supply line 106, and the second cleaning liquid 114 is supplied to the second nozzle via the second supply line 107. It is supplied to the nozzle 112 and supplied separately onto the substrate 101. Thereby, ozone and hydrogen contained in each cleaning solution can be prevented from reacting before the cleaning to lower the concentration, and the concentration of hydroxyl radicals and hydrogen radicals generated on the substrate 101 can be increased.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. In the present embodiment, unlike the first embodiment in which ultraviolet light is introduced into the ultraviolet light irradiation device 103 from a remote light source and irradiated, a light source 117 composed of an ultraviolet light irradiation lamp 115, a reflector 116, and the like is placed in the cleaning tank. And the ultraviolet light 105 is irradiated from the light irradiation window 118. The light irradiation window 118 needs to be made of, for example, quartz so that the light source does not deteriorate due to the splash of the cleaning liquid generated from the cleaning unit. The ultraviolet light 105 is uniformly irradiated to the mixed liquid 104 on the substrate 101 from the light source 117 configured as described above. The conveyance of the substrate 101 and the cleaning liquid supply mechanism are the same as those in the first embodiment, and thus description thereof is omitted.

  Next, a fifth embodiment of the present invention will be described with reference to FIG. In the present embodiment, in the configuration of the third embodiment in which the first cleaning liquid 113 and the second cleaning liquid 114 are separately supplied onto the substrate 101, the light source 117 is disposed in the cleaning tank and the ultraviolet light 105. It is set as the structure which irradiates. Thereby, the concentration of hydroxyl radicals and hydrogen radicals generated on the substrate 101 can be increased as in the third embodiment. The conveyance mechanism for the substrate 101 and the supply mechanism for the cleaning liquid are the same as those in the third embodiment, and the configuration of the light source 117 is the same as that in the fourth embodiment.

  In addition, each said embodiment is an illustration in all the points, Comprising: It is not limited to this, Of course, each embodiment can be used in combination suitably according to a use and the objective. That is, the scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  According to the present invention, in a cleaning method for removing contamination on the surface of an electronic component, a cleaning liquid containing ozone is supplied to the surface of the electronic component, and a high concentration of hydroxyl radicals is generated by irradiating the cleaning liquid with ultraviolet light. Further, a high-concentration hydrogen radical and hydroxyl radical are generated by supplying a liquid mixture of a cleaning liquid containing ozone and a cleaning liquid containing hydrogen to the surface of the electronic component and irradiating the liquid mixture with ultraviolet light.

  As a result, the concentration of hydroxyl radicals can be increased as compared to the conventional method, and the generation concentration of hydrogen radicals can also be increased, and the cleaning ability with respect to impurities such as resist residues, organic substances, and inorganic fine particles adhering to electronic parts is excellent. A cleaning method is provided. Furthermore, since it is possible to perform cleaning with high cleanliness without using an environmentally hazardous substance such as acid, it is possible to improve the yield of semiconductor devices while reducing facility costs and environmental burden. .

  In addition, the ozone and hydrogen concentration in the cleaning liquid is set to a high concentration below the saturation concentration, so that ozone and hydrogen are prevented from being re-released as bubbles while ensuring the ozone and hydrogen concentration during cleaning, and the electronic components are wetted. A decrease in performance can be prevented.

  In addition, by setting the molar concentration ratio of hydrogen and ozone in the mixed solution as appropriate, the cleaning condition specialized for fine particle cleaning is changed to the cleaning condition specialized for organic substance removal through the cleaning condition using both organic substance removal and fine particle removal. It is possible to freely set up to the conditions depending on the type of contamination of the electronic component.

  In addition, since the cleaning device includes a supply nozzle that supplies cleaning liquid onto the electronic component and an ultraviolet light irradiation device that irradiates the cleaning liquid with ultraviolet light on the electronic component, highly reactive hydroxyl radicals and hydrogen radicals are generated. Provided is a cleaning apparatus that can be generated by following a cleaning operation on an electronic component and efficiently removes impurities such as resist residues, organic substances, and inorganic fine particles adhering to the electronic component.

These are the schematic perspective views which show the structure of the washing | cleaning apparatus of 1st Embodiment of this invention. These are side views of the washing | cleaning apparatus of 1st Embodiment. These are side views which show the washing | cleaning apparatus of 2nd Embodiment of this invention. These are side views which show the washing | cleaning apparatus of 3rd Embodiment of this invention. These are side views which show the washing | cleaning apparatus of 4th Embodiment of this invention. These are side views which show the washing | cleaning apparatus of 5th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Substrate 102 Mixed solution supply nozzle 103 Ultraviolet light irradiation device 104 Mixed solution 105 Ultraviolet light 106 First supply line 107 Second supply line 108 Ultraviolet light waveguide line 109 Transport roller 111 First nozzle 112 Second nozzle 113 Second 1 cleaning liquid 114 second cleaning liquid 115 ultraviolet light irradiation lamp 116 reflector 117 light source

Claims (15)

Supplying a first cleaning liquid containing ozone onto the electronic component;
Irradiating the first cleaning liquid with ultraviolet light on an electronic component;
A method for cleaning an electronic component comprising: Mixing a first cleaning liquid containing ozone and a second cleaning liquid containing hydrogen and supplying the mixed liquid onto the electronic component;
Irradiating a mixture of the first and second cleaning liquids with ultraviolet light on an electronic component;
A method for cleaning an electronic component comprising: Supplying the first cleaning liquid containing ozone and the second cleaning liquid containing hydrogen separately onto the electronic component;
Irradiating the first and second cleaning liquids mixed on the electronic component with ultraviolet light;
A method for cleaning an electronic component comprising:   The electronic component cleaning method according to claim 1, wherein the first cleaning liquid contains anode water.   The method for cleaning an electronic component according to claim 2, wherein the second cleaning liquid contains cathode water.   The method for cleaning an electronic component according to claim 1, wherein a light source including ultraviolet light having a wavelength of 300 nm or less is used as the ultraviolet light source.   The method for cleaning an electronic component according to claim 1, wherein an ozone concentration of the first cleaning liquid is set to 5 ppm or more and 60 ppm or less.   The method for cleaning an electronic component according to claim 2, wherein the hydrogen concentration of the second cleaning liquid is set to 0.1 ppm or more and 2 ppm or less.   The method for cleaning an electronic component according to any one of claims 2 to 8, wherein the molar concentration of ozone in the liquid mixture is 0.5 times or more the molar concentration of hydrogen.   The method for cleaning an electronic component according to any one of claims 2 to 8, wherein the molar concentration of hydrogen in the mixed liquid is set to be twice or more the molar concentration of ozone.   The electronic component is any one of a liquid crystal glass substrate, a semiconductor substrate, a metal substrate, a quartz glass substrate, a mask blank substrate, a photomask substrate, and an optical disk substrate. The cleaning method of the electronic component as described in 2. A cleaning apparatus for cleaning an electronic component by the method according to claim 1,
A first supply nozzle for supplying the first cleaning liquid onto the electronic component;
An ultraviolet light irradiation device that irradiates the first cleaning liquid with ultraviolet light on an electronic component. A cleaning apparatus for cleaning an electronic component by the method according to claim 2,
A liquid mixture supply nozzle for supplying the liquid mixture onto the electronic component;
An ultraviolet light irradiation device for irradiating the mixed liquid with ultraviolet light on an electronic component. A cleaning apparatus for cleaning an electronic component by the method according to claim 3,
A first supply nozzle for supplying the first cleaning liquid onto the electronic component;
A second supply nozzle for supplying the second cleaning liquid onto the electronic component;
A cleaning apparatus, comprising: an ultraviolet light irradiation device that irradiates ultraviolet light at a position where the first and second cleaning liquids are mixed on an electronic component.   The low-pressure mercury lamp, high-pressure mercury lamp, excimer ultraviolet lamp, vacuum ultraviolet lamp, halogen lamp, excimer laser, ultraviolet laser, or ultraviolet light emitting diode is used as the ultraviolet light irradiation device. The cleaning device according to claim 14.

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