TWI740267B - Method for wafer cleaning and drying, and wafer cleaning and drying device - Google Patents

Abstract

A method for wafer cleaning and drying, and a wafer cleaning and drying device are provided. The method includes the following steps: providing a cleaning tank for storing a cleaning solution; disposing a wafer vertically into the cleaning solution; continue injecting the cleaning solution to allow excess cleaning solution to flow from an overflow port above the cleaning tank; discharging the cleaning solution from a lower drain port in a slow drain mode; turning off the drain port when a surface of the cleaning solution drops above the wafer; injecting a liquid volatile solvent on the surface in a two-stage manner to form a two-liquid phase layer; turning on the drain port again and drain the cleaning solution in slow drain mode; discharging the cleaning solution in a fast drain mode when a liquid surface of the liquid volatile solvents is below the lowest position of the wafer; and introducing a high temperature nitrogen gas from above the cleaning tank to blow the wafer.

Description

Wafer cleaning and drying method and wafer cleaning and drying device

The present invention relates to a cleaning and drying method and a cleaning and drying device; in detail, it relates to a wafer cleaning and drying method and a wafer cleaning and drying device.

In the prior art, when the wafer is cleaned by a wet process, the wafer needs to be dried immediately to facilitate subsequent processes.

In detail, since the finished products after wafer processing are all nano-level, the particles or chemicals remaining on the surface of the wafer during the processing process will seriously affect the yield of the finished wafer. Effectively remove from the wafer surface.

When the wafer is cleaned by a wet process, the wafer is immersed in a cleaning liquid in a cleaning tank, and the remaining particles or chemicals are removed by washing with the cleaning liquid, and the cleaned The wafer also needs to effectively complete the drying operation before the subsequent process can be carried out.

Therefore, how to complete the cleaning and drying operations of the wafers in the shortest time is an urgent problem in the industry.

One of the objectives of the present invention is to provide a wafer cleaning and drying method and a wafer cleaning and drying device, which can effectively remove particles or chemicals remaining on the wafer, while shortening the working hours of drying the wafer, so as to achieve the shortest time Finish the wafer cleaning and drying operations inside.

To achieve the above objective, a wafer cleaning and drying method disclosed in the present invention includes the following steps:

Provide a cleaning tank with a cleaning fluid;

Dip a wafer vertically into the cleaning solution;

Continuously inject cleaning liquid from one of the water inlets below the cleaning tank, so that excess cleaning liquid flows out of an overflow port above the cleaning tank;

Close the water inlet and open a drain at the bottom of the washing tank to discharge the washing liquid in a slow drain mode;

When one of the cleaning liquid levels drops to the top of the wafer, close the drain of the cleaning tank;

Inject a liquid volatile solvent into the liquid surface of the cleaning liquid in a one-two-stage manner to form one or two liquid phase layers;

Open the drain again, and drain the cleaning liquid in a slow drain mode;

When a liquid level of the liquid volatile solvent is lower than the lowest position of the wafer, the cleaning liquid is discharged in a rapid drainage mode; and

Introduce a high temperature nitrogen gas from the top of the cleaning tank to dry the wafers;

Among them, the steps of injecting a liquid volatile solvent in a two-stage manner are:

Inject the liquid volatile solvent for the first time so that the liquid volatile solvent has a first height;

Let the liquid volatile solvent stand still; and

Inject the liquid volatile solvent again to make the liquid volatile solvent reach a second height.

In the wafer cleaning and drying method of the present invention, the liquid volatile solvent has a first height between 5-6 mm, and the liquid volatile solvent has a second height between 10-15 mm.

In the wafer cleaning and drying method of the present invention, the flow rate in the slow drainage mode is between 3.5 and 5 L/M.

In the wafer cleaning and drying method of the present invention, when high-temperature nitrogen is introduced to dry the wafer, the flow rate of the high-temperature nitrogen is between 380-430 L/M.

In the wafer cleaning and drying method of the present invention, when high-temperature nitrogen is introduced from the top of the cleaning tank to dry the wafers, an air extraction step is further included, which simultaneously extracts the high-temperature nitrogen through an air extraction system at the bottom of the cleaning tank. And one of the pumping pressures of the pumping system is between 60 Pa and 90 Pa.

In the wafer cleaning and drying method of the present invention, the cleaning liquid is heated deionized water, and the liquid volatile solvent is liquid isopropanol.

To achieve the above objective, a wafer cleaning and drying device of the present invention includes a cleaning tank, a support and a liquid volatile solvent introduction pipeline. A cleaning liquid is stored in the cleaning tank, and the cleaning tank has a water inlet arranged at the bottom, an overflow outlet arranged at the upper side, and a drain outlet arranged at the bottom. The bracket is arranged in the cleaning tank to vertically support a wafer. The liquid volatile solvent introduction pipeline is used for introducing a liquid volatile solvent from the periphery above the cleaning tank.

In the wafer cleaning and drying device of the present invention, a drainage plate is further arranged above the cleaning tank, and when the liquid volatile solvent flows out of the liquid volatile solvent introduction pipeline, the drainage plate is used to guide the liquid volatile solvent to be directly injected into one of the cleaning liquids. Liquid level.

The wafer cleaning and drying device of the present invention further includes an air extraction system, which is arranged at the bottom of the cleaning tank.

In the wafer cleaning and drying device of the present invention, the cleaning liquid is heated deionized water, and the liquid volatile solvent is liquid isopropanol.

The present invention relates to a wafer cleaning and drying method and a wafer cleaning and drying device, which can effectively remove particles or chemicals remaining on the wafer while shortening the working hours of drying the wafer, thereby completing the wafer in the shortest time. Round cleaning and drying operations.

In the drawings, FIG. 1 is a step diagram of the wafer cleaning and drying method of the present invention. Figure 2-Figure 11 are schematic diagrams corresponding to the steps in Figure 1.

In detail, as shown in FIG. 1, a wafer cleaning and drying method disclosed in the present invention includes the following steps:

S1: Provide a cleaning tank with a cleaning fluid.

As shown in FIG. 3, a cleaning tank 110 storing a cleaning liquid 200 is provided, and the cleaning liquid 200 is injected from a water inlet 112 below the cleaning tank 110.

S2: Immerse a wafer vertically in the cleaning solution.

As shown in FIG. 4, after the cleaning liquid 200 in the cleaning tank 110 is injected to a certain height, a wafer 300 is vertically immersed in the cleaning liquid 200, so that the wafer 300 is carried by a support 120, and the wafer 300 It is completely immersed in the cleaning fluid 200.

S3: Continuously inject cleaning liquid from one of the water inlets below the cleaning tank, so that the excess cleaning liquid flows out of an overflow port above the cleaning tank.

Please also refer to FIG. 5, when the wafer 300 is vertically immersed in the cleaning liquid 200, and the wafer 300 is completely immersed in the cleaning liquid 200, the cleaning liquid 200 is still continuously injected from a water inlet 112 under the cleaning tank 110. The wafer 200 is rinsed. In this way, the cleaning liquid 200 with particles or chemicals after the wafer 200 is rinsed will be pushed by the newly injected cleaning liquid 200 under the cleaning tank 110 to become the excess cleaning liquid 200, and then from the top of the cleaning tank 110 One of the overflow ports 114 flows out.

That is, the particles or chemicals remaining on the surface of the wafer 300 during the wafer processing process can be effectively removed at this stage.

The wafer 300 has other subsequent processing steps after the cleaning operation is completed, so the cleaned wafer 300 needs to be dried quickly to ensure that the subsequent related processing steps can proceed smoothly. Therefore, we will explain the subsequent drying steps:

S4: Close the water inlet and open a drain at the bottom of the washing tank to discharge the washing liquid in a slow drain mode.

As shown in FIG. 6, since the wafer 300 has effectively removed particles or chemicals remaining on the surface of the wafer 300 in the foregoing steps, after the water inlet 112 is closed, a drain at the bottom of the cleaning tank 110 will be opened 116. The cleaning liquid 200 is discharged from the bottom of the cleaning tank 110 in a slow drainage mode.

S5: When one of the cleaning liquid levels drops to the top of the wafer, close the drain of the cleaning tank.

Next, as shown in FIG. 7, when the cleaning solution 200 is discharged from the bottom of the cleaning tank 110 in a slow drainage mode, and one of the liquid levels of the cleaning solution 200 drops above the wafer 300, the drain port 116 of the cleaning tank 110 is closed.

S6: Inject a liquid volatile solvent into the liquid surface of the cleaning liquid in a one-two-stage manner to form one or two liquid phases.

As shown in FIG. 8, when the liquid level of the cleaning liquid 200 drops to the top of the wafer 300 and the drain 116 of the cleaning tank 110 is closed, a liquid volatile solvent 400 is injected into the liquid of the cleaning liquid 200 in a two-stage manner. Surface to form one or two liquid phase layers.

S7: Open the drain again, and drain the cleaning liquid in a slow drain mode.

As shown in FIG. 9, after the two-phase layer is formed, the drain port 116 is opened again, and the cleaning liquid 200 is discharged in the slow drain mode. In this way, during the slow discharge of the cleaning solution 200, the liquid volatile solvent 400 will be able to completely contact the wafer 300 from top to bottom and gradually volatilize. Since the liquid volatile solvent 400 will also remove the moisture and impurities remaining on the wafer 300 during the volatilization process, this step will surely complete the drying operation of the wafer 300.

S8: When the liquid level of one of the liquid volatile solvents is lower than the lowest position of the wafer, the cleaning liquid is discharged in a rapid drainage mode.

Next, as shown in FIG. 10, when one of the liquid levels of the liquid volatile solvent 400 is lower than the lowest position of the wafer 300, it means that the liquid volatile solvent 400 has covered the surface of the wafer 300 and is no longer exposed to the cleaning liquid. Because of the influence of 200, the cleaning solution 200 can be discharged from the cleaning tank 110 in a quick drain mode to facilitate the subsequent removal of the wafer 300 from the cleaning tank 110.

S9: Introduce a high temperature nitrogen gas from the top of the cleaning tank to dry the wafer.

Finally, as shown in FIG. 11, after the cleaning solution 200 is completely discharged from the cleaning tank 110, a high temperature nitrogen gas 500 can be introduced from the top of the cleaning tank 110 to accelerate the volatilization of the liquid volatile solvent 400 to dry the wafer 300.

Wherein, in S6: the step of injecting the liquid volatile solvent 400 in a two-stage manner, the step may further include the following steps:

S61: Inject the liquid volatile solvent for the first time so that the liquid volatile solvent has a first height.

S62: Let the liquid volatile solvent stand still; and

S63: Inject the liquid volatile solvent again to make the liquid volatile solvent reach a second height.

In detail, as shown in FIG. 12, since the initial process of injecting the liquid volatile solvent 400 into the liquid level of the cleaning liquid 200, the liquid level of the cleaning liquid 200 will show an uneven turbidity phenomenon, so in the S61 stage Only a small amount of liquid volatile solvent 400 with a first height H1 is injected first.

Then, as shown in step S62, the liquid volatile solvent 400 is allowed to stand for the first time so that the cleaning liquid 200 and the liquid volatile solvent 400 present an initial two-phase layer, and then as shown in FIG. 13 and step S63, the liquid is injected again. The volatile solvent 400 makes the liquid volatile solvent 400 reach the second height H2.

At this time, since the liquid volatile solvent 400 is already above the initial two liquid phase layer after the standing in step 62, the liquid volatile solvent 400 injected again in step S63 will not be mixed with the cleaning liquid 200. In the case of surface contact, the occurrence of turbidity can be avoided, and the waiting time for the liquid volatile solvent 400 to stand still can be shortened.

In other words, in the present invention, the step of injecting the liquid volatile solvent 400 in a two-stage manner is used to shorten the waiting time required to stand still after injecting the liquid volatile solvent to the level of the cleaning liquid in the prior art, thereby increasing The working efficiency of the wafer cleaning and drying device method.

In the wafer cleaning and drying method of the present invention, the liquid volatile solvent 400 injected in the first stage has a first height H1 between 5-6 mm, and this height allows the liquid volatile solvent injected in the second stage 400 will not come into contact with the cleaning liquid 200, thereby effectively avoiding turbidity. After the liquid volatile solvent 400 is injected in the second stage, the second height H2 (that is, the total height) of the liquid volatile solvent 400 is between 10 and 15 mm to ensure that in step S7 shown in FIG. 9 When the liquid volatile solvent 400 contacts the wafer 300 from top to bottom and gradually volatilizes, a sufficient amount of the liquid volatile solvent 400 can contact the wafer 300.

In the wafer cleaning and drying method of the present invention, the flow rate in the slow drainage mode is between 3.5 and 5 L/M. This flow rate can ensure that the liquid levels of the cleaning liquid 200 and the liquid volatile solvent 400 maintain a gentle drop during the draining process, so that the liquid volatile solvent 400 contacts the wafer 300 and evaporates.

In the wafer cleaning and drying method of the present invention, when the high temperature nitrogen gas 500 is introduced to dry the wafer 300, the flow rate of the high temperature nitrogen gas 500 is between 380 and 430 L/M. Moreover, when the high temperature nitrogen 500 is introduced from the top of the cleaning tank 110 to dry the wafer 300, an air extraction step may be included, which simultaneously extracts the high temperature nitrogen 500 through the air extraction system 140 at the bottom of the cleaning tank 110, and The gas system 140 has a suction pressure between 60 Pa and 90 Pa.

The introduction of high-temperature nitrogen 500 can speed up the drying operation of the wafer 300, and the use of the air extraction system 140 helps to quickly exhaust the gas with moisture or other impurities after the liquid volatile solvent 400 volatilizes, avoiding re-aligning the wafer Circle 300 causes pollution.

In a preferred embodiment of the wafer cleaning and drying method of the present invention, the cleaning liquid 200 is heated deionized water, and the liquid volatile solvent 400 is liquid isopropanol.

Please refer to FIGS. 3-11 again. The present invention also discloses a wafer cleaning and drying apparatus 100, which includes a cleaning tank 110, a support 120, and a liquid volatile solvent introduction pipe 130 for performing the aforementioned FIG. 1 The wafer cleaning and drying method.

Wherein, a cleaning liquid 200 is stored in the cleaning tank 110, and the cleaning tank 100 has a water inlet 112 disposed below, an overflow port 114 disposed above, and a drain port 116 disposed at the bottom. The support 120 is disposed in the cleaning tank 110 to vertically support a wafer 300. The liquid volatile solvent introduction pipe 130 is used to introduce a liquid volatile solvent 400 from the upper periphery of the cleaning tank 110.

Please continue to refer to FIGS. 12 and 13. In the wafer cleaning and drying apparatus 100 of the present invention, a guide plate 118 is further provided above the cleaning tank 110. After the liquid volatile solvent 400 flows out of the liquid volatile solvent introduction pipe 130, the setting of the guide plate 118 will guide the liquid volatile solvent 400 to be directly injected into a liquid surface of the cleaning liquid 200. In this way, the use of the guide plate 118 can prevent the liquid volatile solvent 400 from flowing through the overflow port 114 above the cleaning tank 110 from being contaminated, and the liquid volatile solvent 400 guided by the guide plate 118 can also reduce the injection of cleaning The turbidity caused by the liquid level of the liquid 200 has the effect of shortening the waiting time required to stand still after injecting the liquid volatile solvent to the liquid level of the cleaning liquid in the prior art.

As shown in FIGS. 3-11, the wafer cleaning and drying apparatus of the present invention further includes an air extraction system 140, which is arranged at the bottom of the cleaning tank 110 to assist the drying operation of the wafer 200 and shorten the drying process. time.

In summary, through the two-stage liquid volatile solvent injection method of the wafer cleaning and drying method of the present invention, and the draft plate of the wafer cleaning and drying device, when the liquid volatile solvent is injected into the cleaning solution During surface processing, the waiting time for the liquid volatile solvent and the cleaning solution to form a stable two-phase layer can be shortened, and the particles or chemicals remaining on the wafer can be effectively removed, thereby completing the cleaning of the wafer in the shortest time. And dry operations.

The above-mentioned embodiments are only used to illustrate the implementation mode of the present invention and explain the technical features of the present invention, and are not used to limit the protection scope of the present invention. Any change or equivalence arrangement that can be easily accomplished by a person familiar with this technology belongs to the scope of the present invention, and the scope of protection of the rights of the present invention shall be subject to the scope of the patent application.

100: Wafer cleaning and drying device 110: cleaning tank 112: water inlet 114: Overflow port 116: Drain 118: Drainage plate 120: bracket 130: Liquid volatile solvent introduction line 140: Exhaust system 200: cleaning fluid 300: Wafer 400: Liquid volatile solvent 500: high temperature nitrogen H1: first height H2: second height

FIG. 1 is a step diagram of the wafer cleaning and drying method of the present invention. 2 is a step diagram of injecting a liquid volatile solvent in a two-stage manner in the wafer cleaning and drying method of the present invention. Fig. 3-Fig. 11 are schematic diagrams corresponding to the process in Fig. 1. Figures 12-13 are schematic diagrams of the guide plate set above the cleaning tank in the wafer cleaning and drying device of the present invention.

100: Wafer cleaning and drying device

110: cleaning tank

112: water inlet

114: Overflow port

116: Drain

118: Drainage plate

120: bracket

130: Liquid volatile solvent introduction line

140: Exhaust system

200: cleaning fluid

300: Wafer

400: Liquid volatile solvent

Claims (9)

A wafer cleaning and drying method includes the following steps: providing a cleaning tank storing a cleaning liquid; immersing a wafer in the cleaning liquid vertically; continuously injecting the cleaning liquid from a water inlet below the cleaning tank, So that the surplus of the cleaning fluid flows out from an overflow at the top of the cleaning tank; close the water inlet, and open a drain at the bottom of the cleaning tank, so that the cleaning fluid is discharged in a slow drainage mode; when the cleaning When one of the liquid levels drops to the top of the wafer, close the drain of the cleaning tank; inject a liquid volatile solvent into the liquid level of the cleaning liquid in a two-stage manner to form one or two liquid phases; again; Open the drain port and drain the cleaning liquid in the slow drain mode; when one of the liquid volatile solvents is lower than the lowest position of the wafer, make the cleaning liquid drain in a fast drain mode; and A high-temperature nitrogen gas is introduced above the cleaning tank to dry the wafer; wherein the step of injecting the liquid volatile solvent in the two-stage manner is: injecting the liquid volatile solvent for the first time so that the liquid volatile solvent has a first A height; standing the liquid volatile solvent; and injecting the liquid volatile solvent again to make the liquid volatile solvent reach a second height. The wafer cleaning and drying method according to claim 1, wherein the first height of the liquid volatile solvent is between 5 and 6 mm, and the second height of the liquid volatile solvent is between 10 and 15 mm between. The wafer cleaning and drying method according to claim 1, wherein the flow rate of the slow drainage mode is between 3.5 and 5 L/M. The wafer cleaning and drying method according to claim 1, wherein when the high temperature nitrogen is introduced to dry the wafer, the flow rate of the high temperature nitrogen is between 380 and 430 L/M. The wafer cleaning and drying method according to claim 1, wherein when the high-temperature nitrogen is introduced from above the cleaning tank to dry the wafer, it further comprises an air extraction step, which is pumped through one of the bottoms of the cleaning tank The gas system synchronously extracts the high-temperature nitrogen, and the gas extraction system has an extraction pressure between 60 Pa and 90 Pa. The wafer cleaning and drying method according to claim 1, wherein the cleaning liquid is heated deionized water, and the liquid volatile solvent is liquid isopropanol. A wafer cleaning and drying device, comprising: a cleaning tank in which a cleaning liquid is stored, the cleaning tank having a water inlet arranged below, an overflow opening arranged above, and a drain opening arranged at the bottom; A support arranged in the cleaning tank to vertically support a wafer; and a liquid volatile solvent introduction pipeline for introducing a liquid volatile solvent from the upper periphery of the cleaning tank; wherein, above the cleaning tank A drainage plate is further provided, and when the liquid volatile solvent flows out of the liquid volatile solvent introduction pipe, the drainage plate is used to guide the liquid volatile solvent to be directly injected into a liquid surface of the cleaning liquid, When injecting the liquid volatile solvent, it includes injecting the liquid volatile solvent for the first time so that the liquid volatile solvent has a first height, standing the liquid volatile solvent, and injecting the liquid volatile solvent again to make the liquid volatile solvent The volatile solvent reaches a second height. The wafer cleaning and drying device according to claim 7, further comprising an air extraction system, which is arranged at the bottom of the cleaning tank. The wafer cleaning and drying device according to claim 7, wherein the cleaning liquid is heated deionized water, and the liquid volatile solvent is liquid isopropanol.

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