CN102800575A

CN102800575A - Method for removing crystal defects of aluminum liner

Info

Publication number: CN102800575A
Application number: CN2011101393786A
Authority: CN
Inventors: 丁海涛
Original assignee: Semiconductor Manufacturing International Shanghai Corp
Current assignee: Semiconductor Manufacturing International Shanghai Corp
Priority date: 2011-05-26
Filing date: 2011-05-26
Publication date: 2012-11-28
Anticipated expiration: 2031-05-26
Also published as: CN102800575B

Abstract

The invention discloses a method for removing crystal defects of an aluminum liner. The method comprises the following steps of: spraying a tetramethylammonium hydroxide (TMAH) solution on the surface of the aluminum liner; washing the surface of the aluminum liner by using deionied water (DIW); and drying the aluminum liner. By the method, the crystal defects of the aluminum liner can be removed.

Description

The crystal defect removal method of aluminium liner

Technical field

The present invention relates to semiconductor technology, particularly a kind of crystal defect removal method of aluminium liner.

Background technology

Aluminium liner (Al Pad) is wafer (wafer) and the extraneous interconnect interface that is connected, and can make wafer be connected with the extraneous metal that forms through the keyed jointing line in the aluminium pad surfaces.The manufacture method of aluminium liner is roughly following: adopt physical vapor deposition (PVD) technology to form aluminum film layer on top layer metallic layer (top metal) surface of wafer, adopt photoetching process and etch process that aluminum film layer is handled then, thereby form the aluminium liner.

After the aluminium liner forms, usually with wafer be positioned over the front opening film magazine (front open unit pod, FOUP) in, get into subsequent processing fully.The commonly used container of FOUP for wafer is temporarily stored in semiconductor manufacture flow path, before wafer changes next board over to from current board, often adopts FOUP that wafer is temporarily stored.The generalized section of Fig. 1 for adopting FOUP that wafer is temporarily stored, as shown in Figure 1, FOUP 101 is the container of an opening, it has slot 102, can be used for wafer W is fixed in the slot 102.Only storing a wafer W with FOUP as 1 is example, and in actual applications, a FOUP can have many group slots, and therefore a FOUP can store a plurality of wafers.

Because metallic aluminium (Al) is very easily oxidized in air, therefore,, can form one deck aluminium oxide (Al on the surface of aluminium liner when wafer is stored in the process of FOUP ₂O ₃) film.In addition, because FOUP comprises plastic material, be accompanied by natural degradation, the fluorine ion (F in the plastic material ^-) can be discharged in the air gradually, and, along with the FOUP increase of service time, the F of release ^-Can be more and more.Airborne steam (H ₂O) meeting and Al ₂O ₃In conjunction with generating aluminium hydroxide (Al (OH) ₃), simultaneously, airborne steam and F ^-In conjunction with generating hydrofluoric acid (HF), Al (OH) ₃Also can further with HF chemical reaction take place generate aluminum fluoride (AlF ₃).If the Al on aluminium liner top layer ₂O ₃Film is because above-mentioned chemical reaction process is etched fully, and the metallic aluminium of its below still can further carry out chemical reaction with steam, hydrofluoric acid, also can generate AlF ₃And Al (OH) ₃

AlF ₃And Al (OH) ₃Be the form of expression of crystal defect (crystal defect), Fig. 2 is the sketch map of crystal defect, and is as shown in Figure 2, the apparent and follow-up keyed jointing line of physics of crystal defect meeting appreciable impact aluminium liner.

Summary of the invention

In view of this, the present invention provides a kind of crystal defect removal method of aluminium liner, can remove the crystal defect of aluminium liner.

For solving the problems of the technologies described above, technical scheme of the present invention is achieved in that

A kind of crystal defect removal method of aluminium liner, this method comprises:

At the surface sprinkling TMAH TMAH of aluminium liner solution;

Adopt deionized water DIW flushing aluminium pad surfaces.

Adopt after the DIW flushing aluminium pad surfaces, this method further comprises: the aluminium liner is dried.

The concentration of said TMAH solution is greater than 0% and less than 10%.

Spray after the said TMAH solution, the said time of staying of TMAH solution on the aluminium liner is greater than 0 second and less than 75 seconds.

Based on the crystal defect removal method of a kind of aluminium liner provided by the present invention, at first at the surface sprinkling TMAH of aluminium liner solution, TMAH and AlF ₃Chemical reaction takes place at normal temperatures, (the CH of generation ₃) ₄NF and Al (OH) ₃Be dissolved in the water with liquid form, then, adopt DIW flushing aluminium liner, the (CH that is dissolved in the water ₃) ₄NF and Al (OH) ₃Rinse out the another kind of crystal defect Al (OH) that also the aluminium pad surfaces itself is had simultaneously ₃Rinse out, visible, scheme of the present invention can be removed the crystal defect of aluminium liner.

Description of drawings

The generalized section of Fig. 1 for adopting FOUP that wafer is temporarily stored.

Fig. 2 is the sketch map of crystal defect.

Fig. 3 is the flow chart of embodiment of the crystal defect removal method of a kind of aluminium liner provided by the present invention.

Embodiment

For making the object of the invention, technical scheme and advantage clearer, below with reference to the accompanying drawing embodiment that develops simultaneously, scheme according to the invention is done to specify further.

Core concept of the present invention is: the form of expression of crystal defect is mainly AlF ₃And Al (OH) ₃, the present invention is at the surface sprinkling TMAH of aluminium liner solution, TMAH and AlF ₃Chemical reaction takes place at normal temperatures, (the CH of generation ₃) ₄NF and Al (OH) ₃Be dissolved in the water with liquid form, adopt DIW flushing aluminium liner then, the (CH that is dissolved in the water ₃) ₄NF and Al (OH) ₃Rinse out, simultaneously also with the another kind of form of expression Al (OH) of crystal defect ₃Rinse out, therefore, scheme of the present invention can be removed the crystal defect of aluminium pad surfaces.

Fig. 3 is the flow chart of embodiment of the crystal defect removal method of a kind of aluminium liner provided by the present invention, and as shown in Figure 3, this method comprises:

Step 301 is at surface sprinkling TMAH (Tetra Methyl Ammonium Hydride, the TMAH) solution of aluminium liner.

The molecular formula of TMAH is (CH ₃) ₄NOH, its can with AlF ₃Chemical reaction takes place at normal temperatures, generates Methanaminium, N,N,N-trimethyl-, fluoride and Al (OH) ₃, wherein, the molecular formula of Methanaminium, N,N,N-trimethyl-, fluoride is (CH ₃) ₄NF, below, adopt chemical equation (1) to represent the principle of above-mentioned chemical reaction:

6(CH ₃) ₄NOH+2AlF ₃+(x+3)H ₂O＝6(CH ₃) ₄NF+2Al(OH) ₃+(x+3)H ₂O (1)

Need to prove that said TMAH solution is solute (TMAH) and solvent (H ₂O) mixture, the concentration of TMAH solution can be for greater than 0% and less than 10% (said concentration is TMAH and the ratio of the quality of TMAH solution) in the present embodiment.

In practical application; We can directly adopt name to be called the product (manufacturing enterprise: TOKYO OHKA KOGYO CO of " developer solution NMD-W 2.38% " usually; LTD) be sprayed on the aluminium liner, " developer solution NMD-W 2.38% " is that a kind of concentration is 2.38% TMAH solution.

(the CH that above-mentioned chemical reaction generated ₃) ₄NF and Al (OH) ₃Be dissolved in the water with liquid form, will in subsequent step, remove, and (the CH that is generated ₃) ₄NF can not cause erosion to the aluminium liner.

Step 302 adopts deionized water (DIW) flushing aluminium pad surfaces.

In this step, adopt the surface of DIW flushing aluminium liner to mainly contain two purposes: the first, can the product in the chemical equation (1) (be dissolved in (CH in the water ₃) ₄NF and Al (OH) ₃) rinse out; The second, because the crystal defect of aluminium pad surfaces also possibly be Al (OH) ₃, because solid-state Al (OH) ₃Be with Powdered surface, therefore, can adopt DIW pulverous Al (OH) attached to the aluminium liner ₃Directly rinse out.

Step 303 dries (spin dry) to the aluminium liner.

In this step, the purpose that dries is that the aluminium liner is carried out drying, to remove the unnecessary DIW of aluminium pad surfaces.

Wherein, drying is a drying means commonly used in the existing manufacture of semiconductor, no longer details here, can implement with reference to corresponding method in the prior art.

So far, this flow process finishes.

In addition, in above-mentioned steps 301, behind the surface sprinkling TMAH of aluminium liner solution, if TMAH is with AlF ₃All remove, because the hydroxyl (OH among the TMAH ^-) also can be further and AlF ₃The metallic aluminium generation chemical reaction of below generates Al (OH) ₃, therefore, if the TMAH solution that is sprayed at aluminium pad surfaces overstand, possibly further cause erosion to metallic aluminium.Certainly, if only metallic aluminium has been caused microetching, this can accept, and what need avoid is the excessive erosion to metallic aluminium.We are through measuring; For the metal aluminium flake of 7000 dusts (A) thickness, if after spraying above that with " developer solution NMD-W 2.38% ", when " the developer solution NMD-W 2.38% " time of staying, (puddle time) was 75 seconds (s); The thickness that the metal aluminium flake is etched is 300A; Because the thickness that is etched is far smaller than metal aluminium flake thickness originally, therefore, can accept less than 75 seconds the time of staying.

With above-mentioned experimental data as a reference, and combine the practical operation experience, in the present invention, we also can be defined as the time of staying of TMAH solution on the aluminium liner greater than 0 second and less than 75 seconds, to prevent the excessive erosion to the aluminium liner.The moment of supposing to begin to spray TMAH solution is T1, and supposing to begin to adopt the moment of DIW flushing is T2, and the then said time of staying of TMAH solution on the aluminium liner is meant T1 to the T2 time period.

Need to prove that also aluminium liner according to the invention is meant the aluminium liner with crystal defect, in practical application; Usually adopt the method for range estimation to judge whether the surface of aluminium liner exists crystal defect; If do not exist, then can directly get into subsequent processing, if exist; Then adopt method provided by the present invention to remove after the crystal defect, get into subsequent processing again.

To sum up, based on technical scheme provided by the present invention, at first at the surface sprinkling TMAH of aluminium liner solution, TMAH and AlF ₃Chemical reaction takes place at normal temperatures, (the CH of generation ₃) ₄NF and Al (OH) ₃Be dissolved in the water with liquid form, then, adopt DIW flushing aluminium liner, the (CH that is dissolved in the water ₃) ₄NF and Al (OH) ₃Rinse out, simultaneously, the another kind of crystal defect Al (OH) that also the aluminium pad surfaces itself is had ₃Rinse out, visible, technical scheme of the present invention can be removed the crystal defect of aluminium liner.

The above is merely preferred embodiment of the present invention, is not to be used to limit protection scope of the present invention.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1. the crystal defect removal method of an aluminium liner, this method comprises:

At the surface sprinkling TMAH TMAH of aluminium liner solution;

Adopt deionized water DIW flushing aluminium pad surfaces.

2. method according to claim 1 is characterized in that, adopts after the DIW flushing aluminium pad surfaces, and this method further comprises: the aluminium liner is dried.

3. method according to claim 1 and 2 is characterized in that the concentration of said TMAH solution is greater than 0% and less than 10%.

4. method according to claim 3 is characterized in that, sprays after the said TMAH solution, and the said time of staying of TMAH solution on the aluminium liner is greater than 0 second and less than 75 seconds.