TW200414337A - Method for reducing particles and defects of wafers - Google Patents

Abstract

A method for reducing particles and defects of wafers is disclosed. A clean step of a lifter is performed after etching and cleaning steps of wafers on the lifter. By using the cleaning solution including ammonium hydrogen peroxide mixture and the mega-sonic shocking, the lifter is cleaned, and particles and defects of wafers is reduced.

Description

200414337 V. Description of the invention (1) The technical field to which the invention belongs: The present invention relates to a wet process for wafers, and more particularly to a wet process method for wafers that can reduce particles and defects. Prior technology: Wet processes used in semiconductor processes are mainly wafer cleaning and wet etching. Among them, the purpose of wafer cleaning is to remove metal impurities, organic contamination, and fine dust on the wafer, and to consider the removal of rough surfaces and possible natural oxides. There are two major types of wafer contamination: one is particles' and the other is film. Microparticle sources include silicon dust, quartz dust, air, dust, dust that is not attached to personnel and process machines, such as photoresist sheets and bacteria. The film is dyed as a foreign substance on the wafer. 'Some films will loosen and fall off and become fine particles.' , Xylene, photoresist developer, oil film and metal film. Both chemical cleaning and photoresist removal are used to remove film contamination. The main chemical cleaning is usually acid cleaning and cleaning tanks for wafer cleaning. The first etching technique used in wet etching is mainly to remove the film that is not covered by photoresist by using the chemical reaction between the film and the specific > valley liquid. The advantages of wetness are simple process and fast output. Because chemistry is used to remove the thin film, the chemical reaction has no directionality, so it belongs to the isotropic moment. The chemical reaction in the wet phase is a reaction between the liquid phase and the solid phase.

200414337 V. Explanation of the invention (2) When the wet etching is performed, first, the reactants in the solution use the diffusion effect to pass through a relatively thin boundary layer to reach the surface of the #etched film. These reactants will then chemically react with the molecules on the surface of the film and produce various products. These products on the surface of the film will also use the diffusion effect to pass through the boundary layer into the solution, and then be discharged with the solution. The main parameters for controlling the wet etching reaction are: solution concentration, etching time, reaction temperature, and stirring with the solution. Because wet etching is itself a chemical reaction. Therefore, the more concentrated the etching solution, or the higher the temperature. The faster the film is removed. Figure 1 shows a schematic side view of a wafer carrying element in a general wet process tank. Please refer to Figure 1. Since the wet process often uses chemicals and acid-base solutions, a robotic arm (not shown) and wafer carrying element 10 must be used to perform the wafer wet process operation. 12 is placed at the front end of the wafer carrier element 10, and the power device can be used to control the rise and fall of the wafer carrier element 10 to immerse or leave the wafer in the wet process tank. Generally, the number of wafers that can be accommodated at the front end of the wafer carrier element 10 is about 50. Each wafer can be erected in a groove at the front end of the wafer carrier element 10, respectively. Figure 2 shows an enlarged schematic view of area 14 in Figure 1. Please refer to FIG. 2. The front end of a general wafer carrier element is composed of a plurality of protrusions 16 and each protrusion 16 has a distance between them to form a groove 18. Therefore, when the crystal The circle 1 2 can be fixed by being placed between the grooves 1 8. Summary of the invention: 200414337 V. Description of the invention (3) In order to prevent chemicals or photoresist residues from contaminating wafers, general wet process equipment regularly cleans and maintains machine equipment. One of the purposes of the present invention is to Provides a method for reducing particulate pollution, which involves adding a cleaning step of the wafer carrier after the wafer is etched and washed to reduce particles and defects on the wafer and extend the interval between machine cleaning and maintenance. 0

In addition, another object of the present invention is to provide a clear spring method of a wafer carrier element. The method is to use a mixed aqueous solution of ammonium oxide and hydrogen peroxide (A mm 0 nium Hydrogen Mixture; APM), and add a method of shaking to the wafer. The carrier and the cleaning tank perform cleaning operations to reduce particles and defects on the wafer. According to the above objective, the method for reducing particulate pollution of the present invention includes: first, a process required to crystallize a wafer by using a wafer carrying element; and then, moving the cleaning bath to perform a cleaning solution on the wafer carrying element The cleaning step of moving the wafer-bearing element into the cleaning tank for the wafer-bearing element. The cleaning solution of this component uses ammonium hydroxide and the shaking action of the cleaning tank to improve the effect. Circularly move to a wet process tank to carry wafer-bearing components, and move the wafer to the wafer for cleaning; after that, remove the wafer for the next process; then, use another cleaning solution to perform crystal comparison In the preferred embodiment, the wafer is supported with a light aqueous solution of peroxide, and good wafer particles and defects can be achieved.

By using the method for reducing the micro-damaged particles and defects in the present invention, the method can effectively reduce the crystal formation, and thus improve the yield and quality of the product. Yue

200414337 V. Description of the invention (4) Implementation mode: In the general wet process, after the wafer 12 is sent to the chemical tank for the etching process, it usually goes through an ultrapure water cleaning step to put the wafer on the wafer such as an etching solution Wait for the residue to be removed. Figure 3 shows a schematic diagram of a general wafer wet process. Please refer to Figure 3 'when the robot arm (not shown) places the wafer on the wafer carrier, then step 100 is performed, and the wafer carrier will move the wafer to the etching bath to let the crystal The circle completely enters the chemical liquid in the etching bath to perform a chemical reaction. When a certain period of time has passed, step 102 is performed to move the wafer carrying element to move the wafer to the cleaning bath. After a certain period of cleaning, step 104 is performed again, and the wafer on the wafer carrier is removed by a robotic arm, and then subsequent steps such as drying are performed. These subsequent steps such as drying are performed by other crystals. Round load-bearing elements are carried out. In general semiconductor factories, there are particles or defects on the wafer, which often lead to defective products. If the chemicals in the wet etching process remain on the equipment, it will also cause particles and defects on the wafer. Therefore, the wet process equipment must be cleaned and maintained regularly to prevent the wafers manufactured in it from being contaminated. The present invention discloses a method for reducing the damage caused by wafers due to particles and defects. In order to make the description of the present invention more detailed and complete, please refer to the following description and cooperate with the diagram in FIG. 4. The present invention finds that when the wafer carrying element 10 shown in FIG. 1 loads the wafer 12 into the chemical bath and performs the etching step, chemicals and chemicals such as photoresist also remain in the protrusion 1 6 with grooves 1 in 8. Although, the subsequent wafer-bearing component 10 will move the wafer to a cleaning bath, and clean it with ultrapure water, for example. 200414337 V. Residues in the description of the invention (5) 18: ^ ::: The load 16 and the groove are set to carry another-batch of wafers = then the wafers * the loaded components 10 are returned to the original batch of wafers for contamination and contamination. Another reason is caused during the engraving and cleaning steps. The method shown in FIG. 4 is proposed by the present invention. In a preferred embodiment of the present invention, the 1_wafer carrying device is equipped with two wet process tanks, such as etching: to move the wafer between the two, and other wet process tanks and lines ^ ^ Wu / month The movement between the washing tanks can be performed by a robotic arm

Please refer to Figure 4, the first parameter, 隹 —H 丰 百 百 百 仃 in step 200, the wafer carrying component is loaded with the wafer by the mechanical 7 ′ and the wafer is moved into the etching bath. Since the chemical in the etching method is not the focus of the present invention, the present invention is not described here. After a certain period of time, step 202 is performed, and the wafer is moved to the cleaning tank by using the power device to move the carrier element. . Among them, in the example f of the present invention, the wafer cleaning is performed using ultrapure water (D · I Water). Then after the wafer cleaning step is completed, step 204 is performed, and the wafer is carried by a robot arm. The wafers on the equipment are moved to the equipment required for the next step.

In the next embodiment, the wafer is subsequently subjected to a drying step to remove the cleaning solution. After that, step 206 is performed, and the wafer-bearing components of the above-mentioned unloaded wafer are returned to the cleaning tank, and the wafer-bearing equipment is cleaned. In a preferred embodiment of the present invention, APM cleaning solution is used to clean the wafer carrier equipment. The so-called APM cleaning solution is a mixed aqueous solution of ammonium hydroxide and hydrogen peroxide (NH 4 0 H + H 2 0 2 + H 2 0), which is a cleaning liquid commonly used in semiconductor manufacturing processes. Therefore, 200414337 V. Description of the invention (6) The above method originally filled with ultrapure water, to generate ΛPM ^ $ ^ 妁 π 冼 tank, first replace the ultrapure water cleaning solution with APM ^ ^ -fe ^, and move the bearing element In the cleaning tank. In addition to using AP monthly cleaning solution to enter wafer wafers, the present invention also uses :::: to operate with ultrasonic vibration when carrying 70 cleaning steps. The present invention has found that by using the above-mentioned APM cleaning solution and / or shaking step, the step 'can have a good effect on reducing the residue on the surface of the wafer carrying element and the cleaning tank. After the wafer-carrying components and the surface of the cleaning bath are subjected to the above cleaning steps, step 200 can be repeated, and then another batch of wafer manufacturing processes can be performed. The invention is characterized in that it does not change the moving path of the wafer carrying element, so that

Wafer-carrying components perform their own cleaning actions between different batches of wafer manufacturing, and use APM solution and shaking steps to remove residues remaining on the surface of wafer-carrying components and cleaning tanks, which can reduce wafers. Particles and pollution issues. It should be noted that the above wafer cleaning using ultrapure water is only an example, and other cleaning liquids can also be used in the present invention, and the present invention is not limited thereto. And the above-mentioned wafer carrying equipment with an etching tank and a cleaning tank is just an example. The number of etching tanks or cleaning tanks can be changed depending on the machine equipment and process. In addition, when there are a plurality of cleaning tanks, the present invention is not limited to which cleaning tank or cleaning tank has a cleaning tank for cleaning wafer carrier elements. By using the method for reducing the particulate pollution of the present invention, the particles and defects on the wafer can be reliably reduced, and the quality of the integrated circuit components on the wafer can be provided. And 'can increase the interval between machine cleaning and maintenance, or even no regular machine cleaning steps. In this way, the production time of the machine can be increased, and the

Page 9 200414337 V. Description of the invention (7) Component productivity. As will be understood by those familiar with this technology, the above descriptions are merely preferred embodiments of the present invention, and are not intended to limit the scope of patent application for the present invention; all others completed without departing from the spirit disclosed by the present invention, etc. Effective changes or modifications should be included in the scope of patent application described below.

Page 10 200414337 The schematic illustration of the preferred embodiment of the present invention will be described in more detail with the following figures, where: Figure 1 is a schematic side view of a wafer carrying element in a general wet process tank, Figure 2 The figure shows an enlarged schematic diagram of area 14 in FIG. 1; FIG. 3 shows a schematic diagram of a general wafer wet etching process; and FIG. 4 shows a schematic diagram of a wafer wet etching process of the present invention. Drawing number comparison description: 10 crystal circle bearing element 12 crystal circle 14 area 16 raised 18 recessed groove 100 step 102 step 104 step 200 step 202 step 204 step 206 step

Claims (1)

200414337 VI. Scope of Patent Application 1. A method for reducing particulate pollution, which is suitable for a wafer wet process. The method for reducing particulate pollution at least includes: moving a wafer carrier element into a cleaning tank, and using a cleaning Liquid to perform cleaning of the wafer carrier. 2. The method for reducing particulate pollution as described in item 1 of the scope of the patent application, wherein the above cleaning solution includes at least a mixed aqueous solution of ammonium hydroxide and hydrogen peroxide. 3. The method for reducing particulate contamination as described in item 1 of the scope of the patent application, further comprising, in the cleaning step of the wafer carrier, causing the cleaning tank to perform an oscillating action. 4. The method for reducing particulate pollution as described in item 3 of the scope of patent application, wherein the above-mentioned oscillating action is an ultrasonic oscillating. 5. — A wafer wet process, including at least: 丨 · moving a wafer to a wet process tank using a wafer carrier element; moving the wafer carrier element, and moving the wafer to a cleaning tank, Cleaning the wafer with a first cleaning solution; removing the wafer located on the wafer carrier element; and moving the wafer carrier element into the cleaning tank, using a second cleaning fluid to perform the crystal Cleaning of round bearing elements. !! Page 12 200414337 6. Scope of Patent Application 6. The wafer wet process described in item 5 of the scope of patent application, wherein the above wet process tank is an etching process tank. 7. The wafer wet process as described in item 5 of the scope of patent application, wherein the first cleaning liquid is ultrapure water. 8. The wet wafer manufacturing process as described in item 5 of the scope of patent application, wherein the second cleaning solution is a mixed aqueous solution of ammonium hydroxide and hydrogen peroxide. 9. The wet wafer manufacturing process as described in item 5 of the scope of the patent application, further includes a step of shaking the cleaning tank during the cleaning step of the wafer carrier element. 10. The wet wafer manufacturing process as described in item 9 of the scope of the patent application, wherein the above-mentioned oscillating motion is an ultrasonic oscillation. 11. The wet wafer manufacturing process described in item 5 of the scope of the patent application, further comprising performing a drying step on the wafer after the wafer cleaning step. 1 2. A method for reducing particulate pollution, which is applicable after a wafer wet process. The method for reducing particulate pollution at least includes: moving a wafer carrier element into a cleaning tank, and shaking the cleaning tank And cleaning the wafer carrier using a cleaning solution, wherein the composition of the cleaning solution includes at least a mixture of ammonium hydroxide and hydrogen peroxide IH1 Page 13 200414337 VI. Patent Application Aqueous solution. 13. The method for reducing particulate pollution as described in item 12 of the scope of patent application, wherein the above-mentioned oscillating action is an ultrasonic oscillating.