KR20080074299A - Substrate etching method - Google Patents

Abstract

A substrate etching method is provided to guarantee etching uniformity by enabling an etch process according to a modified state of etchant even in the case of an evaporation phenomenon of etchant. A first etch process is performed on a substrate during a first time interval. A second etch process is performed on the substrate during a second time interval corresponding to a first percentage of the first time interval(S300). A third etch process is performed on the substrate during a third time interval corresponding to a second percentage of the second time interval(S400). The first etch process can include first and second processes(S100,S200) wherein the first process is performed on the substrate for a predetermined time interval and the second process is performed on the substrate by an EPD(end point detection) method.

Description

Substrate Etching Method {SUBSTRATE ETCHING METHOD}

1 is a flow chart illustrating a substrate etching method in accordance with an embodiment of the present invention.

2A is a block diagram showing a substrate etching apparatus in which an etching process is performed in the substrate etching method according to the embodiment of the present invention.

Figure 2b is a table showing the etching time according to the etching process in the substrate etching method according to an embodiment of the present invention.

3A is a block diagram illustrating a substrate etching apparatus in which an etching process is performed in a substrate etching method according to another embodiment of the present invention.

Figure 3b is a table showing the etching time according to the etching process in the substrate etching method according to another embodiment of the present invention.

The present invention relates to a method for manufacturing a semiconductor, and more particularly, to a method of etching a substrate in a wet manner.

In general, an etching process is almost essential for processing a substrate such as a silicon wafer used as a substrate of a semiconductor memory device or a glass substrate used as a substrate of a liquid crystal display device. An etching gas is required to proceed the etching process in a dry manner, and an etchant is required to proceed the etching process for the substrate in a wet manner.

In particular, in the wet etching process using the etchant, the quality of the etchant, such as vaporization, may change over time. The change of the quality of the etchant causes the condition of the etching process to change, and failure to deal with it actively causes the defect of the etching process. In addition, the change in the quality of the etchant becomes one of the major factors inducing complexity in terms of management of the etching process.

The present invention has been made to solve the above-mentioned problems in the prior art, an object of the present invention to provide a substrate etching method that can eliminate or minimize the defect of the etching process.

The substrate etching method according to the present invention for achieving the above object is characterized by ensuring the uniformity of the etching process by changing the conditions of the etching process according to the state of the etchant.

A substrate etching method according to an embodiment of the present invention, which can implement the above features, includes: performing a first etching process on a substrate for a first time; Subjecting the substrate to a second etching process for a second time corresponding to a first percentage of the first time; And subjecting the substrate to a third etching process for a third time corresponding to a second percentage of the second time.

In an embodiment of the present invention, the second percentage varies as the number of processed sheets of the substrate varies. The second percentage increases as the number of processed sheets of the substrate accumulates.

In an embodiment of the present invention, the first etching process includes a first process of etching the substrate for a predetermined time and a second process of etching the substrate in an endpoint detection manner. The first time is the sum of the time spent in the first process and the time spent in the second process.

In an embodiment of the invention, the third etch proceeds in one etching bath or in a plurality of etching baths. The third etching proceeding in the plurality of etching baths has a uniform etching time in each of the plurality of etching baths.

In an embodiment of the present invention, the first etching process is a time etching process depending on the etching time, the second etching process is an endpoint detection (EPD) etching process that proceeds in an endpoint detection method, and the third etching process Is an over etching process.

In an embodiment of the present invention, the first to third etching processes are wet etching processes using etchant.

A substrate etching method according to a modified embodiment of the present invention that can implement the above features, the first etching for a first time with respect to the substrate, the second etching for the second time in the endpoint detection method for the substrate, the substrate For a third time corresponding to a time of a first percentage of the sum of the first and second times for a third time, for a fourth time corresponding to a second percentage of the third time for the substrate, and The fourth etching is performed by increasing the second percentage as the number of processed sheets of the substrate is accumulated.

In this modified embodiment, the first to fourth etchings are wet etching. The third etching is performed by dividing in a plurality of etching baths. In the third etching proceeding by dividing in the plurality of etching baths, the etching time in each of the plurality of etching baths is uniform.

According to the present invention, it is possible to actively cope with the change in the etching conditions in accordance with the trend of the concentration or viscosity change of the etchant according to the etching conditions such as temperature and time during the etching process on the substrate. Therefore, even if vaporization of the etchant occurs, the etching process may be performed according to the changed state of the etchant, thereby ensuring uniformity of etching and further reducing defects in the etching process.

Hereinafter, a substrate etching method according to the present invention will be described in detail with reference to the accompanying drawings.

Advantages over the present invention and prior art will become apparent through the description and claims with reference to the accompanying drawings. In particular, the present invention is well pointed out and claimed in the claims. However, the present invention may be best understood by reference to the following detailed description in conjunction with the accompanying drawings. Like reference numerals in the drawings denote like elements throughout the various drawings.

(Example)

1 is a flowchart illustrating a substrate etching method according to an embodiment of the present invention.

Referring to FIG. 1, in the substrate etching method according to an embodiment of the present invention, time etching is performed for etching for a predetermined time (S100), and EPD etching is performed for etching for a predetermined time in an endpoint detection method. (EPD Etching) is performed (S200). Thereafter, if necessary, over etching for a predetermined time (Over Etching) is performed to etch the thin film deposited on the substrate to the intended thickness (S300). Alternatively, the over etching process S300 may be performed in one etching bath or may be performed in a so-called even etching process in which several etching baths are performed but the etching time in each etching bath is uniform. . It may be desirable to uniformly set the etching time in each etching bath at the time of uniform etching in terms of maintaining the quality of the etchant in each etching bath uniformly.

The substrate here is, for example, a substrate such as a glass substrate of a liquid crystal display device or a plasma display device, or a silicon wafer of a semiconductor memory element. In addition, the etching process here is a wet etching process using an etchant, for example.

When the above etching processes are performed on a plurality of substrates, the etchant vaporizes, and thus the quality of the etchant such as the concentration or viscosity of the etchant may be lower than the initial value. As the etchant, which has been lowered due to vaporization, is continuously used in the etching process, the etching thickness of the thin film may be less than the intended thickness. Therefore, when the etching process is performed on a plurality of substrates of a predetermined amount and then another etching process of the substrates is performed, additional etching (for example, additional etching on the substrates) is performed for a predetermined time after the over etching process (S300). Additional Etching) process is further performed (S400). In this case, the concentration of the etchant decreases as the number of processed substrates accumulates, thereby increasing an offset time, which is a time required for additional etching. In other words, the lower the quality of the etchant (eg concentration, viscosity, etc.), the longer the etching process.

For example, when the number of processed sheets of the substrate is accumulated in units of 100 sheets, the offset time may be set as shown in Table 1 below. The offset time varies depending on the number of processed sheets of the substrate, and the quality of the etchant decreases as the number of processed sheets of the substrate is accumulated, so that the offset time of the etchant is set to increase as the number of processed sheets of the substrate is accumulated.

The number of substrates Offset time (%) 1 to 100 101-200 10 201 to 300 20 301-400 25 401-500 30 501-600 35 601-700 40 701-800 45 801 to 900 50 901 to 1000 55

As can be seen from Table 1, when the number of substrates is more than 100 sheets and the etching process is to be performed on the next 100 sheets, that is, 101 to 200 sheets after the etching process is performed on 100 substrates. In the etching process for substrates up to 10% of the offset time, that is, about 10% of the over etching time, the further etching process is further performed. Similarly, in the etching process for the substrates from the 201st sheet to the 300th sheet, the additional etching process is further performed for an offset time of 20%, that is, about 20% of the over etching time. The substrate etching method when the offset time is 20% and 30% is described below.

2A is a substrate etching apparatus in which an etching process is performed in a substrate etching method according to an embodiment of the present invention, and FIG. 2B is a table showing an etching time according to an etching process in a substrate etching method according to an embodiment of the present invention. .

Referring to FIG. 2A, a substrate etching apparatus 10 in which a substrate etching method of the present embodiment is performed includes a first etching bath 100 in which a time etching process is performed on a substrate 12, and a process in which an EPD etching process is performed. It comprises a 2 etching bath 200 and the 3rd etching bath 300 which overetch and addition etching progress. The substrate 12 is sequentially introduced into the first to third etching baths 100-300, and then proceeds in the order of time etching, EPD etching, over etching, and additional etching processes. The over etching proceeds for a time corresponding to a constant percentage of the time etching time and the EPD etching time, and the additional etching proceeds for a time corresponding to a constant percentage of the over etching time (hereinafter, offset time).

As an example, the over etching time is set to about 30%, and the offset time of the additional etching is 20%, that is, the time of each etching process assuming that the etching process is performed on the substrates from the 201st sheet to the 300th sheet in Table 1 above. Is shown in the table shown in Figure 2b.

Referring to FIG. 2B as shown in FIG. 2A, the time etching process in the first etching bath 100 is performed for about 20 seconds, and the EPD etching process in the second etching bath 200 is about 16 seconds. Proceed. The over etching process in the third etching bath 300 is about 30%, that is, 10.8 seconds, which is 30% of the sum of the time of the time etching process (20 seconds) and the time of the EPD etching process (16 seconds) (36 seconds). Proceed. The additional etching process then proceeds for 2.16 seconds, which is 20% of the time of the over etching process (10.8 seconds). The above series of etching processes proceed for 48.96 seconds. As described above, the correction process is performed for about 2.16 seconds as a correction due to vaporization of the etchant to compensate for the lack of etching treatment due to the deterioration of the etchant.

3A is a substrate etching apparatus in which an etching process is performed in a substrate etching method according to another embodiment of the present invention, and FIG. 2B illustrates an etching time according to an etching process in a substrate etching method according to another embodiment of the present invention. Table.

Referring to FIG. 3A, as in the above example, the substrate etching apparatus 10 may include a first etching bath 100 in which a time etching process is performed, a second etching bath 200 in which an EPD etching process is performed, and an over etching process. And a third etching bath 300 in which additional etching is performed. The substrate 12 is sequentially introduced into the first to third etching baths 100-300, and then proceeds in the order of time etching, EPD etching, over etching, and additional etching processes. As in the previous example, the over etching proceeds for a time corresponding to a constant percentage of the time etching time and the EPD etching time, and the additional etching proceeds for a time corresponding to a constant percentage of the over etching time, that is, the offset time.

As an example, assuming that the over etching is set to about 30%, and the offset time of the additional etching is 30%, that is, the etching process for the substrates from the 401th sheet to the 500th sheet in Table 1 above is performed. It is shown in the table shown in FIG.

Referring to FIG. 3B as shown in FIG. 3A, the time etching process in the first etching bath 100 is performed for about 20 seconds and the EPD etching process in the second etching bath 200 is about 16 seconds. Proceed. The over etching process in the third etching bath 300 is about 30%, that is, 10.8 seconds, which is 30% of the sum of the time of the time etching process (20 seconds) and the time of the EPD etching process (16 seconds) (36 seconds). Proceed. The addition etch process then proceeds for 3.24 seconds, 30% of the time (10.8 seconds) of the over etch process. The above series of etching processes proceed for 50.04 seconds. In this way, the correction process for about 3.24 seconds as a correction due to the vaporization of the etchant compensates for the lack of etching treatment due to the deterioration of the etchant.

The foregoing detailed description is not intended to limit the invention to the disclosed embodiments, and may be used in various other combinations, modifications, and environments without departing from the spirit of the invention. The appended claims should be construed to include other embodiments.

As described in detail above, according to the present invention, it is possible to actively cope with the change in the etching conditions according to the change in the quality of the etchant according to the etching conditions such as the temperature or time during the etching process on the substrate. Accordingly, even if vaporization of the etchant occurs, the etching process may be performed according to the changed state of the etchant, thereby ensuring uniformity of etching, and furthermore, defects in the etching process may be reduced, thereby improving production yield. have.

Claims (13)

Performing a first etching process on the substrate for a first time; Subjecting the substrate to a second etching process for a second time corresponding to a first percentage of the first time; Subjecting the substrate to a third etching process for a third time corresponding to a second percentage of the second time; Substrate etching method comprising a. The method of claim 1, And the second percentage is varied as the number of processed sheets of the substrate is changed. The method of claim 2, And the second percentage is increased as the number of processed sheets of the substrate is accumulated. The method of claim 1, The first etching process, the substrate etching method comprising a first step of etching for a predetermined time with respect to the substrate, and a second process for etching the end point detection method for the substrate. The method of claim 4, wherein And said first time is a sum of a time required for said first step and a time required for said second step. The method of claim 1, And the third etching proceeds in one etching bath or in a plurality of etching baths. The method of claim 6, And the third etching proceeding in the plurality of etching baths has a uniform etching time in each of the plurality of etching baths. The method of claim 1, The first etching process is a time etching process depending on the etching time, the second etching process is an end point detection (EPD) etching process proceeds in an endpoint detection method, the third etching process is characterized in that the over etching process Substrate etching method. The method of claim 8, And the first to third etching processes are wet etching processes using an etchant. First etching the substrate for a first time, Second etching with respect to said substrate in an endpoint detection manner for a second time, Third etching against the substrate for a third time corresponding to a time of a first percentage of the sum of the first and second times, Performing a fourth etching on the substrate for a fourth time corresponding to a second percentage of the third time, and increasing the second percentage as the number of processed sheets of the substrate accumulates, A substrate etching method, characterized in that. The method of claim 10, And the first to fourth etchings are wet etching. The method of claim 10, And the third etching is performed by dividing in a plurality of etching baths. The method of claim 12, And the third etching divided by the plurality of etching baths has a uniform etching time in each of the plurality of etching baths.

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