CN1983035A - Methods for Reducing Reticle Deposition Defects - Google Patents

Abstract

The present invention relates to a method for reducing photomask deposition defects. In a semiconductor production process, there is a container for transporting photomasks, and the photomask includes a substrate made of an insulating material, and a metal layer is deposited on the surface of the substrate. The present invention discloses a method for isolating and removing environmental pollutants, which includes filling the container with an inert gas to remove the environmental pollutants therein, for example, the inlet of the container is used for the inlet of the purification inert gas, and the outlet of the container is used for the discharge of impurities in the container. The present invention improves the product yield, the photomask production capacity and the photomask service life, reduces the critical dimension loss of the photomask after cleaning, and reduces the adverse effects of the photomask rework rate.

Description

Methods for Reducing Reticle Deposition Defects

technical field

The invention relates to a semiconductor technology, in particular to a container for storing photomasks. More specifically, the present invention relates to a method of reducing photomask precipitation defects (precipitates).

Background technique

In the semiconductor device manufacturing process, a container made of a plastic material with a square section or a rectangular section is usually used to transport items. These items may include silicon wafers, photomasks or other substrates on which integrated circuit components are built. The photomask is a transparent ceramic substrate on which a metal layer is plated to form a circuit pattern. It is usually used in the imaging step of a lithography process, on which the circuit pattern is reproduced on the surface of an electronic substrate, that is, on the surface of a wafer.

Reticle containers are known in the art. In US Patent Publication No. 4,719,705, a step in the semiconductor wafer fabrication process is disclosed that utilizes an adjustable conveyor to move a reticle through an optical slit. The mask stage travels and meets a pair of optical planes, each of which is supported by air bearings. At the same time, pressurized air and vacuum can be used to form a substantially frictionless movement to prevent displacement of the bearing surface. The axial adjustment device of each air bearing can make precise adjustments to the photomask stage and photomask.

In US Patent Publication No. 4,842,136, a dustproof container for a photomask used in the manufacture of integrated circuits to transfer a pattern onto a semiconductor wafer is disclosed. The container includes a housing that contains support pins that fit the mask. Likewise, a plate spring pressing the mask against the support pins, and a release mechanism for releasing the plate spring's pressure on the mask are provided in the housing. The release mechanism responds to a non-mechanical signal (eg, an electronic signal) to release the pressure on the mask. Shape memory alloys can be used in this release mechanism. An opening/closing mechanism is used to open/close the door for covering an opening in the housing for inserting and extracting the mask. Among them, shape memory alloys can also be used in this on/off mechanism. The dust-proof container avoids the use of connecting rods or other mechanical signal transmission systems to effectively prevent dust or foreign particles generated by mechanical friction contact in the housing. In addition, the chance of dust or foreign particles adhering to the mask in this container can be minimized.

In US Patent Publication No. 5,314,068, a container includes a disc-shaped article, such as a photomask. The container includes a bottom member having a support portion for supporting a substantially flat article; a top member cooperates with the bottom member to define a space above the upper surface of the article; In the space, a resilient pressing element presses the article against the support portion; and a fixing element supported by the top element has an engaging element which can engage with the end portion of the bottom element. The engaging element can effectively prevent the top element from being opened up due to the reaction force of the pressing part. Furthermore, a release element part extends to and presses against this fixing element, which opens in the same direction as the top element, thereby releasing the engagement element.

US Patent Publication No. 5,727,685 discloses a cassette or box that accommodates and supports planar substrates such as photomasks. The box has a clamping bar connected to the corner support via a spring or a flexible element and a link. The clip bar is pivotally connected to the bottom corner support, a spring or a flexible element, and is connected to a top corner support. Thus, movement of the loading bar rotates the corner supports away from the reticle supported only by the corners. A booster bar is also used to preposition the mask in a certain direction.

A reticle support mechanism is disclosed in US Patent Publication No. 6,216,873. Within this mechanism, the reticle can be positioned and moved quickly and easily, and it can store and/or transport the reticle securely. One embodiment of the mechanism includes a pair of reticle holders embedded in a container door, and a pair of reticle positioners embedded in the container shell. When the pod shell interacts with the pod door, the reticle holder and reticle retainer portion contacts the reticle chamfer edge and clamps the reticle in a secure position within the pod. Due to the contact with the edge of the photomask, the damage to the upper surface, the lower surface and the vertical edge of the photomask can be avoided.

In US Patent Publication No. 6,247,599, a reticle container having a metal mask is disclosed. In one embodiment, the container includes a container body consisting of a top cover, a bottom cover and four side plates to form a cavity, and one of the side plates provides access to the cavity. The top cover, the bottom cover and the four side plates are all made of an electrical insulating material, and there are at least four supports embedded in the bottom cover to separate the supported insulating objects. A conductive layer covers the bottom cover sufficiently to provide adequate shielding when the insulating article is placed on the support.

The container may additionally include a metal sphere resting on the top. The conductive layer can be made of a metal material, a metal material that does not generate pollution particles, or stainless steel. The conductive layer can also be encapsulated as an inlay on the bottom cover. The top cover, bottom cover and four side panels can be made of a substantially transparent plastic material. The container may additionally include an insert formed on the bottom lid as a conductive layer. The container may additionally include a metal shield substantially similar in shape to the top cover, interposed between the top cover and the insulating article, and forming a metal enclosure around the insulating article with the conductive layer on the bottom cover.

In another embodiment, the container is equipped with a metal shield surrounding the insulating article, and its body consists of a top cover, a bottom cover and four side plates to form a cavity. One of the side plates provides access to the cavity. The top cover, the bottom cover and the four side plates are all made of an electrical insulating material, and there are a plurality of supports on the bottom cover for supporting insulating objects. The metal layer roughly covers the bottom cover, and the cup-shaped metal surrounding layer is placed between the top cover and the insulating article, and substantially surrounds the insulating article with the metal layer at the bottom. In the container, the metal layer and the cup-shaped metal surrounding layer can be made of a metal material free from contamination particles. The container may additionally include a metal sphere resting on the top. This metal layer can form an insert on the bottom cover. The container may additionally include a second metal layer encapsulated as an insert on the bottom lid. The top cover, the bottom cover and the four side plates are all made of a transparent plastic material. The metal layer and the cup-shaped metal surrounding layer can be made of stainless steel. The insulating object placed on the plurality of supports can be a chrome-plated quartz mask plate.

The ESD-free container can be a reticle box for storing chrome reticle flat panels. In another embodiment, a container includes a metal enclosure shielding the insulating article, and its body is composed of a top cover, a bottom cover and four side plates to form a cavity. One of the side plates provides access to the cavity. The top cover, the bottom cover and the four side plates are all made of an electrical insulating material. There are a plurality of supports on the bottom cover to support the insulating article, a metal layer roughly covers the bottom cover, and a cup-shaped metal surrounding layer is juxtaposed with the top cover and generally surrounds the insulating article with the metal layer, and there is a A metal sphere that falls on the roof. The container may additionally include a second metal layer of the insert molded on the bottom lid. The metal layer and the cup-shaped metal surrounding layer can be made of a metal material free from contamination particles.

In US Patent Publication No. 6,338,409 of Neary et al., a Standard Mechanical Interface (SMIF) box for synchronous positioning is disclosed. The mechanical standard interface box includes a box door on which a removable box cover defines an interior space. A set of fittings includes a plate that rests on the door in the interior space and has a downwardly extending core from the plate through an opening in the door. The plate mounted on the door of the box is rotatable and can be used to select the positioning of the items supported on the plate.

The alignment device is for aligning the plate with the box door in a plurality of orthogonal positions. The box door includes an upper flat door, a lower flat door and a bolt mechanism located therein for bolting the box door to the box cover. The alignment device includes an alignment foot extending downwardly from the plate, and a plurality of spaced holes in the door for selectively receiving the alignment foot. The alignment means may include a plurality of alignment feet extending downwardly from the plate, and a plurality of spaced holes in the door for receiving the alignment feet. The alignment means includes a locking ring extending radially outwardly from the core, and a plurality of positions arranged orthogonally to each other within the door for selective engagement with the locking ring. The alignment device may include a plurality of lock rings extending radially outward from the core and positioned orthogonally to each other, and a plurality of positions arranged orthogonally to each other in the box door, respectively for receiving the lock rings, the device It is to press the flat plate down towards the door of the box. The assembly includes a flange on the core. The pressing device includes a positioning spring disposed between the box door and the flange. The box door includes an upper flat door, a lower flat door and a flange clamped therein. The core includes a downward facing groove that can be actuated to rotate the plate by an external engagement device.

Likewise, FIG. 1 shows a conventional photomask delivery box. The photomask transport box 10 includes an upper cover 12 , an upper liner 16 , a support 18 for supporting the photomask substrate 20 , a lower liner 22 , and a lower cover 24 . The upper cover 12 is equipped with a handle 14, which is convenient for the operator to carry. The structure of the support 18 is related to the photomask, especially the chrome layer of the photomask, so as to avoid being scratched by the support during transportation. And there are chromium particles produced.

The problems of the existing conventional methods include the photomask pod that cannot be filled with inert gas as shown in Figure 1, and the 193nm photomasks used in the current 0.13 and 0.09 micron processes may suffer from contamination, which may adversely affect product yield and photomask productivity. Reticle lifetime impairment, critical dimension loss after reticle cleaning, and adverse effects on reticle rework rates. The above-mentioned problems can all be overcome by the present invention.

It can be seen that the above-mentioned existing photomask container obviously still has inconvenience and defects in the method of use, and needs to be further improved urgently. In order to solve the problems existing in the use methods of the existing photomask containers, the relevant manufacturers have tried their best to find a solution, but for a long time no suitable design has been developed, and the general manufacturing method has not been suitable. The manufacturing method can solve the above-mentioned problems, which is obviously a problem that relevant industry players are eager to solve. Therefore, how to create a new method for reducing the deposition defects of the photomask has become a goal that needs to be improved in the current industry.

In view of the defects in the use methods of the above-mentioned existing photomask containers, the inventor actively researches and innovates based on years of rich practical experience and professional knowledge in the design and manufacture of such products, and cooperates with the application of theories, in order to create a A new method for reducing the deposition defects of the photomask can improve the general existing method of using the photomask container and make it more practical. Through continuous research, design, and after repeated trials and improvements, the present invention with practical value is finally created.

Contents of the invention

The main purpose of the present invention is to overcome the defects of the existing photomask container in the use method, and provide a new method for reducing the deposition defects of the photomask. The technical problem to be solved is to provide a Filling the container to remove environmental pollutants so that the method of isolating environmental pollutants is more suitable for practical use.

The purpose of the present invention and the solution to its technical problems are achieved by adopting the following technical solutions. A method for reducing deposition defects of a photomask proposed in accordance with the present invention, using a container for transporting a photomask in a semiconductor manufacturing process, the photomask comprising a substrate made of insulating material and deposited on a surface of the substrate A metal layer of the invention, wherein the method for reducing deposition defects of a photomask is used to remove environmental pollutants in a container, at least including passing a fluid into the container, thereby removing the environmental pollutants.

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures.

In the aforementioned method for reducing deposited defects of a photomask, the repetitive defects formed by the photomask can be reduced by removing these environmental pollutants.

In the aforementioned method for reducing deposition defects of a photomask, the service life of the 193nm photomask can be increased by removing these environmental pollutants.

In the aforementioned method for reducing photomask deposition defects, the exposure process productivity can be increased by removing these environmental pollutants.

In the aforementioned method for reducing photomask deposition defects, the frequency of photomask cleaning can be reduced by removing these environmental pollutants.

In the aforementioned method for reducing photomask precipitation defects, the rework rate of the photomask can be reduced by removing these environmental pollutants.

The aforementioned method of reducing photomask deposit defects, wherein the fluid enters the container through at least one fluid inlet and exits the container through at least one fluid outlet.

In the aforementioned method for reducing photomask deposition defects, the container constitutes a photomask box, a photomask storage or a photomask storage rack.

The aforementioned method for reducing deposition defects of a photomask, wherein the fluid is passed into the container by fixed pressure fluid filling (fixed pres sure fluid fill), variable pressure fluid filling (varied pressure fluid fill), constant pressure fluid purification (fixed pressure fluid fill) pressure fluid purge), varied pressure fluid purge, fixed pressure fluid dilution or varied pressure fluid dilution.

In the aforementioned method for reducing deposition defects of a photomask, the fluid is a pure gas, an inert gas, a mixture gas or an ionized gas.

In the aforementioned method for reducing deposition defects of a photomask, the fluid is nitrogen, oxygen, argon (Ar) or nitrogen monoxide (NO).

Compared with the prior art, the present invention has obvious advantages and beneficial effects. As can be seen from the above, in order to achieve the above object, the present invention provides a container for transporting a photomask in a semiconductor manufacturing process. The photomask includes a substrate made of insulating material and a metal layer deposited on the surface of the substrate. More particularly, it relates to a method of isolating environmental pollutants, the method comprising a container filled with an inert gas, and removing said environmental pollutants through openings in the container. Through the method disclosed in the present invention, an inert gas is used to directly purge the environment inside the container (eg, a pod) to isolate environmental pollutants.

It can be seen from the above that in a semiconductor manufacturing process, the present invention has a container for transporting a photomask, and the photomask includes a substrate made of insulating material, and a metal layer is deposited on the surface of the substrate. The present invention discloses a method for isolating and removing environmental pollutants. The method includes filling the container with an inert gas to remove the environmental pollutants therein. For example, the inlet of the container is used for inert gas for purification, and the The outlet is for the discharge of impurities in the container.

With the above-mentioned technical solutions, the method for reducing the deposition defects of the photomask of the present invention has at least the following advantages:

The invention enables the inert gas to fill the photomask, effectively reduces the pollutants of the 193nm photomask used in the current 0.13 and 0.09 micron process, improves the product yield, photomask production capacity and photomask service life, and reduces Critical dimension loss after mask cleaning and reduced adverse effects on mask rework rates.

To sum up, the novel method for reducing the deposition defects of the photomask of the present invention has the above-mentioned many advantages and practical value, and it has great improvements in both the method of use and the function, and has made great progress in technology, and has produced It achieves easy-to-use and practical effects, and has many improved effects compared with the existing photomask container in the use method, so it is more suitable for practical use, and has wide application value in the industry. It is a novel, progressive and practical new product. design.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the following preferred embodiments are specifically cited below, and are described in detail as follows in conjunction with the accompanying drawings.

Description of drawings

FIG. 1 shows an exploded perspective view of a conventional conventional pod.

FIG. 2 is a schematic cross-sectional view of a transport mask container according to an embodiment of the present invention.

10: box 14: handle

18: Support 22: Lower pad

100: Transport mask container 111: Impurities

121: Fluid inlet 130: Fluid

12: Upper cover 16: Upper gasket

20: Base 24: Outer box

110: Mask 120: Frame

122: Fluid outlet

Detailed ways

In order to further explain the technical means and effects of the present invention to achieve the intended purpose of the invention, the specific implementation and manufacturing method steps of the method for reducing the deposition defects of the photomask proposed according to the present invention will be described below in conjunction with the accompanying drawings and preferred embodiments. , features and their effects are described in detail below.

Through the description of the specific implementation mode, when the technical means and functions adopted by the present invention to achieve the predetermined purpose can be obtained a deeper and more specific understanding, but the accompanying drawings are only for reference and description, and are not used to explain the present invention be restricted.

The present invention relates to a container for transporting a photomask in a semiconductor manufacturing process, and the photomask includes a substrate made of insulating material and a metal layer deposited on the surface of the substrate, in particular with a barrier against environmental pollutants In relation to the method, the method includes passing the container into a fluid, such as nitrogen, to remove the aforementioned environmental contaminants before the mask is exposed.

Through the method disclosed in the present invention, the repeated defects formed by the photomask can be reduced, the service life of the 193nm photomask is increased, the productivity of the exposure process is increased, the frequency of cleaning the photomask is reduced, and the rework rate of the exposure is reduced. For example, the container may be a reticle pod, reticle storage, or the internal reticle shelf of a scanner.

Please refer to FIG. 2 , which shows a transport mask container according to a preferred embodiment of the present invention. The transport photomask container 100 at least includes a photomask 110 and a frame 120 . Both the transport mask container 100 and the frame 120 include at least one fluid inlet 121 and at least one fluid outlet 122 .

As can be seen from FIG. 2 , the photomask 110 is placed on the frame 120 , and the surface of the photomask 110 is attached with impurities 111 . The impurity 111 is particles (such as sulfate) formed after the gas (such as sulfur dioxide (S0 2 )) transported in the mask container 100 is irradiated by a 193 nanometer (nm) light source.

There are three ways to pass the photomask container 100 into the fluid 130. The photomask container 100 and the frame 120 are transported through the fluid inlet 121 with fluid fill, with fluid purge, or with fluid dilution. The internal environment, that is, the impurity 111 on the surface of the photomask is taken away from the surface of the photomask 110 by the fluid 130 , and the impurity 11 is discharged from the fluid outlet 122 .

The above-mentioned three ways of feeding the fluid 130 can all be completed by means of fixed pressure feeding or variable pressure feeding.

This fluid 130 is a pure gas (pure gas), such as nitrogen (N ₂ ) or oxygen (O ₂ ); or an inert gas (inert gas), such as argon (Ar); or a mixture gas (mixture gas), such as monoxide Nitrogen (NO); or ionized gas generated by an ion generator.

In the tests of the present invention, the number of deposited defects (precipitates) on the 193nm photomask was reduced. In Table 1 below, the environment/reticle box/reticle test results using Sunway AIM-100 sulfur dioxide detector are listed:

Table 1

Environment/Reticle Box/Reticle Inspection Results Using Sunway AIM-100 Sulfur Dioxide Detector

area detector position Results (concentration = nanograms/cm2/day) Mask room Microenvironment (no reticle in pod) 12 Microenvironment (reticle in pod) 15 open environment 25 Purge the pod with nitrogen for 1 hour 3 around the scanner Microenvironment (no reticle in pod) 13 open environment 25

It can be seen from Table 1 that after cleaning the pod with an inert gas such as nitrogen for 1 hour, the particle concentration in the pod is greatly reduced from the original 15 nanograms/cm2/day (with a photomask in the pod) to 3 nanograms/cm2/day, effectively reducing the particles in the mask box by 80%.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, may use the technical content disclosed above to make some changes or modify them into equivalent embodiments with equivalent changes, but as long as they do not depart from the technical solution of the present invention, the Technical Essence Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solution of the present invention.

Claims (11)

1. A method for reducing deposition defects of a photomask, characterized in that a photomask consisting of a substrate made of an insulating material and a metal layer deposited on a surface of the substrate is used in a semiconductor manufacturing process The container, wherein the method of reducing deposition defects of a photomask at least includes passing a fluid into the container, thereby removing environmental contaminants. 2. The method for reducing deposited defects of a photomask according to claim 1, wherein the repetitive defects formed by the photomask can be reduced by removing the environmental pollutants. 3. The method for reducing deposition defects of a photomask according to claim 1, wherein the service life of the 193nm photomask can be increased by removing the environmental pollutants. 4. The method for reducing deposition defects of a photomask as claimed in claim 1, wherein the exposure process productivity can be increased by removing the environmental pollutants. 5. The method for reducing deposition defects of a photomask according to claim 1, wherein the frequency of cleaning the photomask can be reduced by removing the environmental pollutants. 6. The method for reducing deposition defects of a photomask according to claim 1, wherein the rework rate of the photomask can be reduced by removing the environmental pollutants. 7. The method of claim 1, wherein the fluid enters the container through at least one fluid inlet and exits the container through at least one fluid outlet. 8. The method for reducing photomask deposition defects according to claim 1, wherein said container constitutes a photomask box, a photomask storage or a photomask storage rack. 9. The method for reducing deposition defects of photomasks according to claim 1, wherein said fluid is passed into the container in the following ways: constant pressure fluid filling, variable pressure fluid filling, constant pressure fluid purification, variable pressure fluid Purification, constant pressure fluid dilution or variable pressure fluid dilution. 10. The method for reducing deposition defects of a photomask according to claim 1, wherein said fluid is a pure gas, an inert gas, a mixture gas or an ionized gas. 11. The method for reducing deposition defects of a photomask according to claim 1, wherein said fluid is nitrogen, oxygen, argon or nitrogen monoxide.

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