A low residual voltage ESD surge protection device with low capacitance structure

Abstract

The present invention discloses a low residual voltage ESD surge protection device with a low capacitance structure, comprising a capacitance reduction tube D1, a TVS tube D4, a Schottky tube D2, an NPN tube T1 and a forward capacitance reduction tube D3 connected by an electrical connection relationship; wherein the capacitance reduction tube D3 provides a forward current path; D1 and T1 form a PNPN structure, which is the main discharge channel; and the TVS tube D4 provides a turn-on voltage. The present invention is reasonably designed, and the protection device of the unidirectional large snapback SCR structure is realized. Through the double trench process, an extremely low capacitance SCR structure protection device is realized, which can meet the current low residual voltage protection needs, and the device has the characteristics of low capacitance, low clamping and large surge current carrying capacity.

Description

Technical Field

[0001] The present invention belongs to semiconductor component devices, and more specifically, relates to a low residual voltage ESD surge protection device with a low capacitance structure. Background Art

[0002] Due to process limitations, the vertical low residual voltage device is limited by the Zener+R2R structure, and the residual voltage has been difficult to reduce. As the signal port protection is weakened by the follow-current problem, the SCR structure becomes the most effective way to reduce the residual voltage of the device. However, in order to realize the unidirectional SCR structure device, a variety of processes are used to make SCR structure protection devices, each with its own advantages. Due to the use of a multi-layer structure, the process becomes very complicated in the forward realization of the device. The planar structure is relatively simple, but in order to obtain the required breakdown voltage, a relatively low doping concentration has to be used to reduce the breakdown voltage, which makes it difficult to achieve a very low capacitance. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a low residual voltage ESD surge protection device with a low capacitance structure, which is reasonably designed and realizes a unidirectional large snapback SCR structure protection device. Through the double trench process, an extremely low capacitance SCR structure protection device is realized, which can meet the current low residual voltage protection needs, and the device has the characteristics of low capacitance, low clamping and large surge current carrying capacity.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A low residual voltage ESD surge protection device with a low capacitance structure is characterized by comprising a capacity reduction tube D1, a TVS tube D4, a Schottky tube D2, an NPN tube T1 and a forward capacity reduction tube D3 which are electrically connected; wherein the capacity reduction tube D3 provides a forward current path; D1 and T1 form a PNPN structure which is a main discharge channel; and the TVS tube D4 provides a turn-on voltage.

[0006] As an optimized technical solution, the TVS tube is composed of an N-type substrate, an N+ expansion area and a P+ expansion area from bottom to top, wherein the cathode of the TVS tube is the N+ expansion area, and the N+ expansion area is located in the central position; the P+ expansion area is used to make the anode of the TVS tube.

[0007] As an optimized technical solution, the main discharge channel is composed of two substrate N+Deep regions, an N-Epi region, a P+ base region and an N+ emitter region from bottom to top; the two substrate N+Deep regions are arranged on both sides of the N-Epi region; the P+ base region is located above the N+ emitter region, and cathode short-circuit holes are reserved at equal distances around the center of the anode of the TVS tube so that the cathode short-circuit holes have the same potential when the gate is triggered.

[0008] The present invention also provides a low residual voltage ESD surge protection device manufacturing process:

[0009] Here are the steps:

[0010] An N+ buried layer region is formed on the highly doped P+ substrate material by injection annealing; an epitaxial layer N-Epi is grown, and an N+Deep region is formed by injection annealing, and then an N+ expansion region and a P+ expansion region are formed respectively by injection annealing; a groove is formed by deep etching, and silicon dioxide is filled in the groove, and then a mesa groove is formed by a wet etching process, and a metal layer is deposited to form a metal interconnection, so that the metal is connected to the substrate N+Deep region, P+ region and N-Epi region.

[0011] Due to the adoption of the above technical scheme, compared with the prior art, the present invention has a reasonable design and realizes a unidirectional large snapback SCR structure protection device. Through the double trench process, an extremely low capacitance SCR structure protection device is realized, which can meet the current low residual voltage protection needs, and the device has the characteristics of low capacitance, low clamping and large surge current carrying capacity.

[0012] The present invention will be further described with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a circuit diagram of an embodiment of the present invention;

[0014] Figure 2 This is a schematic diagram of the overall structure of an embodiment of the present invention after preparation. DETAILED DESCRIPTION

[0015] Example

[0016] like Figure 1 As shown, a low residual voltage ESD surge protection device with a low capacitance structure includes a capacity reduction tube D1, a TVS tube D4, a Schottky tube D2, an NPN tube T1 and a forward capacity reduction tube D3 which are electrically connected; wherein the capacity reduction tube D3 provides a forward current path; D1 and T1 form a PNPN structure which is a main discharge channel; and the TVS tube D4 provides a turn-on voltage.

[0017] The TVS tube is composed of an N-type substrate, an N+ expansion area and a P+ expansion area from bottom to top, wherein the cathode of the TVS tube is the N+ expansion area, and the N+ expansion area is located in the center; the P+ expansion area is used to make the anode of the TVS tube.

[0018] The main discharge channel is composed of two substrate N+Deep regions, an N-Epi region, a P+ base region and an N+ emitter region from bottom to top; the two substrate N+Deep regions are arranged on both sides of the N-Epi region; the P+ base region is located above the N+ emitter region, and cathode short-circuit holes are reserved at equal distances around the center of the anode of the TVS tube so that the cathode short-circuit holes have the same potential when the gate is triggered.

[0019] The above device is a dual-trench process device, the trench provides device isolation, and the trench is used to connect the substrate with the N+IOS and the surface P+ area. The device is an epitaxial low-capacitance device, and N-Epi provides low-capacitance support for the device. The device is a unidirectional device, and can be used to form a dual-channel or multi-channel protection device through an array original package structure.

[0020] like Figure 2 As shown in the figure, the manufacturing process of the low residual voltage ESD surge protection device is: forming an N+ buried layer region on a highly doped P+ substrate material by injection annealing; growing an epitaxial layer N-Epi, forming an N+ Deep region by injection annealing, and then forming an N+ expansion region and a P+ expansion region respectively by injection annealing; deep trench etching forms a groove, the groove is filled with silicon dioxide, and then a mesa groove is formed by a wet etching process, and a metal layer is deposited to form a metal interconnection, so that the metal is connected to the substrate N+ Deep region, P+ region and N-Epi region.

[0021] The present invention is reasonably designed and realizes a unidirectional large snapback SCR structure protection device. Through a double trench process, an extremely low capacitance SCR structure protection device is realized, which can meet the current low residual voltage protection needs. The device has the characteristics of low capacitance, low clamping and large surge current carrying capacity.

[0022] The protection scope of the present invention is not limited to the above embodiments, and all technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A low residual voltage ESD surge protection device with a low capacitance structure, characterized in that: It includes a capacity reduction tube D1, a TVS tube D4, a Schottky tube D2, an NPN tube T1 and a forward capacity reduction tube D3 which are connected by an electrical connection relationship; The capacity reduction tube D3 provides a forward current path; D1 and T1 form a PNPN structure, which is the main discharge channel; TVS tube D4 provides a turn-on voltage; The TVS tube is composed of an N-type substrate, an N+ expansion area and a P+ expansion area from bottom to top, wherein the cathode of the TVS tube is the N+ expansion area, and the N+ expansion area is located in the center; the P+ expansion area is used to make the anode of the TVS tube; The main discharge channel is composed of two substrate N+Deep regions, N-Epi region, P+ base region and N+ emitter region from bottom to top; the two substrate N+Deep regions are arranged on both sides of the N-Epi region; the P+ base region is located above the N+ emitter region, and a cathode short-circuit hole is reserved at an equal distance around the center of the anode of the TVS tube so that the cathode short-circuit hole has the same potential when the gate is triggered; The above device is a dual trench process device, the trench provides device isolation, and the trench is used to connect the substrate with the N+IOS and the surface P+ region; The device is an epitaxial low capacitance device, and N-Epi provides low capacitance support for the device; the device is a unidirectional device, and can form a dual-channel or multi-channel protection device through the array original package structure; The manufacturing process of the low residual voltage ESD surge protection device is as follows: forming an N+ buried layer region on a highly doped P+ substrate material by injection annealing; growing an epitaxial layer N-Epi, forming an N+ Deep region by injection annealing, and then forming an N+ expansion region and a P+ expansion region by injection annealing; Deep trench etching forms trenches, which are filled with silicon dioxide. A wet etching process is then used to form mesa trenches, and a metal layer is deposited to form metal interconnections, connecting the metal to the substrate N+Deep region, P+ region, and N-Epi region.

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