CN101957124B

CN101957124B - Method for drying wafer

Info

Publication number: CN101957124B
Application number: CN2009100549323A
Authority: CN
Inventors: 马杰; 杨爽; 李伟; 许峰嘉
Original assignee: Semiconductor Manufacturing International Shanghai Corp; Chengdu Cension Semiconductor Manufacturing Co Ltd
Current assignee: Semiconductor Manufacturing International Shanghai Corp; Chengdu Cension Semiconductor Manufacturing Co Ltd
Priority date: 2009-07-16
Filing date: 2009-07-16
Publication date: 2012-08-08
Anticipated expiration: 2029-07-16
Also published as: CN101957124A

Abstract

The invention provides a method for drying a wafer. The method comprises the following steps of: placing the wafer into deionized water in a drying groove; introducing isopropanol vapor into the drying groove; introducing nitrogen into the drying groove; discharging the deionized water and the isopropanol from the drying groove; and introducing the nitrogen into the drying groove again and performing a nitrogen drying step, wherein the temperature of the nitrogen is set to be between 47 and 53 DEG C and the introducing time of the nitrogen is between 480 and 500 seconds in the nitrogen drying step, so that on the premise of maintaining good wafer drying effect, the phenomenon of the deformation of an acidproof film on the surface of the wafer is avoided and the properties and the yield of the device are guaranteed.

Description

A kind of drying means of wafer

Technical field

The present invention relates to integrated circuit and make the field, relate in particular to a kind of drying means of wafer.

Background technology

In the manufacturing process of some power chips (power IC),, must carry out backside etch process owing to will expose the drain electrode of the metal-oxide-semiconductor of chip back surface.Because before the backside etch process of wafer is carried out; The front description of wafer is accomplished, at this moment, and the front description of the wafer that needs protection; It is not destroyed by employed corrosive liquid in the backside etch process, therefore need to stick in the front of wafer earlier one deck acid-proof film.Wafer is through after the back etched link; The surface of wafer can stay a lot of residual liquid, owing to be dissolved with impurity in these residual liquid, and therefore; If wait for these residual liquid evaporation drying voluntarily; These impurity can adhere on the surface of wafer again so, pollute, even destroy the structure of wafer.

So, need usually after the etching link wafer to be carried out dried overleaf, so that being adhered to residual liquid, wafer surface removes fully.Industry generally adopts the dry slot of wafer wet rinsing table (wet bench) to carry out the wafer dried, for example the dry slot of the wet bench equipment of U.S. SCP company.When the wafer that the surface is pasted with the acid-proof film carries out dried, need especially note in this dry run, keeping the integrality of the acid-proof film of wafer surface.

In existing dried, be wafer surface moisture content to be dehydrated by isopropyl alcohol (IPA), isopropyl alcohol is used as transport gas with nitrogen.High volatile volatile by isopropyl alcohol can avoid washmarking, particulate and metal impurities to adhere to wafer surface the dehydration of wafer surface moisture content.Carry out the nitrogen drying step at last, feed nitrogen, the isopropyl alcohol of wafer surface is dried up fully.Wherein, in the nitrogen drying step, the feeding time of nitrogen is 300 seconds.In existing dried; What adopt is 90 ℃ nitrogen, and this temperature does not have big influence for common wafer, but has the wafer of acid-proof film for the surface; Can cause the acid-proof film generation deformation of wafer surface, directly cause the figure under the acid-proof film to occur unusual.

So, just need provide a kind of and can keep wafer drying effect preferably, the wafer drying method that can avoid the acid-proof pad pasting to deform again.

Summary of the invention

The present invention provides a kind of drying means of wafer, and to solve existing wafer in the dried process, the acid-proof film that its surface attaches deforms, and causes the front description of wafer to occur unusually, influences the performance of device and the problem of the rate that manufactures a finished product.

For realizing above-mentioned purpose, the present invention proposes a kind of drying means of wafer, comprising: (1) places the deionized water in the dry slot with wafer; (2) feed IPA vapor to said dry slot; (3) feed nitrogen to said dry slot; (4) discharge said dry slot interior deionized water and isopropyl alcohol; And (5) feed nitrogen again, carries out the nitrogen drying step; Wherein, the temperature of said nitrogen is 47 ℃～53 ℃, and in said step (5), the time that said nitrogen feeds is 480 seconds～500 seconds.

Optional, said wafer surface is posted the acid-proof film.

Optional, the thickness of said acid-proof film is 130 microns.

Optional, the flow velocity of said nitrogen is 150slpm.

Optional, in said step (3), the feeding time of said nitrogen is 180 seconds.

Optional, in said step (2), the feeding amount of said IPA vapor is 220ml.

Optional, in said step (1), the deionized water in the said dry slot is in flow regime.

In sum; The present invention provides a kind of drying means of wafer, and the temperature of nitrogen is set between 47 ℃ to 53 ℃, in the nitrogen drying step; The time that nitrogen feeds is set between 480 seconds to 500 seconds; Keeping under the prerequisite of wafer drying effect preferably, the phenomenon of having avoided the acid-proof film to deform has been guaranteed the performance and the yield rate of device.

Description of drawings

Fig. 1 is withering chip architecture sketch map;

Fig. 2 is the flow chart of the wafer drying method that one embodiment of the invention provided;

Fig. 3 is the sketch map of the employed dry slot of wafer drying method that one embodiment of the invention provided.

The specific embodiment

For making the object of the invention, feature and advantage more obviously understandable, the wafer drying method that the present invention proposes is done further explain below in conjunction with accompanying drawing and specific embodiment.

In semiconductor fabrication process, after wafer carries out backside etch process, often need carry out dried to wafer.Wherein, be not destroyed in the etch process overleaf in order to ensure the front description of wafer, the front wafer surface of being everlasting sticks one deck acid-proof film.Therefore, when carrying out dried, wafer surface has the acid-proof film.

Specifically see also Fig. 1, it is the sketch map of withering wafer, need to prove, and among Fig. 1 and the detailed structure of the front description of not shown wafer, the unnecessary details because they can make the present invention and confusion.Wherein, have front description 12 on the substrate 11 of wafer, on front description 12, post acid-proof pad pasting 13, wherein, the height acid-proof film that acid-proof film 13 is produced for ICROS company, the thickness of said acid-proof film 13 is 130 microns.Acid-proof film 13 can protect front description 12 injury-free when carrying out the backside etch process of wafer, and acid-proof film 13 can not pollute wafer.

Traditional wafer drying method is by isopropyl alcohol (IPA) wafer surface moisture content to be dehydrated, and isopropyl alcohol is used as transport gas with nitrogen.High volatile volatile by isopropyl alcohol can avoid washmarking, particulate and metal impurities to adhere to wafer surface the dehydration of wafer surface moisture content.Carry out the nitrogen drying step at last, promptly feed nitrogen, the isopropyl alcohol of wafer surface is dried up fully.In existing drying means; What adopt is 90 ℃ nitrogen; This temperature does not have big influence for common wafer, still has the wafer of acid-proof film for the surface, then can cause the acid-proof film generation deformation of wafer surface; Directly cause the figure under the acid-proof film to occur unusually, and influence the performance and the yield rate of device.

Please continue with reference to figure 2 and Fig. 3; Fig. 2 is the flow chart of the wafer drying method that one embodiment of the invention provided; Fig. 3 carries out detailed introduction below in conjunction with Fig. 2 to Fig. 3 to wafer drying method of the present invention for the sketch map of the employed dry slot of wafer drying method that one embodiment of the invention provided.

At first, wafer is placed the deionized water (S201) in the dry slot, as shown in Figure 3, said dry slot 300 includes inside groove 301 and water jacket 302, in the inside groove 301 deionized water is arranged, and it can be set to static or mobile state.At this moment, make the deionized water in the inside groove 301 be in flow regime, to keep the cleaning of wafer surface.Also offer a discharge outlet 303 in the bottom of dry slot 300, be used to discharge the liquid in the dry slot 300.

After putting wafer well, feed IPA vapor (S202) to said dry slot, as shown in Figure 3, the IPA air inlet 304 through water jacket 302 bottoms feeds IPA vapor in the water jacket 302 of dry slot, and the feeding amount of said IPA vapor is 220ml.

Then; Feed nitrogen (S203) to said dry slot; The first nitrogen air inlet 305 through water jacket 302 bottoms feeds nitrogen to the water jacket of dry slot 302, utilizes said nitrogen IPA vapor to be sent in the inside groove 301 of dry slot, to utilize isopropyl alcohol and glassware for drinking water the principle of good intersolubility is arranged; Make attached to the water on the wafer and replace, thereby moisture content is removed with isopropyl alcohol.The temperature of said nitrogen can be arranged between 47 ℃ to 53 ℃; Be preferably 50 ℃; The flow velocity of said nitrogen is 150slpm; The duration in this step can be 180 seconds, can wafer surface moisture content fully be dewatered with the high volatile volatile that guarantees isopropyl alcohol, avoids washmarking, particulate and metal impurities to adhere to wafer surface.

Next, discharge deionized water and isopropyl alcohol (S204) in the said dry slot, as shown in Figure 3, fast deionized water and isopropyl alcohol to be discharged through the discharge outlet 303 of dry slot 300, the duration in this step can be 150 seconds.

At last, feed nitrogen again, carry out nitrogen drying step (S205), as shown in Figure 3, through the second nitrogen air inlet, the 306 feeding nitrogen on dry slot 300 tops.The temperature of said nitrogen can be arranged between 47 ℃ to 53 ℃; Be preferably 50 ℃, the flow velocity of said nitrogen is 150slpm, and the duration in this step can be set between 480 seconds to 500 seconds; Be preferably 480 seconds; Both can guarantee the drying effect of wafer, shorten process treatment time simultaneously again, improve production capacity.

The temperature of nitrogen is set between 47 ℃ to 53 ℃ among the present invention; Prevented the destruction of the too high acid-proof film to wafer surface of nitrogen temperature; With in the nitrogen drying step, the feeding time of nitrogen is set to guarantee the drying effect of wafer between 480 seconds to 500 seconds simultaneously.

After the wafer drying, just can stop to feed nitrogen, take out wafer, accomplish dried process to wafer.

In sum, wafer drying method provided by the present invention comprises the steps: wafer is placed the deionized water in the dry slot; Feed IPA vapor to said dry slot; Feed nitrogen to said dry slot; Discharge deionized water and isopropyl alcohol in the said dry slot; And feed nitrogen again, carry out the nitrogen drying step; Wherein, the temperature of nitrogen is set between 47 ℃ to 53 ℃, in the nitrogen drying step; The time that nitrogen feeds is 480 seconds～500 seconds; Keeping under the prerequisite of wafer drying effect preferably, the phenomenon of having avoided the acid-proof film to deform has been guaranteed the performance and the yield rate of device.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, belong within the scope of claim of the present invention and equivalent technologies thereof if of the present invention these are revised with modification, then the present invention also is intended to comprise these changes and modification interior.

Claims

1. the drying means of a wafer comprises:

(1) wafer is placed the deionized water in the dry slot, said wafer surface is posted the acid-proof film;

(2) feed IPA vapor to said dry slot;

(3) feed nitrogen to said dry slot;

(4) discharge said dry slot interior deionized water and isopropyl alcohol; And

(5) feed nitrogen again, carry out the nitrogen drying step;

It is characterized in that wherein, the temperature of said nitrogen is 47 ℃～53 ℃, in said step (5), the time that said nitrogen feeds is 480 seconds～500 seconds.

2. the drying means of wafer as claimed in claim 1 is characterized in that, the thickness of said acid-proof film is 130 microns.

3. the drying means of wafer as claimed in claim 1 is characterized in that, the flow velocity of said nitrogen is 150slpm.

4. the drying means of wafer as claimed in claim 1 is characterized in that, in said step (3), the feeding time of said nitrogen is 180 seconds.

5. the drying means of wafer as claimed in claim 1 is characterized in that, in said step (2), the feeding amount of said IPA vapor is 220ml.

6. the drying means of wafer as claimed in claim 1 is characterized in that, in said step (1), the deionized water in the said dry slot is in flow regime.