CN117826541A - Cleaning method of photoetching machine - Google Patents

Abstract

The embodiment of the disclosure provides a cleaning method of a photoetching machine, wherein the photoetching machine comprises a carrying platform, an objective lens arranged above the carrying platform and an exposure light source for providing exposure light beams, and pollutants are attached to the carrying platform; the cleaning method comprises the following steps: providing a control wafer, and placing the control wafer on a carrying platform; and performing an exposure process on the control wafer, wherein an exposure light source irradiates an exposure light beam to the control wafer through the objective lens to heat the control wafer, and the control wafer transfers heat to the pollutants attached to the carrier so as to reduce the adhesiveness between the pollutants and the carrier.

Description

Cleaning method of photoetching machine

Technical Field

The present disclosure relates to the field of semiconductor processing equipment, and in particular, to a cleaning method for a lithographic apparatus.

Background

In integrated circuit processing, a lithographic apparatus is typically used to transfer a pattern formed on a mask or reticle onto a photoresist layer on a wafer. However, when exposing a wafer, the photoresist on the surface of the wafer may be thrown out and attached to a stage on which the wafer is placed to form organic contaminants, thereby ultimately affecting the exposure quality of the wafer.

Disclosure of Invention

The cleaning method of the photoetching machine comprises a carrying platform, an objective lens arranged above the carrying platform and an exposure light source for providing exposure light beams, wherein pollutants are attached to the carrying platform; the cleaning method comprises the following steps:

providing a control wafer, and placing the control wafer on the carrying platform;

and performing an exposure process on the control wafer, wherein the exposure light source irradiates an exposure light beam to the control wafer through the objective lens to heat the control wafer, and the control wafer transfers heat to the pollutants attached to the carrier so as to reduce the adhesiveness between the pollutants and the carrier.

In some embodiments, the exposure energy ranges from 45mj to 60mj during the exposure process performed on the control wafer.

In some embodiments, the thickness of the control wafer ranges from 50nm to 100 nm.

In some embodiments, the lithographic apparatus further comprises: the immersion head is positioned between the objective lens and the carrying platform and comprises a liquid inlet and a liquid outlet; the liquid supply device is communicated with the liquid inlet of the immersion head; and the waste liquid recovery device is communicated with the liquid outlet of the immersion head.

In some embodiments, performing an exposure process on the control wafer further includes: the liquid supply device is used for supplying immersion liquid between the objective lens and the control wafer from the liquid inlet; after the exposure process is carried out on the control wafer, immersion liquid between the objective lens and the control wafer flows out from the liquid outlet to the waste liquid recovery device.

In some embodiments, the control wafer includes a plurality of exposure areas; executing an exposure process on the control wafer, including: the carrier drives the control wafer to move so that the exposure light beam scans a plurality of exposure areas of the control wafer one by one.

In some embodiments, the exposure beam exposes the control wafer for a time ranging from 40s to 90 s.

In some embodiments, after performing an exposure process on the control wafer, the cleaning method further comprises: removing the control wafer from the carrier; and flushing the upper surface of the carrier by adopting a cleaning liquid so as to enable the pollutants to fall off from the carrier.

In some embodiments, the lithographic apparatus further comprises a remote control system for periodically and automatically placing the control wafer on the stage and performing the exposure process on the control wafer to periodically clean the stage.

In some embodiments, the periodic cleaning of the stage is between 1 time/1 day and 1 time/5 days.

The embodiment of the disclosure provides a cleaning method of a lithography machine, which comprises a carrier, an objective lens arranged above the carrier and an exposure light source for providing exposure light beams, wherein pollutants are attached to the carrier; the cleaning method comprises the following steps: providing a control wafer, and placing the control wafer on the carrying platform; and performing an exposure process on the control wafer, wherein the exposure light source irradiates an exposure light beam to the control wafer through the objective lens to heat the control wafer, and the control wafer transfers heat to the pollutants attached to the carrier so as to reduce the adhesiveness between the pollutants and the carrier. So, this disclosed embodiment is through adopting exposure light beam radiation accuse piece to turn into the heat energy with light energy to adopt the accuse piece as the carrier with heat transfer to the pollutant of adhering to on the microscope carrier, thereby heat the pollutant, thereby make the pollutant that is located on the microscope carrier become flexible and thereby drop from the microscope carrier easily, need not to shut down and inspect whether there is the dirty on the microscope carrier of photoetching machine, improved board production efficiency.

The details of one or more embodiments of the disclosure are set forth in the accompanying drawings and the description below. Other features and advantages of the present disclosure will be apparent from the description and drawings.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and other drawings may be obtained according to these drawings without inventive effort to a person of ordinary skill in the art.

FIG. 1 is a block flow diagram of a method for cleaning a lithographic apparatus according to an embodiment of the present disclosure;

FIG. 2 is a process flow diagram of a cleaning method provided by an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a control wafer according to an embodiment of the disclosure;

FIG. 4 is a block diagram of a lithographic apparatus provided by an embodiment of the present disclosure.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present disclosure. However, it will be apparent to one skilled in the art that the present disclosure may be practiced without one or more of these details. In other instances, well-known features have not been described in order to avoid obscuring the present disclosure; that is, not all features of an actual implementation are described in detail herein, and well-known functions and constructions are not described in detail.

In the drawings, the size of layers, regions, elements and their relative sizes may be exaggerated for clarity. Like numbers refer to like elements throughout.

It will be understood that when an element or layer is referred to as being "on" … …, "" adjacent to "… …," "connected to" or "coupled to" another element or layer, it can be directly on, adjacent to, connected to or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on" … …, "" directly adjacent to "… …," "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present disclosure. When a second element, component, region, layer or section is discussed, it does not necessarily mean that the first element, component, region, layer or section is present in the present disclosure.

Spatially relative terms, such as "under … …," "under … …," "below," "under … …," "above … …," "above," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or features described as "under" or "beneath" other elements would then be oriented "on" the other elements or features. Thus, the exemplary terms "under … …" and "under … …" may include both an upper and a lower orientation. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

In integrated circuit processes, a lithographic apparatus (e.g., an immersion lithography apparatus) is typically used to transfer a pattern formed on a mask or reticle onto a photoresist layer on a wafer. With the development of technology, when exposing a wafer, the scanning speed (scan speed) of the photoetching machine on the wafer is faster and faster, and the original speed is gradually increased from 300mm/s to 800mm/s, so that the productivity of the photoetching machine is effectively improved. However, during the process of moving the wafer at a high speed, the photoresist on the surface of the wafer is thrown out and attached to the carrier for placing the wafer to form organic pollutants, and the immersion head in the immersion lithography machine leaks residual water during the process of moving the wafer at a high speed, the residual water brings the pollutants on the carrier out to fall on the surface of the wafer, and the pollutants finally form defects on the surface of the wafer along with the moving track of the wafer, so that the exposure quality of the wafer is affected. The dirt on the carrier is difficult to wash with water, and the machine is usually stopped to check whether the carrier is dirty, so that precious productivity is wasted and the production efficiency of the machine is seriously affected.

Based on this, the following technical solutions of the embodiments of the present disclosure are presented.

The embodiment of the disclosure provides a cleaning method of a photoetching machine, wherein the photoetching machine comprises a carrying platform, an objective lens arranged above the carrying platform and an exposure light source for providing exposure light beams, and pollutants are attached to the carrying platform; as shown in fig. 1, the cleaning method includes the following steps:

step S101, providing a control wafer, and placing the control wafer on a carrying platform;

and S102, performing an exposure process on the control wafer, wherein an exposure light source irradiates an exposure light beam to the control wafer through the objective lens to heat the control wafer, and the control wafer transfers heat to the pollutants attached to the carrier so as to reduce the adhesiveness between the pollutants and the carrier.

According to the embodiment of the disclosure, the exposure light beam radiation control chip is adopted to convert light energy into heat energy, and the control chip is adopted as a carrier to transfer heat to the pollutants attached to the carrier, so that the pollutants are heated, the pollutants on the carrier are loosened and easily fall off from the carrier, the shutdown is not needed to check whether the carrier of the photoetching machine is dirty or not, and the production efficiency of the machine is improved.

In order that the above-recited objects, features and advantages of the present disclosure will become more readily apparent, a more particular description of the disclosure will be rendered by reference to the appended drawings. In describing embodiments of the present disclosure in detail, the schematic drawings are not necessarily to scale and are merely illustrative and should not be taken as limiting the scope of the disclosure.

Fig. 2 is a process flow chart of a cleaning method provided by an embodiment of the disclosure, fig. 3 is a schematic structural diagram of a control wafer provided by an embodiment of the disclosure, and fig. 4 is a block diagram of a photolithography machine provided by an embodiment of the disclosure. The cleaning method according to the embodiments of the present disclosure will be described in further detail with reference to fig. 2 to 4.

As shown in fig. 2, the lithography machine provided in the embodiment of the present disclosure includes a stage 10, an objective lens 17 disposed above the stage 10, and an exposure light source 18 for providing an exposure light beam 181, and a contaminant 11 is attached to the stage 10.

First, step S101 is performed to provide the control wafer 12, and the control wafer 12 is placed on the carrier 10.

Here, the material of the control wafer 12 may be a semiconductor material, and may include at least one elemental semiconductor material (e.g., silicon (Si), germanium (Ge)), at least one III-V compound semiconductor material, at least one II-VI compound semiconductor material, at least one organic semiconductor material, or other semiconductor materials known in the art. In one embodiment, the material of the control wafer 12 is silicon.

Next, step S102 is performed to perform an exposure process on the control wafer 12, and the exposure light source 18 irradiates an exposure light beam 181 to the control wafer 12 through the objective lens 17 to heat the control wafer 12, and the control wafer 12 transfers heat to the contaminant 11 attached to the carrier 10 to reduce adhesion between the contaminant 11 and the carrier 10.

In the disclosed embodiment, the exposure light source 18 is a light source that can emit ultraviolet light, deep ultraviolet light, or extreme ultraviolet light, and may be, for example, a deep ultraviolet laser generator, a plasma discharge lamp, or the like. The exposure light source 18 shown in fig. 2 is located above the objective lens 17. In fact, the exposure light source 18 may be provided at other positions, and an illumination system (not shown) may be provided between the exposure light source 18 and the objective lens 17, the illumination system (not shown) being configured to adjust the exposure light beam 181 generated by the exposure light source 18; the illumination system (not shown) may include various types of optical components, such as one or a combination of refractive, reflective, magnetic, electromagnetic, electrostatic to direct, form, or modulate the exposure beam 181, and direct the exposure beam 181 to the objective lens 17, with the objective lens 17 directing the exposure beam 181 to the control wafer 12. In some embodiments, a mask stage (not shown) for placing a mask is disposed between the illumination system (not shown) and the objective lens 17, and the mask does not need to be placed on the mask stage (not shown) when exposing the control wafer 12.

According to the embodiment of the disclosure, the exposure light beam 181 is adopted to radiate the control wafer 12 to convert light energy into heat energy, and the control wafer 12 is adopted as a carrier to transfer heat to the pollutant 11 attached to the carrier 10, so that the pollutant 11 is heated to reduce the adhesiveness between the pollutant 11 and the carrier 10, and therefore, after the pollutant 11 on the carrier 10 is loosened, the pollutant 11 is easier to fall off from the carrier 10, and the carrier 10 of the photoetching machine does not need to be stopped to check whether the carrier 10 is polluted or not, so that the production efficiency of the machine is improved. In one embodiment, during the exposure process performed on the control wafer 12, the exposure energy ranges from 40mj to 60mj (inclusive), e.g., 42mj, 45mj, 50mj, 53mj, 55mj, 58mj, etc., so that the heat converted by the exposure beam 181 is higher due to the higher exposure energy of the control wafer 12, which is more beneficial for reducing the adhesion between the contaminant 11 and the stage 10, and is more beneficial for subsequently dislodging the contaminant 11 from the stage. Here, the exposure energy refers to the total energy value of the exposure beam 181 radiated on the surface of the control wafer 12 through the objective lens 17 during the execution of the exposure process.

In the embodiment of the disclosure, the control wafer 12 is used as a carrier for transferring heat, instead of a wafer used in a semiconductor process, the wafer is prevented from being damaged or scrapped due to high exposure energy, and the control wafer 12 can be recycled by simply cleaning, so that the cost is saved.

In one embodiment, the thickness of the control wafer 12 ranges between 50nm and 100nm (inclusive), such as 60nm, 70nm, 80nm, 90nm, etc. In the embodiment of the disclosure, the thickness of the control wafer 12 is thinner, so that the efficiency of transferring heat from the control wafer 12 can be improved in the process that the control wafer 12 is used as a carrier to transfer heat to the pollutant 11 attached to the carrier 10. In some embodiments, the surface of the control wafer 12 does not need to be formed with a photoresist layer, thus further improving the efficiency of heat transfer from the control wafer 12.

As shown in fig. 3, in one embodiment, the control wafer 12 includes a plurality of exposure areas 121; performing an exposure process on the control wafer 12 includes: the carrier 10 drives the control wafer 12 to move so that the exposure light beam 181 scans the plurality of exposure areas 121 of the control wafer 12 one by one, thus the pollutants 11 below each exposure area 121 of the control wafer 12 can be sufficiently heated, and the pollutants are easier to clean.

However, the present invention is not limited thereto, and the control wafer 12 may be fixed during the exposure of the control wafer 12, and since the control wafer 12 has a large area and covers the contaminants 11 on the stage 10, the control wafer 12 can transfer heat to all the contaminants 11 attached to the stage 10 even if the control wafer 12 and the stage 10 are fixed, and the light beam 181 irradiates only one of the exposure regions 121 of the control wafer 12.

In some embodiments, the exposure time of the exposure beam 181 to the control wafer 12 ranges from 40s to 90s (including the end point values), such as 50s, 60s, 70s, 80s, etc., to avoid too short exposure time, and insufficient heating of the contaminants 11 to be easily detached from the stage 10.

In one embodiment, the lithographic apparatus is an immersion lithographic apparatus; as shown in fig. 2, the lithographic apparatus further includes: an immersion head 13 located between the objective 17 and the stage 10, the immersion head comprising a liquid inlet 131 and a liquid outlet 132; a liquid supply device 14 which is communicated with a liquid inlet 131 of the immersion head 13; the waste liquid recovery device 15 is communicated with a liquid outlet 132 of the immersion head 13. In some embodiments, the inner profile of the immersion head 13 is a tapered structure matching the geometry of the lens of the objective lens 17, the immersion head 13 being disposed between the objective lens 17 and the control wafer 12 and surrounding the objective lens 17.

In one embodiment, the exposure process is performed on the control wafer 12, and further includes: the liquid supply device 14 supplies immersion liquid 16 from the liquid inlet 131 to the space between the objective lens 17 and the control wafer 12; after the exposure process is performed on the control wafer 12, the immersion liquid 16 located between the objective lens 17 and the control wafer 12 flows out from the liquid outlet 132 to the waste liquid recovery device 15.

In a practical process, when exposing a wafer, the immersion head 13 is used for limiting the immersion liquid 16 between the lower surface of the objective lens 17 and the upper surface of the wafer, and compared with air, the immersion liquid 16 has a higher refractive index, so that the numerical aperture of the objective lens 17 can be increased, the resolution can be improved, and further smaller characteristic line widths can be obtained. In the embodiment of the disclosure, when the control wafer 12 is exposed, although a pattern is not required to be formed on the surface of the control wafer 12, the immersion liquid 16 is filled between the objective lens 17 and the control wafer 12, and when different exposure areas 121 on the surface of the control wafer 12 are exposed, the immersion liquid 16 moves on the surface of the control wafer 12 and always fills the gap between the lower surface of the objective lens 17 and the upper surface of the control wafer 12, so that in the process of exposing the control wafer 12, the exposure light beam 181 passing through the objective lens 17 can continuously heat the immersion liquid 16, the temperature of the immersion liquid 16 is increased, and the heating effect on the control wafer 12 and the cleaning effect on the pollutants 11 are improved. Here, the immersion liquid 16 may be deionized water. But is not limited thereto, the immersion liquid 16 may also be other liquids having a high refractive index.

In one embodiment, after performing the exposure process on the control wafer 12, the cleaning method further includes: removing the control wafer 12 from the carrier 10; the upper surface of the stage 10 is rinsed with a cleaning liquid to cause the contaminants 11 to fall off the stage 10.

Specifically, as shown in fig. 2, the lithographic apparatus further includes a chamber 20, the stage 10 is disposed in the chamber 20, after heating the contaminant 11 attached to the stage 10 to loosen it, the control wafer 12 is moved out of the chamber 20, then a cleaning solution is introduced into the chamber 20 to rinse the stage 10, so that the contaminant 11 falls off from the stage 10, and then the cleaning solution in the chamber 20 is discharged, so that the fallen contaminant 11 is carried out of the chamber 20, and thus, the cleaning of the stage 10 is completed. In practice, the cleaning solution may be deionized water. But is not limited thereto, the cleaning liquid may be other acidic or basic cleaning liquids.

As shown in FIG. 4, in one embodiment, the lithographic apparatus further comprises a remote control system 19, wherein the remote control system 19 is configured to automatically and periodically place the control wafer 12 on the stage 10 and perform an exposure process on the control wafer 12 to periodically clean the stage 10.

In actual operation, firstly, the control wafer 12 is placed on the carrier 10 through the remote control system 19, and the exposure program is determined and the exposure energy is set through the remote control system 19 to execute the exposure process on the control wafer 12; then, after the exposure process is performed on the control wafer 12, the control wafer 12 is moved out of the cavity 20 through the remote control system 19, and the carrying platform 10 is cleaned, so that the carrying platform 10 is automatically cleaned, the carrying platform 10 is not required to be stopped for inspection, the closed environment of the cavity 20 is not damaged, wafer flowing can be normally performed after the carrying platform 10 is cleaned, and the production efficiency is improved.

In some embodiments, the frequency of periodic cleaning of the stage 10 is between 1/1 day and 1/5 days, for example, 1/1 day, 1/2 days, 1/3 days, 1/4 days, 1/5 days, so that periodic automatic cleaning of the photolithography machine is realized, cost is saved, and production efficiency of the machine is improved.

It should be noted that the above-mentioned sequences of steps can be changed by those skilled in the art without departing from the scope of the present disclosure, and the above-mentioned embodiments are merely alternative examples of the present disclosure, and are not intended to limit the scope of the present disclosure, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present disclosure are intended to be included in the scope of the present disclosure.

Claims (10)

1. The cleaning method of the lithography machine is characterized in that the lithography machine comprises a carrier, an objective lens arranged above the carrier and an exposure light source for providing exposure light beams, wherein pollutants are attached to the carrier; the cleaning method comprises the following steps:

providing a control wafer, and placing the control wafer on the carrying platform;

and performing an exposure process on the control wafer, wherein the exposure light source irradiates an exposure light beam to the control wafer through the objective lens to heat the control wafer, and the control wafer transfers heat to the pollutants attached to the carrier so as to reduce the adhesiveness between the pollutants and the carrier.

2. The method of claim 1, wherein the exposure energy ranges from 45mj to 60mj during the exposure process performed on the control wafer.

3. The method of claim 1, wherein the control wafer has a thickness in the range of 50nm to 100 nm.

4. The cleaning method of claim 1, wherein the lithography machine further comprises: the immersion head is positioned between the objective lens and the carrying platform and comprises a liquid inlet and a liquid outlet; the liquid supply device is communicated with the liquid inlet of the immersion head; and the waste liquid recovery device is communicated with the liquid outlet of the immersion head.

5. The method of cleaning of claim 4, wherein performing an exposure process on the control wafer further comprises: the liquid supply device is used for supplying immersion liquid between the objective lens and the control wafer from the liquid inlet; after the exposure process is carried out on the control wafer, immersion liquid between the objective lens and the control wafer flows out from the liquid outlet to the waste liquid recovery device.

6. The cleaning method of claim 1, wherein the control wafer comprises a plurality of exposure areas; executing an exposure process on the control wafer, including: the carrier drives the control wafer to move so that the exposure light beam scans a plurality of exposure areas of the control wafer one by one.

7. The cleaning method of claim 1, wherein the exposure beam exposes the control wafer for a time period in a range of 40s to 90 s.

8. The cleaning method according to claim 1, wherein after performing an exposure process on the control wafer, the cleaning method further comprises: removing the control wafer from the carrier; and flushing the upper surface of the carrier by adopting a cleaning liquid so as to enable the pollutants to fall off from the carrier.

9. The cleaning method of claim 1, wherein the lithography machine further comprises a remote control system for periodically and automatically placing the control wafer on the stage and performing the exposure process on the control wafer to periodically clean the stage.

10. The method of cleaning of claim 9, wherein the periodic cleaning of the stage is between 1/1 day and 1/5 days.