CN103107081A

CN103107081A - Sharp corner passivation method

Info

Publication number: CN103107081A
Application number: CN2011103520803A
Authority: CN
Inventors: 郁新举
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2011-11-09
Filing date: 2011-11-09
Publication date: 2013-05-15
Anticipated expiration: 2031-11-09
Also published as: CN103107081B

Abstract

The invention discloses a sharp corner passivation method. The method includes a first step of forming a lower layer through existing technological processes, wherein the lower layer needs to be subjected to graphic sharp corner passivation, a second step of covering a layer of photoresist and carrying out exposure on the basis of the first step, a third step of carrying out etching to enable high-low appearance to appear on sharp corners, a fourth step of removing the photoresist, and a fifth step of depositing materials to be passivated in a metal sputtering mode, coating the photoresist, and then carrying out exposure and etching to realize passivation. The sharp corner passivation method is capable of realizing rounded corners, can solve the problem that the appearance of the top of metal is sharp, thereby reducing point discharge effects and improving reliability of products.

Description

A kind of method of wedge angle passivation

Technical field

The present invention relates to a kind of method of wedge angle passivation, particularly relate to the method for wedge angle passivation in a kind of semiconductor applications.

Background technology

Insulated gate bipolar transistor (Insolated Gate Bipolar Transistor, IGBT) be a kind of device that is composited by MOSFET and bipolar transistor, it inputs very MOSFET, export very PNP transistor, it combines the advantage of these two kinds of devices, both had advantages of that MOSFET device drive power was little and switching speed is fast, having again the bipolar device saturation pressure reduces and advantage capacious, thereby, obtained using more and more widely in modern power electronics technology.

At present in the semiconductor fabrication of insulated gate bipolar transistor; the back segment metal connecting line is because thickness is thicker; often can run into after metal etch the more sharp-pointed problem of pattern at the top of metal; due to the high pressure resistant property that requires at insulated gate bipolar transistor; if angular existence in metal connecting line; be easy to cause the effect of point discharge in the process of subsequent product energising, puncture thereby cause the serious consequence of finally scrapping that causes product.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of method of wedge angle passivation, has solved the electric discharge phenomena that the edge wedge angle causes, thereby improves the reliability of product.

For solving the problems of the technologies described above, the method for wedge angle passivation of the present invention comprises step:

(1) by existing technological process, form the lower floor that treats to carry out the passivation of figure wedge angle;

(2) on the basis of step (1), apply one deck photoresist and exposure;

(3) carry out etching, make it the height pattern occur;

(4) remove photoresist;

(5) adopt the metal sputtering mode, deposit the material of wanting passivation, apply photoresist, after exposure, etching, realize passivation.

In described step (1), treat to carry out the lower floor of figure wedge angle passivation, comprising: various figure wedge angles are treated the lower floor of passivation, as comprise: aluminum steel lower floor dielectric layer, oxide-film through hole, and the filling of oxide-film through hole; Wherein, the filler of oxide-film through hole comprises: tungsten, maybe can realize the material with the tungsten identical function, as: tungsten can be, also other materials of wire can be can be used as for other.

In described step (2), the thickness of photoresist gets final product greater than 400 nanometers, the demand of concrete thickness depending on follow-up etch amount; In the photoresist exposure, can use the reticle of the figure of passivation to be needed to go exposure, or use is gone exposure than the reticle of the critical size little 10%～20% of the figure of passivation to be needed.

In described step (3), adopt the method for silica etching, form the figure of the silica identical with the figure of passivation to be needed; Etching depth depends on the thickness of figure of the passivation to be needed of deposition.

In described step (5), the material of passivation comprises: metallic aluminium, copper etc., and the thickness of deposition is good greater than 1 micron; The thickness of photoresist depends on passivation layer thickness, generally is greater than 400 nanometers; In photoresist exposure, use the reticle exposure of the critical size-10% of the figure of passivation to be needed～+ 10%; Adopt the method for dry etching, carry out etching, form plain conductor.

The present invention is by forming a kind of anterior layer of height pattern, after follow-up passivating material (being generally the metal aluminum bronze) is grown up, the place can form circular-arc coating at this height pattern, control by the critical size of photoresist again, realize comparatively mellow and full corner, thereby, the sharp-pointed problem of metal top pattern can be solved, thereby reduce the point discharge effect, improve the reliability of product.

Description of drawings

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

Fig. 1 forms the lower floor's schematic diagram that needs the passivation figure;

Fig. 2 is the schematic diagram that applies photoresist and exposure on the structure of Fig. 1;

Fig. 3 carries out the schematic diagram that etching forms the difference of height figure on the structure of Fig. 2;

Fig. 4 has been the schematic diagram of the difference of height figure after photoresist;

Fig. 5 is the schematic diagram that deposition is wanted the material of passivation on the structure of Fig. 4;

Fig. 6 is the design sketch that applies on Fig. 5 basis after photoresist and exposure;

Fig. 7 is the design sketch after Fig. 5 etching;

Fig. 8 is the pattern design sketch after the final passivation of formation.

Embodiment

Now with a kind of passivation of metal wedge angle, the method for wedge angle passivation of the present invention is described.

The method of the metal wedge angle passivation in the present embodiment comprises step:

(1) by existing technological process, form the lower floor's (as shown in Figure 1) that treats to carry out the passivation of figure wedge angle, concrete steps are as follows:

Dielectric layer about method growth one deck 800 nanometers of use chemical vapour deposition (CVD), mode by dry etching, form the oxide-film through hole of 0.35 micron of critical size, after through hole forms, use the mode of metal deposition, titanium deposition titanium nitride and tungsten assurance through hole are fully filled, and the method for then carving by method or the dry back of grinding is removed the tungsten on dielectric layer, the tungsten formation wire in reservation tungsten through hole;

(2) on the basis of step (1), apply one deck photoresist and exposure, result is as shown in Figure 2;

Wherein, the thickness of photoresist is decided according to demand, making with photoresist in this example, thickness is one micron, in the photoresist exposure, can use the reticle of the figure of passivation to be needed to go exposure, or use than the reticle of the critical size little 10%～20% of the figure of passivation to be needed and go exposure, form the identical pattern of the figure of passivation to be needed or the pattern slightly less than critical size;

(3) adopt the method for silica etching, carry out etching, form the figure of the silica identical with the figure of passivation to be needed, make it height pattern (as shown in Figure 3) occur;

Wherein, etching depth depends on the thickness of figure of the passivation to be needed of deposition, and in this example, etch amount is 100 nanometers, and the General Requirements degree of depth is that 50～300 nanometers all can;

(4) use dry method to add the mode of removing photoresist of wet method, remove photoresist, its result as shown in Figure 4;

(5) use the mode of metal sputtering, the metallic aluminium (as shown in Figure 5) that deposition one deck is 4 microns, then apply the photoresist of one deck 4 micron thickness, the use reticle identical with the critical size of the figure of passivation to be needed exposed, its effect as shown in Figure 6, then adopt the mode of dry etching to carry out metal etch, etching effect as shown in Figure 7, thereby realize the passivation (as shown in Figure 8) of metal wedge angle.

Operate according to the method described above, can solve the sharp-pointed problem of metal top pattern, thereby reduce the point discharge effect, improve the reliability of product.

Claims

1. the method for a wedge angle passivation, is characterized in that, comprises step:

(2) on the basis of step (1), apply one deck photoresist and exposure;

(3) carry out etching, make it the height pattern occur;

(4) remove photoresist;

2. the method for claim 1 is characterized in that: in described step (1), treat to carry out the lower floor of figure wedge angle passivation, comprising: the filling of aluminum steel lower floor dielectric layer, oxide-film through hole and oxide-film through hole;

Wherein, the filler of oxide-film through hole comprises: tungsten, maybe can realize the material with the tungsten identical function.

3. the method for claim 1, it is characterized in that: in described step (2), (5), the thickness of photoresist is greater than 400 nanometers.

4. the method for claim 1, is characterized in that: in the exposure of described step (2), use the reticle of the figure of passivation to be needed to go exposure, or use is less by 10%～20% than the critical size of the figure of passivation to be needed.Reticle go the exposure.

5. the method for claim 1, is characterized in that: in described step (3), adopt the method for silica etching, form the figure of the silica identical with the figure of passivation to be needed;

Wherein, etching depth depends on the thickness of figure of the passivation to be needed of deposition.

6. the method for claim 1, is characterized in that: in described step (4), use dry method to add the mode of removing photoresist of wet method, remove photoresist.

7. the method for claim 1, is characterized in that: in described step (5), the material of passivation, comprising: metallic aluminium, copper; Wherein, the thickness of deposition is greater than 1 micron.

8. the method for claim 1 is characterized in that: in the exposure of described step (5), use the reticle exposure of the critical size-10% of the figure of passivation to be needed～+ 10%.

9. the method for claim 1, is characterized in that: the etching in described step (5), employing dry etching.