KR20100053126A - Method and apparatus for rinsing and drying a wafer - Google Patents

Abstract

PURPOSE: A method and an apparatus for rinsing and drying a wafer are provided to significantly improve the cleaning power of a wafer using steam with high kinetic energy and high heat energy. CONSTITUTION: A wafer is loaded into an elevator(4) in a drying chamber(2). The elevator is lowered to a bath(3) in which deionized water is contained. Isopropyl alcohol(IPA) steam is provided to the drying chamber until the IPA steam covers the surface of the deionized water. The elevator is lifted from the bath. The bath discharges the deionized water through a drain line. A gas is sprayed within the chamber in order to dry the wafer.

Description

Method and apparatus for rinsing and drying wafers {METHOD AND APPARATUS FOR RINSING AND DRYING A WAFER}

The present invention relates to a method and apparatus for rinsing and drying wafers, and more particularly, to IPA vapor drying for drying wafers with isopropyl alcohol (hereinafter referred to as 'IPA').

In general, when fabricating a wafer into an integrated circuit, a cleaning process is required to clean the wafer to remove residual chemicals, small particles, contaminants, and the like, which occur during various manufacturing processes. In particular, when manufacturing highly integrated integrated circuits, a cleaning process that removes fine contaminants adhering to the surface of the wafer is very important.

The wafer cleaning step in the semiconductor manufacturing step can be divided into a chemical solution treatment step (chemical treatment step), a rinse step, and a drying step. The chemical solution treatment process is a process of treating a wafer with a chemical solution, the rinsing process is a process of washing the chemical solution treated wafer with deionized water, and the drying process is a process of drying the rinsed wafer.

If the impurities in the wafer are not sufficiently removed, the defect rate of the integrated circuit increases, and the manufacturing cost and reliability of the ultra-precision components are reduced, so the cleaning process is recognized as a very important part in the semiconductor process. During this time the cleaning process proceeds the most times.

At present, the cleaning technology using deionized water is changing from the existing large cleaning equipment to the medium and small cleaning equipment, and a drying apparatus has been essentially installed in these facilities. Thus, the wafer is rinsed in a bath containing deionized water and then dried in a drying apparatus. In the initial stage of the drying apparatus, a spin drying apparatus using a centrifugal force is used. However, the spin drying apparatus may have contaminants remaining on the wafer due to static electricity generation. The limit of performance has been reached, such as the possibility of the pattern being washed out due to the friction between the patterns.

Therefore, a drying method using the marangoni effect has been widely used in recent years to dry the wafer without such a problem. The Marangoni effect is based on the principle that when two different surface tensions exist in one liquid region, the liquid flows from the small surface tension region to the large surface tension region. In other words, the Marangoni drying method applies IPA vapor having a smaller surface tension than deionized water to the surface of the wafer, and slowly lifts the wafer submerged in deionized water into the atmosphere of the IPA atmosphere or slowly discharges the deionized water. It exposes to the atmosphere of IPA atmosphere and adsorbs IPA vapor on the wafer, and replaces the moisture remaining on the wafer to dry. By using the Marangoni drying method, the wafer is prevented from being exposed to the air, thereby minimizing wafer contamination by residues, maximizing the water particle removal effect on the wafer surface, and reducing the drying time. .

Currently, the IPA vapor drying apparatus used for the wafer drying after the final rinse in the semiconductor cleaning process has the following advantages over the spin dryer. First, it prevents particle adsorption by electrostatic forces. Second, to prevent the formation of water spots. Third, it is possible to prevent the wafer from being mechanically broken. As a result, the use of IPA steam drying equipment is gradually expanding due to these advantages.

In the rinsing and drying process in such an IPA steam drying drying apparatus, the quality of deionized water is of great importance with respect to the rinsing process, in which the deionized water is used to remove impurities from the wafer which has been subjected to unit processes for the manufacture of semiconductor devices. Almost theoretically, super deionized water levels close to absolute deionized water are required. In particular, the rapid development of ultra-precision products, such as highly integrated circuits, continues to require higher levels of deionized water. However, the acquisition of high levels of deionized water requires significant costs, and in reality, deionized water has a high contact angle with the surface of the wafer, so that the wafer is conditioned by rinsing through deionized water and in an atmosphere filled with IPA vapor. It penetrates between the fine patterns of and prevents the rinse of chemicals remaining on the wafer.

Therefore, there is a need for a novel wafer rinsing and drying method that allows deionized water to penetrate between fine patterns so that improved rinsing can be achieved in the case of wafers with fine patterns.

The technical problem to be solved by the present invention is to provide a rinsing and drying method of the wafer that can be rinsed by penetrating between the fine pattern of the wafer in the rinsing and drying method of the wafer.

It is another object of the present invention to provide a wafer rinsing and drying method that allows cleaning to be effected even at the top and bottom of the wafer.

Another object of the present invention is to provide a wafer rinsing and drying apparatus capable of carrying out this method.

The present invention relates to a method of rinsing and drying a wafer in an IPA vapor drying apparatus including a bath and a drying chamber, comprising mounting a wafer to an elevator in a drying chamber, and lowering the elevator to a bath filled with deionized water so that the wafer is deionized. Allowing it to enter below the surface, supplying IPA steam and steam to a closed drying chamber in close contact with the bath until the IPA steam and steam covers the surface of the deionized water, lifting the elevator out of the bath; It provides a method of rinsing and drying the wafer comprising the step of discharging the deionized water from the bath through the drain line, supplying a gas to the chamber to dry the wafer.

Preferably, the step of raising comprises: raising at a first speed from the start of the lift until the top of the elevator contacts the surface of the deionized water, the wafer being demounted from when the elevator reaches the surface of the deionized water. Increasing at a second rate until it exits the deionized water completely.

Preferably, the step of raising comprises: raising at a first speed from the start of the rising until the bottom of the wafer reaches the surface of deionized water, and starting from the time when the bottom of the wafer reaches the surface of deionized water. Increasing at a second rate until it exits the deionized water completely.

Preferably, the step of raising comprises: raising at a first speed from the start of the lift until the lift reaches the surface of deionized water, and the lower end of the wafer from the deionized water when the lift reaches the surface of deionized water. Increasing at a second rate until reaching the surface, and increasing at a third rate until the elevator completely exits the deionized water.

Preferably, injecting the gas into the chamber may comprise injecting a hot N ₂ purge gas.

Preferably, the method may further include injecting a low temperature N ₂ gas into the chamber.

Preferably, the steam may be N ₂ steam.

In addition, the present invention is a wafer rinsing and drying apparatus including a bath and a drying chamber, an elevator for mounting a wafer and moving between the bath and the drying chamber, a speed controller for controlling the moving speed of the elevator, spraying IPA vapor into the drying chamber An IPA steam injector, a steam injector for injecting steam into the drying chamber, and a purge gas injector for injecting a high temperature purge gas into the drying chamber are provided.

According to the present invention, since the rinsing process is performed by infiltrating IPA vapor, steam, and deionized water between the fine patterns of the wafer, the chemicals remaining between the patterns of the wafer due to the chemical treatment process can be rinsed more completely.

In addition, the present invention adjusts the speed at which the wafer enters and exits the deionized water according to the degree of rise of the wafer relative to the surface of the deionized water, thereby allowing the IPA vapor and steam to flow between the wafer's fine patterns at the lower and upper ends of the wafer. And deionized water can be penetrated.

In addition, the present invention can greatly improve the wafer cleaning power by performing wafer rinsing and drying using steam having high kinetic energy and thermal energy.

Through these effects, the wafer rinsing and drying process is more effective and efficient, so that higher quality wafers can be mass-produced at no additional cost.

Other specific details of the invention are included in the detailed description and drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, only the embodiments are to make the disclosure of the present invention complete, and the general knowledge in the technical field to which the present invention belongs. It is provided to fully convey the scope of the invention to those skilled in the art, and the invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, with reference to the drawings, a method and apparatus for rinsing and drying a wafer according to an embodiment of the present invention will be described in more detail.

1 is a view schematically showing a wafer rinsing and drying apparatus according to an embodiment of the present invention. Referring to FIG. 1, the wafer rinsing and drying apparatus of the present invention includes a drying chamber 2 containing a wafer and separated from the outside by a wall, filled with deionized water for cleaning the wafer, and separated from the drying chamber 2. And a bath (3) forming a space of a space, an elevator (4) for supporting and lowering and raising a wafer, and an IPA steam and steam supply (5) for supplying IPA steam and steam to the drying chamber (2). The drying chamber 2 is sealed in close contact with the bath 3.

2 illustrates each step of a method of rinsing and drying a wafer according to one embodiment of the invention. (a) is the state of the IPA vapor drying apparatus before injecting a wafer. (b) is a step of mounting the wafer 1 on the elevator 4 in the drying chamber 2 of the IPA vapor drying apparatus. When the wafer 1 is mounted on the elevator 4, a part of the wafer 1 is not covered by the elevator 4 at the contact surface between the elevator 4 and the wafer 1, and the contact area is minimized. It is preferable.

(c) is a step of supplying IPA steam and N ₂ steam into the drying chamber 2.

(d) is a step of lowering the elevator 4 so that the wafer 1 is completely submerged below the surface of the deionized water contained in the bath. The step of lowering the wafer 1 is preferably performed at a low speed to provide sufficient time for deionized water to penetrate between the patterns disposed on the wafer 1.

(e) is a step in which the IPA steam and the N ₂ steam are filled in the drying chamber 2, completely covering the surface of the deionized water, and penetrating to the deionized water. By supplying the IPA steam and the N2 steam to penetrate the deionized water in step (e), deionized water can penetrate between the fine patterns of the wafer 1 in the step of raising the wafer 1.

(f) to (g) are steps for raising the elevator 4 to cause the wafer 1 to escape from the deionized water. When raising the elevator 4, the rising speed can be adjusted according to the position with respect to the surface of the elevator and the deionized water in which the wafer 1 is mounted.

According to one embodiment of the present invention, the rising speed is that the upper part of the elevator 4 on which the wafer 1 is mounted is in contact with the surface of the deionized water since the top of the wafer 1 is in contact with the surface of the deionized water. At the first speed until the top of the elevator 4 contacts the surface of the deionized water until the bottom of the wafer 1 contacts the surface of the deionized water until the It can be distinguished at a third speed until the lowermost part contacts the surface of the deionized water, until the lowermost part of the wafer 1 is completely separated from the surface of the deionized water and the lower part of the elevator 4 contacts the surface of the deionized water. . 3 shows a section in which the first speed, the second speed, and the third speed are applied when the wafer 1 is raised in accordance with this embodiment.

In another embodiment, the ascent rate is the elevator 4 at a first speed from the top of the wafer 1 to the surface of the deionized water until the top of the elevator 4 contacts the surface of the deionized water. It can be distinguished at a second speed from the time when the top of the contacting surface of the deionized water until the bottom of the wafer 1 is completely separated from the surface of the deionized water.

In another embodiment, the ascending rate is at a first speed from the top of the wafer 1 to the surface of the deionized water until the bottom of the wafer 1 contacts the surface of the deionized water. It can be distinguished at a second speed until the bottom of the contact with the surface of the deionized water until the bottom (1) of the wafer is completely separated from the surface of the deionized water.

Here, the 'top' of the wafer refers to the uppermost part in the state where the wafer is mounted, and the part may include the top of the wafer from the bottom of the predetermined range, and the 'bottom' of the wafer Refers to the bottom portion in the mounted state, the portion may include from the bottom of the wafer to the upper portion of the predetermined range. As described above, by adjusting the rising speed of the wafer 1 in accordance with the positional relationship between the wafer 1 and the surface of the deionized water, deionized water and steam can more effectively penetrate between the patterns of the wafer 1. Can provide time.

(h) is a step of injecting a high temperature N ₂ purge gas into the drying chamber 2 while discharging the deionized water from the bath 3 after the wafer 1 is completely discharged from the deionized water. The purge gas is an inert gas used to remove unwanted impurities and the like in the chamber, and Ar or the like may be used in addition to N ₂ . This purge gas is combined with deionized water on the wafer 1 to fall from the wafer 1 to the bath 3 or remains on the wafer 1 in combination with deionized water.

(i) is the step of spraying a low temperature N ₂ gas stream on the wafer 1. Deionized water and purge gas remaining on the wafer 1 are removed by this injected N ₂ gas stream or by natural drying.

(j) is a step of taking out the wafer 1 in which the rinse and drying is completed, in the chamber.

4 illustrates the extent to which deionized water penetrates between patterns of a wafer when the wafer is rinsed in accordance with one embodiment of the present invention. Fig. 4 (a) shows the degree of penetration of deionized water when the chamber 1 is filled with only IPA vapor when the wafer 1 emerges from deionized water. It is understood that deionized water does not penetrate between patterns when the wafer pattern is narrow. Can be. When deionized water comes into contact with a solid, such as a wafer, the free surface of the liquid is at an angle to the solid plane, depending on the cohesion between the liquid molecules and the adhesion between the liquid and the solid wall. For this reason, deionized water generally has a high contact angle in relation to the wafer, and it is highly likely that deionized water cannot penetrate between the fine patterns of the wafer 1.

4 (b) shows the degree of penetration of deionized water when the wafer 1 is full in the chamber to cover the surface of the deionized water before the wafer 1 is taken out of the deionized water, according to one embodiment of the invention. Indicates. In one embodiment, such steam may be hot N ₂ steam. N ₂ steam is a gas having a high kinetic energy, and easily accesses inwards between the patterns even when the patterns are finely disposed. Thus, the wafer 1 is the time out of the deionized water, and if N ₂ steam is filled on the surface of the deionized water, N ₂ of steam is liquefied due to the deionized water is between the fine pattern on the wafer (1) with a de-ionized water molecule Can penetrate Therefore, cleaning can be performed even to impurities between fine patterns.

In addition, the high kinetic and thermal energy of the N ₂ steam enhances the ability to rinse the contaminants between patterns.

Accordingly, compared to the case where the wafer is filled with only IPA vapor before drying out of the deionized water and dried in the conventional invention, when the N ₂ steam is injected together and filled in the chamber, the wafer comes out of the deionized water and reaches a fine pattern of the wafer. It can be cleaned thoroughly and enhanced cleaning is possible due to the high kinetic and thermal energy of steam.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it is to be understood that the embodiments described above are exemplary in all respects and not restrictive.

1 is a view schematically showing a wafer rinsing and drying apparatus according to an embodiment of the present invention.

2 is a view showing each step of rinsing and drying the wafer according to an embodiment of the present invention.

3 is a diagram illustrating a section in which a first speed, a second speed, and a third speed are applied when the wafer is raised according to an embodiment of the present invention.

4 is a diagram illustrating the extent to which deionized water penetrates between patterns of a wafer when the wafer is rinsed according to one embodiment of the present invention.

Claims (8)

A method of rinsing and drying a wafer in an IPA vapor drying apparatus comprising a bath and a drying chamber, Mounting the wafer on an elevator in the drying chamber; Lowering the elevator to the bath filled with deionized water such that the wafer is submerged in the deionized water; Supplying IPA steam and steam to a closed drying chamber in close contact with the bath until the IPA vapor and steam cover the surface of the deionized water; Lifting the elevator out of the bath; Discharging the deionized water through the drain line in the bath; Spraying gas into the chamber to dry the wafer. The method of claim 1, The raising step, Ascending at a first speed from the beginning of the ascent until the top of the elevator contacts the surface of the deionized water; And And raising the wafer at a second speed until the lift reaches the surface of the deionized water until the wafer is completely withdrawn from the deionized water. The method of claim 1, The raising step, Raising at a first speed from the start of the ascent until the bottom of the wafer reaches the surface of the deionized water; And Increasing the wafer at a second rate from the bottom of the wafer to the surface of the deionized water until the wafer is completely withdrawn from the deionized water. The method of claim 1, The raising step, Ascending at a first speed from the beginning of the ascent until the elevator reaches the surface of the deionized water; Ascending at a second speed from when the elevator reaches the surface of the deionized water until the lower end of the wafer reaches the surface of the deionized water; And  And raising the elevator at a third speed until the elevator is completely withdrawn from the deionized water. The method of claim 1, Injecting gas into the chamber comprises injecting hot N ₂ purge gas. The method of claim 5, And injecting a low temperature N ₂ gas into the chamber. 7. The method according to any one of claims 1 to 6, Wherein the steam is N ₂ steam. A wafer rinsing and drying apparatus comprising a bath and a drying chamber, An elevator for mounting the wafer and moving between the bath and the drying chamber; A speed controller controlling a moving speed of the elevator; An IPA steam injector for injecting IPA steam into the drying chamber; A steam injector for injecting steam into the drying chamber; And And a purge gas injector for injecting a high temperature purge gas into the drying chamber.

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