CN104952722A - Metal deposition method and method for removing sharp corner of groove - Google Patents

Abstract

The invention provides a metal deposition method and a method for removing a sharp corner of a groove. Before the metal deposition of a substrate, a wet method is employed at first for the etching of a dielectric layer on the substrate, thereby enabling a groove on the dielectric layer to be smoother. Therefore, a groove hole which may appear in the groove and cannot be alloyed can be avoided during metal deposition. The methods solve a technical problem that a groove in an irregular shape is liable to form a hole, which cannot be removed, during metal deposition, and enable the metal deposition of grooves in different shapes to be carried out successfully.

Description

The method of metal deposition methods and removal groove wedge angle

Technical field

The present invention relates to semiconductor applications, particularly relate to a kind of method of metal deposition methods and removal groove wedge angle.

Background technology

Aluminium is the conductivity metal being only second to silver, copper and gold, the low-resistance requirement of metallization can not only be met, and and silicon dioxide between there is good adhesive force, and aluminium very easily carries out dry etching and forms micro metal line, therefore, in integrated circuit fabrication, aluminum metal is often used by as line, uses and arranges thousands of or millions of foundation micro electric crystal on the wafer surface.But, when aluminium is applied in shallow junction integrated circuit, often can produces point and show especially and resemble and ELECTROMIGRATION PHENOMENON.Al-Si-Cu alloy can improve this two kinds of drawbacks effectively.The silicon of about 1% and aluminium form silicon-aluminum and namely ensure that silicon is formed saturated and effectively prevents point from showing the appearance of elephant especially in aluminium.And a small amount of copper and aluminium form albronze the electric drift resistance of aluminium can be made to significantly improve, thus prevent ELECTROMIGRATION PHENOMENON.

In the manufacturing process of power device, aluminium copper silicon can be used as filling perforation line.Usually, the dielectric layer on first etched substrate surface forms groove, and then carries out metal deposition process, metallic film is filled up groove and covers substrate surface.But, because substrate surface defines the larger groove of depth-to-width ratio, form a metal cavity in the metallic film when Metal deposition inevitably above groove, thus, just can affect the performance of device.Usually, for the cavity in this metallic film, take the means of alloying that metallic atom can be made to rearrange, thus eliminate described metal cavity.But the cavity that what alloy can be eliminated be only limitted in metallic film, when the corner of groove is not filled, when namely there is groove cavity, alloy technique just cannot reach eliminates empty object.

Summary of the invention

For solving the defect existed in prior art, the problem to be solved in the present invention is to provide a kind of metal deposition methods and removes the method for groove wedge angle, makes all smooth Metal deposition processing procedure of the groove of various shape.

For this reason, the invention provides a kind of metal deposition methods, comprise:

There is provided a substrate, described substrate surface is formed with the fluted dielectric layer of tool;

Dielectric layer described in wet etching is with the surface of level and smooth described groove;

Carry out metal deposition process and form metal level on groove and dielectric layer; And

Alloying technology is carried out to described substrate.

Further, the material of described dielectric layer is silicon dioxide.

Further, the solvent adopted during dielectric layer described in wet etching is NH ₃the mixed solution of F and HF.

Further, described NH ₃the volume ratio of F and HF is between 150:1 ~ 200:1.

Further, the time of dielectric layer described in wet etching is between 170 ~ 200 seconds.

Further, described metal level is Al-Si-Cu alloy.

Further, the temperature of described alloying is 450 ~ 500 degrees Celsius.

Further, the time of described alloying is 4 ~ 6 hours.

According to another side of the present invention, a kind of method removing groove wedge angle is also provided, comprises:

There is provided a substrate, described substrate surface is formed with the fluted dielectric layer of tool; And the surface of the level and smooth described groove of dielectric layer described in wet etching is to remove groove wedge angle.

Compared to prior art, the present invention is before carrying out Metal deposition to substrate, and the dielectric layer on first wet etching substrate, makes the groove on dielectric layer rounder and more smooth.Thus, just avoid when carrying out Metal deposition may occur in the trench and cannot eliminate by alloying groove cavity.The invention solves the cavity that cannot eliminate easily appears in groove in irregular shape technical problem when Metal deposition, make all smooth Metal deposition processing procedure of the groove of various shape.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of the angular groove of tool.

Fig. 2 is the schematic diagram of the angular groove of tool shown in Fig. 1 after depositing metal.

Fig. 3 is the schematic flow sheet of metal deposition methods described in one embodiment of the invention.

Fig. 4 is the schematic diagram after the groove elimination wedge angle of substrate described in one embodiment of the invention.

Fig. 5 is the schematic diagram of substrate described in one embodiment of the invention after Metal deposition.

Fig. 6 is the schematic diagram of substrate described in one embodiment of the invention after alloying.

Embodiment

Mention in the introduction, after Metal deposition, easily occur cavity at trench corner place, thus affect the performance of device.Discovery is studied through present inventor, if the groove that etch media layer is formed is the trapezoidal of regular shape or rectangle, now metal successfully can be filled up described groove by Metal deposition, trench corner place there will not be cavity, if but there is groove in irregular shape, when particularly there is wedge angle 1 (as shown in Figure 1), sharp corner is difficult to be deposited to metal, just very likely form empty 2(in the trench as shown in Figure 2), also cannot eliminate even if carry out alloying after Metal deposition.

For this reason, the invention provides a kind of method of metal deposition methods and removal groove wedge angle, before Metal deposition, wet etching dielectric layer, to remove the wedge angle of groove, makes flute surfaces rounder and more smooth.Thus, just avoid when carrying out Metal deposition may occur in the trench and cannot by alloying the cavity of eliminating, make all smooth Metal deposition processing procedure of the groove of various shape.

The metal deposition methods proposed the present invention below in conjunction with the drawings and specific embodiments and the method removing groove wedge angle are described in further detail.According to following explanation and claims, advantages and features of the invention will be more clear.It should be noted that, accompanying drawing all adopts the form that simplifies very much and all uses non-ratio accurately, only in order to object that is convenient, the aid illustration embodiment of the present invention lucidly.

First, provide a substrate 10, described substrate 10 surface is formed with dielectric layer 20, has the groove 21 that etching is formed in described dielectric layer 20.As shown in Figure 1, under normal circumstances, the out-of-shape of groove 21, such as, with wedge angle 1, this is for cause the less demanding of etching technics, to such an extent as to non-formation rule shape is as groove that is trapezoidal or rectangle.Wherein, the material of substrate 10 is such as silicon, the material of dielectric layer 20 is such as silicon dioxide, groove 21 does not run through dielectric layer 20, namely groove 21 does not expose substrate 10, but the present invention is not as limit, groove 21 also can run through whole dielectric layer 20 and expose substrate 10, dielectric layer 20 also silicon nitride, silicon oxynitride, carbon silicon oxynitride etc.In the present embodiment, only there is one deck dielectric layer 20 in substrate 10, in fact multiple dielectric layer 20 can also be there is over the semiconductor substrate 10, other rete can be formed with between substrate 10 and dielectric layer 20, various device architecture can be formed with in substrate 10, in simple graph 1 for blanket substrates.

Then, as shown in Figure 4, wet etching dielectric layer 20, to remove the wedge angle of groove 21, makes groove 21 surface rounder and more smooth, and then carries out follow-up metal deposition process, just avoid may occur in the trench and cannot by alloying the cavity of eliminating.The shape of groove 21 is made to become rule because the present invention only needs the wedge angle of elimination groove 21, instead of whole removing is except dielectric layer 20, therefore the trench wall material solvent that the present invention adopts is the weakness solvent of silicon dioxide, in case remove dielectric layer 20 too much, and the achievement of impact etching.

In a preferred embodiment, the etching solution of employing is NH ₃the mixed solvent of F and HF, described NH ₃the volume ratio of F and HF is 150:1 ~ 200:1.The acid solution of this dilution can remove silicon dioxide well, and don't can destroy the structure of whole groove too much.Under the effect of this kind of acid solution, usually need semiconductor to soak 170 ~ 200 seconds.Effectively can remove silica 1 00 Izod thus right, just can reach the wedge angle eliminating groove 21, make the object that groove 21 polishes, and be unlikely to the structure destroying whole device.The difformity of groove 21 may be there is under other production situation, more or less wedge angle may be there is, when therefore adopting this kind of acid solution, can select according to specific circumstances to soak the different time.Fig. 4 is the schematic diagram after substrate described in one embodiment of the invention eliminates wedge angle.As shown in Figure 4, after acid soak, the groove 21 of substrate 20 becomes more level and smooth, and wedge angle disappears substantially, now can carry out the step of Metal deposition.

Next, as shown in Figure 5, can carry out metal deposition process, metal level 30 is filled with groove 21 well, and groove 21 corner there will not be cavity.But still likely there is metal cavity 31 in metal level 30, in the groove of regular shape, this kind of metal cavity 31 also can exist, this is that the characteristic of Metal deposition processing procedure is brought.In the present embodiment, the material of metal level 30 is Al-Si-Cu alloy, adopts physical vapor deposition (PVD) mode to be formed, and Al-Si-Cu alloy effectively can improve point as line and show especially and resemble and ELECTROMIGRATION PHENOMENON.Certainly, described metal level can also be other material, such as, be aluminium, copper, alusil alloy, aluminium copper etc.

Subsequently, as shown in Figure 6, carry out alloying technology, alloying is process metallic atom being arranged again to METAL HEATING PROCESS, and therefore metal hole 31 has been filled up in the motion of metallic atom naturally, and after alloying, metal cavity 31 is also disappeared.In the present embodiment, the temperature of alloying is 450 ~ 500 degrees Celsius, and the time of alloying is 4 ~ 6 hours.

In sum, the present invention is before carrying out Metal deposition to substrate, and the dielectric layer on first wet etching substrate, eliminates the wedge angle that may exist, make the groove on dielectric layer become round and smooth.Thus, just avoid when carrying out Metal deposition may occur in the trench and cannot eliminate by alloying groove cavity.The invention solves the cavity that cannot eliminate easily appears in groove in irregular shape technical problem when Metal deposition, make all smooth Metal deposition processing procedure of the groove of various shape.

Obviously, those skilled in the art can carry out various change and modification to invention and not depart from the spirit and scope of the present invention.Like this, if these amendments of the present invention and modification belong within the scope of the claims in the present invention and equivalent technologies thereof, then the present invention is also intended to comprise these change and modification.

Claims (9)

1. a metal deposition methods, comprises:

There is provided a substrate, described substrate surface is formed with the fluted dielectric layer of tool;

Dielectric layer described in wet etching is with the surface of level and smooth described groove;

Carry out metal deposition process and form metal level on groove and dielectric layer; And

Alloying technology is carried out to described substrate.

2. metal deposition methods as claimed in claim 1, is characterized in that: the material of described dielectric layer is silicon dioxide.

3. metal deposition methods as claimed in claim 1, is characterized in that: the solvent adopted during dielectric layer described in wet etching is NH ₃the mixed solution of F and HF.

4. metal deposition methods as claimed in claim 3, is characterized in that: described NH ₃the volume ratio of F and HF is between 150:1 ~ 200:1.

5. metal deposition methods as claimed in claim 4, is characterized in that: the time of dielectric layer described in wet etching is between 170 ~ 200 seconds.

6. metal deposition methods as claimed in claim 1, is characterized in that: described metal level is Al-Si-Cu alloy.

7. metal deposition methods as claimed in claim 1, is characterized in that: the temperature of described alloying is 450 ~ 500 degrees Celsius.

8. metal deposition methods as claimed in claim 1, is characterized in that: the time of described alloying is 4 ~ 6 hours.

9. remove a method for groove wedge angle, comprising:

There is provided a substrate, described substrate surface is formed with the fluted dielectric layer of tool; And

The surface of the level and smooth described groove of dielectric layer described in wet etching is to remove groove wedge angle.