TWI666755B - Electrostatic discharge protection structure, integrated circuit, and method for protecting core circuit of integrated circuit from electrostatic discharge event received by conductive pad of the integrated circuit - Google Patents

Abstract

An electrostatic discharge protection structure for protecting a core circuit of an integrated circuit from an electrostatic discharge event received by a conductive gasket, which includes a first conductive layer, a clamping element, and a first electrical connection portion connected by a second electrical connection. unit. The first conductive layer is formed under the conductive pad and includes a first conductive portion, an isolation portion, and a second conductive portion. The isolation portion is surrounded by the first conductive portion and the second conductive portion. The first conductive portion is electrically connected between the conductive pad and the second conductive portion. The clamping element is used for clamping the electrostatic discharge event. The first electrical connection portion is coupled between the first conductive portion of the first conductive layer and the clamping element. The second electrical connection portion is coupled between the second conductive portion of the first conductive layer and the core circuit.

Description

Electrostatic discharge protection structure, integrated circuit and method for protecting core circuit of integrated circuit from electrostatic discharge event received by conductive pad

The invention relates to electrostatic discharge protection (ESD protection), in particular to an electrostatic discharge that uses a floor plan design of a conductive layer to protect the core circuit of an integrated circuit from an electrostatic discharge event. Protection architecture, and related integrated circuit and electrostatic discharge protection methods.

In order to prevent the core circuit of the integrated circuit from being damaged due to electrostatic discharge current (ESD current), the integrated circuit will use a clamp circuit provided therein to clamp the electrostatic discharge current. However, once the electrostatic discharge current flows into the core circuit before flowing into the clamping circuit, the integrated circuit cannot prevent the core circuit from being damaged by the electrostatic discharge. Therefore, an innovative electrostatic discharge protection mechanism is needed to enhance the ability of electrostatic discharge protection.

In view of this, one object of the present invention is to provide an electrostatic discharge protection architecture that uses a floor plan design of a conductive layer to protect a core circuit of an integrated circuit from an electrostatic discharge event, and related Integrated circuit and electrostatic discharge protection method to solve the above problems.

According to an embodiment of the present invention, an electrostatic discharge protection architecture is disclosed. The electrostatic discharge protection structure is used to protect a core circuit of an integrated circuit from an electrostatic discharge event received by a conductive pad. The electrostatic discharge protection structure includes a first conductive layer, a clamping element, a first electrical connection portion and a second electrical connection portion. The first conductive layer is formed under the conductive pad, wherein the first conductive layer includes a first conductive portion, an insulating portion, and a second conductive portion, and the insulating portion is formed by the first conductive portion. A portion is surrounded by the second conductive portion, and the first conductive portion is electrically connected between the conductive pad and the second conductive portion. The clamping element is used for clamping the electrostatic discharge event. The first electrical connection portion is coupled between the first conductive portion of the first conductive layer and the clamping element. The second electrical connection portion is coupled between the second conductive portion of the first conductive layer and the core circuit.

According to an embodiment of the present invention, it discloses a integrated circuit. The integrated circuit includes a conductive pad, a core circuit and an electrostatic discharge protection structure. The electrostatic discharge protection structure is coupled to the conductive pad and the core circuit to protect the core circuit from being damaged by an electrostatic discharge event received by the conductive pad. The electrostatic discharge protection structure includes a first conductive layer, a clamping element, a first electrical connection portion and a second electrical connection portion. The first conductive layer is formed under the conductive pad, wherein the first conductive layer includes a first conductive portion, an insulating portion, and a second conductive portion, and the insulating portion is formed by the first conductive portion. A portion is surrounded by the second conductive portion, and the first conductive portion is electrically connected between the conductive pad and the second conductive portion. The clamping element is used for clamping the electrostatic discharge event. The first electrical connection portion is coupled between the first conductive portion of the first conductive layer and the clamping element. The second electrical connection portion is coupled between the second conductive portion of the first conductive layer and the core circuit.

According to an embodiment of the present invention, a method for protecting a core circuit of an integrated circuit from an electrostatic discharge event received by a conductive pad is disclosed. The method includes the following steps: providing a first conductive layer under the conductive pad, wherein the first conductive layer includes a first conductive portion, an insulating portion, and a second conductive portion, the insulating portion Is surrounded by the first conductive portion and the second conductive portion, and the first conductive portion is electrically connected between the conductive pad and the second conductive portion; a first electrical connection is made Part is coupled between the first conductive part of the first conductive layer and a clamping element, wherein the clamping element is used for clamping the electrostatic discharge event; and a second electrical connection part is coupled to the first Between the second conductive portion of the conductive layer and the core circuit.

The electrostatic discharge protection mechanism provided by the present invention can preferentially direct the electrostatic discharge current to the clamping component through the design of the conductive path (such as the layout planning / layout design of the conductive layer / metal layer), thereby preventing the electrostatic discharge current from directly Flow into the core circuit. In addition, the electrostatic discharge protection mechanism provided by the present invention can have a higher current carrying capacity (which can avoid / reduce the electromigration effect) and a smaller parasitic capacitance.

The use of “certain vocabulary” in the specification and subsequent application areas refers to specific components. Those who belong to this field should be understandable, and manufacturers may use different terms to refer to the same components. The scope of this specification and subsequent applications does not use the difference in names as a means of distinguishing components, but the difference in function of components as a basis for distinction. The "containment" mentioned in the entire specification and subsequent claims is an open-ended term and should be interpreted as "including but not limited to". In addition, the term "coupling" includes any direct and indirect electrical connection means. Therefore, the description in the text that a first device is electrically connected to a second device means that the first device can be directly connected to the second device, or indirectly connected to the second device through other devices or connection means.

FIG. 1 is a functional block diagram of an integrated circuit according to an embodiment of the present invention. The integrated circuit 100 may include, but is not limited to, a conductive pad 102, a core circuit 104, and an ESD protection structure 110. The core circuit 104 is coupled between a power voltage VDD and a ground voltage GND, and can perform corresponding functions / operations according to different control signals (not shown in FIG. 1) received by the conductive pad 102. (Such as timing control or source driving). The ESD protection structure 110 is coupled to the conductive pad 102 and the core circuit 104 and can be used to protect the core circuit 104 from being damaged by one of the electrostatic discharge events E _ESD received by the conductive pad 102. In this embodiment, the ESD protection architecture 110 may include (but is not limited to) a clamping element 122 and a clamping element 124, wherein the clamping element 122 is coupled between the conductive pad 102 and the power supply voltage VDD to clamp the electrostatic discharge event. E _ESD , and the clamping element 124 is coupled between the conductive pad 102 and the ground voltage GND to clamp the electrostatic discharge event E _ESD . By way of example (but the invention is not limited thereto), the clamping element 122 may be implemented by a diode D1, and / or the clamping element 124 may be implemented by a diode D2.

In order to avoid an electrostatic discharge current I _ESD generated in response to an electrostatic discharge event E _ESD flowing directly into the core circuit 104 without a clamping circuit (such as clamping elements 122/124), the ESD protection architecture 110 may use a conduction path / conduction path ( conductive path) design (such as floorplan / layout design of conductive layer / metal layer) to control the direction of the electrostatic discharge current I _ESD to ensure that the electrostatic discharge current I _ESD does not flow into the clamping circuit. Flow into the core circuit 104. It is worth noting that because the electrostatic discharge protection path and related operations related to diode D1 (clamping element 122) shown in FIG. 1 are related to diode D2 (clamping element 124) shown in FIG. 1 The ESD protection path and its related operations are similar / same. For the sake of brevity, the following describes the ESD protection mechanism provided by the present invention with the ESD protection path related to the diode D1 shown in FIG. 1. Further explanation is as follows.

Please refer to Figure 2 together with Figure 1. FIG. 2 is a schematic diagram of an embodiment of a partial structure of the ESD protection structure 110 shown in FIG. 1. In this embodiment, the conductive pad 102 is coupled to the ESD protection structure 110 via an electrical connection portion 241. The electrical connection portion 241 can conduct / guide the electrostatic discharge current I _ESD from the conductive pad 102. To the electrostatic discharge protection structure 110. In addition to the diode D1, the ESD protection structure 110 may further include (but is not limited to) a plurality of conductive layers 231 to 237 (such as a plurality of metal layers), an electrical connection portion 242, and an electrical connection portion 243. Each of the conductive layers 231 to 237 is formed below the conductive pad 102, and each of the plurality of conductive layers 231 to 237 is electrically connected between the conductive pad 102 and the diode D1. The conductive layer 231 is coupled to the diode D1 through the electrical connection portion 242 to provide a conductive path between the conductive pad 102 and the diode D1, and is coupled to the core circuit 104 through the electrical connection portion 243 to A conductive path is provided between the conductive pad 102 and the core circuit 104.

Through the design of the conduction path, the ESD protection structure 110 can ensure that the ESD current I _ESD does not flow into the core circuit 104 before flowing into the diode D1. Please refer to Figure 2 and Figure 3 together. FIG. 3 is a schematic diagram of an embodiment of a floorplan layout of one of the conductive layers 231 shown in FIG. 2. In the embodiment shown in FIG. 3, the conductive layer 231 may include (but is not limited to) a first conductive portion 352, an insulating portion 353, and a second conductive portion 354, wherein the isolation portion 353 is surrounded by the first conductive portion 352 and the second conductive portion 354, and the first conductive portion 352 is electrically connected between the conductive pad 102 and the second conductive portion 354. In addition, the electrical connection portion 242 is coupled between the first conductive portion 352 of the conductive layer 231 and the diode D1, and the electrical connection portion 243 is coupled to the second conductive portion 354 of the conductive layer 231. And the core circuit 104.

In the case where a current flows into the conductive layer 231 through the conductive pad 102, since the conductive layer 231 is electrically connected to the conductive pad 102 through the first conductive portion 352, the current may flow in from the first conductive portion 352 Diode D1 or core circuit 104. For example (but the present invention is not limited to this), the current may flow into the diode D1 (corresponding to a first conductive path) sequentially through the first conductive portion 352 and the electrical connection portion 242, or may be sequentially The first conductive portion 352, the second conductive portion 354, and the electrical connection portion 243 flow into the core circuit 104 (corresponding to a second conductive path). It is worth noting that the insulating portion 353 can cause the current flowing into the conductive layer 231 to be conducted in the direction of the electrical connection portion 242 (conduction direction A11), rather than directly in the direction of the electrical connection portion 243 (conduction direction) A12) to conduct. Since the electrical connection portion 242 is electrically connected to the diode D1, once the current flows through the first conductive portion 352 of the conductive layer 231, all (or almost all) of the current will pass through the electrical connection portion 242. Flow into diode D1. In other words, the first conductive path is the main conductive path of the current.

Therefore, when the electrostatic discharge event E _ESD occurs, the conductive layer 231 can receive the electrostatic discharge current I _ESD from the conductive pad 102 by using the first conductive portion 352, and the electrical connection portion 242 can transfer the electrostatic discharge current I _ESD ( All or almost all of the electrostatic discharge current I _ESD ) is guided / conducted to the diode D1 to suppress the electrostatic discharge current I _ESD . By designing the conductive paths, conductive layer 231 may preferentially I _ESD ESD current through the first conductive portion 352 is electrically connected to the guide portion 242 and / or two conducting diode D1, thereby preventing the ESD current I _ESD flows directly into The core circuit 104 flows into the diode D1 instead of first. In other words, before the electrostatic discharge current I _ESD flows into the core circuit 104 through the first conductive portion 352, the second conductive portion 354, and the electrical connection portion 243, the electrical connection portion 242 can discharge all or almost all of the electrostatic discharge current I _{ESD is} directed / conducted to diode D1. In this way, the ESD protection architecture 110 can ensure that all or almost all of the ESD current I _ESD flows into the diode D1 first and not into the core circuit 104 first.

In this embodiment, the isolation portion 353 may be implemented by an opening (such as an air gap opening) of the conductive layer 231. However, this is not intended as a limitation of the present invention. For example, it is also feasible to use an electrically insulating material (such as a dielectric material) to implement the insulating portion 353. For another example: the insulating portion 353 may also be an opening filled with an electrically insulating material. As long as the conductive layer 231 can include an insulating portion to prevent all (or almost all) of the received current from flowing directly into the electrical connection portion 243 (ie, along the conduction direction A12) instead of flowing into the electrical connection portion 242, design The above related changes all follow the spirit of the present invention and fall into the scope of the present invention.

In addition, in the embodiment shown in FIG. 2, the conductive layer 231 coupled to the core circuit 104 may be a top conductive layer (above other conductive layers (ie, a plurality of conductive layers 232 to 237)). top conductive layer), so it can have a thicker thickness, higher current capability (to avoid / reduce electromigration effect (EM effect)), and smaller parasitic capacitance. Please note that this is not intended as a limitation of the present invention. In a design change, a conductive layer coupled to the core circuit 104 may be one of the plurality of conductive layers 232 to 237 instead of the top conductive layer. In another design variation, a conductive layer coupled to the core circuit 104 may be a conductive layer having the largest thickness among the plurality of conductive layers 231 to 237.

The above description is for illustrative purposes only and is not intended as a limitation of the present invention. For example, the number of layers of the conductive layer formed between the conductive pad 102 and the diode D1 shown in FIG. 2 is not used as a limitation of the present invention. In some embodiments, one or more layers may be formed between a conductive pad (such as conductive pad 102 shown in FIG. 2) and a clamping element (such as diode D1 shown in FIG. 2). Conductive layer. In addition, in some embodiments, the clamping elements 122/124 shown in FIG. 1 may be implemented by other types of clamping circuits.

The layout plan layout shown in FIG. 3 is for illustrative purposes only and is not intended as a limitation of the present invention. FIG. 4 to FIG. 6 are schematic diagrams illustrating various embodiments of the layout planning and layout of the conductive layer 231 shown in FIG. 2. In the embodiment shown in FIG. 4, the insulating portion 453 of the conductive layer 431 may cause a current (such as an electrostatic discharge current) flowing into the first conductive portion 452 to flow through the electrical connection portion 242 (conduction direction A21). ) To prevent the current from flowing directly to the electrical connection portion 243 through the second conductive portion 454 (conduction direction A22). In the embodiment shown in FIG. 5, the insulating portion 553 of the conductive layer 531 can cause a current (such as an electrostatic discharge current) flowing into the first conductive portion 552 to flow / flow through the electrical connection portion 242 (conduction direction A31). ) To prevent the current from flowing directly to the electrical connection portion 243 through the second conductive portion 554 (conduction direction A32). In the embodiment shown in FIG. 6, the insulating portion 653 of the conductive layer 631 can cause a current (such as an electrostatic discharge current) flowing into the first conductive portion 652 to flow through the electrical connection portion 242 (conduction direction A41). ) To prevent the current from flowing directly to the electrical connection portion 243 (the conduction direction A42) through the second conductive portion 654. As a skilled artist, after reading the relevant descriptions in Figures 1 to 3, they should be able to understand that the electrostatic discharge protection mechanism shown in Figures 4 to 6 can preferentially guide / conduct the electrostatic discharge current to the clamping components, and then It is avoided that the electrostatic discharge current flows directly into the core circuit, so further explanation will not be repeated here.

The electrostatic discharge protection mechanism provided by the present invention can be simply summarized in FIG. 7. FIG. 7 is a flowchart of an embodiment of a method for protecting a core circuit of an integrated circuit from an electrostatic discharge event received by a conductive pad. For convenience of explanation, the method shown in FIG. 7 is described below with the electrostatic discharge protection structure 110 shown in FIG. 2 and FIG. 3. In addition, if the results obtained are substantially the same, the steps need not be performed in the order shown in FIG. 7. For example, certain steps can be inserted in it. The method shown in Figure 7 can be briefly summarized as follows.

Step 710: Provide a conductive layer 231 under the conductive pad 102. The conductive layer 231 may include a first conductive portion 352, an isolation portion 353, and a second conductive portion 354. The isolation portion 353 is surrounded by the first conductive portion 352 and the second conductive portion 354, and the first conductive portion 352 is electrically connected between the conductive pad 102 and the second conductive portion 354.

Step 720: The electrical connection portion 242 is coupled between the first conductive portion 352 of the conductive layer 231 and a clamping element (diode D1), wherein the clamping element is used to clamp the electrostatic discharge event.

Step 730: The electrical connection portion 243 is coupled between the second conductive portion 354 of the conductive layer 231 and the core circuit 104.

In an implementation example, when the electrostatic discharge event occurs, the method can use the first conductive portion 352 of the conductive layer 231 to receive an electrostatic discharge current generated in response to the electrostatic discharge event. In addition, before the electrostatic discharge current flows into the core circuit 104 through the second conductive portion 354 of the conductive layer 231 and the electrical connection portion 243, the method can use the electrical connection portion 242 to guide / conduct the electrostatic discharge current to the core circuit 104. Clamping components. As the skilled artisan can understand the operation details of each step in the process shown in FIG. 7 after reading the relevant descriptions of FIG. 1 to FIG. 6, further description will not be repeated here.

In summary, the electrostatic discharge protection mechanism provided by the present invention can preferentially guide the electrostatic discharge current to the clamping component through the design of the conductive path (for example, the layout planning / layout design of the conductive layer / metal layer). Prevent electrostatic discharge current from flowing directly into the core circuit. In addition, the electrostatic discharge protection mechanism provided by the present invention can have a higher current carrying capacity (which can avoid / reduce the electromigration effect) and a smaller parasitic capacitance. The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the scope of patent application of the present invention shall fall within the scope of the present invention.

100‧‧‧Integrated Circuit

102‧‧‧Conductive gasket

104‧‧‧Core Circuit

110‧‧‧ Electrostatic discharge protection architecture

122, 124‧‧‧ clamping elements

231 ～ 237, 431, 531, 631‧‧‧ conductive layer

241, 242, 243‧‧‧ Electrical connection

352, 452, 552, 652‧‧‧ the first conductive part

353, 453, 553, 653‧‧‧ isolated parts

354, 454, 554, 654‧‧‧ The second conductive part

710, 720, 730‧‧‧ steps

A11, A12, A21, A22, A31, A32, A41, A42‧‧‧ Conduction direction

VDD‧‧‧ supply voltage

GND‧‧‧ ground voltage

E _ESD ‧‧‧ Electrostatic discharge event

I _ESD ‧‧‧ Electrostatic discharge current

D1, D2‧‧‧ diodes

FIG. 1 is a functional block diagram of an integrated circuit according to an embodiment of the present invention. FIG. 2 is a schematic diagram of an embodiment of a partial structure of the electrostatic discharge protection structure shown in FIG. 1. FIG. 3 is a schematic diagram of an embodiment of the layout planning and layout of one of the conductive layers shown in FIG. 2. FIG. 4 is a schematic diagram of an embodiment of the layout planning and layout of one of the conductive layers shown in FIG. 2. FIG. 5 is a schematic diagram of an embodiment of the layout planning and layout of one of the conductive layers shown in FIG. 2. FIG. 6 is a schematic diagram of an embodiment of the layout planning and layout of one of the conductive layers shown in FIG. 2. FIG. 7 is a flowchart of an embodiment of a method for protecting a core circuit of an integrated circuit from an electrostatic discharge event received by a conductive pad.

Claims (18)

An electrostatic discharge protection structure is used to protect a core circuit of an integrated circuit from an electrostatic discharge event received by a conductive pad. The electrostatic discharge protection structure includes: a first conductive Layer formed under the conductive pad, wherein the first conductive layer includes a first conductive portion, an insulating portion, and a second conductive portion, and the insulating portion is formed by the first conductive portion and Surrounded by the second conductive portion, and the first conductive portion is electrically connected between the conductive pad and the second conductive portion; a clamping element for clamping the electrostatic discharge event; a first electrical A conductive connection portion is coupled between the first conductive portion of the first conductive layer and the clamping element; and a second electrical connection portion is directly connected to the second conductive portion of the first conductive layer And the core circuit. The electrostatic discharge protection structure described in item 1 of the patent application scope further comprises: at least a second conductive layer formed under the conductive pad, wherein the at least one second conductive layer is electrically connected to the conductive pad And the clamping element; wherein the first conductive layer is a top conductive layer formed on the at least one second conductive layer. The electrostatic discharge protection structure described in item 1 of the patent application scope further comprises: at least a second conductive layer formed under the conductive pad, wherein the at least one second conductive layer is electrically connected to the conductive pad And the clamping element; wherein the thickness of the first conductive layer is greater than the thickness of each second conductive layer in the at least one second conductive layer. According to the electrostatic discharge protection structure described in item 1 of the scope of patent application, wherein when the electrostatic discharge event occurs, the first conductive layer uses the first conductive part to receive an electrostatic discharge current generated in response to the electrostatic discharge event ; And before the electrostatic discharge current flows into the core circuit through the second conductive portion and the second electrical connection portion, the first electrical connection portion guides the electrostatic discharge current to the clamping element. The electrostatic discharge protection structure described in item 1 of the patent application scope, wherein the isolation portion is an opening of the first conductive layer. The electrostatic discharge protection structure according to item 1 of the patent application scope, wherein the clamping element includes a diode. An integrated circuit includes: a conductive pad; a core circuit; and an electrostatic discharge protection structure coupled to the conductive pad and the core circuit to protect the core circuit from being received by the conductive pad. Damage caused by an electrostatic discharge event, wherein the electrostatic discharge protection structure includes: a first conductive layer formed under the conductive pad, wherein the first conductive layer includes a first conductive portion, an isolation portion, and A second conductive portion, the insulating portion is surrounded by the first conductive portion and the second conductive portion, and the first conductive portion is electrically connected to the conductive pad and the second conductive portion A clamping element for clamping the electrostatic discharge event; a first electrical connection portion coupled between the first conductive portion of the first conductive layer and the clamping element; and a second The electrical connection portion is directly connected between the second conductive portion of the first conductive layer and the core circuit. The integrated circuit according to item 7 of the scope of patent application, wherein the electrostatic discharge protection structure further comprises: at least a second conductive layer formed under the conductive pad, wherein the at least one second conductive layer is electrically connected Between the conductive pad and the clamping element; wherein the first conductive layer is a top conductive layer formed above the at least one second conductive layer. The integrated circuit according to item 7 of the scope of patent application, wherein the electrostatic discharge protection structure further comprises: at least a second conductive layer formed under the conductive pad, wherein the at least one second conductive layer is electrically connected Between the conductive pad and the clamping element; wherein the thickness of the first conductive layer is greater than the thickness of each second conductive layer in the at least one second conductive layer. According to the integrated circuit described in item 7 of the scope of patent application, when the electrostatic discharge event occurs, the first conductive layer uses the first conductive portion to receive an electrostatic discharge current generated in response to the electrostatic discharge event; And before the electrostatic discharge current flows into the core circuit through the second conductive portion and the second electrical connection portion, the first electrical connection portion will guide the electrostatic discharge current to the clamping element. According to the integrated circuit described in item 7 of the scope of patent application, the isolated portion is an opening of the first conductive layer. The integrated circuit according to item 7 of the scope of patent application, wherein the clamping element includes a diode. A method for protecting a core circuit of an integrated circuit from an electrostatic discharge event received by a conductive pad includes the following steps: providing a first conductive layer under the conductive pad, wherein the The first conductive layer includes a first conductive portion, an insulating portion, and a second conductive portion, the insulating portion is surrounded by the first conductive portion and the second conductive portion, and the first conductive portion The conductive portion is electrically connected between the conductive pad and the second conductive portion; a first electrical connection portion is coupled between the first conductive portion of the first conductive layer and a clamping element Wherein the clamping element is used for clamping the electrostatic discharge event; and a second electrical connection portion is directly connected between the second conductive portion of the first conductive layer and the core circuit. The method according to item 13 of the scope of patent application, further comprising the following steps: providing at least a second conductive layer under the conductive pad, wherein the at least one second conductive layer is electrically connected to the conductive pad and the conductive pad; The components are clamped; wherein the first conductive layer is a top conductive layer formed over the at least one second conductive layer. The method according to item 13 of the scope of patent application, further comprising the following steps: providing at least a second conductive layer under the conductive pad, wherein the at least one second conductive layer is electrically connected to the conductive pad and the conductive pad; The components are clamped; wherein the thickness of the first conductive layer is greater than the thickness of each second conductive layer in the at least one second conductive layer. The method according to item 13 of the scope of patent application, further comprising the following steps: when the electrostatic discharge event occurs, using the first conductive part of the first conductive layer to receive an electrostatic discharge generated in response to the electrostatic discharge event Current; and before the electrostatic discharge current flows into the core circuit through the second conductive portion and the second electrical connection portion, the electrostatic discharge current is guided to the clamping element by the first electrical connection portion. The method according to item 13 of the patent application, wherein the isolation portion is an opening of the first conductive layer. The method of claim 13, wherein the clamping element comprises a diode.