TWI220772B - Airflow environmental measurement system - Google Patents

Abstract

The present invention relates to a measurement system, and more particularly to an airflow environmental measurement system, which can smoothly and precisely measure the thickness of a wafer. The airflow environmental measurement system at least comprises: a display screen, a stage, a lens, a first gas nozzle, a gas supply source, a second gas nozzle, a transport slot, an exhaust system, a transmission device, a first flow regulation valve, a second flow regulation valve, a first conductive tube, a second conductive tube, a third conductive tube, a standard platen, and a standard sheet. The first and second gas nozzles are employed to continuously spray gas on a wafer and a measuring reference point to form a gas screen, so that the gas evaporated from the wafer under test flows with the gas screen, and further flows to the outside of the measurement system via the transport slot and exhaust device, thereby smoothly and precisely measuring the thickness of the wafer.

Description

1220772 V. Description of the invention 0) 5-1 Field of the invention: The present invention relates to a measurement system, and more particularly to an airflow environment-type measurement system. The invention is applied to the measurement of the thickness of a wafer, and the air curtain generated by the first nozzle and the second nozzle is used to make the gas volatilized from the wafer flow with the air curtain and be opened through a transmission. And an air extraction device flows outside the measurement system to prevent the lens and the measurement reference point from being contaminated, so as to smoothly and accurately measure the thickness of the wafer. 5-2 Background of the Invention: A semiconductor wafer is mainly made of a sandwich structure including a silicon layer / silicon dioxide layer / silicon layer. The traditional method is to form the two silicon wafers on one plane respectively. A stone dioxide layer is formed, and then the surfaces of the two silicon dioxide layer films are combined with each other at a high temperature to form a sandwich structure. However, if the thickness of only one layer is unknown, both the earlier invention and the present invention can be used to measure the thickness of any layer and to accurately understand the optical characteristics of each layer. The thickness of each layer in the wafer is a very important control parameter in the semiconductor manufacturing process, because the thickness of each layer will affect the electrical properties and resistance of the semiconductor device. For example: if the barrier layer (b a r r e e r 1 a y e r) is too thin, when the semiconductor element starts to operate when the current is passed in, the barrier layer will

1220772 V. Description of the invention (2) Leakage current will occur without exerting its proper blocking function, which will cause semiconductor elements to lose their due performance. Therefore, how to accurately measure the thickness of each layer of the wafer is Quite important subject. A semiconductor wafer is a product made from many layers of material through many deposition steps. In these deposition steps, different gases are used according to the needs of the process, such as: gas (ch 1 〇rine; C 1 2), boron chloride (BC1 3) and hydrogen bromide (HBr), these gases usually easily interact with the atmosphere to form solid phase by-products. Once these by-products adhere to the amount The surface φ of the instrument for measuring the thickness of the wafer can easily cause too large an error in the measured data, and the thickness of the material layer in the wafer cannot meet the design requirements, which will affect the quality of the semiconductor wafer. Referring to the first figure, this is a schematic diagram of a conventional measurement system for measuring the thickness of a material layer on a semiconductor wafer. Before the measurement system starts to operate, the measurement system must be calibrated to make the data obtained after the measurement more accurate. First, a reference piece 15 is placed on the reference platform 10 in the measurement system as a measuring reference point. The reference wafer 15 is a wafer slice of known thickness. Next, use a conveying device 2 7 Φ to move the reference platform 10 to the lens 30 and start the calibration of the lens 30. After the calibration of the lens 30 is completed, the reference platform 10 will leave the area below the lens 30 by the conveying device 27, and the stage 20 will be moved to the crystal of the measurement system by the guidance of the conveying device 27 at the same time. Round the entry so you can start

1220772 5. Description of the invention (3) Wafer measurement procedure. After the wafer 25 is subjected to chemical mechanical polishing (chemical mechanical PQ 1 i sh i ng) or engraving process, the wafer is first transported to the wafer input port of the measurement system through a wafer boat 60 and borrowed. A robot arm 65 holds the wafer 25 on the mirror table 20 in the measurement room. Next, the stage is moved below the lens by a conveying device 27, and the thickness of the wafer 25 is measured. With the lens 30, the light is directed to the surface of the wafer 25, and the shell material returned by the light is transmitted. Displayed on the display screen 50 'The thickness of the wafer 25 is determined by analyzing the data on the display screen 50. ^ ^ aa, so the wafer science mechanical grinding produces volatility 2 7 moves to the lens circle 2 5 inside swings the lens 3 0 surface 5 so it must be > and the measurement system will damage the mirror circle 2 5 the material 2 5 is easy Generate or gas engraving. When the solid phase formed on the gas starting below the crystal 30, the lens head in the lens system is often wiped and the material is often delayed. The volatile process is usually rounded at 25. The by-product head that is easy to crystallize is used for a precise operation. The gas is formed in a manner that a circle of 25 thickness is adhered to the object on the mirror stage while the crystal density is measured to maintain the density of the material. In addition, when passing through a wafer such as a wafer 25, it is easier to produce 20, and the degree of measurement is measured by the conveying device. The accuracy of the circular thickness measurement on the surface of the crystal lens 30 and the accuracy of the ring lens measurement. Equipment, once wiped improperly, the gas from the inside of the wafer 25 will be volatilized to the measurement reference point and the gas will also diffuse through

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Page 6 1220772 V. Description of the invention (4) Error. Once the lens correction process is inaccurate, the wafer thickness measured in the subsequent measurement will also have a large error, and serious defects may occur in subsequent processes. In today's technology, the volume of semiconductor components is getting smaller and smaller, and the thickness of each layer of material in the wafer is getting thinner and thinner, so the tolerance range of the thickness of each material layer is getting smaller and smaller. When measuring the thickness of a wafer with a traditional measurement system, the volatilization of the gas inside the wafer can easily contaminate the lens and cause errors in the measurement and errors in the lens calibration process caused by the contamination of the reference film. Accuracy of actual wafer thickness measurement. When the error is too large, serious defects will occur in subsequent processes, affecting the quality of the product, and increasing the cost of production. 5-3 Purpose and Summary of the Invention: In view of the above-mentioned background of the invention, the conventional measurement system easily causes the gas emitted from the wafer to contaminate the lens and the reference film, and influences the measurement system to measure the actual wafer thickness The accuracy and affect the quality of the product and increase the cost of production. The main purpose of the present invention is to prevent the lens from being contaminated by the gas emitted from the inside of the wafer by a gas flow environment type measurement system. A second object of the present invention is to prevent a gaseous volatilization from the wafer from being used as a basis for measuring a reference point by an airflow environment-type measuring system.

Page 7 1220772 V. Description of the invention (5) quasi film. A third object of the present invention is to improve the accuracy of the actual wafer thickness measurement by the measurement system through an airflow environment-type measurement system. The fourth object of the present invention is to improve the quality of the ®3 product by using an airflow environment-type measurement system. A fifth object of the present invention is to improve the efficiency of the process operation by an airflow environment-type measurement system. Another object of the present invention is to extend the service life of the lens and reduce the cost of production and operation through an airflow environment-type measurement system. According to the above-mentioned object, the present invention provides an airflow environment-type measurement system, which uses a first gas nozzle and a second gas nozzle to continuously eject gas from a lens and a measurement reference point, so that The volatilized gas in the wafer flows with the air curtain and flows out of the measurement system through the transmission opening and extraction device to prevent the lens and the measurement reference point from being contaminated and measured smoothly and accurately. Wafer thickness. The gas emitted from the first nozzle and the second nozzle can be controlled by the first flow regulating valve and the second flow regulating valve, so as to avoid the defect of measurement system pollution caused by too large or too small gas flow. The invention can also improve the quality of the product and reduce the cost of production and operation. The invention can further extend the service life of the lens and speed up the manufacturing process

Page 8 1220772 V. Description of the invention (6) Operational efficiency. 5-4 Detailed Description of the Invention: Some embodiments of the present invention will be described in detail as follows. However, in addition to the detailed description, the present invention can be widely implemented in other embodiments, and the scope of the present invention is not limited, which is subject to the scope of subsequent patents. In the semiconductor manufacturing process, the most important time to measure the thickness of the wafer material layer is after chemical mechanical polishing or the engraving process. In the chemical mechanical grinding process, the thickness of the abrasive material layer is usually controlled by the length of the grinding time. However, the surface quality of the wafer after CMP, such as surface flatness, will affect the quality of subsequent processes. Therefore, a measurement system must be used to measure the thickness of the wafer after the CMP process in order to smoothly Carry out subsequent processes. The etching process usually also controls the amount of material removal by the length of the etching process. Therefore, after the etching process, a measurement system must also be passed to accurately control the thickness of the wafer material layer to avoid the thickness of the wafer material layer. Large errors affect the quality of the product. Referring to the second figure, this is a schematic diagram of the airflow environmental measurement system of the present invention. The airflow environmental measurement system of the present invention includes at least a display screen 500, a stage 200, a lens 300, a first gas nozzle 400,

Page 9 1220772 V. Description of the invention (7) A gas supply source 7 50, a second gas nozzle 4 50, a transfer opening 7 0 0, an air extraction system 9 0 0, and a conveying device 2 7 0. A first flow regulating valve 420, a second flow regulating valve 470, a first conduit 820, a second conduit 870, a third conduit 800, a reference platform 100, and a reference plate 150. The first duct 8 2 0 connects the gas supply source 7 5 0 and the first gas nozzle 4 0 0. The second duct 8 7 0 connects the gas supply source 7 5 0 and the second gas nozzle 4 50. The third duct 8 0 0 connects the transmission opening 7 0 0 and the exhaust system 9 0 0. The first flow regulating valve 4 2 0 is located on the first gas nozzle 4 0 0 and the second flow regulating valve 4 7 0 is located on the second gas nozzle 4 50. The reference platform 1 0 0 and the stage 2 0 0 are both located on the conveyor 2 7 0. This conveying device 270 can move the reference platform 100 and the mirror stage 200 in the first and second axial directions. The first gas nozzle 4 0 0 is located on one side of the reference platform 1 0 0 and the second gas nozzle 4 50 is located on one side of the stage 2 0 0. Before the air-flow environmental measurement system starts to operate, the gas must be supplied first. The source 7 50 is turned on, and the gas passes through the first duct 8 2 0 and the second duct 8 40 and is ejected from the first gas nozzle 4 0 0 and the second gas nozzle 4 50 to form an air curtain 4 inside the measurement system. 8 0. Next, turn on the air extraction system 900 to increase the flow capacity of the air curtain 480 and define the flow direction of the air curtain 480 at the same time. With the suction generated by the exhaust system 9 0 0, the air curtain 4 8 0 will pass through Luan Lu to open the gate 7 0 0 and the third duct 8 0 0 to guide this air curtain to the exhaust treatment area of the plant area 9 5 0 Treat it so that the air curtain 480 does not spread to other areas of the measurement system through the effect of diffusion. The extraction system 900 contains at least one extraction motor, or a test tube structure. Air curtain 4 8 0 The gas used can be an inert

Page 10 1220772 V. Description of the invention (8) The gas (i n e r t g a s) or nitrogen. The gas supply source 750 and the extraction system 9 0 0 must be kept on during the measurement process. The transmission opening 7 0 0 is an opening in the measurement system, which is used to collect the air curtain 4 8 0 and serve as a passage when the air curtain 4 8 0 is discharged. Next, a reference piece 150 is placed on the reference platform 100 in the measurement system as a measurement reference point. The reference wafer 150 is a wafer slice of known thickness. Next, a reference device 100 is used to move the reference platform 100 to the area below the lens 300, and the calibration of the lens 300 is started. After the lens 300 calibration is completed, the reference platform will leave the area under the lens φ head 3 0 0 by the conveying device 2 70, and the lens stage 2 0 will be moved to the same time by the guide of the conveying device 2 7 0 The wafer input port of the measurement system to start the wafer measurement process. After the wafer 250 has undergone the chemical mechanical grinding or etching process, the wafer is first transported to the wafer input port of the measurement room through a wafer boat 600 and held by a robot arm 650. The wafer 2 50 is sent to the stage 2 7 in the measurement room. Next, by a conveying device 270, the stage 200 is moved below the lens 300, and the thickness of the wafer 250 is measured. The lens 3 0 is used to direct the light toward the surface of the wafer 2 50 and the data returned by the light is displayed on the display repair screen 5 0 9. The wafer 2 is determined by analyzing the data on the display screen 5 0 0 The thickness of 5. Because the material in the wafer 250 is usually shaped by gas deposition

1220772 Five 'invention description (9), so the crystal 250 is easy to produce volatile gas. And after processing such as chemical mechanical polishing or etching, the inside of the wafer 250 is more likely to generate volatile gases. When the wafer 250 is placed on the stage 200 and is moved below the lens 300 by the conveying device 27, the thickness measurement of the wafer 250 is started, and this is evaporated from the inside of the wafer 250. The emitted gas will be taken away by the air curtain 4 80 sprayed by the second gas nozzle 450, so that this gas will not adhere to the lens 300 and avoid the formation of a solid phase on the lens 300. ....... a _ 3 0 0 The accuracy of the measurement. The gas curtain 4 8 from the first gas nozzle 4 0 [can prevent the gas volatilized from the inside of the wafer 2 5 through diffusion

And deposited on the reference film 150, resulting in an error when the lens 300 is corrected. This d wafer 2 500 internal volatilized gas follows the flow mode of the air curtain, and through the suction generated by the suction system 9 00, it is opened by transmission 7000 and the third pen tube 802 ' This gas is guided to the factory waste gas treatment area 95 ° for treatment, so that this gas will not be spread to other areas of the measurement system through the effect of diffusion ^ and cause more serious pollution. °°-, the system lens 300 is a precision measurement device. If you use: ^ ΐ environmental measurement system, it can reduce the 4 rate of lens 300 pollution, and the opportunity to wipe the lens 300. Not only speeds up the process

In order to prevent the increase of production cost caused by improper cleaning of the lens, TG = the accuracy of Γ00 measurement. Usually, the lens takes a fixed process, and the measurement error caused by 3 0 0 is caused by vibration. But with j: ΐ: lens 3 0 0 can also be installed on the-conveying device to measure the operating efficiency of the system. < Put on the clothes?

1220772 V. Description of the invention (10) In the airflow environmental measurement system of the present invention, the flow control of the air curtain 4 8 0 is also very important. Therefore, the first gas nozzle 4 0 0 and the second gas nozzle 4 5 0 A first flow regulating valve 420 and a second flow regulating valve 470 are required to control the flow of the air curtain. If the flow rate of the air curtain 4 8 0 is too high, the air curtain 4 8 0 will not be able to follow a fixed path through the suction of the air extraction device 9 0 0 to the exhaust gas treatment area 9 50 and will be scattered in the measurement system. Cause more serious pollution. If the flow rate of the air curtain 480 is too low, the gas volatilized from the wafer 250 will still easily adhere to the lens 300 and cause errors in the measurement results. With the needs of the process, the flow regulating valve can also be installed with a gas supply source 750 0 _ or the first duct 8 2 0 and the second duct 8 4 0 to control the first gas nozzle 4 0 0 and the second gas nozzle. The air curtain emitted by 4 50 has a flow of 480. In the measurement system of the airflow environment of the present invention, the main function of the second gas nozzle 450 is to avoid the pollution of the lens 300 from the volatilized gas inside the wafer, and the main function of the first gas nozzle 400 is In order to prevent the reference sheet 150 from being contaminated by the volatilized gas inside the wafer 250. Therefore, the second gas nozzle 4 0 0 cannot be sprayed toward the lens 3 0 0 to prevent the air curtain 4 8 0 from bringing the gas volatilized from the wafer 2 5 0 to the lens 3 0 0 and contaminating the lens 3 0 0 defect. The first gas nozzle 4 0 0 and the second gas nozzle 4 5 0 can be determined according to the needs of the process. _ Determine whether to be installed on the conveying device 2 7 0 and follow the reference platform 1 0 0 and the mirror stage 2 0 0. Give full play to the functions of the air curtain 480 and increase the efficiency of the process operation.

Page 13 1220772 V. Description of the invention (11) According to the above-mentioned object, the present invention provides an airflow environment-type measurement system, which continuously uses a first gas nozzle and a second gas nozzle to continuously measure the lens and the reference point for measurement. The air curtain formed by the ejected gas allows the gas volatilized from the wafer to flow with the air curtain and flow out of the measurement system through the transmission opening and extraction device to avoid the lens and the measurement reference The spot was contaminated and the thickness of the wafer was measured smoothly and accurately. The gas sprayed from the first nozzle and the second nozzle can be controlled by the first flow regulating valve and the second flow regulating valve, so as to avoid the defect of the measurement system pollution caused by the excessive or small gas flow. The invention can also improve the quality of the product and reduce the cost of production and operation. The invention can prolong the service life of the lens and the efficiency of accelerating the manufacturing process. It not only has practical effects, but also has a design never seen before. It has improved efficacy and progress. Apply for it in accordance with the law. For this reason, the examiners are kindly invited to examine it in detail, and pray that the grant of a patent may be granted as soon as possible. The above description is only a preferred embodiment of the present invention. This embodiment is only used for illustration, not for limiting the scope of patent application of the present invention. It can still be implemented without departing from the essence of the present invention. Such changes should still fall within the scope of the present invention. Therefore, the scope of the present invention is defined by the following patent application scope.

Page 14 1220772 Brief description of the drawings The first diagram is a schematic diagram of a conventional measurement system; and the second diagram is a schematic diagram of an airflow environment-type measurement system of the present invention. Main symbols: 1 0 reference platform 1 5 reference reference point 2 0 stage 2 5 wafer 2 7 conveying device 3 0 lens 5 0 display screen 6 0 crystal boat 6 5 mechanical arm 1 0 0 reference platform 1 5 0 Reference reference point 2 0 0 Stage 2 5 0 Wafer 2 7 0 Transport device 3 0 0 Lens 4 0 0 First gas nozzle 4 2 0 First flow regulating valve 4 5 0 Second gas nozzle 4 7 0 Second flow adjustment valve

Page 15 1220772 Simple description of the diagram 5 0 0 Display screen 6 0 0 Crystal boat 6 5 0 Robotic arm 7 0 0 Transmission opening 8 0 0 Third duct 8 2 0 First duct 8 4 0 Second duct 9 0 0 Extraction device 9 50 0 Exhaust gas treatment area

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Claims (1)

1220772 6. Scope of patent application 1. An airflow environment-type measurement system, wherein the measurement system includes at least: a stage, wherein the stage is located on a conveying device, which is used to place a wafer, a reference platform, The reference platform is located on the conveying device and on one side of the stage, and is used to place a reference piece; a lens, where the lens is located above the stage, is used to measure the wafer and the reference piece; A gas supply source, wherein the gas supply source is used to supply a gas j a first gas nozzle, wherein the first gas nozzle is located on one side of the reference platform and is used to eject the gas; a second gas nozzle Wherein the second gas nozzle is located on one side of the stage and is used to spray the gas; a first conduit, wherein the first conduit is used to connect the first gas nozzle and the gas supply source; a second A duct, wherein the second duct is used to connect the second gas nozzle and the gas supply source; a transmission opening gate, wherein the transmission opening gate is an opening for discharging the Thereof; and a suction device, wherein the suction line by means of a third conduit means connected to the transfer gate opening, for generating a suction force to remove the gas. 2. If the system of the first scope of the patent application, wherein the above first conduit to Page 17 1220772 VI. Scope of patent application It does not include a flow regulating valve. 3. The system according to item 1 of the patent application scope, wherein the above-mentioned second conduit includes at least a flow regulating valve. 4. If the system of item 1 of the patent application scope, wherein the above-mentioned extraction device includes at least one extraction motor. 5. If the system of item 1 of the patent application scope, wherein the above-mentioned suction device includes at least one venturi structure. | 6. If the system of item 1 of the patent application scope, wherein the above-mentioned gas is an inert gas. 7. The system of item 1 in the scope of patent application, wherein the above-mentioned gas is a nitrogen gas. 8. The system according to item 1 of the patent application range, wherein the above-mentioned gas supply source includes at least a flow regulating valve. 9. An airflow environment-type measurement system, wherein the system includes at least: a stage, wherein the stage is located on a conveying device for placing a wafer, and a reference platform, wherein the reference platform is located on the conveying device Bit Page 18 1220772 6. The scope of the patent application is on one side of the stage and is used to place a reference piece; a lens, where the lens is located above the stage, is used to measure the wafer and the reference piece; a gas A supply source, wherein the gas supply source is used to supply a gas, 'a first gas nozzle, wherein the first gas nozzle is located on one side of the reference platform, and the first gas nozzle includes at least a first flow regulating valve, A second gas nozzle, wherein the second gas nozzle is located on one side of the stage, and the second gas nozzle includes at least a second flow regulating valve, which is used to spray the gas; A first conduit, wherein the first conduit is used to connect the first gas nozzle and the gas supply source; a second conduit, wherein the second conduit is used to connect the second gas nozzle and the gas supply source; Transmission opening, wherein the transmission opening is an opening for discharging the gas; and an air extraction device, wherein the air extraction device is connected to the transmission opening by a third conduit, To produce a suction to remove the gas. 10. The system according to item 9 of the scope of patent application, wherein the above-mentioned first conduit includes at least a flow regulating valve. 1 1. The system according to item 9 of the scope of patent application, wherein the above-mentioned second conduit to Page 19 1220772 VI. Scope of patent application It does not include a flow regulating valve. 1 2. The system according to item 9 of the scope of patent application, wherein the above-mentioned extraction device includes at least an extraction motor. 1 3. The system according to item 9 of the scope of patent application, wherein the above-mentioned suction device includes at least one venturi structure. 14. The system according to item 9 of the scope of patent application, wherein said gas is an inert gas. 15. The system according to item 9 of the scope of patent application, wherein the above-mentioned gas is a nitrogen gas. 16. The system according to item 9 of the scope of patent application, wherein said gas supply source includes at least a flow regulating valve. 1 7. An airflow environment-type measurement system, wherein the system includes at least: a stage, wherein the stage is located on a conveying device for placing a wafer; a reference platform, wherein the reference platform is located on the conveyance The device is located on one side of the stage and is used to place a reference piece; a lens, wherein the lens is located above the stage and used to measure the wafer and the reference piece; Page 20 1220772 VI. Patent application scope A gas supply source, wherein the gas supply source is used to supply a gas, a first gas nozzle, wherein the first gas nozzle is located on one side of the reference platform and is located on the conveying device A second gas nozzle, wherein the second gas nozzle is located on one side of the stage and on the conveying device, and is used to eject the gas; a first duct, wherein the The first conduit includes at least a first flow regulating valve, the first conduit is used to connect the first gas nozzle and the gas supply source, and a second conduit, wherein the second conduit includes at least a second flow regulating valve, The second conduit is used to connect the second gas nozzle and the gas supply source; a transmission opening gate, wherein the transmission opening gate is an opening for discharging the gas; and an air extraction device, wherein the air extraction The device is connected to the transmission opening by a third conduit for generating a suction force to remove the gas. 18. The system according to item 17 of the scope of patent application, wherein the above-mentioned suction device includes at least one venturi tube structure. 19. The system according to item 17 of the scope of patent application, wherein said gas is an inert gas. 2 0. The system of item 17 in the scope of patent application, wherein the above-mentioned gas is a Page 1212772 Page 22