CN102528638A

CN102528638A - Chemical-mechanical grinding method and equipment for copper

Info

Publication number: CN102528638A
Application number: CN201010620262XA
Authority: CN
Inventors: 邓武锋
Original assignee: Semiconductor Manufacturing International Shanghai Corp
Current assignee: Semiconductor Manufacturing International Shanghai Corp; Semiconductor Manufacturing International Beijing Corp
Priority date: 2010-12-29
Filing date: 2010-12-29
Publication date: 2012-07-04

Abstract

The invention provides a chemical-mechanical grinding method and equipment for copper. According to the invention, a grinding step is added on the basis of the prior art. A copper residual layer on a medium layer opening is ground by using a grinding liquid with high copper selection ratio, so that the copper residual layer on the opening can be fully removed, and the performance of a device can be improved effectively.

Description

A kind of chemomechanical copper grinding process and equipment

Technical field

The present invention relates to technical field of manufacturing semiconductors, particularly a kind of chemomechanical copper grinding process and equipment.

Background technology

Along with being showing improvement or progress day by day of semiconductor integrated circuit manufacturing process, live width is done littler and littler, and for the resistance capacitance that reduces the back segment interconnection structure postpones (RC delay), the dielectric material that adopts low-k is as dielectric layer, and employing copper metal is as the material of interconnection line.Because the copper metal is difficult to etching, industry is introduced mosaic technology or dual-damascene technics manufactured copper interconnection line.In the manufacturing approach of copper interconnecting line, at first form the dielectric layer of low-k; Then, in this dielectric layer, form opening; Then, plated metal copper on said opening neutralization medium layer, and carry out planarization through cmp, and remove the copper on the said dielectric layer, in opening, form copper interconnecting line.

Please referring to Fig. 1 a to Fig. 1 d, Fig. 1 a to Fig. 1 d is the generalized section of each step corresponding construction of the chemomechanical copper grinding process of prior art.

Generalized section shown in Fig. 1 a, copper metal layer 110 are layer to be ground, and this copper metal layer 110 is covered on the substrate 100 with opening 102, and fills up said opening 102.Between said substrate 100 and copper metal layer 110, has barrier layer 104.

Generalized section shown in Fig. 1 b is carried out the first step and is ground, and removes the segment thickness of copper metal layer 110, accomplish the grinding of this first step after, the thickness that copper metal layer 110 remaines in substrate 100 surfaces are T.

Shown in Fig. 1 c, carry out the grinding in second step, to remove the copper metal layer beyond the opening 102 fully, the copper metal layer that remaines in the said opening 102 is 110a; Simultaneously, the barrier layer 104 beyond the opening 102 also possibly be removed segment thickness.

Shown in Fig. 1 d, carry out the grinding in the 3rd step, continue to grind the copper metal layer 110a in the opening 102, up to the barrier layer 104 of removing fully beyond the said opening 102, remaining copper metal layer is 112 in the said opening 102.

In the said method,, remove the copper metal layer beyond the said opening 102 through the chemical mechanical milling tech of three steps completion copper; The main grinding technics in described each stage (Main Polish) is after completion; Before the grinding technics that carries out follow-up phase or follow-up other technology; The capital is cleaned with deionized water, with the particulate pollutant of avoiding grinding generation or residue to the grinding technics of follow-up phase or the influence of other technology.Special, three steps described in the prior art are usually carried out on the different grinding pads of same milling apparatus, on each grinding pad, carry out the grinding of a certain step, accomplish the cmp of copper, and substrate will be passed through the different polishing pad successively.

But when adopting the chemomechanical copper grinding process of prior art; If produce depression owing to carrying out cmp during the metal level through hole under forming copper metal layer; Then forming opening 102 and in opening 102, also can produce depression during deposited copper metal level 110 in the relevant position; Therefore when in opening 102, forming copper-connection if after adopting said method to accomplish cmp; On the copper-connection that is positioned at opening 102, have toward the contact meeting that copper is residual can't to be removed, thereby have influence on the performance of device.

Summary of the invention

The technical problem that the present invention will solve provides a kind of chemomechanical copper grinding process; When forming copper-connection to solve the chemomechanical copper grinding process that adopts prior art; Have toward the contact meeting that copper is residual can't to be removed on the copper-connection in opening, thereby have influence on the problem of the performance of device.

For solving the problems of the technologies described above, the present invention provides a kind of chemomechanical copper grinding process, may further comprise the steps:

One object to be ground is provided, and said object to be ground comprises: copper metal layer, said copper metal layer are layer to be ground; Said copper metal layer is covered on the dielectric layer with opening, and fills up said opening; Has the barrier layer between said dielectric layer and the said copper metal layer; Said opening and the copper metal that is filled in the said opening have concave shape;

Carry out the first step and grind, remove most of thickness of said copper metal layer;

Carried out for second step and grind, remove the copper metal layer beyond the said opening fully, keep the copper metal layer in the said opening; Also there is the copper residual layer owing to exist said concave shape to make through grinding on the said opening in back;

Carried out for the 3rd step and grind, remove the barrier beyond the said opening, and remove the said copper residual layer of part;

Carried out for the 4th step and grind, the ratio that adopts copper grinding rate and oxide grinding rate grinds greater than 50 to 1 lapping liquid, removes said copper residual layer fully.

Optional, also carried out for the 5th step at last and grind, remove the said dielectric layer of part, make it reach specific thicknesses.

Optional, carry out after the said first step grinds, the thickness of remaining copper metal layer is between 200 to 300nm.

Optional, after grinding through said the 5th step, the residual thickness of said second dielectric layer is 120 to 150nm.

Accordingly, said chemical-mechanical grinding device has the grinding head more than 4 or 4, and each said grinding head correspondence is provided with a grinding pad.Optional, said chemical-mechanical grinding device has 5 grinding heads.

Chemomechanical copper grinding process of the present invention has increased grinding steps on the basis of existing technology; Select the copper residual layer on the dielectric layer opening to be ground through adopting copper than high lapping liquid; The copper residual layer on the opening can be removed fully, thereby the performance of device can be effectively improved.

Description of drawings

Fig. 1 a to Fig. 1 d is the generalized section of each step corresponding construction of the chemomechanical copper grinding process of prior art;

Fig. 2 a to Fig. 2 f is the generalized section of each step corresponding construction of chemomechanical copper grinding process of the present invention;

Fig. 3 contrasts sketch map for the structure of the chemical-mechanical grinding device that prior art and the present invention adopt respectively.

The specific embodiment

For make above-mentioned purpose of the present invention, feature and advantage can be more obviously understandable, below specific embodiments of the invention do detailed explanation.

Chemomechanical copper grinding process of the present invention multiple substitute mode capable of using realizes; Be to explain below through preferred embodiment; Certainly the present invention is not limited to this specific embodiment, and the general replacement that the one of ordinary skilled in the art knew is encompassed in protection scope of the present invention undoubtedly.

Please referring to 2a to Fig. 2 f, Fig. 2 a to Fig. 2 f is the generalized section of each step corresponding construction of chemomechanical copper grinding process of the present invention.

Referring to Fig. 2 a, Fig. 2 a carries out the inventive method device architecture generalized section before, and shown in Fig. 2 a, copper metal layer 220 is a layer to be ground, and said copper metal layer 220 is covered on second dielectric layer 210 with opening 211, and fills up said opening 211; Has barrier layer 212 between said second dielectric layer 210 and the said copper metal layer 220; Said second dielectric layer 210 is positioned on first dielectric layer 200, is formed with metal interconnected through hole 201 in said first dielectric layer 200; Said metal interconnected through hole 201 positions are because the effect of cmp has certain depression, thereby cause the opening 211 that forms in said second dielectric layer 210 and the copper metals that are filled in the said opening 211 also have concave shape.

Chemomechanical copper grinding process of the present invention may further comprise the steps:

At first,, carry out the first step and grind, remove most of thickness of said copper metal layer 220 referring to Fig. 2 b; Preferably, make the thickness of remaining copper metal layer 220 between 200 to 300nm.

Secondly,, carried out for second step and grind,, keep the copper metal layer 211a in the said opening 211 to remove the copper metal layer beyond the said opening 211 fully referring to Fig. 2 c; Also there is copper residual layer 220a owing to exist said concave shape to make through grinding on the said opening 211 in back;

Once more,, carried out for the 3rd step and grind, remove the barrier 212 beyond the said opening 211, and remove the said copper residual layer of part 220a referring to Fig. 2 d;

Once more, referring to Fig. 2 e, carried out for the 4th step and grind; The ratio that adopts copper grinding rate and oxide grinding rate grinds greater than 50 to 1 lapping liquid; The Cu Slurry of U.S. Jia Bai company C7092 for example, Japanese Fujimi Cu slurry 7105 is to remove said copper residual layer 220a fully;

At last,, carried out for the 5th step and grind, remove said second dielectric layer 210 of part, make it reach the thickness of technological requirement referring to Fig. 2 f; Preferably, after grinding through said the 5th step, the residual thickness of said second dielectric layer 210 is 120 to 150nm.

Please referring to Fig. 3, Fig. 3 contrasts sketch map for the structure of the chemical-mechanical grinding device that prior art and the present invention adopt respectively.As shown in Figure 3; Three steps of the chemomechanical copper grinding process of prior art are carried out on the different grinding pads of same milling apparatus usually; On each grinding pad, carry out the grinding of a certain step, so among Fig. 3 three grinding heads and three grinding pads are arranged in the employed milling apparatus of prior art.Owing to increased the grinding of two steps, therefore milling apparatus used in the present invention is compared with the milling apparatus that prior art adopted and has been increased by two grinding heads and grinding pad in the chemomechanical copper grinding process of the present invention.

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. chemomechanical copper grinding process may further comprise the steps:

2. chemomechanical copper grinding process as claimed in claim 1 is characterized in that, also carries out for the 5th step at last and grinds, and removes the said dielectric layer of part, makes it reach specific thicknesses.

3. chemomechanical copper grinding process as claimed in claim 1 is characterized in that, carries out after the said first step grinds, and the thickness of remaining copper metal layer is between 200 to 300nm.

4. chemomechanical copper grinding process as claimed in claim 1 is characterized in that, after grinding through said the 5th step, the residual thickness of said second dielectric layer is 120 to 150nm.

5. a chemical-mechanical grinding device that is used for the described chemomechanical copper grinding process of claim 1 is characterized in that, said chemical-mechanical grinding device has the grinding head more than 4 or 4, and each said grinding head correspondence is provided with a grinding pad.

6. chemical-mechanical grinding device as claimed in claim 5 is characterized in that, said chemical-mechanical grinding device has 5 grinding heads, and each said grinding head correspondence is provided with a grinding pad.