JPH01196126A - Dry etching device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a dry etching apparatus used, for example, in a semiconductor manufacturing process, and more specifically, to a dry etching apparatus that accurately determines the end point of etching and achieves a planned design value. This invention relates to a dry etching device that can finish etching at a certain depth.

[Prior Art] Conventionally, dry etching apparatuses used in semiconductor manufacturing processes have been proposed that are configured to control the depth of etching, that is, to determine the end point of etching using laser beam interferometry. There is. This device uses laser beam interferometry to determine the film thickness of the sample.
The purpose is to estimate the end point of etching by measuring the etching speed from the time change.

[Problems to be Solved by the Invention] However, in a dry etching apparatus that employs such a laser beam interferometry method, the sample being etched must be irradiated with a laser beam from outside the reaction chamber. There was a problem in that there were restrictions on the location.

In view of these points, the present invention provides a dry etching apparatus that does not impose restrictions on the position of the sample, accurately determines the end point of etching, and can finish etching at a depth that is in accordance with the planned design value. The purpose is to provide.

[Means for Solving the Problems] As shown in FIGS. 1 and 2 of the embodiment drawings, the try etching apparatus according to the present invention includes impurity monitoring means 1 for determining the etching end point and etching end control means 2. It is equipped with and configured.

Here, the etching end point determination impurity monitoring means 1 monitors the removal from the etching end point determination impurity, which has been injected into the etched portion of the workpiece 3 in advance, from the workpiece 3;
When the etching end point determining impurity is no longer detected, the etching end point determining impurity non-detection signal φN is supplied to the etching end control means 2.

Further, the etching end control means 2 is configured to control the progress of etching and to end the progress of etching when it is supplied with an impurity non-detection signal φN for determining the etching end point from the impurity monitoring means for determining the etching end point. Ru.

[Operation] When using the dry etching apparatus according to the present invention, an impurity for determining the etching end point is injected into the etched portion 22 of the workpiece 3 in advance. That is, the impurity for determining the etching end point is implanted to the depth where etching is planned. This can be easily done by using certain ion implanters.

When etching is performed in this manner, the impurity for determining the etching end point, which has been injected in advance into the etched portion of the workpiece 3, is etched together with the etching portion of the workpiece 3. It is detached from the workpiece 3. Here, the etching end point determination impurity monitoring means] indicates that the etching end point determination impurity is the workpiece 3.
While the etching is being removed from the workpiece 3, the force plate etching detecting the impurity for determining the etching end point advances to the bottom of the etched part, that is, to the planned depth, and the etching end point is determined to be removed from the workpiece 3. When the impurities for etching end point are no longer present, the impurities for determining the etching end point are no longer detected. At this time, this etching end point determination impurity monitoring means]
An impurity non-detection signal φr4 for determining the etching end point is supplied to the etching end control means 1, and the etching end control means 1 receives the impurity non-detection signal φr4 for determining the etching end point.
, is supplied, the etching process is terminated in response to the impurity non-detection signal φ for determining the etching end point. Therefore, the etching is completed at the originally planned depth.

[Example] First, referring to FIG. 1, an example of a dry etching apparatus according to the present invention will be described in which the present invention is applied to a parallel plate type reactive sputter etching apparatus used in a semiconductor manufacturing process. Let's explain using an example.

In this FIG. 1, 4 indicates a reaction chamber, and this reaction chamber 4
is formed into a hollow cylindrical body, and an upper electrode 5 and a lower electrode 6 formed in a disk shape are provided at the upper and lower parts of the chamber, respectively, and the workpiece is placed on the lower electrode 6. A certain silicon substrate 3 is placed. Here, the upper electrode 5 is connected to a scum conduit 7 at its center, and a gas inlet 8 for introducing etching scum into the reaction chamber 4 is provided at the center. Moreover, this upper electrode 5
is grounded via a gas conduit 7.

On the other hand, the lower electrode 6 is connected via a capacitor 9 to, for example, 1
High frequency power supply 10 that outputs high frequency power of 3.56MH2
is connected to the output terminal of That is, in this embodiment, the upper electrode 5 and the lower electrode 6 are configured as an anode and a cathode, respectively. Further, the high frequency power source 10 is configured to be turned on and off by the etching end control means 2. Further, a waste discharge port 11 is provided at the center of the bottom surface of the reaction chamber 4, and this waste discharge port 11
A gas exhaust pipe 12 is connected to the gas exhaust pipe 12.

In addition, a quartz glass engaging hole 1 is provided in the side wall portion of the reaction chamber 4.
4 is provided, and a quartz glass 15 is engaged with this quartz glass engagement hole 14. One end of a glass fiber 16 is connected to the outer surface of the quartz glass 15, and the other end of the glass fiber 16 is connected to the far side of the spectrometer 17.

Here, the quartz glass 15, the glass fiber 16, and the spectroscope 17 constitute an impurity monitoring means 1 for determining the end point of etching. It is designed to supply This spectrometer 17 monitors and determines whether or not the light supplied via the glass fiber 16 contains light emitted from impurities for determining the etching endpoint that have been injected into the etched portion of the silicon substrate 3 in advance. When the etching end point determining impurity is no longer detected, the etching end point determining impurity non-detection signal φ is supplied to the etching end control means 2.

Furthermore, when the etching end point determination impurity non-detection signal φN is supplied from the spectroscope 17, the etching end control means 2 controls the high frequency power supply 10 in response to the etching end point determination impurity non-detection signal φ. , the gas system device 18 and the drive system device 19, respectively, and supply the high frequency power supply 10, the waste system device 18, and the drive system device 1 with drive stop signals.
The etching is completed by stopping the driving of the etching device 9.

For example, by using the dry etching apparatus of the example shown in FIG.
Silicon substrate 3, such as forming isolation grooves, etc.
Therefore, when etching is to be carried out, after forming an etching resist with a required pattern on the silicon substrate 3, impurities (for example, B, P) for determining the etching end point are added to the portion of the silicon substrate 3 to be etched in advance. The ions are implanted using a predetermined ion implantation device. That is, the impurity for determining the etching end point is implanted to the desired depth of the surface to be etched.

Thereafter, this silicon substrate 3 is placed on the lower mold fi 6, the inside of the reaction chamber 4 is reduced to a predetermined pressure, the high frequency power source 10 is turned on, high frequency power is supplied to the lower electrode 6, and the gas conduit 7 Etching is started by supplying a predetermined etching gas, for example, CF4, from the gas inlet 8 through the gas inlet 8. In this way, the etching gas C
F4 dissociates in the plasma and generates active radicals F8 as well as ions such as F+ and CF3+, and chemical reactions due to active radicals F3 and F+ ions and CF3
Collision of positive ions and the like against the substrate occurs, and etching of the portion of the silicon substrate 3 to be etched progresses. Along with this etching, impurities for determining the etching end point are also etched, detached from the silicon substrate 3, floated in the reaction chamber 4, and are exhausted together with other exhaust gases.

In this case, the impurity for determining the etching end point emits light due to heat generated by etching, for example, heat generated by collision with F+ ions, CF3+4 ions, etc., and emits light having a specific spectrum.

Here, the spectroscope 17 monitors whether the light supplied via the glass fiber 16 contains light emission due to etching end point determination impurities injected in advance into the portion of the silicon substrate 3 to be etched. While the planned etching target area is being etched, the removal of impurities from the silicon substrate 3 for determining the etching end point is detected by the emitted light. When the etching progresses to a depth of , the impurity for determining the etching end point disappears. Luminescence due to determination impurities is no longer detected. Therefore, at this point, the spectrometer 17 supplies the etching end point determination impurity non-detection signal φN to the etching end control means 2, and the etching end control means 2 supplies the etching end point determination impurity non-detection signal φ. In response to the impurity non-detection signal φN for determining the etching end point, drive stop signals are supplied to the high frequency power source 10, the gas system device 18, and the drive system device 19, respectively. Device 18 and drive system device 1
The two drives are stopped to complete the etching process.

Therefore, according to the example in FIG. 1, etching is completed at the originally planned depth.

In this way, according to the example in FIG. 1, impurities for determining the etching end point (e.g., ρ) are implanted in advance into the etched portion of the silicon substrate 3, which is the workpiece, and then etching is performed. In this case, the etching is configured so that the etching ends when the etching end point determination impurity desorbed from the silicon substrate 3 disappears, that is, when the etching progresses to the planned depth. Therefore, unlike in the case of laser beam interferometry, there is no restriction on the position of the silicon substrate 3, and the etching end point can be determined with high precision, and the etching can be completed at the depth as planned.

Next, referring to FIG. 2, another embodiment of the present invention will be described.

In the example shown in FIG. 2, desorption of impurities for determining the etching end point from the silicon substrate 3 is monitored by measuring whether or not the impurities for determining the etching end point are contained in the exhaust gas flowing through the waste discharge path 12. Etching is terminated when the exhaust gas no longer contains impurities for determining the end point of etching. That is, in the example shown in FIG. 2, a sample exhaust gas extraction pipe 20 is connected to the gas exhaust pipe 12, and a part of the exhaust gas is sent as a sample to the gas analyzer 21 via the sample exhaust gas extraction pipe 20. This gas analyzer 21 constantly measures the presence or absence of impurities for determining the etching end point, and when the impurities for determining the etching end point are no longer detected, the impurities for determining the etching end point are detected as in the case of the spectrometer 17. The detection signal φN is supplied from the gas analyzer 21 to the etching termination control means 2, and the other features are the same as in the example shown in FIG. That is, in the example shown in FIG. 2, the sample exhaust gas extraction tube 20 and the gas analyzer 21 constitute the impurity monitoring means 1 for determining the end point of etching. In the example shown in FIG. 2 as well, the same effects as in the example shown in FIG. 1 can be obtained.

In the above embodiment, the impurity monitoring means 1 for determining the etching end point constituted by the spectroscope 17 and the impurity monitoring means 1 for determining the etching end point constituted by the gas analyzer 21 are provided separately. Although the above description has been made regarding the case in which these devices are provided, they may also be provided together.

Furthermore, in the above embodiments, the case where the present invention is applied to a reactive sputter etching apparatus has been described, but the present invention can be applied to various other dry etching apparatuses such as a plasma etching apparatus.

[Effects of the Invention] According to the present invention, when etching end point determination impurities are injected into the etched portion of the workpiece in advance and etching is performed thereafter, the etching impurity that is detached from the workpiece is Etching is configured to end when impurities for end point determination are gone, that is, when etching has progressed to a predetermined depth, so there are no constraints on the sample position as in the case of laser beam interferometry. An excellent effect can be obtained in that the end point of etching can be determined with high precision without causing any problems, and the etching can be completed at the depth according to the planned design value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a block diagram showing another embodiment of the present invention. 1... Impurity monitoring means for determining the end point of etching 2...
Etching end control means 3...Silicon substrate 4...Reaction chamber 5...
Upper electrode 6... Lower electrode 8... Gas inlet 10... High frequency power supply 11... Gas exhaust port 15... Quartz glass 16... Glass fiber 17... Spectrometer 20... Exhaust for sample Waste extraction tube 21...gas analyzer

Claims (1)

[Scope of Claims] A dry etching apparatus in which a workpiece is disposed in a reaction chamber and etching process is performed on the workpiece using an etching gas, in which a portion of the workpiece to be etched is injected in advance. The etching end point monitors the desorption of the etching end point determining impurities from the workpiece and outputs an etching end point determining impurity non-detection signal when the etching end point determining impurities are no longer detected. A dry etching apparatus comprising: impurity monitoring means for determination; and etching termination control means configured to terminate the progress of etching in response to the impurity non-detection signal for determining etching end point.