TW476115B - Device for reducing the wafer damage from ammonia vapor - Google Patents

Abstract

A device for reducing the wafer damage from ammonia vapor in the wafer cleaning process, wherein the device comprises at least a mask fixed in a wafer cleaning tank for condensing the vapor distributed from the ammonia liquid entering from the bottom of the wafer cleaning tank. The ammonia water liquid transmission pipe comprises at least an U-shape tube for connection to the bottom of the wafer cleaning tank to transmit the ammonia water to the wafer cleaning tank and trap the ammonia vapor passing the U-shape tube. Furthermore, it comprises a second mask in the auxiliary tank device at the periphery of the wafer cleaning tank and fixed on the auxiliary tank for condensing the vapor distributed from the ammonia liquid entering from the bottom of the auxiliary tank. The transmission pipe connecting to the bottom of the auxiliary tank comprises at least an U-shape tube to trap the ammonia vapor passing the U-shape tube so as to reduce the damage of silicon wafer from ammonia vapor.

Description

476115 V. Description of the invention (1) Field of the invention: The present invention relates to a semiconductor manufacturing process, and in particular, to a device and method for reducing damage to a wafer by ammonia vapor (va ρ 〇 r) during a wafer cleaning process. . Background of the Invention: The ULS I process has far more stringent requirements for the smoothness of the surface of semiconductor substrates, fine particles and contaminants such as metals and organic residues than the VLSI process. For example, the requirements of the ULSI process must reach gate oxide layers less than 5nm, metal or metal silicide contacts, and high-quality epitaxial layers. When the component size is reduced to the sub-micron level, the extremely cleaned surface requires: Particles, organic pollutants, metal pollutants. ! Secondly, the surface microrougness and natural oxide | (native oxide) are not allowed. For example, when the process is a 0.35 // m process, the gate oxide layer is about 100 angstroms, and in the 0.1 / m process, the gate oxide I layer is about 40 angstroms, and the surface is slightly rough. It should reach the atomic level. The natural | oxidized layer is another uncertain factor that affects the thickness control of the gate oxide. The natural | oxidized layer often obstructs chemical vapor deposition and also prevents epitaxial growth. 0 The famous RCA cleaning procedure in the 1970s It has been widely used in silicon 476115. 5. Description of the invention (2) The circle is cleaned and continuously improved to meet the requirements of the ULSI process. Relevant supporting equipment, including deionized water with zero oxygen content, pure gas delivery system, special design to avoid particle generation, and the use of ultra-high sonic cleaning (megasonic cleaning; the output frequency of the converter is as high as 850 to 900 k Η Z) to promote dissociation of the particles. The RCA cleaning program includes two sequential cleaning programs such as N Η 40 Η-Η 2〇2_ Η 20 (Generally known as standard cleaning 1 (SC-1), composed at 70 to 80 ° C The ratio is 1: 1: 5 to 1: 2: 7. Another cleaning is called the second standard cleaning (standard 丨 c 1 eaning 2 (SC-2)), and the composition ratio is HC1 at 70 to 80 ° C: H 20 2- Η 2〇 = 1: 1: 6 to 1: 2: 8. Both of these cleanings are based on hydrogen peroxide and can be oxidized at high pH (SC-1). Effective removal

I I organic pollutants and particles. The low pH (SC-2) removes the adsorption of metal contaminants by forming soluble | i complexes. SC-1 cleaning with parallel crystals Ultra-high sonic vibration cleaning on round surfaces is a type that can be below 40 ° G

I | temperature removes organic or inorganic particles on the wafer surface. According to some research reports, the removal of particles can be classified into the following mechanisms: | (1) dissolution; (2) gradual oxidation and then dissolution; (3) the wafer surface is shed by weak etching; (4) ) The micro-particles and the wafer surface are removed due to the repulsive charge of each other. Among them, (1) and (2) cause the particles to be dissolved by oxidation through an oxidant. 476115 V. Description of the invention (3) and (3) and (4) are due to electrical repulsion. In the SC-1 cleaning procedure, Η 20 provides oxidation, and ammonia NH 40H provides wafers and particles with a negative hydroxide (0H-) negative charge to remove the particles. ΝΗ40Η acts like an etchant. As a result, the micro-roughness of the surface of the silicon wafer is deteriorated. In order to reduce the impact of SC-1 cleaning program on micro-roughness, the common practices are categorized as follows: (1) reduce the proportion of NH 40 下 if allowed; (2). Reduce the temperature of the cleaning tank; (3). Reduce the cleaning time . In addition, research shows that ammonia vapor is more likely to attack the surface of silicon wafers than ammonia solution in the SC-1 tank. Liquid ammonia is less prone to problems due to the protective film produced by helium 20 helium agent and deionized water, but Ammonia vapor is not. Especially when the wafer is wetted with difluoric acid (di ρ) to remove the natural oxide layer, and then introduced into the SC-1 tank but not fully immersed in the SC-1 cleaning solution, the exposed wafer surface is exposed to ammonia vapor. Gas surface, which will erode the wafer surface due to the adsorption of ammonia vapor on the wafer surface. This adsorption often evaporates due to high temperature during high temperature processes, such as bubble explosion and voids (VO id), which affects the subsequent process yield. Therefore, how to reduce the ammonia vapor so as to reduce the damage to the wafer is an important part of the wafer cleaning environment. However, traditionally, as shown in FIG. 1, ammonia water is almost directly injected into the wafer cleaning tank 100 containing Η 20 2 and Η 20 through the pipeline 1 10, and ammonia replenisher is injected through the pipeline 1 2 0 Wafer cleaning tank 1 0 0 Auxiliary tank 1 0 5 is next to the large wafer cleaning tank 100, because ammonia water is directly injected (preferably, the transfer pipe is close to the bottom of the wafer cleaning tank 1 0 0 , But the above practices will still produce

476115 V. Description of the invention (4) A large amount of ammonia vapor is generated. Just like a splash. This is true even if the wind pressure HEPA is reduced above the machine. The above-mentioned diversion tube will cause the ammonium vapor pressure to be on the high side. The present invention provides a method for reducing the bell vapor pressure in a large amount to improve the yield. Object and Summary of the Invention: An object of the present invention is to provide a method for reducing damage to a wafer by a chemical solution vapor. Another object of the present invention is to provide a cover in a wafer cleaning tank and an auxiliary tank to reduce the damage of the chemical solution vapor to the wafer. The invention relates to a device for reducing damage to a wafer by an ammonia vapor during a wafer cleaning process. The device includes at least a cover fixed in a wafer i cleaning tank for coagulation to enter from the bottom of the wafer cleaning tank. The vapour emitted by the ammonia liquid. The ammonia water liquid conveying pipe includes at least a U-shaped tube to be connected to the bottom of the wafer cleaning tank to transport the ammonia water to the wafer cleaning tank and trap i ammonia vapor passing through the U-shaped tube. In addition, a second cover including an auxiliary tank device i around the wafer cleaning tank is fixed to the auxiliary tank for coagulating the auxiliary tank.

Vapours from the ammonia liquid entering the bottom of the tank. The conveying pipe connected to the bottom of the auxiliary tank also has at least one U-shaped tube to catch the ammonia vapor passing through the U-shaped tube to reduce the damage of the ammonia wafer to the silicon wafer.

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4 / D11D V. Description of the invention (5) In order to minimize the ammonia vapor as much as possible, and thus improve the yield of the product. As the above-mentioned cover and U-shaped tube can be small, to prevent the diffusion of vapor and damage the wafer. Detailed description of the invention: Yes Whereas, as invented the old days, +, ^ Ru Guang, ^, Yue Hall, as described, traditional RCA cleaning, such as SC-1 cleaning # _ γ 3 Wudougu used, the official injection or supplement of helium water Often, the exposed stone after the oxide layer is wetted with acetic acid (HP) is removed from the natural environment. Therefore, the present invention will = = hurt 'especially in high temperature processes; such as t. An effective design to reduce vapor pressure. : The gas-water diversion tube of the present invention (the formula is 2 0 0, please refer to the dry as shown in Figure 2! 1 2nd, 2 2 0 and wafer cleaning tanks 丨 have at least -u-shaped pipeline; == 伟The ammonia water diversion tube 210 is designed as # 八 91 ηΛιΛ &...; knife 2 0A so that most of the vapor is first captured by the u-shaped tube | Road, and, enter ammonia water upwards, and a cover 212 is fixed above the pipe 210A, so that ^ blocks the volatilization of ammonia vapor, especially when the liquid level is lower than the direction of the pipe 210A i. The steam above the wafer cleaning tank 200. Its ^ for ammonia water replenishment pipeline 2 2 0 is also designed to have at least a u-shaped,-, 2 2 0A so that most of the steam is first U The shape of the pipe section 2 2 0 A internal circuit 2 2 β β is captured from the wafer cleaning tank 2 0 0 around the auxiliary tank 2 0 5 bottom tube is injected with ammonia water upwards, and a cover 476 115 is also fixed above the tube 220 A V. Description of the invention (6) 2 2 2 In order to block the volatilization of ammonia vapor, the cover 2 2 2 is about 10-500mm higher than the bottom tube 2 2 0B. Through the U-shaped tube and cup cover of the present invention, Most of the ammonia vapor pressure is reduced. Except for the wafer pressure above the wafer cleaning tank, since the vapor pressure has been greatly suppressed, the natural vapor pressure can be well controlled by the wind pressure (HEP A) above the wafer cleaning tank. The invention has the following advantages: (1) Because the U-shaped pipeline part and the wafer slot are added with a cover, the cost increase is limited, but the ammonia vapor pressure can be reduced to a minimum, except for natural vapor. (2) Because the ammonia vapor pressure is greatly reduced, the damage of silicon wafers from i erosion can be minimized, and the yield of the product can be further improved. (3) The present invention can also be applied to other than ammonia vapor. Damage to wafers by external chemical liquids

I! The present invention is described above only with a preferred embodiment, and is not intended to limit the scope of application of the present invention. Those skilled in the art can make some changes or modifications without departing from the spirit of the present invention. The scope of patent protection should be included in the scope of patent application described below.

476115 Brief description of the drawings Brief description of the drawings: The preferred embodiment of the present invention will be described in more detail in the following explanatory texts with the following figures: Figure 1 shows the traditional ammonia water delivery pipe, wafer cleaning tank, auxiliary tank , And its related location diagram. FIG. 2 shows a schematic diagram of an ammonia water delivery pipe, a wafer cleaning tank, an auxiliary tank, and related positions according to an embodiment of the present invention. Drawing number comparison table: Wafer cleaning tank 100 Auxiliary tank 105 Main pipeline 110 Replenishment liquid pipeline 120 Wafer cleaning tank 200 Ammonia water deflector (or conveying pipe) 210 Piping pipe section 210A Bottom pipeline 210B Cover 212 Ammonia water Make-up diversion tube 220

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Claims (1)

476115 VI. Application Patent Scope 1. A device for reducing damage to a wafer by vapor emitted by a chemical solution during wafer cleaning, the device at least includes: a cover fixed in a wafer cleaning tank for Condensate the vapor emitted from the chemical solution entering from the bottom of the wafer cleaning tank. 2. For example, the device of the scope of patent application of the invention further includes a chemical solution conveying pipe having at least one U-shaped tube portion, which is connected to the bottom of the wafer cleaning tank to convey the chemical solution to the wafer cleaning tank and trap (trap) ) Vapor emitted from the chemical solution through the U-shaped tube. 3. If the device in the scope of application for patent No. 1 further includes an auxiliary tank device around the wafer cleaning tank, a second cover is fixed to the auxiliary tank to condense the place of the chemical solution entering from the bottom of the auxiliary tank. The steam emitted by the emitted steam. I 丨 4. If the device in the scope of patent application No. 3, further includes a chemical solution delivery supply pipe with at least one U-shaped | pipe section, connected to the bottom of the auxiliary tank, for | transporting chemical solution to the auxiliary tank, and supplement Catch (trap) the vapour emitted by the U-tube | the chemical solution. II | 5. The device according to item 1 of the scope of patent application, wherein the above-mentioned cover is located at the position where the chemical solution delivery pipe extends to the bottom of the wafer cleaning tank at about 10-500 mm. 0 476115 6. Patent application Scope '6. —A device for reducing the damage of the vapor to the wafer during the wafer cleaning process, the device includes at least: a cover fixed in a wafer cleaning tank for condensing the crystal Steam from ammonia liquid entering the bottom of the round cleaning tank. 7. If the device of the scope of application for patent No. 6 further includes an ammonia water liquid conveying pipe having at least one U-shaped tube part, it is connected to the bottom of the wafer cleaning tank to transport ammonia water to the wafer cleaning tank and trap. Ammonia vapor passing through the U-shaped tube. · I 8. If the device in the scope of patent application No. 6 includes an auxiliary tank device around the wafer cleaning tank, a second cover is fixed to the auxiliary tank to condense ammonia entering from the bottom of the auxiliary tank. Vapors emitted by a liquid. i I-| | + 9. The device according to item 6 of the patent application scope, further comprising at least one U-shape; an ammonia water liquid conveying pipe of an i-pipe part for trapping through the U-shaped pipe; j 丨Of ammonia vapor. I 10. The device according to item 8 of the scope of patent application, further comprising a chemical solution delivery supply pipe having at least one U-shaped | φ pipe portion, connected to the bottom of the auxiliary tank, and used to transport the chemical solution to the auxiliary tank, and Trap the vapour emitted by the chemical solution through the U-shaped tube. 1 1. The device according to item 6 of the scope of patent application, wherein the above-mentioned cover is in position Page 12 476115 VI. Scope of patent application The chemical solution delivery pipe extends to about 10-500 mm above the bottom of the wafer cleaning tank. 12. —A device for reducing the damage of the vapor to the wafer during the wafer cleaning process, the device includes at least: a cover fixed at the bottom of the wafer cleaning tank, the cover is used to prevent ammonia vapor due to It is volatilized and dispersed above the wafer cleaning tank, and an ammonia water liquid conveying pipe is connected to the bottom of the wafer cleaning tank, wherein the ammonia water liquid conveying pipe has at least one U-shaped pipe for catching ammonia vapor. 1 3. If the device in the scope of patent application No. 12 further includes an auxiliary tank around the wafer cleaning tank, a second cover of the device is fixed to the auxiliary tank for coagulation | condensation entering from the bottom of the auxiliary tank Vapors emitted by ammonia liquid. 14. The device according to item 13 of the scope of patent application, further comprising a chemical solution transporting supply pipe having at least one U i-shaped tube portion, connected to the bottom of the auxiliary tank, using I to transport the chemical solution to the auxiliary tank, and catching up (Trap) Vapor emitted from the chemical solution through the U-shaped tube I. ! '| l5. The device according to item 13 of the patent application scope, wherein the above-mentioned cover is located at a position of about 10-500 mm above the bottom of the wafer cleaning tank extending from the chemical solution delivery pipe.