CN101399219B

CN101399219B - Preparing method for through-hole between metallic layers and filling method

Info

Publication number: CN101399219B
Application number: CN2007100941077A
Authority: CN
Inventors: 陈福成; 朱骏
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2007-09-28
Filing date: 2007-09-28
Publication date: 2011-11-02
Anticipated expiration: 2027-09-28
Also published as: CN101399219A

Abstract

The invention discloses a method for preparing and filling via holes between metal layers, which comprises: after metal in an under layer is etched, a first layer of intermetallic dielectric medium for isolation is deposited and steps formed when the metal in the under layer is etched are covered; the intermetallic dielectric medium for isolation on the metal in the under layer is removed through a chemical-mechanical planarization process; then, a layer of aluminum is deposited; lithography is carried out by using a via hole mask and a negative photoresist so as to define a protective layer of a via hole pattern; afterward, the aluminum layer is etched to prepare aluminum plugs for filling the via holes; a second layer of intermetallic dielectric medium for isolation is deposited, and the steps formed by the aluminum plugs are covered; after that, the intermetallic dielectric medium for isolation on the aluminum plugs is removed by the chemical-mechanical planarization process. The method adopts the aluminum plugs to fill the via holes, thus greatly improving the electroconductibility between metals in the interconnection process and solving the problem that the aluminum plugs are difficult to be realized after the size of device is reduced in the original process at the same time. The method can be widely applied in the processes for preparing semiconductor devices.

Description

The preparation of through-hole between metallic layers and fill method

Technical field

The present invention relates to the preparation and the fill method of through-hole between metallic layers in a kind of semiconductor manufacturing.

Background technology

In traditional semiconductor technology, all use tungsten plug technology to fill the through hole that connects usefulness between the double layer of metal.Adopting the purpose of tungsten plug technology, mainly is because adopt sputtering technology to finish preparation usually as the aluminum of metal connecting line, along with reducing of the size of through hole, owing to sputtering technology can't cause loose contact to the through hole depths by the sputtered aluminum that atomic weight is less; And the tungsten material can be realized by chemical vapor deposition method, and chemical vapor deposition method and even atomic layer deposition technology can satisfy the requirement of high-aspect-ratio, so all uses tungsten plug technology to fill the through hole that double layer of metal connects in the traditional handicraft.

Fig. 1 a to Fig. 1 e is that the technology of a concrete tungsten plug through hole (W-plug) connects the structural representation in the two metal layers preparation flow:

(1) after the lower metal etching of connecting through hole was finished, separator between depositing metal (intermetal dielectric) (was seen Fig. 1 a);

(2) adopt positive photoresist (positive photo resist) and through hole mask to carry out photoetching, define via hole image (seeing Fig. 1 b);

(3) dry etching intermetallic separator is prepared through hole (seeing Fig. 1 c);

(4) tungsten deposit, filling vias is to connect two metal layers (seeing figure d);

(5) with the smooth technology of chemical machinery (Chemical Mechanical Polishing), remove unnecessary tungsten (seeing Fig. 1 e) on the intermetallic separator, through hole is filled and is finished, and and then is the deposit of upper strata metal.

A defective of above-mentioned tungsten plug via process is: the conductance of tungsten is not high, so cause in the electromigration (EM) of the metal throuth hole of reality badly, also can cause bigger capacitance/resistance delay effect, and the difficulty of through hole fill process is bigger in the preparation.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of preparation and fill method of through-hole between metallic layers, and prepared through hole packing material can effectively improve the conductance of through hole.

For solving the problems of the technologies described above, the preparation of through-hole between metallic layers of the present invention and fill method may further comprise the steps:

(1) after the lower metal etching is finished, deposit ground floor intermetallic isolation dielectric, and the step that forms when covering the lower metal etching;

(2) remove intermetallic isolation dielectric on the described lower metal with chemical-mechanical planarization technology;

(3) depositing metal aluminium lamination;

(4) utilize through hole reticle and negative photoresist photoetching, form the protective layer of via hole image;

(5) etching metal aluminium lamination is prepared the aluminium plug, makes through hole and fills;

(6) isolate dielectric between the deposit second layer metal, and the step of aluminium coating plug formation;

(7) remove aluminium intermetallic isolation dielectric beyond the Great Wall with chemical-mechanical planarization technology.

By the aluminium plug of preparing of the inventive method as the through hole filler, because the conductivity of aluminium will be much better than tungsten, so the conductivity of intermetallic interconnected technology is greatly improved.The problem that the aluminium plug is difficult to realize after the device dimensions shrink in original technology has been avoided and solved simultaneously to method of the present invention simultaneously.

Description of drawings

The present invention is further detailed explanation below in conjunction with accompanying drawing and embodiment:

Fig. 1 a is the structural representation after the intermetallic separator is filled in the common process;

Fig. 1 b is the structural representation of definition lead to the hole site in the common process;

Fig. 1 c is the structural representation that via etch is finished in the common process;

Fig. 1 d is the structural representation of tungsten plug deposit in the common process;

Fig. 1 e is the structural representation after the tungsten plug is made CMP and ground in the common process;

Fig. 2 is a method flow block diagram of the present invention;

Fig. 3 is the structural representation in the method preparation flow of the present invention.

Embodiment

Adopting present common aluminium in the present embodiment is the metal connecting line material, and the through hole that adopts negative photoresist and aluminium technology to make between the metal connecting layer is filled.To the flow chart of Fig. 2, be elaborated below in conjunction with the structural representation in the preparation flow of Fig. 3:

(1) after lower floor's aluminium lamination etching is finished, deposit ground floor intermetallic isolation dielectric (intermetal dielectric), thickness need cover the formed step of lower floor's aluminium lamination, guarantees that promptly the groove complete filling that lower floor's aluminium lamination etching is formed is full;

(2) adopt the smooth technology of chemical machinery (Chemical Mechanical Polishing), remove unnecessary separator dielectric on the lower metal face;

(3) another metal aluminium lamination of deposit on lower floor's aluminium lamination, as the through hole packing material, the depositing technics of aluminium is the most frequently used sputtering method;

(4) utilize the reticle and negative photoresist (the negative photo resist) photoetching of through hole, make the protective layer of via hole image;

(5) dry etching metal aluminium lamination is prepared the aluminium plug, in order to filling vias;

(6) isolate dielectric (inter metal dielectric) between the deposit second layer metal, thickness should guarantee the formed step of aluminium coating plug;

(7), remove the unnecessary isolation dielectric of aluminium beyond the Great Wall with the smooth technology of chemical machinery (Chemical Mechanical Polishing).

Preparation method of the present invention utilizes the aluminium plug to do intermetallic connecting through hole and fills, and has avoided W plug chemical mechanical planarization technology simultaneously; As everyone knows, the conductivity of aluminium will be much better than the conductivity of tungsten, and like this, the resistance of metal throuth hole greatly reduces, and the capacitance/resistance delay effect will obtain bigger improvement.

Claims

1. the preparation of a through-hole between metallic layers and fill method is characterized in that, comprise the steps:

(1) after the lower metal etching is finished, deposit ground floor intermetallic isolation dielectric, the step that ground floor intermetallic isolation dielectric forms when covering the lower metal etching;

(3) removing the dielectric surface of separator unnecessary on the lower metal face another metal level of deposit again, its material is an aluminium;

(4) form the position of the connection of ground floor metal and second layer metal at needs, it is the position of ground floor via hole image, utilize the photolithography plate of through hole to carry out photolithographic exposure, after the negative photoresist exposure, the photoresist of the via hole image of exposure place is residual, do not have the photoresist of exposure to be developed removal, form the photoresist protective layer at ground floor via hole image place;

(6) isolate dielectric between the deposit second layer metal behind the formation metallic aluminium plug through hole, thickness guarantees the formed step of aluminium coating plug;

2. it is characterized in that in accordance with the method for claim 1: the etching technics of metal aluminium lamination is a dry etching in the described step (5).

3. it is characterized in that in accordance with the method for claim 1: the depositing technics of described metal aluminium lamination is a sputtering technology.