KR100478503B1 - Method for forming the end of point detection in semiconductor device - Google Patents

Abstract

The present invention relates to an etching end point control device and an etching end point control method using the same, and in particular, the DC bias of the etching target layer to monitor the etching device applied to the dry etching process using the plasma to monitor the change in the preset etching target layer By detecting the etching end point in comparison with the value, it is possible to detect the etching state of the front surface of the wafer without the need for additional equipment to detect the etching end point, thereby improving the characteristics and reliability of the semiconductor device. Get

Description

Etching end point control device and etching end point control method using the same {Method for forming the end of point detection in semiconductor device}

The present invention relates to an etching method of a semiconductor device, and more particularly, to an etching end point control device applied to an etching step using a plasma and an etching end point control method using the same.

In general, a dry etch technique in a semiconductor manufacturing process includes a main etch process for an etch target layer 12 formed on a sublayer 11 as shown in FIG. 1. and an overetch step 15 applied from the end of point detection (EPD). The stock etch process 14 and the transient etch process 15 are divided on the basis of an etch end point (EPD), where reference numeral 13 shows a photoresist pattern used as an etch mask.

In order to control the etching end point (EPD) as described above, a simple optical plasma analysis method, an RF impedance analysis method, a time determination method and the like are conventionally used.

Hereinafter, the problem appearing when the etching end point is determined using the etching end point control method of the semiconductor according to the related art will be described in more detail.

FIG. 2 is a block diagram illustrating an apparatus for controlling an etching end point using a simple optical plasma analysis method of the prior art, and FIG. 3 is a block diagram illustrating an apparatus for controlling an etching end point using an RF impedance analysis method as another example of the prior art.

First, as shown in FIG. 2, the single optic plasma analyzer is a quantitative analysis of signal changes before and after the etch endpoint (EPD) using an optical analysis technique for a specific etch reactant in the plasma. A plasma etching apparatus (16) for mounting a wafer subjected to a unit device process and applying a source power and a radio frequency bias power to etch the wafer with plasma of a process gas ), A single optical probe 17 for detecting the spectrum of the plasma, and a main controller for analyzing and storing the etching end point 18 by analyzing the spectrum generated from the optical probe 17. controller) 19. Since the intensity of the signal monitored by the optical analysis technique using the one optical probe 17 is proportional to the area of the etched section, the signal intensity and the etch end point are relatively weak in the highly integrated device manufacturing process. Small signal changes before and after EPD) limit the application of the process, and quantitative analysis prevents active response to signal changes by wafer or lot.

On the other hand, as shown in Figure 3, another etching end point control apparatus of the prior art is the impedance of the plasma chamber for the etching progress in the RF impedance (RF Impedance) analysis method using the impedance sensor 20 for impedance (Impedance) detection It is a method of determining the etch end point (EPD) using the change. However, the impedance method is also similar to the simple optical plasma analysis method shown in FIG. 2, and thus the intensity of the detection signal is proportional to the area of the etched cross section, and the electrical amount is used to further change the noise characteristic according to the equipment state. It is sensitive and it is impossible to detect the exact etching end point.

Although not shown in the drawing, the time determination method is a method of determining an expected etch end point using a measured etch rate, and the micro / macro loading effect in which the etch rate is changed by a difference in pattern size and area of an etch target. It is impossible to reflect variables such as (micro / macro loading effect), so the accuracy of the etching end point for the cell region is reduced. In addition, there is a problem in that delicate process conditions must be applied in order to secure stability because it is impossible to cope with minute changes in deposition conditions before etching and changes in the state of the etching apparatus that may occur during the semiconductor manufacturing process.

That is, when the etching end point control methods of the prior art are used as described above, it is difficult to accurately control the etching end point during etching or contact etching for forming a pattern of a semiconductor device.

The present invention is to solve the problems of the prior art as described above, an object of the present invention is to accurately detect the etching state by detecting the etching state of the front surface of the wafer without having a separate device in the etching apparatus using a general plasma An etch end point control apparatus that can be detected and an etch end point control method using the same are provided.

In order to achieve the above object, the present invention compares a monitor for detecting a change in the DC bias value applied to the plasma etching apparatus, a change in the DC bias value detected by the monitor and a change curve of a predetermined DC bias value. A comparison detector for detecting an etching end point, and when the comparison detector detects an etching end point, and provides an etching end control device comprising a controller for controlling the plasma etching device to terminate the etching.

In addition, the present invention comprises the steps of setting a change curve of the DC bias value for the etching target layer, detecting the DC bias value applied to the plasma etching apparatus while plasma etching the semiconductor substrate on which the etching target layer is formed using a plasma etching apparatus And detecting the etching end point by comparing the detected change of the DC bias value with a change curve of the preset DC bias value, and controlling the plasma etching apparatus to stop the etching when the etching end point is detected. Provide an endpoint control method.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

4 is a block diagram illustrating an apparatus for controlling an etch end point using a change state of a DC bias value according to an exemplary embodiment of the present invention.

As shown in FIG. 4, the etching end point control apparatus according to an embodiment of the present invention includes a monitor 200 for monitoring and detecting a DC bias value applied to the plasma etching apparatus 100, and the DC bias value input from the monitor. When the change is compared to a preset change curve of the DC bias value and the shape of the etch endpoint (EPD Shape) is displayed, when the comparison detector 300 and the comparison detector 300 detect as the etch endpoint, the plasma etch device is detected. It consists of a controller 400 for controlling the 100 to terminate the etching.

Here, the plasma etching apparatus 100 induces a plasma state of a process gas injected by receiving source power and RF bias power and using the same to generate a semiconductor device. Etching device. Here, the plasma etching apparatus 100 includes a wafer chuck 41 for supporting the target wafer 42 for dry etching. The monitor 200 of the etching end point control apparatus according to the embodiment of the present invention is RF. It is connected between the bias power and the wafer chuck 41.

Next, a method of controlling an etching process using the etching endpoint control apparatus according to an exemplary embodiment of the present invention will be described with reference to FIGS. 5A, 5B, and 6.

5A and 5B are views illustrating a case where an etch end control apparatus using a change state of a DC bias value according to an embodiment of the present invention is applied to a pattern consisting of a metal layer and an insulating layer, and FIGS. 6A and 5B. Is a diagram showing a change in DC bias value for a pattern consisting of a metal layer and an insulating layer.

First, the metal layer 60 is etched and wired in a structure in which an insulating layer 50 made of an oxide, which is a lower layer, and a metal layer 60 made of aluminum (Al) are sequentially stacked on the wafer (not shown). Consider the process of forming it.

As shown in FIG. 5A, a photoresist film is applied on the metal layer 60 and a photolithography process is performed to form a photoresist pattern 70 defining a metal wiring formation region.

Subsequently, as illustrated in FIG. 5B, the metal layer 60 is etched using the photoresist pattern 70 as an etching mask to form the metal wiring 62. In this case, the etching process of etching the metal layer 60 is controlled by a stock etching process in which an etching end point (EOP) of the metal layer 60, which is an etching target layer, is determined, and a transient etching process for the lower insulating layer 50.

Here, the etching process for forming the metal wiring will be described in more detail.

First, a DC bias curve which appears when etching the metal layer 60 as an etch target layer and the insulating layer 50 as a lower layer thereof is set in advance, and the wafer 42 on which the metal layer 60 and the insulating layer 50 are formed is plasma-etched. Etching of the metal layer 60 is started by attaching to (100).

In the process of etching the metal layer 60, the monitor 200 mounted on the plasma etching apparatus 100 monitors the value of the DC bias that varies according to its thickness and material.

The monitor 200 transmits the change of the DC bias value to the comparison detector 300, and the compare detector 300 compares the change curve of the preset DC bias value with the change of the DC bias value input from the monitor 200. When the change form of the DC bias value set to the etching end point (EOP) appears, the controller 400 notifies that the etching end point is detected. Accordingly, the controller 400 controls the plasma etching apparatus 100 to terminate the etching.

6 shows an abrupt change in the DC bias value when etching proceeds to reach the interlayer boundary as an example of the DC bias curve. When the appropriate point is set as the etching end point by using the abrupt change point of the DC bias value as a mark, it is slightly over-etched, that is, as shown in FIG. 5B, all of the metal layers 60 are etched and the upper portion of the insulating film 50 below The etching may be terminated in some etched states.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

According to the present invention, the etching end point is determined by comparing the change of the DC bias value monitored in the general plasma etching apparatus with the predetermined DC bias value for the etching target layer, so that the etching end point can be detected without the provision of another device. As a result, the cost of the manufacturing process can be reduced and the uniform etching end point can be detected, thereby improving the reliability of the semiconductor device to be manufactured.

1 is a cross-sectional view illustrating a progress state of a dry etching process of a general semiconductor device;

2 is a block diagram showing an etching end point control apparatus using a simple optical plasma analysis method of the prior art,

3 is a block diagram showing an etching end point control device using an RF impedance analysis method as another example of the prior art;

4 is a block diagram illustrating an etching end point control apparatus using a change state of a DC bias value according to an embodiment of the present invention;

5A to 5B are views illustrating a case where an etch end control apparatus using a change state of a DC bias value according to an embodiment of the present invention is applied to a pattern consisting of a metal layer and an insulating layer;

FIG. 6 is a view illustrating a change in the DC bias value for the pattern formed of the metal layer and the insulating layer of FIG. 5B.

  -Explanation of symbols for the main parts of the drawing-

100: plasma etching apparatus 200: monitor

300: comparison detector 400: controller

Claims (4)

A monitor for detecting a change in the DC bias value applied to the plasma etching apparatus; A comparison detector for detecting an etching end point by comparing the change of the DC bias value detected by the monitor with a change curve of a predetermined DC bias value; A controller for controlling the plasma etching apparatus to terminate the etching when the comparison detector detects an etching end point Etching end point control device comprising a. In claim 1, The comparison detector stores a change curve of the DC bias value of the layer to be etched and a change curve of the DC bias value indicating the etch end point, and compares it with the DC bias value input from the monitor to change the DC bias value indicating the etch end point. Etch end control device that detects the end of the etching when the shape of the curve appears. Setting a change curve of the DC bias value for the etching target layer; Detecting a DC bias value applied to the plasma etching apparatus while plasma etching the semiconductor substrate on which the etching target layer is formed using the plasma etching apparatus; Detecting an etching end point by comparing the detected change of the DC bias value with a change curve of a predetermined DC bias value; Stopping the etching by controlling the plasma etching apparatus when an etching end point is detected; Etch endpoint control method comprising a. The method of claim 3, wherein the detecting of the etching end point is performed by comparing the detected change of the DC bias value with a change curve of a predetermined DC bias value. The change curve of the DC bias value representing the etch end point is stored by storing the change curve of the DC bias value of the etch target layer and the change curve of the DC bias value indicating the etch end point and comparing it with the DC bias value input from the monitor. Etch endpoint control method, which is a process of detecting as an etch endpoint when it appears.