TW202102822A - Spectrum detection equipment, End Point Detector, and method wherein the system includes a diffraction grating, an image sensor, and a baffle between the diffraction grating and the image sensor - Google Patents

Abstract

The invention provides a spectrum detection equipment, an End Point Detector, and a method. The system includes a diffraction grating, an image sensor, and a baffle between the diffraction grating and the image sensor. The baffle defines at least one slit. The diffraction grating is used to divide the incident light into multiple light components. The position of the slit corresponds to a position of one light component. The side of the slit facing the image sensor is arranged with an optical lens, which is used to expand the light component. The image sensor is used to collect the expanded light component to obtain a light intensity of a characteristic spectrum corresponding to the light component. Because the position of the slit corresponds to the position of the light component, and the side of the slit facing the image sensor has an optical lens, the beam of the light component can be expanded by the optical lens to expand the projection area of the light component on the image sensor. Accordingly, the image sensor can use more pixels to collect the light components to increase the signal-to-noise ratio of the image sensor at a lower cost. Therefore, the detection sensitivity of the End Point Detector can be improved.

Description

Spectral detection equipment, endpoint detection system and method

The invention relates to the field of semiconductor technology, and more specifically, to a spectrum detection equipment, an endpoint detection system and a method.

With the development of semiconductor manufacturing processes, people have higher and higher requirements for the integration and performance of components. Since the accuracy of etching is directly related to the feature size and performance of the components, people usually equip the etching process with an End Point Detector (EPD) to track the process progress and determine the etching end point.

In the conventional technology, the endpoint detection system mainly uses optical detection, drive motor current detection, temperature detection and other methods to perform endpoint detection. Among them, Optical Emission Spectroscopy (OES) is the most commonly used and most effective optical inspection method. It uses spectral inspection equipment to detect the spectrum generated by the etching of the etched object in real time. There will be obvious changes in the spectrum. Therefore, by continuously monitoring the spectrum, it can be determined whether the current etching material is completely etched, that is, whether the etching end point has been reached.

However, the signal-to-noise ratio of the conventional spectroscopic detection equipment is low, resulting in low detection sensitivity of the conventional endpoint detection system using the OES method, and does not use accurate detection of the etching endpoint.

In view of this, the present invention provides a spectrum detection device, an endpoint detection system and a method to improve the signal-to-noise ratio of the spectrum detection device.

In order to achieve the above objectives, the present invention provides the following technical solutions:

A spectrum detection device for performing spectrum detection on plasma, comprising a diffraction grating, an image sensor, and a baffle between the diffraction grating and the image sensor, the baffle having at least one slit ；

The diffraction grating is used to divide incident light into a plurality of light components arranged in sequence along a specific direction, and the light beam in each of the light components has a different wavelength;

The position of the slit corresponds to the position of one of the light components, the side of the slit facing the image sensor has an optical lens, and the optical lens is used to adjust the position corresponding to the slit Beam expansion of light components;

The image sensor is used to collect the light component after the beam expansion, so as to obtain the light intensity of the characteristic spectrum corresponding to the light component after the beam expansion.

Optionally, the baffle has a first slit; the plurality of light components includes a first light component;

The position of the first slit corresponds to the position of the first light component, the side of the first slit facing the image sensor has a first optical lens, and the first optical lens is used for Performing beam expansion on the first light component;

The image sensor is used to collect the expanded first light component to obtain the light intensity of the first characteristic spectrum corresponding to the first light component.

Optionally, the baffle has a second slit; the plurality of light components includes a second light component;

The position of the second slit corresponds to the position of the second light component, the side of the second slit facing the image sensor has a second optical lens, and the second optical lens is used for Performing beam expansion on the second light component;

The image sensor is used to collect the expanded second light component to obtain the light intensity of the second characteristic spectrum corresponding to the second light component.

Optionally, the baffle has a first slit and a second slit; the multiple light components include a first light component and a second light component;

The position of the first slit corresponds to the position of the first light component, the side of the first slit facing the image sensor has a first optical lens, and the first optical lens is used for Performing beam expansion on the first light component;

The position of the second slit corresponds to the position of the second light component, the side of the second slit facing the image sensor has a second optical lens, and the second optical lens is used for Performing beam expansion on the second light component;

The image sensor is used to collect the expanded first light component to obtain the light intensity of the first characteristic spectrum corresponding to the first light component, and collect the expanded second light component to obtain the The light intensity of the second characteristic spectrum corresponding to the second light component is determined based on the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum to determine whether the etching end point is reached.

Optionally, the baffle has a movable third slit; the plurality of light components include a first light component and a second light component;

The third slit includes a first position and a second position, the first position corresponds to the position of the first light component, and the second position corresponds to the position of the second light component;

The third slit has a third optical lens on the side facing the image sensor, and the third optical lens moves with the third slit for controlling the first light component and the Expand the second light component;

The image sensor is used to collect the expanded first light component to obtain the light intensity of the first characteristic spectrum corresponding to the first light component, and collect the expanded second light component to obtain the The light intensity of the second characteristic spectrum corresponding to the second light component is determined based on the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum to determine whether the etching end point is reached.

Optionally, it also includes a reflector;

The reflector is arranged around the projection of the light component on the image sensor, and the reflector extends between the baffle and the image sensor.

An endpoint detection system, including a first spectrum detection device, a second spectrum detection device, a spectroscopic element, and a processing element;

The spectroscopic element is used to divide the light generated when the etched object is etched into a first light and a second light, and make the first light enter the first spectrum detection device, and make the second light enter the In the second spectrum detection device, the etched object includes a first dielectric layer and a second dielectric layer sequentially arranged in an etching direction;

The first spectrum detection device is the spectrum detection device as described above; the first spectrum detection device is used to obtain the light intensity of a first characteristic spectrum according to the first light, and the first characteristic spectrum is the first The characteristic spectrum of a dielectric layer;

The second spectrum detection device is the spectrum detection device as described above; the second spectrum detection device is used to obtain the light intensity of a second characteristic spectrum according to the second light, and the second characteristic spectrum is the second medium Characteristic spectrum of the layer;

The processing element is used for judging whether the etching end point of the first dielectric layer is reached according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum.

Optionally, the light splitting ratio of the light splitting element is 1:1.

An endpoint detection method, applied to the endpoint detection system as described above, and the method includes:

The spectroscopic element divides the light generated by the etching of the object to be etched into a first light and a second light, and makes the first light enter the first spectrum detection device, and the second light enters the second spectrum detection device, so The etched object includes a first dielectric layer and a second dielectric layer sequentially arranged in an etching direction;

The first spectrum detection device obtains the light intensity of a first characteristic spectrum according to the first light, and the first characteristic spectrum is the characteristic spectrum of the first medium layer;

The second spectrum detection device obtains the light intensity of a second characteristic spectrum according to the second light, and the second characteristic spectrum is the characteristic spectrum of the second dielectric layer;

The processing element determines whether the etching end point of the first dielectric layer is reached according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum.

An endpoint detection system, including spectrum detection equipment and processing elements;

The spectrum detection device is the spectrum detection device as described above; the spectrum detection device is used to obtain the light intensity of the first characteristic spectrum and the light intensity of the second characteristic spectrum according to the light generated when the etched object is etched. The etched object includes a first dielectric layer and a second dielectric layer sequentially arranged in the etching direction, the first characteristic spectrum is a characteristic spectrum of the first dielectric layer, and the second characteristic spectrum is a characteristic of the second dielectric layer spectrum;

The processing element is used for judging whether the etching end point of the first dielectric layer is reached according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum.

An endpoint detection method, applied to the endpoint detection system as described above, and the method includes:

The spectrum detection device obtains the light intensity of the first characteristic spectrum and the light intensity of the second characteristic spectrum according to the light generated when the etched object is etched. The etched object includes a first medium layer and a second medium arranged in sequence in the etching direction. Layer, the first characteristic spectrum is the characteristic spectrum of the first dielectric layer, and the second characteristic spectrum is the characteristic spectrum of the second dielectric layer;

The processing element determines whether the etching end point of the first dielectric layer is reached according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum.

Optionally, when the baffle has a movable third slit, the spectrum detection device obtains the light intensity of the first characteristic spectrum and the light intensity of the second characteristic spectrum according to the light generated when the etched object is etched, including:

The diffraction grating divides the collected light generated when the etched object is etched into a plurality of light components arranged in sequence along a specific direction, and the light beam in each of the light components has a different wavelength, wherein the multiple light components include the first A light component and a second light component;

The third slit is located at the first position, the third optical lens expands the first light component, and the image sensor collects the expanded first light component to obtain the first light component corresponding to the first light component. The light intensity of the characteristic spectrum;

The third slit is located at the second position, the third optical lens expands the second light component, and the image sensor collects the expanded second light component to obtain the corresponding The light intensity of the second characteristic spectrum.

Compared with the conventional technology, the technical solution provided by the present invention has the following advantages:

In the spectrum detection equipment, endpoint detection system and method provided by the present invention, a baffle is arranged between the diffraction grating and the image sensor. The baffle has a slit. The position of the slit is different from the light component to be collected. The positions are corresponding, and the side of the slit facing the image sensor has an optical lens, which is used to expand the light component to enlarge the projection area of the light component on the image sensor, so that the image sensor The detector uses more pixels to collect light components, so that the signal-to-noise ratio of the image sensor can be improved at a lower cost, and the detection sensitivity of the endpoint detection system can be improved.

As in the background art, the signal-to-noise ratio of the conventional spectral detection equipment is low. As shown in Figure 1, a conventional spectrum detection device includes a diffraction grating 11 and an image sensor 12. As shown in Figure 2, the diffraction grating 11 is used to divide the light emitted by the etched object 10 into the Z direction. A plurality of light components arranged in sequence, each light component having its own specific wavelength. The image sensor 12 is used to collect two light components A and B of a plurality of light components, wherein one light component A includes the first characteristic spectrum of the first dielectric layer 101 being etched, and the other light component B includes The second characteristic spectrum of the second dielectric layer 102 at the bottom of the first dielectric layer 101. Since the light intensity of the first characteristic spectrum is greater when the first dielectric layer 101 is etched, and the light intensity of the second characteristic spectrum is greater when the second dielectric layer 102 is etched, the difference between these two characteristic spectra is By comparing the light intensity, it can be judged whether the first dielectric layer 101 being etched has reached the etching end point.

However, since the spectral widths of the first characteristic spectrum and the second characteristic spectrum are relatively narrow, about 20 nm, only 6% of the effective pixels in the image sensor 12 are used to collect the required light components A and B. The signals collected by the remaining pixels need to be removed as noise interference, so that the signal-to-noise ratio of the image sensor 12 is low, and the detection sensitivity of the endpoint detection system is low.

Based on this, the present invention provides a spectrum detection device to overcome the above-mentioned problems in the prior art, including a diffraction grating, an image sensor, and a baffle between the diffraction grating and the image sensor. The baffle has At least one slit;

The diffraction grating is used to divide the incident light into a plurality of light components arranged in sequence along a specific direction, and the light beam in each of the light components has a different wavelength;

The position of the slit corresponds to the position of a light component, the side of the slit facing the image sensor has an optical lens, and the optical lens is used to expand the beam of one light component;

The image sensor is used to collect a light component after beam expansion to obtain the light intensity of a characteristic spectrum corresponding to a light component.

In the spectrum detection equipment, endpoint detection system and method provided by the present invention, a baffle is arranged between the diffraction grating and the image sensor, the baffle has a slit, and the position of the slit is the same as the position of the light component to be collected Correspondingly, and the side of the slit facing the image sensor has an optical lens, which is used to expand the light component to expand the projection area of the light component on the image sensor, so that the image sensor The detector uses more pixels to collect light components, so that the signal-to-noise ratio of the image sensor can be improved at a lower cost, and the detection sensitivity of the endpoint detection system can be improved.

The above is the core idea of the present invention. In order to make the above objectives, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Description, obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person with ordinary knowledge in the technical field without making progressive work shall fall within the protection scope of the present invention.

The embodiment of the present invention provides a spectrum detection device, as shown in Figure 3, comprising a diffraction grating 31, an image sensor 32, and a baffle 33 located between the diffraction grating 31 and the image sensor 32. The board 33 has at least one slit 330. Of course, the spectrum detection device in the embodiment of the present invention also includes a reflector that changes the optical path, and other devices, which will not be repeated here.

Wherein, the diffraction grating 31 is used to divide the incident light emitted by the light source 30 into a plurality of light components sequentially arranged along a specific direction, and the light beam in each light component has a different wavelength. The arrangement of multiple light components can be arranged in sequence from top to bottom along the Z direction, or can be arranged in sequence from the inside of the paper to the outside of the paper. In the embodiment of the present invention, only the arrangement in the Z direction from top to bottom is taken as an example for illustration , But not limited to this, the arrangement direction of the multiple light components is determined by the grating structure of the diffraction grating 31.

It should be noted that the light source 30 in the embodiment of the present invention may be an optical receiver facing the plasma processing cavity, so that the light generated in the plasma processing cavity is received by the receiver and then transmitted through the optical fiber into the spectrum detection device of the present invention. The spectrum emitted in the plasma processing chamber will vary with changes in the etching material layer, etching gas, and reaction by-product composition.

In the embodiment of the present invention, the position of each slit 330 corresponds to the position of a light component, wherein the slit 330 can transmit light, and the baffle around the slit 330 can shield light, that is, the function of the slit 330 Is the light component corresponding to the transmission position. Moreover, the side of the slit 330 facing the image sensor 32 has an optical lens 331. As shown in FIG. 4, the projection of the optical lens on the baffle 33 completely covers the slit 330. The optical lens 331 is used for narrowing the slit 330. The light component corresponding to the position of the slit 330 is expanded to enlarge the projection area of the light component on the image sensor 32, so that the image sensor 32 uses more pixels to collect the light component, thereby improving the image. The signal-to-noise ratio of the image sensor 32 improves the detection sensitivity of the endpoint detection system. Optionally, the optical lens 331 is a scattering lens.

It should be noted that when the multiple light components are arranged from top to bottom, the slit 330 is a strip-shaped slit with a lateral width greater than the longitudinal width, and when the multiple light components are arranged from left to right, the slit 330 is lateral. A stripe-shaped slit with a width smaller than the longitudinal width, so that the required light component can be transmitted to the image sensor 32 through the slit 330, so that the unnecessary light component cannot be transmitted to the image sensor 32, so that It is avoided that the light component after beam expansion is confused with other light components, which affects the detection accuracy of the image sensor 32. It should also be noted that the position of the slit 330 in the embodiment of the present invention can be set as required, so as to collect the required spectrum.

In the embodiment of the present invention, the image sensor 32 is used to collect the expanded light components to obtain the light intensity of the characteristic spectrum corresponding to the expanded light components. Optionally, the image sensor 32 is a CCD (Charge-coupled Device). Optionally, the spectrum detection device in the embodiment of the present invention is a spectrometer. Of course, the present invention is not limited to this.

In the embodiment of the present invention, a baffle 33 is provided between the diffraction grating 31 and the image sensor 32. The baffle 33 has a slit 330, and the position of the slit 330 corresponds to the position of the light component to be collected. And the side of the slit 330 facing the image sensor 32 has an optical lens 331, which is used to expand the light component to expand the projection area of the light component on the image sensor 32, so that the image The image sensor 32 uses more pixels to collect light components. Since the signal-to-noise ratio of the image sensor 32 increases in proportion to the square root of the number of pixels, the image sensor 32 can be increased by The number of pixels increases the signal-to-noise ratio of the image sensor 32, and in the embodiment of the present invention, the cost of the baffle 33 and the optical lens 331 is lower, that is, the embodiment of the present invention adopts a lower cost increase The signal-to-noise ratio of the image sensor 32 is improved, and the detection sensitivity of the endpoint detection system is improved.

In another embodiment of the present invention, as shown in Figure 3, the baffle 33 has two slits, the two slits are the first slit 330a and the second slit 330b, and the diffraction grating 31 is divided into The plurality of light components includes a first light component A and a second light component B.

Wherein, the position of the first slit 330a corresponds to the position of the first light component A, the side of the first slit 330a facing the image sensor 32 has a first optical lens 331a, and the first optical lens 331a is used to A light component A is beam expanded.

The position of the second slit 330b corresponds to the position of the second light component B. The side of the second slit 330b facing the image sensor 32 has a second optical lens 331b, and the second optical lens 331b is used for controlling the second light component. Component B is beam expanded.

The image sensor 32 is used to collect the expanded first light component A, obtain the light intensity of the first characteristic spectrum corresponding to the first light component A, and collect the expanded second light component B to obtain the second light The light intensity of the second characteristic spectrum corresponding to the component B is determined based on the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum to determine whether the etching end point is reached.

Since the first characteristic spectrum is the characteristic spectrum of the first dielectric layer, the second characteristic spectrum is the characteristic spectrum of the second dielectric layer at the bottom of the first dielectric layer, and when the first dielectric layer is etched, the first characteristic spectrum is The light intensity ratio of the two characteristic spectra is within the first range. When the first dielectric layer is etched and the second dielectric layer is etched, the light intensity ratio of the first characteristic spectrum to the second characteristic spectrum is within the second range, based on Therefore, as long as the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum is obtained, and the ratio of the light intensity is compared with the first range and the second range, if it is within the first range and close to the first range, Within a range of boundary values, the first dielectric layer is about to be etched, that is, the etching end point of the first dielectric layer is about to be reached. If it is within the second range, the first dielectric layer has been etched, that is, the etching end point has been reached. .

In another embodiment of the present invention, as shown in FIG. 5, the baffle 33 has a movable third slit 330c, and the plurality of light components divided by the diffraction grating 31 includes the first light component A and the second light component A. Component B.

Wherein, the third slit 330c includes a first position a and a second position b, the first position a corresponds to the position of the first light component A, and the second position b corresponds to the position of the second light component B.

The side of the third slit 330c facing the image sensor 32 has a third optical lens 331c, and the third optical lens 331c moves with the third slit 330c for performing processing on the first light component A and the second light component B. Expand beam.

The image sensor 32 is used to collect the expanded first light component to obtain the light intensity of the first characteristic spectrum corresponding to the first light component, and to collect the expanded second light component to obtain the second light component corresponding to the second light component. The light intensity of the characteristic spectrum is determined based on the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum to determine whether the etching end point has been reached.

That is, when the third slit 330c moves to the first position a, the third optical lens 331c moves to the first position a along with the third slit 330c, and the position of the third slit 330c differs from the first light component A. Corresponding to the position, the third optical lens 331c expands the first light component A, and the image sensor 32 collects the expanded first light component A to obtain the light intensity of the first characteristic spectrum corresponding to the first light component A;

When the third slit 330c moves to the second position b, the third optical lens 331c moves with the third slit 330c to the second position b. The position of the third slit 330c corresponds to the position of the second light component B. The three optical lenses 331c expand the second light component B, and the image sensor 32 collects the expanded second light component B to obtain the light intensity of the second characteristic spectrum corresponding to the second light component B.

In this embodiment, the position of the third slit 330c can be changed by driving the baffle 33 to move in the Z direction by a driving component such as a motor. Of course, the present invention is not limited to this. In other embodiments, it can also be The first position a and the second position b are respectively provided with a slit, and by shielding one of the slits, the movement of the third slit 330c between the first position a and the second position b is realized.

In addition, in this embodiment, the movement time of the third slit 330c can be controlled according to the preset time or the light intensity of the characteristic spectrum. For example, at the beginning of etching, the third slit 330c is first set to the first position a, and the light intensity of the first characteristic spectrum is collected. When the light intensity of the first characteristic spectrum reaches the preset time or the preset value, the first characteristic spectrum is moved. There are three slits 330c, so that the third slit 330c is at the second position b, and the light intensity of the second characteristic spectrum is collected.

In an embodiment of the present invention, as shown in Figure 6, the baffle 33 in a spectrum detection device has only one slit, that is, the baffle has a first slit 330a; the multiple light components include the first light component A.

The position of the first slit 330a corresponds to the position of the first light component A, the side of the first slit 330a facing the image sensor 32 has a first optical lens 331a, and the first optical lens 331a is used for controlling the first light component A. The component A is beam expanded; the image sensor 32 is used to collect the expanded first light component A, and obtain the light intensity of the first characteristic spectrum corresponding to the first light component A.

In another embodiment of the present invention, as shown in FIG. 7, the baffle 33 in another spectrum detection device has a second slit 330b; the plurality of light components includes the second light component B.

The position of the second slit 330b corresponds to the position of the second light component B. The side of the second slit 330b facing the image sensor 32 has a second optical lens 331b, and the second optical lens 331b is used for controlling the second light component. Component B is beam expanded.

The image sensor 32 is used to collect the expanded second light component B to obtain the light intensity of the second characteristic spectrum corresponding to the second light component B.

That is to say, in the embodiment of the present invention, the light intensity of the first characteristic spectrum can be obtained by one spectrum detection device, the light intensity of the second characteristic spectrum can be obtained by another spectrum detection device, and then the light intensity of the first characteristic spectrum can be obtained according to the The ratio of the intensity to the light intensity of the second characteristic spectrum determines whether the etching end point is reached.

Optionally, as shown in Figure 8, the spectrum detection device in the embodiment of the present invention further includes a mirror 332; the mirror 332 is arranged around the projection of the light component on the image sensor 32, and the mirror 332 is in the block. The board 33 and the image sensor 32 extend between.

Specifically, the mirror 332 not only surrounds the projection of the light component A on the image sensor 32 but also surrounds the projection of the light component B on the image sensor 32. Based on this, the light reflected and escaped by the image sensor 32 is reflected back to the image sensor 32 by the mirror 332, so that light loss can be reduced.

The embodiment of the present invention also provides an endpoint detection system, as shown in Figure 9, including a spectrum detection device and a processing element. Optionally, the spectrum detection device in the embodiment of the present invention is a spectrometer, and the processing element is a processor or a computer.

The spectrum detection device is the spectrum detection device shown in FIG. 3, that is, the baffle 33 in the spectrum detection device has a first slit 330a and a second slit 330b. Alternatively, the spectrum detection device is the spectrum detection device shown in FIG. 5, and the spectrum detection device has a movable third slit 330c.

The spectrum detection equipment is used to obtain the light intensity of the first characteristic spectrum λ1 and the light intensity of the second characteristic spectrum λ2 according to the light generated when the etched object is etched. The etched object includes the first dielectric layer 301 arranged in sequence in the etching direction. And the second dielectric layer 302, as shown in Fig. 10, the first characteristic spectrum λ1 is the characteristic spectrum of the first dielectric layer 301, and the second characteristic spectrum λ2 is the characteristic spectrum of the second dielectric layer 302, where in the etching direction The sequential arrangement means that the second dielectric layer 302 will be etched after the first dielectric layer 301 is etched. The processing element is used to determine whether the etching end point of the first dielectric layer 301 is reached according to the ratio of the light intensity of the first characteristic spectrum λ1 to the light intensity of the second characteristic spectrum λ2.

In the embodiment of the present invention, by arranging a baffle with a slit between the diffraction grating and the image sensor, and an optical lens for amplifying the beam at the slit, it is possible to increase the performance of the spectrum detection equipment at a lower cost. The signal-to-noise ratio improves the sensitivity of the endpoint detection system. Although there are also schemes in the prior art to improve the sensitivity of the endpoint detection system by algorithms or by using expensive and high-sensitivity image sensors, compared with them, the spectral detection device with high signal-to-noise ratio in the embodiment of the present invention The cost is lower.

The embodiment of the present invention also provides an endpoint detection method, which is applied to the endpoint detection system shown in Figure 9. As shown in Figure 11, the method includes:

S101: The spectrum detection device obtains the light intensity of the first characteristic spectrum and the light intensity of the second characteristic spectrum according to the light emitted when the etched object is etched, and the etched object includes the first medium layer and the second medium arranged in sequence in the etching direction Layer, the first characteristic spectrum is the characteristic spectrum of the first dielectric layer, and the second characteristic spectrum is the characteristic spectrum of the second dielectric layer;

S102: The processing element determines whether the etching end point of the first dielectric layer is reached according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum.

Specifically, when the etched object, such as the first dielectric layer, is etched, the etched material will be excited and dissociated by the radio frequency electric field to form plasma. After the emitted light is collected by the spectrum detection device, the light intensity of the spectrum of each wavelength will be obtained. The light intensity of the first characteristic spectrum and the light intensity of the second characteristic spectrum can be obtained, and then the processing element can judge whether it reaches the first characteristic spectrum according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum. The etching end point of the dielectric layer.

When the spectrum detection device is the spectrum detection device shown in Figure 3, the spectrum detection device obtains the light intensity of the first characteristic spectrum and the light intensity of the second characteristic spectrum according to the light generated when the etched object is etched, including:

The diffraction grating 31 divides the collected light generated when the etched object is etched into a plurality of light components sequentially arranged along a specific direction Z. The light beam in each light component has a different wavelength, wherein the multiple light components include the first light component A and the second light component B; the first slit 330a transmits the first light component A, the first optical lens 331a expands the first light component A, the second slit 330b transmits the second light component B, and the second optical The lens 331b expands the second light component B; the image sensor 32 collects the expanded first light component A, obtains the light intensity of the first characteristic spectrum corresponding to the first light component A, and collects the expanded beam The second light component B obtains the light intensity of the second characteristic spectrum corresponding to the second light component B.

When the spectrum detection device is the spectrum detection device shown in Figure 5, that is, when the baffle 33 has a movable third slit 330c, the spectrum detection device obtains the first characteristic spectrum according to the light generated when the etched object is etched. The light intensity and the light intensity of the second characteristic spectrum include:

The diffraction grating 31 divides the collected light generated when the etched object is etched into a plurality of light components sequentially arranged along a specific direction Z. The light beam in each light component has a different wavelength, wherein the multiple light components include the first light component A and the second light component B;

The third slit 330c is located at the first position a, the third optical lens 331c expands the first light component A, and the image sensor 32 collects the expanded first light component A to obtain the corresponding first light component A The light intensity of the first characteristic spectrum;

The third slit 330c is located at the second position b, the third optical lens 331c expands the second light component B, and the image sensor 32 collects the expanded second light component B to obtain the second light component B corresponding The light intensity of the second characteristic spectrum.

In this embodiment, the position of the third slit 330c can be changed by driving the baffle 33 to move in the Z direction by a driving component such as a motor. Of course, the present invention is not limited to this. In other embodiments, it can also be The first position a and the second position b are respectively provided with a slit, and by shielding one of the slits, the movement of the third slit 330c between the first position a and the second position b is realized.

In addition, in this embodiment, the movement time of the third slit 330c can be controlled according to the preset time or the light intensity of the characteristic spectrum. For example, at the beginning of etching, the third slit 330c is first set to the first position a, and the light intensity of the first characteristic spectrum is collected. When the light intensity of the first characteristic spectrum reaches the preset time or the preset value, the first characteristic spectrum is moved. There are three slits 330c, so that the third slit 330c is at the second position b, and the light intensity of the second characteristic spectrum is collected.

The embodiment of the present invention also provides an endpoint detection system, as shown in Figure 12, including a first spectrum detection device, a second spectrum detection device, a spectroscopic element, and a processing element. Optionally, both the first spectrum detection device and the second spectrum detection device in the embodiment of the present invention are spectrometers, and the processing element is a processor or a computer.

Wherein, the spectroscopic element is used to divide the light generated when the etched object is etched into the first light and the second light, and make the first light enter the first spectrum detection device, and make the second light enter the second spectrum detection device; Optionally, the light splitting ratio of the light splitting element is 1:1, that is, the light splitting element distributes half of the emitted light to the first spectrum detection device and the other half to the second spectrum detection device.

The first spectrum detection device is the spectrum detection device shown in Figure 6; the first spectrum detection device is used to obtain the light intensity of the first characteristic spectrum λ1 according to the first light, and the first characteristic spectrum λ1 is the characteristic of the first dielectric layer 301 spectrum;

The second spectrum detection device is the spectrum detection device of Figure 7; the second spectrum detection device is used to obtain the light intensity of the second characteristic spectrum λ2 according to the second light, and the second characteristic spectrum λ2 is the characteristic spectrum of the second dielectric layer 302, The second dielectric layer 302 is located at the bottom of the first dielectric layer 301 in the etching direction;

The processing element is used to determine whether the etching end point of the first dielectric layer 301 is reached according to the ratio of the light intensity of the first characteristic spectrum λ1 to the light intensity of the second characteristic spectrum λ2.

The embodiment of the present invention also provides an endpoint detection method, as shown in FIG. 13, which is applied to the endpoint detection system shown in FIG. 12, and the method includes:

S201: The spectroscopic element divides the light emitted during the etching of the etched object into a first light and a second light, and makes the first light enter the first spectrum detection device, and the second light enters the second spectrum detection device, and the etched object Comprising a first dielectric layer and a second dielectric layer arranged in sequence in the etching direction;

S202: The first spectrum detection device obtains the light intensity of the first characteristic spectrum according to the first light, and the first characteristic spectrum is the characteristic spectrum of the first medium layer;

S203: The second spectrum detection device obtains the light intensity of the second characteristic spectrum according to the second light, the second characteristic spectrum is the characteristic spectrum of the second dielectric layer, and the second dielectric layer is located at the bottom of the first dielectric layer in the etching direction;

S204: The processing element determines whether the etching end point of the first dielectric layer is reached according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum.

Specifically, when the etched object, such as the first dielectric layer, is etched, the etched material will be excited and dissociated by the radio frequency electric field to form a plasma, and the emitted light is divided into the first light and the second light by the light splitting element, and the first light is incident To the first spectrum detection device, the second light is incident on the second spectrum detection device, and then the first spectrum detection device obtains the light intensity of the first characteristic spectrum according to the first light, and the second spectrum detection device obtains the second light according to the second light. According to the light intensity of the characteristic spectrum, the processing element judges whether it reaches the etching end point of the first dielectric layer according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum. Among them, the process of obtaining the characteristic spectral light intensity by the spectral detection device is similar to the above, and will not be repeated here.

It should be noted that if it is determined that the etching end point of the first dielectric layer is reached, the processing element can issue a prompt to remind the staff to stop the etching equipment, or the processing element can directly control the etching equipment to stop working to ensure the accuracy of etching and avoid excessive occurrence. Etching situation.

It should also be noted that in the embodiment of the present invention, not only can the detection sensitivity of the endpoint detection system be improved by setting slits and optical lenses, but also the detection sensitivity of the endpoint detection system can be improved by increasing the accuracy of the diffraction grating 31. Go into details again.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown in this document, but should conform to the widest scope consistent with the principles and novel features disclosed in this document.

10: Object to be etched 11: Diffraction grating 12: Image sensor 30: light source 31: Diffraction grating 32: Image sensor 33: bezel 101: The first dielectric layer 102: second dielectric layer 301: The first dielectric layer 302: second dielectric layer 330: slit 330a: first slit 330b: second slit 330c: third slit 331: optical lens 331a: the first optical lens 331b: second optical lens 331c: third optical lens 332: Mirror A: The first light component a: first position B: second light component b: second position S101, S102, S201, S202, S203, S204: steps Z: direction

In order to more clearly describe the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are merely It is an embodiment of the present invention. For those with ordinary knowledge in the technical field, other schemas can be obtained according to the provided schema without making progressive labor. Figure 1 is a schematic diagram of the structure of a conventional spectrum detection equipment; Figure 2 is a schematic diagram of the arrangement of multiple light components shown in Figure 1; Figure 3 is a schematic structural diagram of a spectrum detection device provided by an embodiment of the present invention; Figure 4 is an enlarged view of the partial structure of the baffle shown in Figure 3; Figure 5 is a schematic structural diagram of another spectrum detection device provided by an embodiment of the present invention; Figure 6 is a schematic structural diagram of another spectrum detection device provided by an embodiment of the present invention; Figure 7 is a schematic structural diagram of another spectrum detection device provided by an embodiment of the present invention; Figure 8 is a schematic structural diagram of another spectrum detection device provided by an embodiment of the present invention; Figure 9 is a schematic structural diagram of an endpoint detection system provided by an embodiment of the present invention; Figure 10 is a graph of a characteristic spectrum provided by an embodiment of the present invention; Figure 11 is a flowchart of an endpoint detection method provided by an embodiment of the present invention; Figure 12 is a schematic structural diagram of another endpoint detection system provided by an embodiment of the present invention; Figure 13 is a flowchart of another endpoint detection method provided by an embodiment of the present invention.

30: light source

31: Diffraction grating

32: Image sensor

330: slit

330a: first slit

330b: second slit

331: optical lens

331a: the first optical lens

331b: second optical lens

A: The first light component

B: second light component

Z: direction

Claims (12)

A spectrum detection device is used to perform spectrum detection on plasma. It includes a diffraction grating, an image sensor, and a baffle between the diffraction grating and the image sensor. The baffle has at least A slit The diffraction grating is used to divide incident light into a plurality of light components arranged in sequence along a specific direction, and each light beam of the plurality of light components has a different wavelength; The position of the slit corresponds to the position of one light component of the plurality of light components, and the side of the slit facing the image sensor has an optical lens, and the optical lens is used for matching the position corresponding to the slit. The light component of the beam is expanded; The image sensor is used to collect an expanded light component to obtain the light intensity of the characteristic spectrum corresponding to the expanded light component. The device according to claim 1, wherein the baffle has a first slit; the plurality of light components includes a first light component; The position of the first slit corresponds to the position of the first light component, the side of the first slit facing the image sensor has a first optical lens, and the first optical lens is used for the first optical component. Beam expansion of light components; The image sensor is used to collect an expanded first light component to obtain the light intensity of the first characteristic spectrum corresponding to the expanded first light component. The device according to claim 1, wherein the baffle has a second slit; the plurality of light components includes a second light component; The position of the second slit corresponds to the position of the second light component, the side of the second slit facing the image sensor has a second optical lens, and the second optical lens is used for the second optical component. Beam expansion of light components; The image sensor is used to collect an expanded second light component to obtain the light intensity of the second characteristic spectrum corresponding to the expanded second light component. The device according to claim 1, wherein the baffle has a first slit and a second slit; the plurality of light components includes a first light component and a second light component; The position of the first slit corresponds to the position of the first light component, the side of the first slit facing the image sensor has a first optical lens, and the first optical lens is used for the first optical component. Beam expansion of light components; The position of the second slit corresponds to the position of the second light component, the side of the second slit facing the image sensor has a second optical lens, and the second optical lens is used for the second optical component. Beam expansion of light components; The image sensor is used to collect an expanded first light component to obtain the light intensity of a first characteristic spectrum corresponding to the expanded first light component, and collect an expanded second light component to obtain the The light intensity of a second characteristic spectrum corresponding to the expanded second light component is determined based on the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum to determine whether the etching end point is reached. The device according to claim 1, wherein the baffle has a movable third slit; the plurality of light components include a first light component and a second light component; The third slit includes a first position and a second position, the first position corresponds to the position of the first light component, and the second position corresponds to the position of the second light component; The third slit has a third optical lens on the side facing the image sensor, and the third optical lens moves with the third slit for performing the first light component and the second light component. Beam expansion The image sensor is used to collect an expanded first light component to obtain the light intensity of a first characteristic spectrum corresponding to the expanded first light component, and collect an expanded second light component to obtain The light intensity of a second characteristic spectrum corresponding to the expanded second light component is determined according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum to determine whether the etching end point is reached. The device according to any one of claims 1 to 5, which further includes a reflector; The reflector is arranged around the projection of the light component on the image sensor, and the reflector extends between the baffle and the image sensor. An endpoint detection system, which includes a first spectrum detection device, a second spectrum detection device, a spectroscopic element, and a processing element; The light splitting element is used to divide the light generated when an etched object is etched into a first light and a second light, and make the first light enter the first spectrum detection device, and make the second light enter the first light Two spectrum detection equipment, the etched object includes a first dielectric layer and a second dielectric layer sequentially arranged in the etching direction; The first spectrum detection device is the spectrum detection device according to claim 2; the first spectrum detection device is used to obtain the light intensity of a first characteristic spectrum according to the first light, and the first characteristic spectrum is the first The characteristic spectrum of the dielectric layer; The second spectrum detection device is the spectrum detection device according to claim 3; the second spectrum detection device is used to obtain the light intensity of a second characteristic spectrum according to the second light, and the second characteristic spectrum is the second medium Characteristic spectrum of the layer; The processing element is used for judging whether the etching end point of the first dielectric layer is reached according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum. The system according to claim 7, wherein the light splitting ratio of the light splitting element is 1:1. An endpoint detection method, which is applied to the endpoint detection system according to claim 7 or 8, and the method includes: The spectroscopic element divides the light generated when the etched object is etched into the first light and the second light, and causes the first light to enter the first spectrum detection device, and the second light to enter the second spectrum Detection equipment, the etched object includes the first dielectric layer and the second dielectric layer sequentially arranged in an etching direction; The first spectrum detection device obtains the light intensity of the first characteristic spectrum according to the first light, and the first characteristic spectrum is the characteristic spectrum of the first dielectric layer; The second spectrum detection device obtains the light intensity of the second characteristic spectrum according to the second light, and the second characteristic spectrum is the characteristic spectrum of the second dielectric layer; The processing element determines whether the etching end point of the first dielectric layer is reached according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum. An endpoint detection system, which includes a spectrum detection device and a processing element; The spectrum detection device is the spectrum detection device according to claim 4 or 5; the spectrum detection device is used to obtain the light intensity of the first characteristic spectrum and the light intensity of the second characteristic spectrum according to the light generated when an etched object is etched. Light intensity, the etched object includes a first dielectric layer and a second dielectric layer sequentially arranged in the etching direction, the first characteristic spectrum is the characteristic spectrum of the first dielectric layer, and the second characteristic spectrum is the first dielectric layer. The characteristic spectrum of the second dielectric layer; The processing element is used for judging whether the etching end point of the first dielectric layer is reached according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum. An endpoint detection method, which is applied to the endpoint detection system according to claim 10, the method comprising: The spectrum detection device obtains the light intensity of the first characteristic spectrum and the light intensity of the second characteristic spectrum according to the light generated when the etched object is etched, and the etched object includes the first dielectric layer sequentially arranged in the etching direction And the second dielectric layer, the first characteristic spectrum is the characteristic spectrum of the first dielectric layer, and the second characteristic spectrum is the characteristic spectrum of the second dielectric layer; The processing element determines whether the etching end point of the first dielectric layer is reached according to the ratio of the light intensity of the first characteristic spectrum to the light intensity of the second characteristic spectrum. The method according to claim 11, wherein when the baffle has a movable third slit, the spectrum detection device obtains the light intensity and the light intensity of the first characteristic spectrum according to the light generated when the etched object is etched The light intensity of the second characteristic spectrum includes: The diffraction grating divides the collected light generated when the etched object is etched into a plurality of light components arranged in sequence along a specific direction, each of the plurality of light components has a different wavelength, wherein the plurality of light components Including a first light component and a second light component; The third slit is located at a first position, a third optical lens expands the first light component, and the image sensor collects an expanded first light component to obtain the expanded first light component. The light intensity of the first characteristic spectrum corresponding to a light component; The third slit is positioned at a second position, the third optical lens expands the second light component, and the image sensor collects an expanded second light component to obtain the expanded first light component The light intensity of the second characteristic spectrum corresponding to the two light components.

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