CN100438019C - Vertical electrostatic discharge protection device structure - Google Patents

Abstract

The invention discloses a vertical electrostatic discharge protection element structure, which at least comprises a first metal layer, a dielectric layer and a second metal layer. The first metal layer is arranged on the substrate and provided with a plurality of first metal gaps. And the first metal notches at least comprise metal sharp corners. The dielectric layer is arranged on the first metal layer, and the second metal layer is arranged on the dielectric layer. And a vertical path of electrostatic discharge is formed between the metal sharp corner of the first metal layer and the second metal layer.

Description

Component Structure of Vertical ESD Protection

technical field

The invention relates to a component structure for electrostatic discharge protection, and in particular to a protection component structure that can provide a vertical path for electrostatic discharge.

Background technique

With the advancement of semiconductor technology, the volume of various electronic components is getting smaller and smaller, and various physical phenomena are also causing problems as the size of electronic components shrinks. Electrostatic discharge (ESD) effect is one example.

The release of energy due to electrostatic discharge may damage circuit structures, such as thin film transistors in flat panel displays, which may cause serious damage at very small electrostatic currents. Therefore, there have been various designs of electrostatic protection circuits traditionally, and their functions are similar to lightning rods. At present, most of these ESD protection circuits are planar designs, and only a few are designed with vertical protection circuits. However, this type of protective element is designed in a flat plate, and its electrostatic discharge discharge voltage (breakdown voltage) depends on the thickness of the insulating layer material, so the application range is small and the effect is not great.

Contents of the invention

In view of this, the purpose of the present invention is to provide a vertical electrostatic discharge protection element structure, which utilizes the exposure limit of optical lithography technology (commonly known as yellow light process) to form the required discharge structure. Since the tip is formed on the metal element or a thinner dielectric layer is formed, the tip discharge can be performed with a smaller discharge voltage, providing a path for static electricity to drain.

According to the purpose of the present invention, a vertical electrostatic discharge protection device structure is proposed, which at least includes a first metal layer, a dielectric layer and a second metal layer. The first metal layer is disposed on the substrate, and the first metal layer has a plurality of first metal gaps. And the first metal notches at least include metal sharp corners. The dielectric layer is disposed on the first metal layer, and the second metal layer is disposed on the dielectric layer. A vertical path for electrostatic discharge is formed between the sharp metal corner of the first metal layer and the second metal layer.

According to the object of the present invention, another vertical electrostatic discharge protection device structure is proposed, which at least includes a first metal layer, a dielectric layer and a second metal layer. The first metal layer is disposed on the substrate, the dielectric layer is disposed on the first metal layer, and the dielectric layer has a plurality of dielectric gaps. The second metal layer is disposed on the dielectric layer, and a downward point is formed corresponding to the dielectric gap. The dielectric gap through the dielectric layer provides a lower discharge voltage than the surrounding area, so as to facilitate the vertical electrostatic discharge of the device structure.

According to the object of the present invention, another vertical electrostatic discharge protection device structure is proposed, which at least includes a first metal layer, a dielectric layer and a second metal layer. The first metal layer is disposed on the substrate, and the side edge of the first metal layer has a first finger pattern. The dielectric layer is disposed on the first metal layer, the second metal layer is disposed on the dielectric layer, and the side edge of the second metal layer has a second finger pattern. The first finger pattern and the second finger pattern are misaligned to provide at least one vertical path for electrostatic discharge.

According to the purpose of the present invention, a method for manufacturing a vertical electrostatic discharge protection device structure is proposed, comprising the following steps: first, forming a first metal layer on the substrate; then, forming a dielectric layer on the first metal layer; then, A second metal layer is formed on the dielectric layer. At least one of the first metal layer and the dielectric layer has a plurality of gaps, and when the gaps are formed on the first metal layer, the gaps at least include a sharp metal corner. At least one static discharge vertical path is formed between the first metal layer and the second metal layer through one of the gaps or metal sharp corners.

In order to make the above objects, features, and advantages of the present invention more comprehensible, the present invention will be described in more detail below in conjunction with the accompanying drawings and preferred embodiments.

Description of drawings

FIG. 1A shows a top view of the first thin film transistor of Embodiment 1;

Fig. 1B is a vertical cross-sectional view showing the device structure of the first thin film transistor along section line AA' in Fig. 1A;

FIG. 1C shows a top view of the second thin film transistor of Embodiment 1;

Figure 1D shows a vertical cross-sectional view of the device structure of the second thin film transistor along section line AA' in Figure 1C;

FIG. 1E shows a top view of the third thin film transistor of Embodiment 1;

Figure 1F shows a vertical cross-sectional view of the element structure of the third thin film transistor along section line AA' in Figure 1E;

FIG. 2 shows a flow chart of forming a thin film transistor with a vertical ESD protection device structure;

3 shows a schematic diagram of a thin film transistor and a photoresist for forming it;

FIG. 4A shows a top view of a thin film transistor of Embodiment 2; and

FIG. 4B is a vertical cross-sectional view of an element structure of a thin film transistor along the section line BB' in FIG. 4A.

simple notation

10: Substrate

20, 110, 110a, 410: first metal layer

30: Positive photoresist layer

35: notch

35a: sharp corner

100a, 100b, 100c, 400: thin film transistors

112a: Metal notch

115a: Metal sharp corners

120, 120a, 420: dielectric layer

122, 422: insulating layer

124, 124a, 424: channel layer

130, 430: second metal layer

135: tip

412, 432: side edge

415: First Finger Graphics

416: first protrusion

435: Second Finger Graphics

436: second protrusion

Detailed ways

Embodiment one

Please refer to FIG. 1A , which shows a top view of a first thin film transistor according to Embodiment 1. Referring to FIG. The first thin film transistor 100 a includes a first metal layer 110 a , a dielectric layer 120 and a second metal layer 130 . The first metal layer 110 a and the second metal layer 130 are separated by the dielectric layer 120 . Please refer to FIG. 1B again, which shows a vertical cross-sectional view of the device structure of the first thin film transistor along the section line AA' in FIG. 1A. The first metal layer 110a is disposed on the substrate 10, and the first metal layer 110a has a plurality of metal gaps 112a. Moreover, metal sharp corners 115a are included between the metal notches 112a. The dielectric layer 120 is disposed on the first metal layer 110 a. The dielectric layer 120 includes an insulating layer 122 and a channel layer 124 . The second metal layer 130 is disposed on the dielectric layer 120 . A vertical path p1 of electrostatic discharge is formed between the sharp metal corner 115 a of the first metal layer 110 a and the second metal layer 130 , as shown by the dotted line in the figure.

Please refer to FIG. 1C and FIG. 1D at the same time, which respectively depict a top view of the second thin film transistor of Embodiment 1, and a vertical cross-sectional view of the device structure of the second thin film transistor along the section line AA' in FIG. 1C. The main difference between the second type thin film transistor 100b and the first type thin film transistor 100a is that: the dielectric layer 120a of the second type thin film transistor 100b has a dielectric gap, for example, a channel gap 125a is provided in the channel layer 124a, and the second type The first metal layer 110 of the thin film transistor 100b does not have metal sharp corners. As shown in FIG. 1D , the dielectric layer 120a includes an insulating layer 122 and a channel layer 124a, and the channel layer 124a has a channel gap 125a. The channel gap 125a provides a thinner dielectric layer area, so that the discharge voltage of the first metal layer 110 and the second metal layer 130 at the channel gap 125a is lower, and a discharge path p2 passing through the channel gap 125a is formed. The second metal layer 130 forms a downward tip 135 corresponding to another channel gap, forming another discharge path between the thinner part of the dielectric layer 120 a and the first metal layer 110 .

Please refer to FIG. 1E and FIG. 1F at the same time, which respectively depict the top view of the third thin film transistor of Embodiment 1, and the vertical cross-sectional view of the device structure of the third thin film transistor along the section line AA' in FIG. 1E. The main difference between the third type of thin film transistor 100c and the first type of thin film transistor 100a is that the channel layer 124a of the dielectric layer 120a of the third type of thin film transistor 100c has a channel gap 125a, and the second metal layer 130 corresponds to the other side of the channel. The channel indentation forms a downward point 135 . As shown in FIG. 1F , the channel gap 125a of the dielectric layer 120a is located above the metal corner 115a of the first metal layer 110a , so a discharge path p3 can be vertically formed through the metal corner 115a and the channel gap 125a. The same tip 135 forms another discharge path between another dielectric gap of the dielectric layer 120a and the first metal layer 110a.

As for the manufacturing method of the vertical ESD protection device structure of the present invention, please refer to FIG. 2 , which shows a flow chart of a thin film transistor with a vertical ESD protection device structure. Please also refer to FIG. 3 , which shows a schematic diagram of a thin film transistor and its formation photoresist.

First, as shown in step 1, a first metal layer 20 is formed on the substrate 10 . Next, as shown in step 2, a dielectric layer (not shown) is formed on the first metal layer 20, and the dielectric layer includes an insulating layer and a channel layer. The material of the insulating layer includes, for example, silicon nitride or silicon oxide, and the material of the channel layer, for example, includes amorphous silicon or polysilicon, or silicon.

Then, as shown in step 3, a second metal layer (not shown) is formed on the dielectric layer. At least one of the first metal layer 20 and the dielectric layer has a plurality of gaps. When the notch is formed on the first metal layer 20 , the notch at least includes metal sharp corners, and an electrostatic discharge vertical path formed between the first metal layer 20 and the second metal layer passes through the metal sharp corners. Taking FIG. 3 as an example, a positive photoresist layer 30 is formed on the first metal layer 20 . Next, a photomask is provided on the positive photoresist layer 30 , the photomask has a plurality of openings, and the width of the openings can be random, from small to large or from large to small. Due to the limitation of the exposure resolution of the photolithography process (yellow light process) itself, different exposure depths are generated for the positive photoresist layer 30 under openings with different widths. Then, exposure is performed to form a plurality of notches 35 on the photoresist layer 30 . The plurality of notches 35 include at least sharp corners 35a. Finally, the positive photoresist layer 30 and the first metal layer 20 are etched to form, for example, a plurality of metal gaps 112 a as shown in FIG. 1B . Since the etching pattern will correspond to the shape of the positive photoresist layer 30, the sharp corner 35a corresponding to the first metal layer 20 will form, for example, the metal sharp corner 115a in FIG. A discharge path passing through the sharp metal corner 115a is formed between the two metal layers 130 . Using the same manufacturing method, a thinner dielectric layer as shown in FIG. 1D , that is, the channel gap 125 a (P2 discharge path) can also be formed on the dielectric layer.

However, those skilled in the technical field of the present invention can understand that the technology of the present invention is not limited to forming notches and sharp corners only on the first metal layer. The channel gap 125a as shown in FIG. 1D can also be formed on the dielectric layer (not shown) in the same manner as above. When the gap is formed on the dielectric layer, a vertical path for electrostatic discharge is formed between the first metal layer 20 and the second metal layer (not shown) through the gap. In addition, the present invention can also use a negative photoresist material to form a similar notch pattern.

Embodiment two

In the thin film transistor of the second embodiment, a slightly dislocated pattern, such as a finger pattern, is formed in the vertical direction at the side edges of the first and second metal layers, thereby generating a vertical path for electrostatic discharge. Please refer to FIG. 4A , which shows a top view of a thin film transistor according to the second embodiment. The thin film transistor 400 of the second embodiment includes a first metal layer 410 , a dielectric layer 420 and a second metal layer 430 . And the side edge 412 of the first metal layer 410 has a first finger pattern 415 , and the side edge 432 of the second metal layer 430 has a second finger pattern 435 . The first finger pattern 415 and the second finger pattern 435 respectively include a plurality of first protrusions 416 and a plurality of second protrusions 436, and a plurality of first protrusions 416 and a plurality of second protrusions 436 Misalignment occurs in the vertical direction.

Please refer to FIG. 4B, which shows a vertical cross-sectional view of a thin film transistor device structure along the section line BB' in FIG. 4A. The first metal layer 410 is disposed on the substrate 10 , the dielectric layer 420 is formed on the first metal layer 410 , and the dielectric layer 420 includes an insulating layer 422 and a channel layer 424 . The second metal layer 430 is disposed on the dielectric layer 420, and the plurality of first protrusions 416 of the first finger pattern 415 of the first metal layer 410 and the second finger pattern 435 of the second metal layer 430 The plurality of second protrusions 436 are dislocated in the vertical direction, so as to generate the vertical path p4 of the electrostatic discharge.

However, those who have ordinary knowledge in the technical field to which the present invention belongs can understand that the technology of the present invention is not limited thereto. The structures of the first embodiment and the second embodiment can be matched with each other and implemented on the thin film transistor at the same time. That is to say, on the same thin film transistor, the first metal layer can have metal sharp corners and the first finger pattern at the same time, the dielectric layer can have dielectric gaps, and the second metal layer can have the second finger pattern. If the element structures of the above embodiments are combined and implemented, the effect of electrostatic discharge protection can be further exerted.

The device structure of the vertical ESD protection disclosed in the above-mentioned embodiments of the present invention is mainly to form a sharp metal corner on the first metal layer, or/and form a thin dielectric gap on the dielectric layer. Or form dislocation finger patterns at the side edges of the first metal layer and the second metal layer, so that a discharge path can be formed between the two metal layers through metal sharp corners or dielectric gaps or dislocation finger patterns to release Charge, to avoid when the charge accumulation exceeds the discharge voltage, electrostatic discharge will be generated and the components will be damaged.

In summary, although the present invention is disclosed above with preferred embodiments, it is not intended to limit the present invention. Those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, The protection scope of the present invention should be defined by the claims.

Claims (8)

1. the component structure of a vertical electrostatic discharging protection comprises at least:

The first metal layer is arranged on the substrate, and this first metal layer has a plurality of first metal breach, and comprises the first metal wedge angle at least in these a plurality of first metal breach;

Dielectric layer is arranged on this first metal layer; And

Second metal level is arranged on this dielectric layer;

Wherein between this of this first metal layer first metal wedge angle and this second metal level, form the vertical-path of static discharge,

Wherein the lateral margin place of the lateral margin place of this first metal layer with the first finger-like figure and this second metal level has the second finger-like figure, and this first finger-like figure and the dislocation of this second finger-like figure.

2. component structure as claimed in claim 1, wherein this dielectric layer has a plurality of dielectric breach, and one of them is positioned at these a plurality of dielectric breach on the vertical-path of this static discharge.

3. component structure as claimed in claim 1, wherein this first finger-like figure comprises that a plurality of first protuberances and this second finger-like figure comprise a plurality of second protuberances.

4. component structure as claimed in claim 1, this dielectric layer comprises insulating barrier and channel layer, this channel layer is arranged on this insulating barrier.

5. the component structure of a vertical electrostatic discharging protection comprises at least:

The first metal layer is arranged on the substrate;

Dielectric layer is arranged on this first metal layer, and this dielectric layer has a plurality of dielectric breach; And

Second metal level is arranged on this dielectric layer, to forming downward tip by a plurality of dielectric breach;

These a plurality of dielectric breach by this dielectric layer provide than around lower discharge voltage, carry out vertical static discharge in order to this component structure,

Wherein the lateral margin place of the lateral margin place of this first metal layer with the first finger-like figure and this second metal level has the second finger-like figure, and this first finger-like figure and the dislocation of this second finger-like figure.

6. component structure as claimed in claim 5, wherein this first metal layer has more a plurality of first metal breach, and comprises the first metal wedge angle at least in these a plurality of first metal breach.

7. component structure as claimed in claim 5, wherein this first finger-like figure comprises that a plurality of first protuberances and this second finger-like figure comprise a plurality of second protuberances.

8. component structure as claimed in claim 5, this dielectric layer comprises insulating barrier and channel layer, this channel layer is arranged on this insulating barrier.

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