CN109216345B - Electrostatic discharge protection architecture, integrated circuit and protection method of core circuit thereof - Google Patents

Abstract

An electrostatic discharge protection structure for protecting the core circuit of an integrated circuit from electrostatic discharge events received by a conductive pad comprises a first conductive layer, a clamping element, a first electrical connection portion and a second electrical connection portion. The first conductive layer is formed below the conductive pad and comprises 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 to clamp 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

ESD protection structure, integrated circuit and protection method for its core circuit

technical field

The present invention relates to electrostatic discharge protection (ESD protection), and more particularly to an ESD protection structure that utilizes a floor plan design of a conductive layer to protect a core circuit of an integrated circuit from damage caused by electrostatic discharge events , and related integrated circuits and electrostatic discharge protection methods.

Background technique

In order to prevent the core circuit of the integrated circuit from being damaged due to ESD current, the integrated circuit uses a clamp circuit disposed therein to clamp the ESD current. However, once the ESD current flows into the core circuit before flowing into the clamp circuit, the integrated circuit cannot prevent the core circuit from being damaged by ESD. Therefore, an innovative ESD protection mechanism is required to improve the capability of ESD protection.

SUMMARY OF THE INVENTION

In view of this, one of the objectives of the present invention is to provide an ESD protection structure that utilizes a floorplan design of a conductive layer to protect the core circuit of an integrated circuit from ESD events, and related ESD protection structures. Integrated circuits and electrostatic discharge protection methods to solve the above problems.

According to an embodiment of the present invention, an electrostatic discharge protection structure is disclosed. The ESD protection architecture is used to protect a core circuit of an integrated circuit from an ESD 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 and the second conductive portion. Surrounded by two conductive parts, and the first conductive part is electrically connected between the conductive pad and the second conductive part. The clamping element is used to clamp 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, an integrated circuit is disclosed. 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 for protecting the core circuit from 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 and the second conductive portion. Surrounded by two conductive parts, and the first conductive part is electrically connected between the conductive pad and the second conductive part. The clamping element is used to clamp 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 one 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 part, an isolation part and a second conductive part, the isolation part is formed by the first conductive part A conductive 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; a first electrical connection portion is coupled to the first conductive portion between the first conductive portion of the layer and a clamping element, wherein the clamping element is used to clamp the electrostatic discharge event; and a second electrical connection is coupled between the second conductive portion of the first conductive layer and the between the core circuits.

The electrostatic discharge protection mechanism provided by the present invention can preferentially guide the electrostatic discharge current to the clamping element through the design of the conductive path (for example, the layout planning/layout design of the conductive layer/metal layer), thereby preventing the electrostatic discharge current from directly flowing into core circuit. In addition, the ESD protection mechanism provided by the present invention may have higher current carrying capability (which may avoid/reduce electromigration effects) and smaller parasitic capacitance.

Description of drawings

FIG. 1 is a functional block diagram of an embodiment of an integrated circuit of the present invention.

FIG. 2 is a schematic diagram of an embodiment of a partial structure of the ESD protection structure shown in FIG. 1 .

FIG. 3 is a schematic diagram of an embodiment of a floorplan layout of the conductive layer shown in FIG. 2 .

FIG. 4 is a schematic diagram of an embodiment of a floorplan layout of the conductive layer shown in FIG. 2 .

FIG. 5 is a schematic diagram of an embodiment of a floorplan layout of the conductive layer shown in FIG. 2 .

FIG. 6 is a schematic diagram of an embodiment of a floorplan layout of the conductive layer shown in FIG. 2 .

7 is a flow diagram of one embodiment of a method of the present invention for protecting a core circuit of an integrated circuit from an electrostatic discharge event received by a conductive pad.

Description of reference numbers:

100 integrated circuits

102 Conductive gasket

104 Core circuit

110 ESD Protection Architecture

122, 124 Clamping element

231～237, 431, 531, 631 Conductive layer

241, 242, 243 Electrical connection part

352, 452, 552, 652 The first conductive part

353, 453, 553, 653 Isolation part

354, 454, 554, 654 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 diode

Detailed ways

Certain terms are used in the specification and subsequent claims to refer to particular elements. It should be understood by those of ordinary skill in the art that manufacturers may refer to the same element by different nouns. The scope of this specification and subsequent patent applications does not take the difference in name as a way to distinguish elements, but takes the difference in function of the elements as a basis for distinction. The "comprising" mentioned in the entire specification and claims is an open-ended term, so it should be interpreted as "including but not limited to". Furthermore, the term "coupled" herein includes any direct and indirect means of electrical connection. Therefore, if it is described herein that a first device is electrically connected to a second device, it means that the first device can be directly connected to the second device or indirectly connected to the second device through other devices or connecting means.

FIG. 1 is a functional block diagram of an embodiment of an integrated circuit 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 supply voltage VDD and a ground voltage GND, and can perform corresponding functions/operations (not shown in FIG. 1 ) 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 an electrostatic discharge event 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 ESD events 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 . For 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 prevent an electrostatic discharge current I _ESD generated in response to an electrostatic discharge event E _ESD from directly flowing into the core circuit 104 without a clamping circuit (such as the clamping elements 122 / 124 ), the ESD protection structure 110 may utilize a conduction path/conduction path The design of the conductive path (such as the floorplan/layout design of the conductive layer/metal layer) to control the flow of the electrostatic discharge current I _ESD to ensure that the electrostatic discharge current I _ESD does not flow before the clamp circuit It flows into the core circuit 104 first. It is worth noting that since the ESD protection path and its related operations involved in the diode D1 (clamping element 122 ) shown in FIG. The 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 involved in the diode D1 shown in FIG. 1 . Further explanation is as follows.

Please refer to Figure 2 in conjunction 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 , wherein the electrical connection portion 241 can conduct/guide the electrostatic discharge current I _ESD from the conductive pad 102 to the ESD protection framework 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 231-237 (such as a plurality of metal layers), an electrical connection part 242 and an electrical connection part 243, wherein the plurality of conductive layers The layers 231-237 are all formed under the conductive pad 102, and each conductive layer among the plurality of conductive layers 231-237 is electrically connected between the conductive pad 102 and the diode D1. The conductive layer 231 is coupled to the diode D1 via an electrical connection 242 to provide a conductive path between the conductive pad 102 and the diode D1, and is coupled to the core circuit 104 via an electrical connection 243 to provide a conductive pad Conductive path between 102 and 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 the conductive layer 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 insulating portion 354 The 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 between the second conductive portion 354 of the conductive layer 231 and the core circuit 104 between.

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 into the diode D1 from the first conductive portion 352 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 conduction path) through the first conductive portion 352 and the electrical connection portion 242 in sequence, or may pass through the first conduction path in sequence. The 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 isolation portion 353 can cause the current flowing into the conductive layer 231 to be conducted toward the direction of the electrical connection portion 242 (conduction direction A11 ), rather than directly toward 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 flow into the diode D1 through the electrical connection portion 242 . In other words, the above-mentioned first conduction path is the main conduction path of the current.

Therefore, when the electrostatic discharge event E _ESD occurs, the conductive layer 231 can use the first conductive portion 352 to receive the electrostatic discharge current I _ESD from the conductive pad 102 , and the electrical connection portion 242 can discharge the electrostatic discharge current I _ESD (all the or almost all of the electrostatic discharge current I _ESD ) is directed/conducted to diode D1 to suppress the electrostatic discharge current I _ESD . Through the design of the conduction path, the conductive layer 231 can preferentially guide/conduct the electrostatic discharge current I _ESD to the diode D1 through the first conductive portion 352 and the electrical connection portion 242 , thereby preventing the electrostatic discharge current I _ESD from directly flowing into the core circuit 104 . not first into diode D1. 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 conduct all or almost all of the electrostatic discharge current I _ESD into the core circuit 104 . Lead/conduct to diode D1. As such, the ESD protection architecture 110 can ensure that all or almost all of the ESD current I _ESD flows into the diode D1 first rather than 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 to be 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 isolation portion 353 . For another example, the isolation portion 353 can 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 current received from directly flowing into the electrical connection portion 243 (ie, along the conduction direction A12) instead of flowing into the electrical connection portion 242, the design Related changes all follow the spirit of the present invention and fall within 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 (top conductive layer) formed above other conductive layers (ie, the plurality of conductive layers 232-237). conductive layer), thus can have thicker thickness, higher current capability (can avoid/reduce electromigration effect (EM effect)) and smaller parasitic capacitance. Note that this is not intended to be a limitation of the present invention. In a design variation, a conductive layer coupled to the core circuit 104 may also be one of the plurality of conductive layers 232-237 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 - 237 .

The above description is for illustrative purposes only, and is not intended to be used 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 intended to be a limitation of the present invention. In some embodiments, one or more conductive 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 ) . Additionally, in some embodiments, the clamping elements 122/124 shown in FIG. 1 may also be implemented by other types of clamping circuits.

The floorplan layout shown in FIG. 3 is for illustrative purposes only and is not intended to be a limitation of the present invention. 4 to 6 are schematic diagrams illustrating various embodiments of the floorplanning 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 can cause a current (such as electrostatic discharge current) flowing into the first conductive portion 452 to flow to/through the electrical connection portion 242 (conduction direction A21), preventing The current flows directly through the second conductive portion 454 to the electrical connection portion 243 (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 electrostatic discharge current) flowing into the first conductive portion 552 to flow to/through the electrical connection portion 242 (conduction direction A31), preventing the The current flows directly through the second conductive portion 554 to the electrical connection portion 243 (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 electrostatic discharge current) flowing into the first conductive portion 652 to flow to/through the electrical connection portion 242 (conduction direction A41), preventing The current flows directly through the second conductive portion 654 to the electrical connection portion 243 (conduction direction A42). After reading the relevant descriptions of FIGS. 1 to 3 , those skilled in the art should be able to understand that the ESD protection mechanism shown in FIGS. 4 to 6 can preferentially lead/conduct the ESD current to the clamping element, thereby avoiding the ESD current It directly flows into the core circuit, so further description will not be repeated here.

The ESD protection mechanism provided by the present invention can be simply summarized in FIG. 7 . 7 is a flow diagram of one embodiment of a method of the present invention for protecting a core circuit of an integrated circuit from an electrostatic discharge event received by a conductive pad. For the convenience of description, the method shown in FIG. 7 is described below with reference to the electrostatic discharge protection structure 110 shown in FIG. 2 and FIG. 3 . Furthermore, the steps do not necessarily have to be performed in the order shown in FIG. 7 if substantially the same results are obtained. For example, certain steps may be inserted therein. The method shown in Figure 7 can be briefly summarized as follows.

Step 710 : Provide a conductive layer 231 under the conductive pad 102 , wherein 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 : Coupling the electrical connection portion 242 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 : Coupling the electrical connection portion 243 between the second conductive portion 354 of the conductive layer 231 and the core circuit 104 .

In an implementation example, when the ESD event occurs, the method may utilize the first conductive portion 352 of the conductive layer 231 to receive an ESD current generated in response to the ESD event. Furthermore, before the ESD current flows into the core circuit 104 via the second conductive portion 354 and the electrical connection portion 243 of the conductive layer 231, the method may utilize the electrical connection portion 242 to guide/conduct the ESD current to the clamp element. Since those skilled in the art should be able to understand the operation details of each step in the process shown in FIG. 7 after reading the relevant descriptions of FIGS. 1 to 6 , further descriptions are not repeated here.

To sum up, the ESD protection mechanism provided by the present invention can preferentially guide the ESD current to the clamping element through the design of the conductive path (for example, the layout planning/layout design of the conductive layer/metal layer), thereby preventing the Electrostatic discharge current flows directly into the core circuitry. In addition, the ESD protection mechanism provided by the present invention may have higher current carrying capability (which may avoid/reduce electromigration effects) and smaller parasitic capacitance.

Claims (18)

1. An electrostatic discharge protection structure for protecting a core circuit of an integrated circuit from an electrostatic discharge event received by a conductive pad, the electrostatic discharge protection structure comprising: A first conductive layer is formed under the conductive pad, wherein the first conductive layer includes a first conductive part, an isolation part and a second conductive part, and the isolation part is formed by the first conductive part and the Surrounded by a 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 connection portion coupled between the first conductive portion of the first conductive layer and the clamping element; and A second electrical connection portion is coupled between the second conductive portion of the first conductive layer and the core circuit. 2. The ESD protection structure of claim 1, further comprising: at least one second conductive layer is formed under the conductive pad, wherein the at least one second conductive layer is electrically connected between the conductive pad and the clamping element; The first conductive layer is a top conductive layer formed above the at least one second conductive layer. 3. The electrostatic discharge protection structure of claim 1, further comprising: at least one second conductive layer is formed under the conductive pad, wherein the at least one second conductive layer is electrically connected between the conductive pad and the clamping element; 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. 4. The ESD protection structure of claim 1, wherein when the ESD event occurs, the first conductive layer utilizes the first conductive portion to receive an ESD current generated by the ESD event; and Before the ESD current flows into the core circuit through the second conductive portion and the second electrical connection portion, the first electrical connection portion guides the ESD current to the clamping element. 5. The ESD protection structure of claim 1, wherein the isolation portion is an opening of the first conductive layer. 6. The ESD protection structure of claim 1, wherein the clamping element comprises a diode. 7. An integrated circuit comprising: a conductive gasket; a core circuit; and An electrostatic discharge protection structure coupled to the conductive pad and the core circuit for protecting the core circuit from an electrostatic discharge event received by the conductive pad, wherein the electrostatic discharge protection structure includes: A first conductive layer is formed under the conductive pad, wherein the first conductive layer includes a first conductive part, an isolation part and a second conductive part, and the isolation part is formed by the first conductive part and the Surrounded by a 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 connection part coupled between the first conductive portion of the first conductive layer and the clamping element; and A second electrical connection portion is coupled between the second conductive portion of the first conductive layer and the core circuit. 8. The integrated circuit of claim 7, wherein the ESD protection structure further comprises: at least one second conductive layer is formed under the conductive pad, wherein the at least one second conductive layer is electrically connected between the conductive pad and the clamping element; The first conductive layer is a top conductive layer formed above the at least one second conductive layer. 9. The integrated circuit of claim 7, wherein the ESD protection structure further comprises: at least one second conductive layer is formed under the conductive pad, wherein the at least one second conductive layer is electrically connected between the conductive pad and the clamping element; 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. 10. The integrated circuit of claim 7, wherein when the electrostatic discharge event occurs, the first conductive layer utilizes the first conductive portion to receive an electrostatic discharge current generated by the electrostatic discharge event; and in the 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. 11. The integrated circuit of claim 7, wherein the isolation portion is an opening of the first conductive layer. 12. The integrated circuit of claim 7, wherein the clamping element comprises a diode. 13. A method for protecting a core circuit of an integrated circuit from an electrostatic discharge event received by a conductive pad, comprising the steps of: A first conductive layer is provided under the conductive pad, wherein the first conductive layer includes a first conductive part, an isolation part and a second conductive part, and the isolation part is formed by the first conductive part and the first conductive part. Surrounded by two conductive parts, and the first conductive part is electrically connected between the conductive pad and the second conductive part; coupling a first electrical connection 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 coupled between the second conductive portion of the first conductive layer and the core circuit. 14. The method of claim 13, further comprising the steps of: at least one second conductive layer is provided under the conductive pad, wherein the at least one second conductive layer is electrically connected between the conductive pad and the clamping element; The first conductive layer is a top conductive layer formed above the at least one second conductive layer. 15. The method of claim 13, further comprising the steps of: at least one second conductive layer is provided under the conductive pad, wherein the at least one second conductive layer is electrically connected between the conductive pad and the clamping element; 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. 16. The method of claim 13, further comprising the steps of: when the electrostatic discharge event occurs, utilizing the first conductive portion of the first conductive layer to receive an electrostatic discharge current generated by the electrostatic discharge event; and Before the ESD current flows into the core circuit through the second conductive portion and the second electrical connection portion, the ESD current is guided to the clamping element by the first electrical connection portion. 17. The method of claim 13, wherein the isolation portion is an opening of the first conductive layer. 18. The method of claim 13, wherein the clamping element comprises a diode.

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