KR20010094276A - control system for compensating etch amount of semiconductor wafer - Google Patents

Abstract

PURPOSE: A control system for compensating an etching amount of a semiconductor wafer is provided to process uniformly a semiconductor device by compensating a variation of feature according to an operating time of a semiconductor processing system. CONSTITUTION: A setup menu(40)for etching amount compensation is to select three compensation standards such as a practical processing time of a chamber, the number of wafer performing an etching process, and a standby time for performing a process. An etching amount compensation method setup menu(70) of and an etching amount setup menu(80) are provided as menus of an input screen. An etching amount compensation direction setup menu(50) is provided as a menu of the input screen. The etching amount compensation method setup menu(70) provides a menu for selecting the compensation using an absolute time and the compensation using percentage. A compensation unit setup menu(90) is provided to set up a time unit in the etching amount setup menu(80). In addition, an etching amount compensation function selection menu(20), a chamber setup menu(30), and an etching amount function application setup menu(60) are provided.

Description

Control system for compensating etch amount of semiconductor wafer

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to the manufacture of semiconductor devices, and more particularly, to a control system that compensates for changes in the process characteristics of equipment resulting from the continued use of etching, ashing or cleaning processing facilities. will be.

For example, semiconductor device processing equipment such as deposition equipment or etching equipment generally has a chamber for processing the wafer. The processing of wafers is performed according to the processing time, RF time, operating time of the processing equipment, and part life time. Deposition rate and etching rate differ.

When a film is deposited on an actual semiconductor substrate or etched, it may appear differently depending on time or RF time. In general, the deposition rate and the etching rate tend to decrease gradually over time. Such changes in the natural conditions of the chamber have not had a significant effect on the device until now, but as devices are integrated, for example, devices having a design rule of 0.21 μm or less have a very small device margin due to the design rule. It has been found to affect scattering.

For example, when using multiple plants, the end point time is different and the etching rate is different, which makes the problem even more severe when mass production with many plants.

The graph of FIG. 1 is a graph showing data obtained by actually monitoring the change in the etching rate according to the increase in the number of wafers processed in the high density plasma etching equipment. May vary). As can be seen from the change in the actual measurement line of the graph, the etching rate decreases linearly with the increase in the number of moving sheets (the trend line), but it shows the decreasing trend irregularly. Of course, even if the significant difference between the measured line and the trend line is not seen to be very large, even this significant difference can adversely affect the production of a uniform quality product.

Therefore, if the significant difference in the etching rate is not compensated for, a process in which the etching time is short or in a process in which there is no margin for the etching target may be in a state where there is no margin according to the etching progress time depending on the equipment. For example, during the SAC etching of a specific device, the stopper etching time is 10 seconds, but if there is a change in the etching rate with time, a not open state occurs.

In general, when the specification of the etching rate is set in several facilities, the specification according to the design rule is determined from the average of the etching rates of the various facilities. Basically, specification deviation is caused by significant differences between facilities, significant differences between wafers, and number of device etching progresses. out) phenomenon occurs.

The change in the etching rate of the equipment is solved to some extent by stable process conditions, but a solution for the shortcomings needs to be provided. As the design rules become more stringent, the amount of etching tends to have a greater impact on device characteristics. Therefore, a very serious problem may arise if there is no compensation tool due to the change in the etching rate.

2A to 2C show the process steps for stopper etching. 2A shows the state before etching, and FIGS. 2B and 2C show the state after etching, respectively. The stopper etched region 10a is given a very small margin with an etching time of 10 ". Fig. 2B shows that the surface 10b, which is the state after etching in the stopper etching, is normally etched so that there is no problem in device characteristics. 10c) is insufficiently etched and the etching surface is in an abnormal state. This problem occurs when the etching time is 10 " but the etch amount is reduced, so the change in the etching amount must be compensated for. In other words, the etching amount varies depending on the number of chambers to be processed, and in particular, for the manufacture of highly integrated devices, the etching time is short and the tool process is required in the strict process step. Without such compensation, uniformity in process quality cannot be guaranteed. Such compensation is necessary not only in the etching process but also in the ashing process or the cleaning process, and further, the compensation concept needs to be applied to the overall semiconductor processing equipment.

The object of the present invention is to compensate for the change in characteristics of the semiconductor processing equipment with the passage of the operating time, to uniformly process the semiconductor device, to improve the process quality and to reduce the defective rate, thereby reducing the cost.

1 is a graph showing the change in the etch rate according to the number of running in the etching equipment.

2A is a state diagram before an etching process, FIG. 2B is a state diagram after a normal etching process, and FIG. 2C is a state diagram after an abnormal etching process.

3 shows an input screen for setting a function to be added to an etching facility for automatic etching amount compensation.

4 is a flowchart illustrating a process of applying a concept of the present invention.

<Description of the symbols for the main parts of the drawings>

10a, 10b, 10c: stopper etched area 12: underetched

In order to achieve the above object, a control system for controlling a process of an etching facility for manufacturing a semiconductor device is provided. The etching facility process control system includes a menu for setting a compensation standard such as the use time of an etching chamber or the number of wafers undergoing an etching process, and an etching compensation method to be applied by the etching facility according to the compensation standard set when the etching process is performed. And an input screen including a menu for setting an etching compensation amount, and reading data set through the display screen.

The etching compensation method may be selectively applied according to a method of increasing or decreasing an etching process time with respect to a standard etching process time or by applying a percentage (% rate) to the standard etching process time. It is preferable.

Also, to further enhance the function, select a menu for selecting a chamber to apply the etching amount compensation, a menu for selecting whether to compensate the increase or decrease of the etching amount, and a step of an etching process to apply the etching amount compensation. It is preferable to further provide a menu for setting a menu for setting the reset conditions of the set values for the etching amount compensation.

Other features and advantages of the present invention will become more apparent with reference to the following detailed description and accompanying drawings that illustrate the features of various embodiments of the invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

In general, an etching facility is equipped with a computer terminal (not shown) for controlling the process performance of the facility. This computer terminal is responsible for setting the process conditions of the etching equipment or controlling the overall operation necessary for the performance of the process.

FIG. 3 shows an input screen for setting a function to be added to an etching facility for automatic compensation of the etching amount.

The etching facility periodically performs a cleaning operation (cleaning operation) for maintenance. The cycle of the cleaning operation may be based on various criteria, such as the actual process time of the chamber, the number of wafers subjected to etching, or the waiting time for performing the process.

In order to compensate the etching amount, it is necessary to provide a compensation criterion for determining which standard to compensate for the etching amount. The compensation criterion of the etching amount can also be applied by selecting any one of the above criteria. Therefore, the etching amount compensation reference setting menu 40 is provided to select the above three compensation criteria. If the compensation criterion is set to the actual process time of the chamber, apply the etching compensation rate according to the process time based on the set process time and apply the new etching compensation rate from the beginning when the operation time of the etching facility reaches the set process time. Get started. The same concept can be understood even when the number of wafers subjected to etching processing is set as a compensation standard.

In addition, a menu 70 for setting the etching amount compensation method and a menu 80 for setting the etching compensation amount are provided as menus on the input screen. In addition, a menu 50 for setting the compensation direction of the etching amount is also provided.

Compensation of the etching amount may be performed by compensating the etching amount by adding or subtracting the compensation time to the standard etching time, or by applying a compensation rate to the standard etching time. Therefore, the etch amount compensation method setting menu 70 provides a menu for selecting any one of a method of compensating by applying the etch amount compensation rate expressed as a percentage and the compensation by the absolute time.

In addition, it may be based on the operator's empirical judgment or the data obtained by the automatic calculation using empirical experimental data, which is beyond the scope of the present invention. do. However, the menu 80 for setting the compensation amount needs to be provided.

Further, in association with the absolute time compensation scheme, a compensation unit menu 90 for setting a time unit of a number set in the compensation amount menu 80 should be provided. Compensation units for time are milliseconds (msec), seconds (sec), and minutes (min).

The compensation direction setting menu 50 of the etching amount is a menu for setting whether to compensate the compensation amount, that is, the compensation time or the compensation rate in the direction of increasing or decreasing the standard etching time. For example, when the 'decrease' button is selected, the standard etching time is reduced by the compensation amount set in the compensation amount menu 80.

Meanwhile, in addition to the above menu, various other menus are further provided on the input screen.

The first is a menu 20 for determining whether to apply the etching amount compensation function. This menu is provided with selection buttons (normal on, normal off, manual on, manual off) for setting whether to apply the process during normal process execution or in a manual manner.

The etching facility may be equipped with one or more chambers. In preparation of the etching apparatus having a plurality of chambers, a menu 30 for setting a chamber to which the etching amount compensation function is applied is provided.

The etching process goes through several process steps. Depending on the installation, the number of process steps may vary. In some cases, etch compensation does not always need to be applied to all process steps. In view of this, a menu 60 for setting which process step to apply the etching amount compensation function is provided. The figure shows five step buttons, but you can add more.

Meanwhile, the process equipment is periodically cleaned for maintenance, and after cleaning, the menu 100 for selecting whether to initialize all previously set values in the various menus above or use the existing set values is also provided. do. In addition, a menu 110 is provided to select whether to initialize all previously set values in the various menus above or to use the existing set values even when the chamber is opened or at ATM.

The input screen having the above function is programmed to be provided in the control system of the etching facility. The input screen for setting the conditions for the compensation of the process amount can be extended to deposition equipment or wet stripper ashing equipment.

4 is a flowchart illustrating a process of applying a concept of the present invention. In FIG. 4, when the compensation condition for the process amount set in the input screen of FIG. 3 is determined, the computer system reads the set value through the input screen and uses the reference data to control the operation of the process equipment. That is, the set compensation condition is reflected in the existing process condition to configure the current process condition 120. Based on this current process condition 120, the computer system controls the operation of the process equipment, in particular the process conditions of the chamber and its operation. In this environment, when the wafer for the etching process is prepared and the etching process is performed, a process in which the compensation amount is reflected may be performed.

In process quantities such as etching amount and deposition amount, the process characteristics of the chamber change depending on the process progress time of the process equipment or the number of wafers processed. Despite this characteristic change, the present invention can perform a uniform process by providing a compensation condition setting screen that can compensate a process amount (eg, etching amount) corresponding to the change amount in a computer system controlling the process equipment. Provide the necessary requirements. In particular, this function can be applied to the process equipment used to manufacture high-density semiconductor devices, thereby reducing the problem of poor quality due to process dispersion, thereby contributing to cost reduction and competitiveness.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below. I can understand that you can.

Claims (3)

An etching amount compensation control system for controlling a process of an etching facility for manufacturing a semiconductor device, A menu for setting a compensation criterion, such as the use time of an etching chamber or the number of wafers undergoing an etching process, and an etching compensation method and an etching compensation amount to be applied by the etching facility according to the compensation criteria set when the etching process is performed. Etching amount compensation control system characterized in that it has a function of displaying an input screen having a menu for, and reading the data set through the display screen. The method of claim 1, wherein the etching compensation method is any one of a method of compensating by increasing or decreasing an etching process time with respect to a standard etching process time or a method of compensating by applying a% rate with respect to the standard etching process time. Etching amount compensation control system. The etching screen according to claim 1 or 2, wherein the input screen includes a menu for selecting a chamber to which the etching amount compensation is applied, a menu for selecting whether to compensate the etching amount toward an increase or decrease, and an etching to which the etching amount compensation is applied. And a menu for selecting a step of the process and a menu for setting reset conditions of the set values relating to the etching amount compensation.