CN103107081B

CN103107081B - A kind of method of sharp corner passivation

Info

Publication number: CN103107081B
Application number: CN201110352080.3A
Authority: CN
Inventors: 郁新举
Original assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2011-11-09
Filing date: 2011-11-09
Publication date: 2016-02-10
Anticipated expiration: 2031-11-09
Also published as: CN103107081A

Abstract

The invention discloses a kind of method of sharp corner passivation, comprise step: 1) by existing technological process, form the lower floor waiting to need to carry out figure sharp corner passivation; 2) in step 1) basis on, coating one deck photoresist also exposes; 3) etch, make it occur height pattern; 4) photoresist is removed; 5) adopt the mode of metal sputtering to deposit the material wanting passivation, coating photoresist, after exposure, etching, realize passivation.The present invention can realize comparatively mellow and full corner, thus, can solve metal top pattern acute problem, thus reduces point discharge effect, improves the reliability of product.

Description

A kind of method of sharp corner passivation

Technical field

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

Background technology

Insulated gate bipolar transistor (InsolatedGateBipolarTransistor, IGBT) be a kind of device be 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 there is the advantage that MOSFET element driving power is little and switching speed is fast, there is again bipolar device saturation pressure reduce and advantage capacious, thus, obtain in modern power electronics technology and apply more and more widely.

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

Summary of the invention

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

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

(1) by existing technological process, the lower floor waiting to need to carry out figure sharp corner passivation is formed;

(2) on the basis of step (1), coating one deck photoresist also exposes;

(3) etch, make it occur height pattern;

(4) photoresist is removed;

(5) adopt metal sputtering mode, carry out depositing the material wanting passivation, coating photoresist, after exposure, etching, realize passivation.

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

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

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

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

The present invention is by forming a kind of front layer of height pattern, after follow-up passivating material (being generally metal aluminum bronze) is grown up, arc-shaped can be formed coated at this height pattern place, controlled by the critical size of photoresist again, realize comparatively mellow and full corner, thus, metal top pattern acute problem can be solved, thus reduce point discharge effect, improve the reliability of product.

Accompanying drawing explanation

Below in conjunction with accompanying drawing and embodiment, the present invention is further detailed explanation:

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

Fig. 2 applies photoresist and the schematic diagram of exposure in the structure of Fig. 1;

Fig. 3 carries out etching the schematic diagram forming difference of height figure in 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 wants the material of passivation in the structure of Fig. 4;

Fig. 6 be apply on Fig. 5 basis photoresist and exposure after design sketch;

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

Fig. 8 is the pattern design sketch after forming final passivation.

Embodiment

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

The method of the metal sharp corner passivation in the present embodiment, comprises step:

(1) by existing technological process, form the lower floor's (as shown in Figure 1) waiting to need to carry out figure sharp corner passivation, concrete steps are as follows:

The method of chemical vapour deposition (CVD) is used to grow up the dielectric layer of one deck 800 ran, by the mode of dry etching, form the oxide-film through hole of critical size 0.35 micron, after through hole is formed, use the mode of metal deposition, titanium deposition titanium nitride and tungsten ensure that through hole is fully filled, and the tungsten on dielectric layer is removed by the method for then being carved by method or the dry back of grinding, and the tungsten retained in tungsten through hole forms wire;

(2) on the basis of step (1), coating one deck photoresist also exposes, and result as shown in Figure 2;

Wherein, the thickness of photoresist is determined according to demand, thickness is with photoresist made to be one micron in this example, in photoresist exposure, the reticle of the figure of passivation to be needed can be used to go exposure, or use and go exposure than the reticle of critical size little 10% ~ 20% of the figure of passivation to be needed, 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 oxide etch, etch, form the figure of the silica identical with the figure of passivation to be needed, make it occur height pattern (as shown in Figure 3);

Wherein, etching depth depends on the thickness of the 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 50 ~ 300 nanometers;

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

(5) mode of metal sputtering is used, the metallic aluminium (as shown in Figure 5) of deposition one deck 4 microns, then the photoresist of one deck 4 micron thickness is applied, the reticle identical with the critical size of the figure of passivation to be needed is used to expose, 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, thus realizes the passivation (as shown in Figure 8) of metal wedge angle.

Operate according to the method described above, metal top pattern acute problem can be solved, thus reduce point discharge effect, improve the reliability of product.

Claims

1. a method for sharp corner passivation, is characterized in that, comprises step:

(2) on the basis of step (1), coating one deck photoresist also exposes;

(3) etch, make it occur height pattern;

(4) photoresist is removed;

(5) adopt metal sputtering mode, carry out depositing the material wanting passivation, coating photoresist, after exposure, etching, realize passivation;

In described step (1), wait the lower floor needing to carry out figure sharp corner passivation, comprising: the filling of aluminum steel underlying dielectric layer, oxide-film through hole and oxide-film through hole; Wherein, the filler of oxide-film through hole, comprising: tungsten, maybe can realize the material with tungsten identical function.

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

3. the method for claim 1, it 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 the reticle of the critical size little 10% ~ 20% of the figure than passivation to be needed to go exposure.

4. the method for claim 1, is characterized in that: in described step (3), adopts the method for oxide etch, forms the figure of the silica identical with the figure of passivation to be needed;

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

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

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

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

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