KR20030016458A - method for inter-locking tool induce shift data in overlay measuring apparatus - Google Patents

Abstract

PURPOSE: A method for inter-locking tool induce shift data in overlay measuring equipment is provided to obtain an accurate align value by setting up a job file having a good reading accuracy and using the job file in a mass production. CONSTITUTION: Predetermined tool induce shift data is received and stored. The tool induce shift data is received from a measuring unit for measuring the overlay of a wafer by setting up and executing the job file. The measured tool induce shift data is compared with the stored tool induce shift data to determine whether the error value of the comparison result falls within a predetermined range. When the error value falls outside the predetermined range, an interlock function is performed to stop updating the tool induce shift data and to display an error state.

Description

Method for inter-locking tool induce shift data in overlay measuring apparatus}

TECHNICAL FIELD The present invention relates to overlay measurement in semiconductor device manufacturing, and more particularly to a method of tool induce shift data interlock in overlay equipment.

In the case of recent semiconductor devices, high integration is essential for achieving low cost and high quality required for securing competitiveness. In order to achieve high integration, scale-down including thinning and shortening of gate oxide film thickness and channel length of a transistor device is accompanied, and accordingly, a technology and a manufacturing system of a semiconductor manufacturing process are being developed in various forms.

Processing of wafers for mass production of semiconductor devices is an essential task for constructing electronic circuits having the same pattern on each chip in the wafer. In such a wafer processing operation, various kinds of films are formed on the surface of each semiconductor wafer in a lot unit, and the operation of selectively etching specific portions of the wafer using a pattern mask is repeatedly performed.

In general, a photolithography process, which is one of semiconductor manufacturing processes, is performed in order of a coating process, an alignment and exposure process, a developing process, an overlay measuring process, a critical dimension measuring process, and the like. Here, the coating process and the developing process are usually performed by a spinner (also called a track equipment), and the alignment and exposure process are usually performed by a stepper. The two equipments are usually referred to as inline equipment because they are connected in-line and perform the above processes one by one, and the coating, alignment, exposure, and developing processes belong to the inline process.

The overlay measurement process performed immediately after the inline process is completed is a process of checking whether any device pattern is accurately aligned using overlay equipment. In the overlay measurement process, an overlay pattern typically formed in a scribe lane located between main chips on a wafer is used. Overlay accuracy, i.e., measurement of the overlapping accuracy of semiconductor devices, is to verify that the alignment of the device pattern formed by the previous photolithography process with the device pattern formed by the current photolithography process is performed correctly. This is accomplished by comparing the deviation from the previous and current device patterns by radiating the set light beam onto the aligned wafer and detecting the reflected light beam reflected from the wafer.

In the semiconductor manufacturing process using wafers of 8 inches or less in diameter, only the number of purchases in a lot of 25 sheets is sampled and checked in consideration of the production efficiency of the line during overlay measurement. However, in the case where the diameter of the wafer becomes larger than 12 inches, the performance of such sampling check degrades the reliability of the overlap accuracy for one lot. Due to the high integration of the device, the overlay deviation required for devices below D17 is about 30 nm. However, when all 25 wafers in one lot are measured, only 20 nm of wafer to wafer is measured. This is because the deviation is difficult to match. As a result, as the aperture of the wafer is enlarged, the risk of causing an overlay failure is increased. Moreover, if quarter-micro design rules are applied on wafers larger than 12 inches, misalignment of variable sheet wafers can lead to maximization of yield scatter. As a result, the cost burden for 12-inch wafers is also increasing.

The overlay equipment first performs job file setup prior to performing overlay measurements. In the job file setup, a tool induce shift data specification is input as a parameter related to tool induce shift (TIS). As a result, if a tool-induced shift occurs largely according to the optical alignment state of the overlay equipment and the film quality profile of the wafer, the overlay equipment or the film quality profile is not good, and thus the accurate setup and correction of the overlay equipment is necessary. will be.

Conventionally, accurate calibration is difficult and reading accuracy is deteriorated by setting up a job file and checking tool end shift and unconditionally updating (update) the checked tool end shift data.

Accordingly, it is an object of the present invention to provide a method that can solve the above conventional problems.

It is another object of the present invention to provide a tool induce shift data interlock method in overlay equipment.

It is another object of the present invention to provide a tool induce shift data interlock method in overlay equipment that can obtain accurate alignment values by setting up and applying a job file having good reading accuracy to mass production.

According to an aspect of the present invention for achieving the above object, a method for interlocking tool produce shift data in overlay equipment includes receiving and storing defined tool produce shift data from an input unit; Receiving tool produce shift data from a measurement unit for measuring overlay of a wafer by setting up and executing a job file, comparing the measured tool produce shift data with the stored tool produce shift data and Checking whether it is within a set range, and performing an interlock function when the error value is out of the set range to prohibit the updating of the tool produce shift data and display an error state.

According to the method configuration described above, an accurate alignment value is obtained by setting up and applying a job file having good reading accuracy to mass production.

Figure 1 is a schematic block diagram showing the connection of the overlay equipment and the inline system applied to the present invention

2 is a hardware block diagram of the overlay device of FIG.

3 is a flow chart showing a control flow of a tool induce shift data interlock in overlay equipment according to an embodiment of the present invention.

4 is an exemplary view showing a screen display of the monitor of FIG.

Hereinafter, a preferred embodiment of a method for interlocking tool produce shift data in overlay equipment according to the present invention will be described with reference to the accompanying drawings. Although shown in different drawings, components that perform the same or similar functions are denoted by the same reference numerals.

Figure 1 is a schematic block diagram showing the connection of the overlay equipment and the inline system applied to the present invention. Referring to FIG. 1, an overlay device 30 connected with inline equipment 10 and 20 is shown. In the figure, step S10 denotes a coating step of applying a photoresist film such as a photoresist, S20 indicates an alignment step, S30 indicates an exposure step, and S40 indicates a developing step. As such, when the inline process consisting of coating, alignment, exposure, and development processes is completed, the step of performing an overlay measurement is performed by the overlay equipment 30. The overlay device 30 must already have a job file set up in order to make overlay measurements correctly before making overlay measurements. To this end, the overlay device 30 receives the tool produce shift data specification as a parameter related to the tool produce shift with the internal functional blocks as shown in FIG. 2, and performs data correction.

Referring to FIG. 2, which illustrates a hardware block diagram of the overlay apparatus of FIG. 1, a measurement unit 110 for overlay measurement, an input unit 150 for receiving an operator's input, and a command received from the input unit 150 are set in advance. The controller 100 performs overall control of the operation of the equipment and setup of the job file according to the program, the monitor 120 connected to the controller 100 to display the status of the job, and various data for driving the job file and the equipment. The memory unit 140 is stored, and is configured as a drive unit 130 for driving the equipment under the control of the controller 100.

3 is a flow chart showing a control flow of the tool induce shift data interlock in the overlay device according to an embodiment of the present invention, and includes steps S110 to S170.

Hereinafter, a tool induce shift data interlock method in overlay equipment according to an embodiment of the present invention will be described in detail with reference to the above drawings. After the controller 100 of FIG. 2 performs an operation of initializing various registers and flags in step S110 of FIG. 3, the controller 100 receives tool induce shift data defined in step S120 from the input unit 150 to set up a job file. This is stored in the set storage area of the memory unit 140. Of course, in this case, the operator of the overlay equipment should input the tool produce shift data specification as a parameter related to the tool produce shift through the input unit 150 such as a keyboard or the like. In step S120 the controller 100 receives the tool induce shift data from the measurement unit 110 for measuring the overlay of the wafer by the setup and execution of the job file. In operation S140, the measured tool produce shift data is compared with the stored tool produce shift data to check whether the error value is within a set range. If the error value is within the set range, the normal operation routine of step S160 is performed. If the error value is out of the set range, steps S150 and S160 are sequentially performed. In step S150, an interlock function is performed to prohibit updating of the tool produce shift data. In step S170, an error state is displayed. As a result of step S170, the same as that of FIG. 4 appears on the screen of the monitor 120.

4 shows an example of the screen display of the monitor shown in FIG. 2, in which the tool induce shift data is shown on the screen 40 as indicated by reference numeral 41, and a bar 43 is displayed on the bottom of the screen. Bar 42 is the bar that is indexed in normal operation.

As a result, if the tool induce shift data interlock without updating the data when an error occurs during the setup in the overlay equipment more than a prescribed range as described above, it is possible to set up a job file with good reading accuracy. Here, the interlock is a software interlock indicating prohibition of data update. Therefore, by performing overlay measurement at the time of mass production in the corrected state, it is possible to more accurately obtain the alignment measurement value.

Meanwhile, the measurement unit 110 of FIG. 2 may be configured as an overlay measuring stage installed in the overlay measurement chamber and a halogen light control device installed on the upper surface of the overlay measurement chamber. After the developing process is completed, when the wafer is moved to the overlay measurement chamber of the overlay measurement unit 110, the movement is detected by the light emitting element and the light receiving element installed in the overlay measurement chamber. Thus, the halogen lamp is turned on by the control operation of the halogen light control device. The wafer moved to the overlay measuring stage is seated at the set position on the stage, and then the overlay measurement is performed. The overlay measurement is performed by scanning the beam of light generated by the halogen lamp on an aligned wafer and detecting the reflected beam of light reflected from the wafer to determine the degree of deviation from the previous and current device patterns. Is performed by comparison. For more details regarding the actual overlay measurement, reference may be made to US Pat. No. 5,468,580, issued Nov. 21, 1995, to inventor Tanaka in the US. The patent discloses a technique for measuring an amount of overlay deviation between measurement patterns after forming the first and second overlay measurement patterns.

In addition, the overlay pattern at the time of overlay can be manufactured as follows. The photosensitive material is coated on the substrate, and then exposed and developed to form an inner box. An overlay pattern is prepared by applying an arbitrary film on a substrate including the inner box, and then applying a photosensitive material on the film, exposing and developing to form an outer box having a larger area than the inner box. It is also possible to use an overlay inspection pattern as disclosed in U.S. Patent No. 5,633,505, issued May 27, 1997, to a number of inventors Zhengwen except United States.

Although the foregoing description has been given by way of example only with reference to the accompanying drawings, it will be apparent to those skilled in the art that the present invention may be variously modified or changed within the scope of the technical idea of the present invention. Such modifications and variations will also fall within the scope of the present invention. For example, in the case of different matters, the method of performing interlock can be variously modified or changed.

According to the present invention as described above, there is an effect of obtaining a correct alignment value by setting up a job file with good reading accuracy and applying it to mass production. Therefore, there is an advantage that the yield is improved to reduce the cost burden.

Claims (3)

In the tool produce shift data interlock method in overlay equipment: Receiving and storing defined tool produce shift data from an input; Receiving tool induce shift data from a measurement unit for measuring overlay of a wafer by setting up and executing a job file; Comparing the measured tool produce shift data with the stored tool produce shift data and checking whether the error value is within a set range; Performing an interlock function when the error value is out of a set range to prohibit updating of the tool produce shift data and display an error state. The method of claim 1, wherein the interlock is a software interlock indicating prohibition of data update. The method of claim 1, wherein the overlay equipment uses a halogen light control device as a measurement unit.