Electrostatic protection structure

Abstract

The present invention relates to an electrostatic protection structure. The electrostatic protection structure includes a conductive body and a conductive protrusion, wherein the conductive body surrounds a chip to be protected and is grounded, and the conductive protrusion is arranged on the conductive body. The present invention can effectively eliminate static electricity by tip discharge by arranging a conductive protrusion on the conductive body, thereby avoiding a large amount of charge accumulation in the electrostatic protection structure, thereby ensuring the stability and safety of the chip.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to an electrostatic protection structure. Background Art

[0002] Chips can also be called integrated circuits. With the continuous development of integrated circuit manufacturing technology, chip packaging density and integration are getting higher and higher, chip size is getting smaller and smaller, and the interference between circuit modules is becoming more and more obvious. Electrostatic protection becomes more important.

[0003] The excess charge caused by the ESD (ElectroStatic discharge) phenomenon will be transmitted into the specific circuit through the input and output pins of the specific circuit in a very short time, thereby destroying the specific circuit of the chip.

[0004] In the current chip packaging layout, a seal ring structure is generally set around the chip. There is a certain distance between the seal ring structure and the chip to effectively separate the edge of the semiconductor chip. The main purpose of the seal ring structure is to protect the IC from cutting stress, water vapor and moisture intrusion or electrostatic charge discharge when cutting the IC. However, due to various limitations of actual processes, the smooth conductive lines that constitute the seal ring cannot effectively eliminate static electricity by grounding.

[0005] How to effectively eliminate static electricity problems in chip circuits and ensure the stability and safety of the chip remains a technical problem that urgently needs to be solved in this field. Summary of the invention

[0006] The present invention provides an electrostatic protection structure to effectively eliminate static electricity in a chip circuit and ensure the stability and safety of the chip.

[0007] An embodiment of the present invention provides an electrostatic protection structure, including:

[0008] A conductive body surrounding the chip to be protected and grounded; and

[0009] At least one conductive protrusion is disposed on the conductive body.

[0010] In one embodiment, the conductive body is an open guard ring circuit starting from the first end and ending at the second end.

[0011] In one embodiment, the electrostatic protection structure further includes a test pad, and the test pad is disposed at two ends of the open protection ring circuit.

[0012] In one embodiment, the protection ring circuit includes a plurality of conductive circuits, and each of the conductive circuits has the conductive protrusion.

[0013] In one embodiment, the conductive protrusion on the conductive circuit close to the chip faces away from and / or toward the chip.

[0014] In one embodiment, the patterns of the conductive circuits in the multiple turns of conductive circuits are the same or different.

[0015] In one embodiment, the conductive protrusions of adjacent conductive circuits in the multi-circle conductive circuit are arranged in a staggered manner.

[0016] In one embodiment, the conductive protrusions of each conductive circuit have the same or different shapes.

[0017] In one embodiment, the outermost conductive circuit of the conductive body has the conductive protrusions arranged at intervals in a direction facing away from the chip.

[0018] In one embodiment, the conductive protrusion is a rectangular protrusion.

[0019] In summary, an embodiment of the present invention provides an electrostatic protection structure. Wherein, the electrostatic protection structure includes a conductive body and at least one conductive protrusion, the conductive body surrounds the chip to be protected, and the conductive body is grounded, and the conductive protrusion is arranged on the conductive body. It can be understood that when there is charge accumulation on the surface of the conductor, the charge density is related to the shape of the conductor surface. The greater the curvature of the conductor surface, the greater the surface charge density. When the charge density reaches a certain value, tip discharge will occur. Therefore, the present invention can effectively eliminate static electricity by tip discharge by arranging a conductive protrusion on the conductive body, thereby avoiding a large amount of charge accumulation in the electrostatic protection structure, thereby ensuring the stability and safety of the chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of an electrostatic protection structure provided by an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of another electrostatic protection structure provided by an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of a short circuit and / or open circuit in an electrostatic protection structure provided by an embodiment of the present invention;

[0023] Figure 4 A partial structural schematic diagram of another electrostatic protection structure provided by an embodiment of the present invention;

[0024] Figure 5 A schematic structural diagram of an electrostatic protection structure provided in an embodiment of the present invention, the inner side of which has a conductive protrusion pointing toward a chip. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0026] See also Figure 1 and Figure 2 An embodiment of the present invention provides an electrostatic protection structure, which includes a conductive body 100 and at least one conductive protrusion 200. The conductive body 100 surrounds the chip to be protected and is grounded. The conductive protrusion 200 is arranged on the conductive body 100.

[0027] It can be understood that when there is charge accumulation on the surface of the conductor, the charge density is related to the shape of the conductor surface and is the largest at the sharp part. When the charge density reaches a certain value, tip discharge will occur. Therefore, the present invention can effectively eliminate static electricity by tip discharge by providing a conductive protrusion 200 on the conductive body, avoiding a large amount of charge accumulation in the electrostatic protection structure, thereby ensuring the stability and safety of the chip.

[0028] In one embodiment, the conductive body 100 is an open guard ring circuit starting from a first end and ending at a second end.

[0029] In this embodiment, the open protection ring circuit starts from the first end and ends at the second end, completely surrounds the chip to be protected, and has a certain distance from the chip to effectively separate the edges of the chip, so as to prevent the chip from being affected by cutting stress, water vapor and moisture intrusion or electrostatic charge discharge during cutting.

[0030] In one embodiment, the electrostatic protection structure further includes a test pad 300 , wherein the test pad 300 is disposed at both ends of the open protection ring circuit.

[0031] See also Figure 3It can be understood that during the cutting process, the dicing knife speed, the position of the ejector pin / the height of the ejector pin and the nozzle pressure, the plastic package frame not being in place, and the abnormal bending of the cutting ribs can cause chip cracks, resulting in serious failures and reliability quality problems during the welding from IC to the PCB board or in the process of use. When cracks appear on the chip, the protective ring circuit surrounding it will also open the node G due to the cracks. Therefore, the test pad 300 can provide a detection signal for the protective ring circuit, and then obtain the resistance of the protective ring circuit, and when the resistance of the protective ring circuit becomes infinite, it is determined that the protective ring circuit part between the two test pads 300 is open, and at this time, there may be cracks in the chip.

[0032] In addition, during the manufacturing or subsequent packaging process, a short circuit may also be caused inside the protective ring. Similarly, if there is a short-circuit node S in the protective ring circuit, the test pad 300 can provide a detection signal to the protective ring circuit to obtain the resistance of the protective ring circuit. And when the resistance of the protective ring circuit becomes smaller, it is determined that there is a short circuit in the protective ring circuit. It should be pointed out that the short circuit in the protective ring circuit refers to when the protective ring circuit includes multiple turns of conductive circuits, there is a connection between two adjacent turns of circuits.

[0033] It should be noted that the present invention does not limit the position of the test pad 300 , and the position can be set according to actual needs.

[0034] In one embodiment, the conductive body 100 is a closed protection ring circuit.

[0035] In one embodiment, the electrostatic protection structure may be rectangular, circular or other irregular shapes, and its specific shape may be set according to the peripheral shape of the chip to be protected.

[0036] In one embodiment, the protection ring circuit includes a plurality of conductive circuits, and each of the conductive circuits has a plurality of conductive protrusions 200 .

[0037] It can be understood that when the protection ring circuit includes multiple turns of conductive circuits, and each of the conductive circuits has multiple conductive protrusions 200, the number of conductive protrusions 200 can be increased to effectively avoid the accumulation of large amounts of charge, thereby further improving the ability to eliminate static electricity. In addition, when the conductor charge is small and the conductive protrusion 200 is sharp, the tip discharge is mostly a corona discharge, which is only carried out in a local area near the tip, ionizing the air in this area. Since the discharge energy is small, it will not cause damage to the equipment or the human body. In addition, the protection ring circuit can also include only one turn of conductive circuit; or, the number of turns of the conductive circuit is not an integer.

[0038] In one embodiment, the patterns of the conductive circuits in the multiple turns of conductive circuits are the same or different.

[0039] In a specific embodiment, the shapes of the multiple turns of the conductive circuit may be consistent or inconsistent. For example, the protective ring circuit may include 3 turns of conductive wire circuits, see Figure 4 The innermost conductive circuit 100a is similar in structure to the outermost conductive circuit 100c, both of which are equivalent to forming a cone-shaped conductive protrusion 200 on a smooth circuit, while the conductive circuit 100b in the middle position extends in a square wave or sawtooth shape, and the right angle of the square wave or the sharp angle of the sawtooth forms the conductive protrusion 200. By reasonably setting the relative position between the conductive protrusions 200 on the two adjacent circles of conductive circuits, the distance between adjacent conductive coils can be reduced, thereby increasing the number of circles of the conductive circuit as much as possible within a limited space, and further enhancing the electrostatic protection function of the electrostatic protection structure. Alternatively, while ensuring that there are a certain number of conductive circuits, the size of the electrostatic protection structure is reduced by reducing the distance between two adjacent conductive circuits, thereby reducing the size of the packaged chip structure. This embodiment does not limit the shape of the conductive circuit, and the actual shape of each circle of the conductive circuit can be designed according to specific needs.

[0040] In one embodiment, the conductive protrusions of adjacent conductive circuits in the multi-circle conductive circuit are arranged in a staggered manner.

[0041] It can be understood that when the conductive protrusions of adjacent conductive circuits in the multi-circle conductive circuit are arranged in a staggered manner, it can not only enhance the electrostatic protection function of the electrostatic protection structure or reduce the size of the electrostatic protection structure, but also reduce the distance between the tops of the conductive protrusions 200. When the charge is constant, the electric field between the tops of the conductive protrusions 200 is increased so that discharge can be carried out when the charge is very small, further reducing the accumulation of charge.

[0042] In one embodiment, the conductive protrusion on the conductive line close to the chip faces away from and / or toward the chip. Figure 5 Some of the conductive protrusions on the same conductive circuit face away from the chip, while other parts of the conductive protrusions face toward the chip, thereby avoiding the accumulation of charge on any side of the conductive circuit; and the number of conductive protrusions 200 can be increased to further improve the electrostatic protection function of the electrostatic protection structure.

[0043] In one embodiment, the conductive protrusions of each conductive circuit have the same or different shapes. In this embodiment, the conductive protrusions 200 can be in any shape, such as a cone, a right angle, a triangle, etc.

[0044] In one embodiment, the outermost conductive circuit of the conductive body has the conductive protrusions arranged at intervals in the direction opposite to the chip. It can be understood that the instantaneous voltage during electrostatic discharge can reach 2000V to 10000V, which may cause damage to external devices or chip circuits. By making the outermost conductive circuit have the conductive protrusions arranged at intervals in the direction opposite to the chip, discharge can be achieved inside the electrostatic protection structure to avoid damage to external devices or chip circuits due to static charge discharge.

[0045] In one embodiment, the conductive protrusion is a rectangular protrusion. It is understood that when the conductive protrusion is a rectangular protrusion, if there is a crack, even if the crack exists at the conductive protrusion, it will cause the conductive circuit to be open. Therefore, the rectangular protrusion can not only perform tip discharge, but also be used to check whether the conductive circuit is complete.

[0046] In one embodiment, the width of the electrostatic protection structure is 0.5 μm to 10 μm. In this embodiment, the width of the electrostatic protection structure is limited to 0.5 μm to 10 μm, which can form an effective conductive protrusion 200 in the conductive circuit, and the packaged chip volume will not be too large due to the excessive width of the electrostatic protection structure.

[0047] In one embodiment, the electrostatic protection structure is made of polysilicon, tungsten, copper or aluminum. It can be understood that the electrostatic protection structure of the chip has a conductive function, and can be made of conductive metal materials or non-metallic conductive materials. Therefore, when forming a conductive layer of the chip, the electrostatic protection structure can be formed simultaneously to simplify the process. For example, when forming the metal layer of the chip, the electrostatic protection structure is made simultaneously. In addition, the electrostatic protection structure can also be made using a separate process. In a specific manufacturing process, the electrostatic protection structure can be formed by electroplating or deposition process. Among them, the deposition process can include chemical vapor deposition (CVD), low pressure CVD (LPCVD), plasma enhanced CVD (PECVD), atomic layer deposition (ALD) and plasma enhanced ALD (PEALD).

[0048] In summary, an embodiment of the present invention provides an electrostatic protection structure. Wherein, the electrostatic protection structure includes a conductive body and at least one conductive protrusion, the conductive body surrounds the chip to be protected, and the conductive body is grounded, and the conductive protrusion is arranged on the conductive body. It can be understood that when there is charge accumulation on the surface of the conductor, the charge density is related to the shape of the conductor surface. The greater the curvature of the conductor surface, the greater the surface charge density. When the charge density reaches a certain value, tip discharge will occur. Therefore, the present invention can effectively eliminate static electricity by tip discharge by arranging a conductive protrusion on the conductive body, thereby avoiding a large amount of charge accumulation in the electrostatic protection structure, thereby ensuring the stability and safety of the chip.

[0049] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An electrostatic protection structure, characterized in that: include: A conductive body, surrounding the chip to be protected, and the conductive body is grounded; and A conductive protrusion is disposed on the conductive body, and the conductive body is an open guard ring circuit starting from a first end and ending at a second end; The test pad is arranged at two ends of the open protection ring circuit. The conductive body includes a plurality of conductive circuits, and each conductive circuit has the conductive protrusion.

2. The electrostatic protection structure according to claim 1, characterized in that: The conductive protrusions on the conductive circuits close to the chip face away from and / or toward the chip.

3. The electrostatic protection structure according to claim 1, characterized in that: The patterns of the conductive circuits in the multiple turns of conductive circuits are the same or different.

4. The electrostatic protection structure according to claim 1, characterized in that: The conductive protrusions of adjacent conductive circuits in the multi-circle conductive circuit are arranged in a staggered manner.

5. The electrostatic protection structure according to claim 1, characterized in that: The conductive protrusions of the conductive circuits may have the same or different shapes.

6. The electrostatic protection structure according to claim 1, characterized in that: The conductive circuit on the outermost side of the conductive body has the conductive protrusions arranged at intervals in a direction facing away from the chip.

7. The electrostatic protection structure according to claim 1, characterized in that: The conductive protrusion is a rectangular protrusion.

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