A monitoring device and method for source region doping of trench mos

Abstract

The application discloses a kind of monitoring device and method of source region doping of trench MOS, design two identical components in first layer, there is a difference in two components, the difference is that the connection relationship of source region and contact hole, so that the total resistance R1 of one component is obtained by the first diffusion resistance of its source region and the second diffusion resistance of its body region in parallel, also so that the total resistance R2 of second component is equal to the second diffusion resistance of its body region, by preset algorithm, total resistance R1 and total resistance R2 are calculated, to obtain the calculated value, and the calculated value is compared with the design value, to quickly obtain the deviation of monitoring source region doping of trench MOS, without destructive dissection test to chip.

Description

Technical Field

[0001] This invention relates to the field of semiconductor detection technology, and in particular to a monitoring device and method for source region doping of trench MOS. Background Technology

[0002] MOSFET chips are discrete semiconductor devices. Based on their physical structure, MOSFET chips can be broadly classified into two categories: planar MOSFETs and trench MOSFETs. The fabrication process of trench MOSFETs includes key steps such as trench formation, gate formation, body and source region formation, contact hole and metal electrode formation, and intermediate measurement. The source region of a MOSFET is typically located on the surface of the body region, and its diffusion depth is less than that of the body region. The doping type of the body region is opposite to that of the substrate and source region. Taking an N-channel MOSFET as an example, the substrate is N-type doped, the body region is P-type doped, and the source region is N-type doped.

[0003] The body and source regions of a trench MOS are diffusion regions formed by ion implantation followed by high-temperature annealing. Fluctuations in the process can cause changes in the doping concentration and / or depth of the body region and the doping concentration and / or depth of the source region, thereby affecting the threshold voltage and even the avalanche characteristics (EAS) of the trench MOS. Summary of the Invention

[0004] The purpose of this invention is to address the technical problems existing in the background art by proposing a monitoring device and method for source region doping of trench MOS.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention in the first aspect is as follows:

[0006] A monitoring device for source region doping of a trench MOS includes two components. Each component includes a first layer, a second layer, and a trench. The first layer includes a substrate, a body region, and a source region stacked sequentially. The second layer is deposited on the first layer and has multiple contact holes filled with metal electrodes. The trench extends sequentially into the source region and the body region to form a first diffusion resistor and a second diffusion resistor in the source region and the body region, respectively. The trench is filled with a first material and a second material. The multiple contact holes extend into the body region. The source regions of the two components have different structures. The source region of one component is connected through multiple contact holes, so that the first diffusion resistor and the second diffusion resistor in the first component are connected in parallel to obtain a total resistance R1. The source region of the second component is not connected to multiple contact holes, so that the second diffusion resistor in the two components serves as the total resistance R2.

[0007] Preferably, the boundary of the source region of one component is located on the center line of the width of the trench, and a portion of the boundary of the source region of the other component is located on the center line of the width of the trench.

[0008] Preferably, the distance between the boundary of another part of the source region of the two components and the contact hole is S, where .μm <S<μm。

[0009] Preferably, the groove includes a main annular groove and four secondary annular grooves. The four secondary annular grooves are respectively connected to the four sides of the main annular groove, and four contact holes are provided, which are respectively connected to the areas surrounded by the four secondary annular grooves.

[0010] Preferably, the main annular groove is a rectangular surrounding structure to enclose and form the total resistance, wherein the total resistance is either total resistance R1 or total resistance R2.

[0011] Preferably, the total resistance has an equilateral rectangular shape.

[0012] Preferably, the total resistance is a van der Burg resistor.

[0013] Preferably, the first material comprises silicon dioxide covering the inner wall of the trench.

[0014] Preferably, the second material comprises polycrystalline silicon that fills the remaining space in the trench.

[0015] The technical solution adopted in the second aspect of the present invention is as follows:

[0016] A method for monitoring source doping in a trench MOS, characterized in that it is applied to a monitoring device for source doping in a trench MOS as described above, and the method for monitoring source doping in a trench MOS includes:

[0017] The total resistance R1 and total resistance R2 in the two components are measured separately to obtain the first total resistance value and the second total resistance value;

[0018] Based on a preset algorithm, the first total resistance value is compared with the second total resistance value to obtain the calculated value;

[0019] The calculated value is compared with the preset design value to determine the deviation of the source region doping of the trench MOS.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects: Two identical components are designed in the first layer, with one difference between the two components. The difference lies in the connection relationship between the source region and the contact hole, so that the total resistance R1 of one component is obtained by the parallel connection of the first diffusion resistance of its source region and the second diffusion resistance of its body region. The total resistance R2 of the two components is also equal to the second diffusion resistance of its body region. The total resistance R1 and the total resistance R2 are calculated by a preset algorithm to obtain the calculated value, and the calculated value is compared with the design value to quickly obtain the deviation of the source region doping of the monitoring trench MOS without the need for destructive dissection testing of the chip. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the planar structure of one of the components of the present invention as shown in the first aspect embodiment;

[0022] Figure 2 This is a schematic diagram of the planar structure of two components of the present invention as shown in the first aspect embodiment;

[0023] Figure 3 This is a cross-sectional view of one of the components of the present invention in a first aspect embodiment;

[0024] Figure 4 This is a cross-sectional view of two components of the present invention as described in the first aspect embodiment;

[0025] Figure 5 This is a monitoring flowchart of a second aspect embodiment of the present invention.

[0026] Reference numerals: 100 First layer, 101 Source region, 102 Body region, 200 Second layer, 201 First contact hole, 202 Second contact hole, 203 Metal electrode, 300 Trench, 301 First material, 302 Second material, 303 Main annular trench, 304 Sub-annular trench, 400 Resistor. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or a specific connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0031] like Figure 1 as well as Figure 4 As shown, the present invention provides a monitoring device for source region doping of a trench MOS in a first aspect, comprising two components, the components comprising a first layer 100, a second layer 200 and a trench 300, the first layer 100 comprising a substrate 101, a body region 102 and a source region 103 stacked sequentially, and the second layer 200 being deposited on the first layer 100.

[0032] Specifically, in this embodiment, the monitoring device is actually located in the dicing channel of the wafer. Specifically, the preparation of the monitoring device is also included in the chip fabrication process such as wafer etching, and is carried out synchronously with the wafer etching. For example, the trench, source region, and body region of the monitored trench MOS are formed synchronously with the trench 300, source region 103, and body region 102 in the two components, respectively. In addition, the gate oxide layer in the trench of the monitored trench MOS is formed synchronously with the first material and the second material in the trench 300 of the two components. Except for the source region 103, the other structures in the two components are the same.

[0033] The second layer 200 has multiple contact holes 201, and the contact holes 201 are filled with metal electrodes 202. The trench 300 is sequentially inserted into the source region 103 and the body region 102 to form a first diffusion resistor and a second diffusion resistor in the source region 103 and the body region 102, respectively. The trench 300 is filled with a first material 301 and a second material 302. The multiple contact holes 201 are inserted into the body region 102. The source regions 103 in the two components have different structures. The source region 103 of one component is connected through multiple contact holes 201, so that the first diffusion resistor and the second diffusion resistor in the one component are connected in parallel to obtain the total resistance R1. The source region 103 of the other component is not connected to multiple contact holes 201, so that the second diffusion resistor in the two components is used as the total resistance R2.

[0034] As mentioned above, the source areas 103 in the two components are configured differently. Specifically, the source area 103 of one component is connected through multiple contact holes 201, while the source area 103 of the other component is not connected to the multiple contact holes 201, as shown in the attached figure. Figure 3 and attached Figure 4 As shown, in one component, the metal electrode 202 in the contact hole 201 can be connected. Since the source region 103 and the body region 102 are stacked, and the contact hole 201 passes through the source region 103 and the body region 102 in sequence, the first diffusion resistance in the source region 103 and the second diffusion resistance in the body region 102 are in parallel. According to the calculation method of parallel resistance, the total resistance R1 and the corresponding total resistance value can be quickly obtained. Similarly, in the second component, the source region 103 is not connected to the contact hole 201, which means that the metal electrode 202 in the contact hole 201 is only connected to the body region 102. Therefore, there is only the second diffusion resistance of the body region 102 here, which means that the second diffusion resistance of the body region 102 in the two components can be considered to be equal to its total resistance R2.

[0035] Furthermore, the boundary of the source region 103 of one component is located on the center line of the width of the trench 300, and a portion of the boundary of the source region 103 of the other component is located on the center line of the width of the trench 300.

[0036] The distance between another part of the boundary of the source region 103 of the second component and the contact hole 201 is S, where 0.5μm <S<2μm。

[0037] The groove 300 includes a main annular groove 303 and four secondary annular grooves 304. The four secondary annular grooves 304 are respectively connected to the four sides of the main annular groove 303. The contact hole 201 is provided with four holes and is respectively connected to the area surrounded by the four secondary annular grooves 304.

[0038] As attached Figure 1 and attached Figure 2 As shown, it should be noted that the boundary of the source region 103 of the first component is located on the center line of the width of the trench 300. It can be understood that the boundary of the trench 300 is folded inward, and the inward folding distance is half of the width of the trench 300 x 1, which finally results in the source region 103. The source region 103 of the second component is similar, with an inward folding distance of half the width of the trench 300 x 2. However, when the boundary of the source region 103 of the second component is in the four sub-annular trenches 304, it does not surround the four contact holes 201, which also means that the source region 103 is not connected to the four metal electrodes 202.

[0039] Furthermore, the main annular groove 303 is a rectangular surrounding structure to enclose and form a total resistor 305, wherein the total resistor 305 is a total resistor R1 or a total resistor R2. The structural shape of the total resistor 305 is an equilateral rectangle, and the total resistor 305 adopts a van der Bauer resistor.

[0040] Furthermore, the first material 301 includes silicon oxide covering the inner wall of the trench 300, and the second material 302 includes polycrystalline silicon filling the remaining space of the trench 300.

[0041] like Figure 5 As shown, in a second aspect, the present invention provides a method for monitoring source doping in a trench MOS, characterized in that it is applied to a monitoring device for source doping in a trench MOS as described above, and the method for monitoring source doping in a trench MOS includes:

[0042] S1. Detect the total resistance R1 and total resistance R2 in the two components respectively to obtain the first total resistance value and the second total resistance value;

[0043] S2. Based on the preset algorithm, calculate the first total resistance value and the second total resistance value to obtain the calculated value;

[0044] S3. Compare the calculated value with the preset design value to determine the deviation of the source region doping of the trench MOS.

[0045] Specifically, the total resistance R1 is actually obtained by connecting the first diffusion resistor (marked R12) and the second diffusion resistor (marked R11) in parallel in one of its components. The formula for calculating parallel resistances is: R1 = R11 * R12 / (R11 + R12).

[0046] The total resistance R2 is actually obtained directly from the second diffusion resistor (marked R21) in the two components. The reason is as described above, the source region 103 is not connected to the contact hole 201, so R2 = R21.

[0047] Since the two components are identical in all aspects except for the source region 103, the body region 102 in the two components is the same, and the corresponding two second diffusion resistors are also the same, i.e., R11 = R21.

[0048] Based on the above calculation transformation, we can obtain: R12=R1*R2 / (R2-R1).

[0049] Furthermore, since the source region of the monitored trench MOS is formed synchronously with the source region 103 in the two components, the resistance (R symbol) in the source region of the monitored trench MOS is the same as the first diffusion resistance in the two components, i.e., R = R12.

[0050] Therefore, R = R1 * R2 / (R2 - R1), and the structure obtained by this formula can be the design value or the calculated value by a preset algorithm.

[0051] When the source region of the monitored trench MOS deviates during the doping process (ion implantation, high-temperature annealing), the above algorithm formula can be used to calculate the corresponding value. By comparing the calculated value with the design value, it can be determined whether a deviation has occurred. R2 does not have a source region 103, so it is not affected. Specifically, R1 has changed. By step-by-step calculation, the degree of deviation can be found, thus achieving high accuracy of the monitoring device.

[0052] When actually obtaining the resistance value of two components, a current (I1) is directly applied between two adjacent metal electrodes 202 in the component. Taking one component as an example, the voltage (V1) between the other two adjacent metal electrodes 202 is measured. According to the basic formula of the van der Burg resistance test, R1 = 4.532 * V1 / I1 can be obtained. The resistance value test method for the other two components is the same.

[0053] The above describes a monitoring device and method for source region doping of a trench MOS, or various embodiments thereof, provided in conjunction with specific content. It is not intended that the specific implementation of this invention is limited to these descriptions. Any methods or structures similar to or identical to those of this invention, or any technical deductions or substitutions made based on the concept of this invention, should be considered within the scope of protection of this invention.

Claims

1. A device for monitoring source region doping of a trench MOS, characterized by, include: Two components, the components comprising: The first layer (100) includes a substrate (101), a body region (102) and a source region (103) stacked sequentially. The second layer (200) is laid on the first layer (100). The second layer (200) is provided with a plurality of contact holes (201), and the contact holes (201) are filled with metal electrodes (202). A trench (300) is inserted sequentially into the source region (103) and the body region (102) to form a first diffusion resistor and a second diffusion resistor in the source region (103) and the body region (102) respectively. The trench (300) is filled with a first substance (301) and a second substance (302). The plurality of contact holes (201) are respectively inserted into the body region (102); The source regions (103) in the two components have different structures. The source region (103) of one component is connected through multiple contact holes (201), so that the first diffusion resistor and the second diffusion resistor in the first component are connected in parallel to obtain a total resistance R1. The source region (103) of the other component is not connected to multiple contact holes (201), so that the second diffusion resistor in the other component serves as the total resistance R2.

2. The monitoring device for source region doping of a trench MOS according to claim 1, characterized in that, Firstly, the boundary of the source region (103) of the component is located on the center line of the width of the trench (300), and secondly, a portion of the boundary of the source region (103) of the component is located on the center line of the width of the trench (300).

3. The monitoring device for source region doping of a trench MOS according to claim 2, characterized in that, Secondly, the distance between another portion of the boundary of the source region (103) of the component and the contact hole (201) is S, where 0.5 μm <S<2μm。 4. The monitoring device for source region doping of a trench MOS according to claim 1, characterized in that, The groove (300) includes a main annular groove (303) and four secondary annular grooves (304). The four secondary annular grooves (304) are respectively connected to the four sides of the main annular groove (303). The contact hole (201) is provided with four holes and is respectively connected to the area surrounded by the four secondary annular grooves (304).

5. The monitoring device for source region doping of a trench MOS according to claim 4, characterized in that, The main annular groove (303) is a rectangular surrounding structure to enclose and form a total resistance (305), wherein the total resistance (305) is a total resistance R1 or a total resistance R2.

6. The monitoring device for source region doping of a trench MOS according to claim 1, characterized in that, The first material (301) comprises silicon oxide covering the inner wall of the trench (300).

7. The monitoring device for source region doping of a trench MOS according to claim 1, characterized in that, The second material (302) comprises polycrystalline silicon that fills the remaining space of the trench (300).

8. A method for monitoring source region doping in a trench MOS transistor, characterized in that, A monitoring device for source doping of a trench MOS as described in any one of claims 1-7, wherein the method for monitoring source doping of the trench MOS comprises: The total resistance R1 and total resistance R2 in the two components are measured respectively to obtain the first total resistance value and the second total resistance value; Based on a preset algorithm, the first total resistance value is compared with the second total resistance value to obtain a calculated value; The calculated value is compared with the preset design value to determine the deviation of the source region doping of the trench MOS.

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