TWI230389B - Method and apparatus for drying semiconductor wafer - Google Patents

Abstract

This invention discloses a method and an apparatus to dry a semiconductor wafer through the use of an isopropyl alcohol (IPA) drying apparatus. This invention employs a vapor generator to produce IPA vapor. The IPA vapor used for drying wafers is produced and stored in a closed system. Subsequently, a quartz tube is used to transport the IPA vapor to a porous hollow plate in a drying tank. The IPA vapor can homogeneously diffuse from the porous hollow plate. This invention can easily control the use of IPA vapor and thus increase manufacturing process safety.

Description

1230389 V. Description of the invention ο) 5-1 Field of the invention: The present invention relates to a method and device for drying semiconductor wafers, and more particularly to a method for drying semiconductor wafers using an isopropyl alcohol (IPA, isopropyl alcohol) dryer. And device. 5-2 Background of the Invention: Currently, isopropyl alcohol drying devices are widely used for drying semiconductor wafers. Compared with the isopropyl alcohol drying device, the use of the isopropyl alcohol drying device can reduce the chance of mechanical damage to the semiconductor wafer, and can easily dry and clean the surface of the wafer. Isopropylene Refer to the first figure, this is a typical isopropyl alcohol drying device. The alcohol drying device contains a drying tank 100, which is the main container used to isolate the wafer and remove the moisture thereon. During the wafer drying process, a plurality of semiconductor wafers 110, such as the wafers washed immediately after the etching process, are transferred into the drying tank 100 by a robot arm and carried by a wafer support frame 1 12. The isopropanol solution 120 is contained in the drying tank 100, and is heated to the boiling point by a heater 1 1 4 at the bottom to generate isopropyl alcohol vapor and fill the drying tank 100. A number of cooling or condensation coils 130 are arranged around the surface above the interior of the drying tank 100.

1230389 V. Description of the invention (2) Isopropanol vapor 1 2 2 will adhere to the surface of the semiconductor wafer 1 1 0 and combine with the water thereon to form an isopropanol co-solution (co-so 1 u t i on). When the semiconductor wafer 110 rises to the position of the condensation coil 130, the isopropanol co-solution will evaporate and the moisture on the wafer will be taken away at the same time. The drying tank 1 0 0 also contains a liquid collecting tray 1 3 2 which surrounds the inside of the drying tank 1 0 below the condensation coil 1 3 0. It is used to collect liquid droplets and then is discharged from an isopropanol waste liquid discharge port 1 3 4 discharge. The drying tank 100 also contains an isopropanol exhaust gas outlet port 1 36 to exhaust the isopropanol exhaust gas. However, the isopropyl alcohol solution of the current isopropyl alcohol drying device is continuously heated and volatilized, and waste is formed if it is not used. . Coupled with open system operation, there is a risk of environmental pollution. And the continuous generation of isopropanol vapor will also adhere to the dried wafer from time to time and cause wafer contamination. 5-3 Objects and Summary of the Invention: An object of the present invention is to provide a method for drying a semiconductor wafer using an isopropyl alcohol drying device. Another object of the present invention is to provide an apparatus for drying a semiconductor wafer using an isopropanol drying apparatus. Another object of the present invention is that the design of the present invention can easily control

1230389 V. Description of the invention (3) Use of propanol vapor and increase process safety. According to the above-mentioned object, the present invention provides a method for drying a semiconductor wafer using a drying device. The method includes at least the following steps. First, a solution is evaporated to generate a vapor, wherein the solution can form a mutual soluble substance with water, and can be rapidly volatilized at a temperature of less than 100 degrees. Then, a drying tank is provided. Next, the vapor is transferred to a porous hollow plate in a drying tank. In the next step, at least one wafer is dried in a drying tank, in which the vapor will diffuse out uniformly from the porous hollow flat plate. The present invention further provides an apparatus for drying a semiconductor wafer using a drying apparatus. This device includes at least the following components. A steam generator is used to generate a vapor. A gas transmission tube, one end of which is connected to a steam generator for transmitting steam. A drying tank, in which a porous hollow flat plate is attached to a bottom of the drying tank and connected to the other end of the gas transfer tube. In addition, the porous hollow flat plate has a porous surface facing upward, and the vapor will diffuse out uniformly from the porous surface. 5-4 Detailed Description of the Invention: The present invention provides a method for drying a semiconductor wafer using an isopropyl alcohol drying device. The method of the present invention will be explained in detail with a flowchart in the figure.

1230389 V. Description of the invention (4) First, provide an isopropanol solution (step 2 10) and transfer it to a steam generator. An isopropanol vapor is then generated and stored in the vapor generator (step 220). The isopropanol solution generates isopropanol vapor when heated to the Buddha's point in the vapor generator via a heater. Next, the isopropanol vapor is transferred to a porous hollow plate in the drying tank (step 230). Isopropanol vapor is transferred and insulated using quartz tubes. The porous hollow flat plate in the drying tank is located at the bottom and has a porous surface facing upward. In the present invention, a process sensor can be used to set the process parameters (step 2 2 2), and the parameters are transmitted to the controller, and the controller can control the amount of the isopropanol solution entering the steam generator and the steam generator. And the amount of isopropanol vapor entering the drying tank (step 224). Then, a plurality of semiconductor wafers are transferred into a drying tank by a robot arm and carried by a wafer support frame. These wafers are then dried in a drying tank (step 240). Isopropanol vapor will diffuse out of a porous surface of the porous hollow plate and adhere to the surface of these wafers. Isopropanol vapor will combine with the water on it to form an isopropanol co-solution. The isopropanol co-solution will then evaporate and dry the wafer. The isopropanol exhaust gas is discharged from an exhaust gas discharge port (step 24 2), and the isopropanol waste liquid is discharged from a waste liquid discharge port (step 244). Referring to the third figure, the present invention also provides an apparatus for drying a semiconductor wafer using an isopropyl alcohol drying apparatus. This device is effective with a simple design

Page 7 1230389 V. Improvement of invention description (5) Overcome the shortcomings of the conventional isopropanol drying device. In addition, the isopropyl alcohol solution can also be replaced with another solution that can produce a miscible substance with water and rapidly volatilize at a temperature of less than 100 degrees. First, the device has a drying tank 10, and the material of the drying tank 10 may be quartz. The plurality of semiconductor wafers 1 1 can be transferred into the drying tank 10 by a robot arm and carried by a wafer support frame 12. A number of cooling or condensing coils 30 are arranged around the surface above the interior of the drying tank 10. In addition, there is a porous hollow flat plate 46 on the bottom of the drying tank 10, and this porous hollow flat plate 46 has a porous surface facing upward. In the present invention, the isopropyl alcohol vapor used to dry the wafer is manufactured and stored in a closed system, such as a vapor generator 40, and the isopropyl alcohol solution is supplied to the vapor generator 4 through the isopropyl alcohol solution supplier 5 4 After 0, the heater in the steam generator will heat the isopropanol solution to a boiling point to generate isopropanol vapor. In addition, there is a liquid control valve 55 to control the isopropanol solution into the steam generator 40. Then, by using a quartz tube 42 2 isopropanol vapor is transferred from the steam generator 40 to the porous hollow flat plate 46 in the drying tank 10. The quartz tube 4 2 further includes a gas control valve 43 and a pressure gauge 44 to monitor the pressure in the tube and control the amount of isopropanol vapor entering the drying tank. Next, the isopropanol vapor 20 will evenly diffuse out of a porous surface of the porous hollow flat plate 46 and adhere to the surfaces of these semiconductor wafers 1. The isopropyl alcohol vapor 2 0 at an environment of 80 ° C Combined with the water on it to form an isopropanol co-solution. Then, when the semiconductor wafer 11 rises to the height of the condensation coil 30 and the environment of 25 ° C, the isopropanol co-solution will volatilize and reach the moisture level.

Page 8 1230389 V. Description of the invention (6) The purpose of removing dry wafers. Finally, the isopropanol exhaust gas is discharged from an exhaust gas discharge port 3 4, and the isopropanol waste liquid is discharged from a waste liquid discharge port 36. The waste liquid discharge port 36 can be designed to be inclined downward by the bottom of the drying tank 10, so that the waste liquid can be discharged down without the need of an extra liquid collecting tray. In addition, the device can use a process sensor 50 to measure process parameters and send the parameters to the controller 52 for control. The process sensor is a collection of tools for measuring temperature and vapor sampling, measuring specific gravity and composition. Any instrument with the above functions can be used. The implementation of the controller 52 is a combination of software and hardware. Its simple functional block diagram is shown in the fourth figure.丨 p The signal sent by the chip into the drying tank and the end of the contact time between the chip and the steam (block 4 1 0) is sent by the process sensor to the controller 4 2 0 (block 4 2 0), and the controller will control the isopropanol vapor. Control valve opening and closing (block 4 3 0). In addition, the temperature and vapor composition signals in the drying tank or the temperature, pressure, and level signals in the steam generator (block 4 1 1) are transmitted by the process sensor to the controller 4 2 0 (block 4 2 0), and then controlled. The device will control the opening and closing of the isopropanol vapor control valve or control the temperature, pressure and liquid level in the vapor generator (block 4 3 1). In this way, the amount of the isopropanol solution entering the steam generator, the operation of the steam generator, and the amount of the isopropanol vapor entering the drying tank can be controlled. # In summary, the present invention provides a method and an apparatus for drying a semiconductor wafer by using an isopropyl alcohol drying apparatus. The present invention uses a closed system to generate and store isopropanol vapor, which can increase process safety

1230389 V. Description of invention (7). Then, a quartz tube was used for the transmission of isopropanol vapor, and the tube was equipped with a control valve and a pressure gauge. The design of the invention can effectively control the timing and amount of isopropyl alcohol vapor used, can reduce the waste of vapor and save heating energy. In addition, the design of the present invention does not hinder the generation of isopropanol vapor in the next cycle.

The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of patent application of the present invention. Any other equivalent changes or modifications made without departing from the spirit disclosed by the present invention shall be included in the following Within the scope of patent application.

Page 10 1230389 Brief description of the diagram The first diagram is a schematic diagram of a conventional isopropanol drying device. The second figure is a schematic flow chart of a wafer drying method according to the method of the present invention. The third figure is a schematic view of a wafer drying apparatus disclosed according to the method of the present invention. The fourth figure is a block diagram of a simple function of the controller disclosed by the method of the present invention. Symbols of the main parts: 1 〇 Drying trough 1 1 Wafer 1 2 Wafer support 2 0 Isopropanol vapor 3 0 Condensation coil 3 4 Isopropanol exhaust outlet 3 6 Isopropanol exhaust outlet 4 0 Isopropanol Steam generator 4 2 Gas transmission tube 4 3 Gas control valve 4 4 Pressure gauge 4 6 Porous hollow flat plate

1230389 Simple illustration of the drawing 5 0 process sensor 5 2 process controller 5 4 isopropanol solution supplier 5 5 liquid control valve 1 0 0 drying tank 1 1 0 wafer 1 12 wafer support 1 1 4 heater 1 2 0 Isopropanol solution 1 2 2 Isopropanol vapor 1 3 0 Condensing coil 1 3 2 Manifold pan 1 3 4 Isopropanol waste liquid discharge port 1 3 6 Isopropanol waste discharge port 2 1 0 Step 2 2 0 Step of manufacturing isopropanol vapor 2 2 2 Step of setting process sensor parameters 2 2 4 Controller 2 3 0 Step of transmitting isopropyl alcohol vapor to porous hollow flat plate in drying tank 2 4 0 In drying tank Step 2 of drying wafer 2 Step 2 of isopropyl alcohol waste discharge step 2 4 4 Step of isopropyl alcohol waste liquid discharge step 4 1 0 Wafer transmission signal and wafer contact vapor time signal 4 1 1 Temperature, vapor composition signal and vapor in drying tank Generator internal temperature

1230389 on page 12 Brief description of the degree, pressure, and level signals 4 2 0 Controller 4 3 0 Isopropanol vapor control valve on / off function 4 3 1 Isopropanol vapor control valve opening and closing function and steam control Generator temperature, pressure, level functions

Page 13

Claims (1)

1230389 Case No. 90110459_Revision of the month of June _. Application scope 1. A method for drying a semiconductor wafer using a drying device, the method at least comprises: evaporating a solution to generate a vapor, wherein the solution can be generated with water A miscible substance, which can volatilize rapidly at a temperature of less than 100 degrees; a drying tank is provided, wherein the drying tank includes a process sensor; and the vapor is transmitted to a drying tank through a gas transmission tube. In the porous hollow flat plate, the gas transmission pipe includes a control valve; a controller is used to control the control valve, and to control an amount of steam, wherein the controller is connected to the process sensor and the control valve to utilize the A signal generated when the process sensor detects the steam controls the control valve; and at least one wafer is dried in the drying tank, wherein the steam is evenly diffused from the porous hollow flat plate. / 2. The method according to item 1 of the scope of patent application, wherein the above solution may be an isopropanol solution. 3. The method according to item 1 of the scope of patent application, wherein the material of the drying tank is quartz. 4. The method according to item 1 of the patent application range, wherein the above-mentioned gas transmission tube is a quartz tube. The above quartz tube is more 5. If the method of applying for the first item of the scope of the patent is 1230389, the case number is 90110459, the date is amended. 6. The scope of the patent application includes a pressure gauge. 6. The method of claim 1 in which the above-mentioned porous hollow flat plate is located on a bottom of the drying tank. 7. The method according to item 6 of the patent application, wherein the above-mentioned porous hollow flat plate has a porous surface and faces upward. 8 · — Place dry porous silica feed. Use this control to make dry and semi-evaporated to provide a sense of process. Use a hollow tube package. Its process valve is made of dry porous propanol (IPA, isopropyl alcohol) to dry the conductor wafer. Method, the method includes at least: an alcohol solution to generate an isopropanol vapor; a tank, wherein the material of the drying tank is quartz and includes a isopropyl isopropyl dryer; and a quartz tube to transport the isopropyl Alcohol vapor flows into a flat plate in the drying tank, wherein the porous hollow flat plate has a porous surface and contains a control valve; a controller controls the control valve to control one of the isopropanol vapors and the controller is connected to the A process sensor and the control valve are used to control a signal generated when the sensor detects the isopropanol vapor; and at least one chip is in the drying tank, wherein the isopropanol vapor will spread uniformly in the hollow flat plate come out. 9. The method according to item 8 of the patent application, wherein the above-mentioned quartz tube is Page 15 1230389 Case No. 90110459 Month Amendment 6. The scope of patent application includes a pressure gauge. 10. A device for drying a semiconductor wafer using a drying device, the device includes at least: a steam generator for generating a vapor; a gas transmission tube, one end of which is connected to the steam generator for transmitting the vapor The gas transmission tube includes a control valve; a drying tank, in which a porous hollow flat plate is attached to a bottom of the drying tank and connected to the other end of the gas transmission tube, and the porous hollow flat plate has a face-up A porous surface, and the vapor will diffuse out uniformly from the porous surface, the drying tank further includes a process sensor; and a controller, the controller is connected to the selection sensor and the control valve to make use of the A signal generated when the process sensor detects the steam inside the drying tank controls the control valve and controls an amount of the steam. 1 1. The device according to item 10 of the scope of patent application, wherein the above-mentioned vapor is an isopropanol vapor. 12. The device according to item 10 of the scope of patent application, wherein the material of the drying tank is quartz. 13. The device according to item 10 of the scope of patent application, wherein the above-mentioned gas transmission tube is a quartz tube. Page 16 1230389 Case No. 90110459_Year Month Amendment __ VI. Scope of Patent Application 1. For the device with scope of patent application No. 10, the gas transmission tube mentioned above contains a pressure gauge. 15.— A device for drying semiconductor wafers using an isopropyl alcohol (IPA, isopropyl alcohol) dryer, the device includes at least: a vapor generator for generating an isopropyl alcohol vapor; a gas transmission tube, one end of which Connected to the vapor generator for transmitting the isopropanol vapor, wherein the gas transmission tube further includes a pressure gauge and a control valve to control an input amount of the isopropanol vapor; A drying tank including a process sensor, wherein a porous hollow flat plate is attached to a bottom of the drying tank and connected to the other end of the gas transmission tube, and the porous hollow flat plate has a porous surface facing the person. And the vapor will diffuse out uniformly from the porous surface; and / or a controller, the controller is connected to the process sensor and the control valve to detect the isopropanol in the drying tank by the process sensor A signal generated during the steam controls the control valve and controls the amount of steam input. 16. The device according to item 15 of the scope of patent application, wherein the material of the drying tank is quartz. 17 · The device according to item 15 of the scope of patent application, wherein the above-mentioned gas transmission tube is a quartz tube. Page 17