Electrical test structure for measuring effective width of resistance section and calculation method
By calibrating the resistor thickness and material property errors using a five-terminal test structure, the problem of insufficient accuracy in resistor segment width measurement was solved, achieving high-precision and high-efficiency resistor segment width measurement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-24
- Publication Date
- 2026-03-27
AI Technical Summary
In existing technologies, the calculation method for the effective width of the resistor segment is affected by the resistor thickness and material properties, resulting in insufficient measurement accuracy.
A five-terminal test structure is adopted. By introducing resistor segments of different widths and a five-terminal circuit structure, the error introduced by the thickness and material property changes is directly calibrated, and the effective width is calculated.
It improves the accuracy and generalization ability of resistance segment width measurement, is applicable to resistors manufactured with different materials and processes, simplifies the calibration process, and improves testing efficiency.
Smart Images
Figure CN121752032A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of semiconductor integrated circuits, and in particular to an electrical test structure for measuring the effective width of a resistance segment and a calculation method. BACKGROUND
[0002] The effective width (W eff ) of a wafer resistance segment is an important parameter of a semiconductor device. It refers to the width of the resistance segment that actually participates in conduction under certain conditions. Accurate measurement of the width is crucial for ensuring the performance and reliability of the device. By measuring the effective width of the polysilicon gate and metal wiring, the conduction performance of the transistor, the switching speed, and the signal transmission efficiency of the entire integrated circuit can be evaluated. This helps to optimize the design, improve the integration and operating frequency of the device, and detect deviations and defects in the manufacturing process, such as inconsistent line widths, short circuits, or open circuits, thereby ensuring the stability and reliability of the product.
[0003] The existing method for calculating the width is usually a four-terminal Kelvin structure method, which measures the resistance and then calculates the width based on the resistance. However, the resistance calculated by this method is not only affected by the width of the resistance, but also by the thickness and material of the resistance, which affects the accuracy of the calculation. Therefore, the existing calculation method has the problem of not being accurate enough.
[0004] Therefore, there is a need in the prior art for an improved electrical test structure for measuring the effective width of a resistance segment. SUMMARY
[0005] In view of the above, the purpose of the embodiments of the present application is to provide an electrical test structure for measuring the effective width of a resistance segment and a calculation method, which improves the original test structure to a five-terminal test structure, thereby eliminating the influence of metal thickness and material.
[0006] To achieve the above purpose, the embodiments of the present application provide an electrical test structure for measuring the effective width of a resistance segment, which includes a resistance segment and first to fifth terminals. The resistance segment includes a first width segment and a second width segment. The first width segment is provided with a first terminal and a second terminal at one end away from the second width segment. The first width segment and the second width segment are connected at a third terminal. The second width segment is provided with a fourth terminal and a fifth terminal at one end away from the first width segment. The widths of the first width segment and the second width segment are not equal.
[0007] In some embodiments, the resistance segment includes a polysilicon resistance and a metal resistance.
[0008] In some embodiments, the metal at the metal resistance is aluminum or copper.
[0009] In some embodiments, the resistance segments are integrated on a semiconductor wafer silicon substrate.
[0010] In some embodiments, each of the end electrode pad materials is aluminum or copper.
[0011] In some embodiments, each of the end electrodes comprises, from bottom to top, a pad layer and a protective layer, the pad layer is made of aluminum or copper, and the protective layer is a silicon nitride layer.
[0012] Another aspect of the present application also provides a method for measuring the effective width of a resistance segment, using the above-mentioned electrical test structure, comprising: obtaining the shape information, taking the length value, and measuring the widths of the first width segment and the second width segment to obtain the first width and the second width, respectively; applying a current between the first end electrode and the fifth end electrode, and obtaining the resistance and the bias resistance of the first width segment and the resistance and the bias resistance of the second width segment, respectively, through the five-terminal circuit structure; calculating the ineffective width from the first width, the second width, and the resistance and the bias resistance of the first width segment and the second width segment, and further calculating the effective width from the ineffective width.
[0013] In some embodiments, the resistance and the bias resistance of the first width segment obtained through the five-terminal circuit structure comprise: applying the current to the first width segment and the current to the second width segment, and measuring the voltage between the first end electrode and the third end electrode and the voltage between the third end electrode and the fifth end electrode, calculating the resistance from the voltage and the current, and further calculating the bias resistance from the resistance value and the length and width values.
[0014] In some embodiments, the calculation formula of the bias resistance is:
[0015] wherein, R represents the resistance; W represents the actual width; and L represents the length.
[0016] In some embodiments, the calculation formula of the effective width is:
[0017]
[0018] wherein, is the effective width; is the actual width; is the ineffective width; is the length of the first width segment; is the length of the second width segment; is the actual width of the first width segment; is the actual width of the second width segment; the resistance of the first width section; the resistance of the second width section.
[0019] The present application has at least the following beneficial technical effects: The electrical test structure of the present application can directly compare or calibrate errors that may be introduced due to changes in resistance thickness and material properties by introducing resistance sections of different widths and a five-terminal structure. The five-terminal test method is not only suitable for resistance measurement of a single material or thickness, but also for resistors manufactured by different materials and different processes, and has strong generalization ability, which means that in various application scenarios, the method can provide reliable and accurate effective width measurement results. Traditional methods may need complex calibration steps to compensate for resistance thickness and material differences, while the five-terminal test method actually performs self-calibration during the test process by built-in resistance sections of different widths, greatly simplifying the calibration process and improving test efficiency. BRIEF DESCRIPTION OF DRAWINGS
[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other embodiments can be obtained from these drawings without creative labor.
[0021] Figure 1 A schematic diagram of an electrical test structure for measuring the effective width of a resistance section provided by the present application; Figure 2 A parameter labeling schematic diagram of a two-section resistance section provided by the present application.
[0022] Explanation of reference signs: 10, resistance section; 11, first width section; 12, second width section; 20, first terminal; 30, second terminal; 40, third terminal; 50, fourth terminal; 60, fifth terminal. DETAILED DESCRIPTION
[0023] In order to make the purpose, technical solutions and advantages of the present application more clear and obvious, the following will further describe the embodiments of the present application in combination with specific embodiments and with reference to the drawings.
[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. For example, the terms "length", "width", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, merely describe the orientation in the drawings on which the application is illustrated and are not intended to be limiting.
[0025] The terms "comprise", "comprising", "include", "including", "have" and "having" and any variations thereof in the specification and in the claims are intended to cover both the singular and the plural unless otherwise indicated; the terms "first", "second", "third", etc. are used to distinguish different objects and are not to be construed as limiting the scope of the application. The term "plurality" means two or more, unless otherwise indicated.
[0026] In the specification and claims of the application and in the above description, when an element is referred to as being "fixed to" or "attached to" or "disposed on" or "connected to" another element, it can be directly or indirectly fixed to, attached to, disposed on or connected to the other element. For example, when an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element.
[0027] Furthermore, all references herein to "example" mean that a particular feature, structure, or characteristic being discussed can be included in at least one example of the application. The appearances of the phrase "in example" in various places in the specification are not necessarily all referring to the same example, nor are they necessarily mutually exclusive of one another. As will be apparent to those of ordinary skill in the art, embodiments described herein can be combined with one another.
[0028] The wafer needs to be tested for electrical properties before it is shipped out to verify whether its performance meets the requirements. In the prior art, the resistance of the wafer is measured by a four-terminal Kelvin structure, and the width of the poly or metal is inversely deduced from the resistance. The width is inversely deduced from the correlation between the measured resistance and the on-line size measurement value. The resistance value is not only affected by the resistance width, but also by the thickness and material, which is not accurate enough.
[0029] As Figure 1The schematic diagram of the electrical test structure for measuring the effective width of the resistance segment provided by the present application includes a resistance segment 10 and first to fifth terminals. The resistance segment 10 includes a first width segment 11 and a second width segment 12. The first width segment 11 is provided with a first terminal 20 and a second terminal 30 at an end away from the second width segment 12. The first width segment 11 and the second width segment 12 are connected and provided with a third terminal 40. The second width segment 12 is provided with a fourth terminal 50 and a fifth terminal 60 at an end away from the first width segment 11. The widths of the first width segment 11 and the second width segment 12 are not equal.
[0030] Further, the resistance segment 10 includes a polysilicon resistance and a metal resistance. The polysilicon layer can be formed on the wafer surface by chemical vapor deposition (CVD), physical vapor deposition (PVD), etc. The effective width of the polysilicon layer usually refers to the conductive channel width between the polysilicon gate and the source-drain region in the transistor structure, which determines the conductivity and switching speed of the transistor. The metal layer is a conductive layer on the wafer, which is usually made of aluminum (Al), copper (Cu) or other conductive metals in some embodiments. The line width and pitch of the metal layer determine the speed of signal transmission and the performance of the chip.
[0031] Further, the resistance segment 10 is integrated on a semiconductor wafer silicon substrate.
[0032] Further, each terminal pad material is aluminum or copper. The pads (PADs) connected on the wafer are usually made of metal materials, which need to have good conductivity, corrosion resistance and good adhesion to other materials. However, the specific material selection may vary depending on different wafer manufacturing processes, design requirements and cost considerations. Those skilled in the art can select according to actual needs.
[0033] Further, each terminal includes a pad layer and a protective layer from bottom to top. The material of the pad layer is aluminum or copper, and the protective layer is a silicon nitride layer. Silicon nitride is a high-hardness inorganic material with excellent heat resistance and corrosion resistance. It can be used as a protective layer for the pad to provide additional mechanical protection and chemical stability.
[0034] The structure of the present application will be further described in conjunction with specific embodiments.
[0035] The structure of the present application comprises a resistance section 10 and first to fifth terminals, wherein the resistance section 10 comprises a first width section 11 and a second width section 12, the first width section 11 is provided with a first terminal 20 and a second terminal 30 at an end away from the second width section 12, the first width section 11 and the second width section 12 are provided with a third terminal 40 at a connection position, the second width section 12 is provided with a fourth terminal 50 and a fifth terminal 60 at an end away from the first width section 11, and the first width section 11 is half the width of the second width section 12. The resistance section 10 is a copper wire resistance, and each terminal comprises a pad layer and a protective layer from bottom to top, the material of the pad layer is aluminum, and the protective layer is a silicon nitride layer.
[0036] In another aspect of the present application, a method for measuring the effective width of a resistance section is also provided, which uses the above-mentioned electrical test structure, as shown in Figure 2 Fig. 2 shows a parameter labeling diagram of a two-section resistance section provided by the present application, and the method comprises the following steps: S1: obtaining shape information, taking length values, and measuring the widths of the first width section and the second width section to obtain the first width and the second width, respectively; S2: applying a current between the first terminal and the fifth terminal, and obtaining the resistance and the bias resistance of the first width section and the resistance and the bias resistance of the second width section through the five-terminal circuit structure; S3: calculating the invalid width through the first width, the second width, and the resistance and the bias resistance of the first width section and the second width section, and further calculating the effective width through the invalid width.
[0037] Further, the resistance and the bias resistance of the first width section obtained through the five-terminal circuit structure comprise: applying a current to the first width section and a current to the second width section, measuring the voltage between the first terminal and the third terminal and the voltage between the third terminal and the fifth terminal, calculating the resistance through the voltage and the current, and calculating the bias resistance through the resistance value and the length and width values.
[0038] Further, the calculation formula of the bias resistance is:
[0039] wherein R represents resistance, Ω; W represents actual width, cm; and L represents length, cm.
[0040] Further, the calculation formula of the effective width is:
[0041]
[0042] wherein, is the effective width, cm; is the actual width, cm. is the invalid width, cm; is the first width segment length, cm; is the second width segment length, cm; is the actual width of the first width segment, cm; is the actual width of the second width segment, cm; is the resistance of the first width segment, Ω; is the resistance of the second width segment, Ω.
[0043] The method of the present application is an improvement based on the four-terminal Kelvin structure, introducing a fifth terminal, providing a high-precision resistance or current measurement technology. In current measurement applications, the five-terminal structure uses a special pad layout and connection method to reduce the impact of solder resistance on measurement results, thereby improving the overall accuracy of the system. In addition, by introducing resistance segments of different widths and a five-terminal structure, errors that may be introduced due to changes in resistance thickness and material properties can be directly compared or calibrated; the five-terminal test method not only applies to resistance measurement of a single material or thickness, but also adapts to resistors of different materials and different manufacturing processes, with strong generalization ability.
[0044] The above is the exemplary embodiment disclosed by the present application, but it should be noted that various changes and modifications can be made without departing from the scope of the embodiments disclosed by the present application as defined by the claims. The functions, steps and / or actions of the method claims described herein need not be performed in any particular order. Furthermore, although the elements of the embodiments disclosed by the present application can be described or claimed in individual form, they can also be understood as plural unless explicitly limited to a single.
[0045] It should be understood that, as used herein, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly dictates otherwise. It should also be understood that "and / or" as used herein refers to any and all possible combinations of one or more of the associated listed items.
[0046] The above-mentioned embodiment number of the embodiments of the present application is only for description, not representing the advantages and disadvantages of the embodiments.
[0047] Those skilled in the art should understand that the above discussion of any embodiment is only exemplary, and is not intended to mean that the scope of the embodiments disclosed by the present application (including claims) is limited to these examples; under the idea of the embodiments of the present application, the above embodiments or technical features in different embodiments can also be combined, and there are many other changes of different aspects of the embodiments of the present application as above. In order to be brief, they are not provided in details. Therefore, any omission, modification, equivalent replacement, improvement, etc. made in the spirit and principle of the embodiments of the present application shall be included in the protection scope of the embodiments of the present application.
Claims
1. An electrical test structure for measuring the effective width of a resistance segment, characterized in that, It includes a resistor segment and first to fifth terminals. The resistor segment includes a first width segment and a second width segment. The first width segment has a first terminal and a second terminal at the end away from the second width segment. A third terminal is provided at the connection between the first width segment and the second width segment. The second width segment has a fourth terminal and a fifth terminal at the end away from the first width segment. The widths of the first width segment and the second width segment are not equal.
2. The electrical test structure for measuring the effective width of a resistance segment according to claim 1, characterized in that, The resistor segment includes polysilicon resistors and metal resistors.
3. The electrical test structure for measuring the effective width of a resistance segment according to claim 2, characterized in that, The metal at the metal resistor is aluminum or copper.
4. The electrical test structure for measuring the effective width of a resistance segment according to claim 1, characterized in that, The resistor segment is integrated on a semiconductor wafer silicon substrate.
5. The electrical test structure for measuring the effective width of a resistance segment according to claim 1, characterized in that, Each terminal pad is made of aluminum or copper.
6. The electrical test structure for measuring the effective width of a resistance segment according to claim 1, characterized in that, Each terminal includes a pad layer and a protective layer from bottom to top. The pad layer is made of aluminum or copper, and the protective layer is a silicon nitride layer.
7. A method for measuring the effective width of a resistance segment, using the electrical test structure as described in any one of claims 1 to 5, comprising: Obtain shape information, assign length values, and measure the widths of the first and second width segments to obtain the first width and second width, respectively; A current is applied between the first terminal and the fifth terminal, and the resistance and bias resistance of the first width segment, the resistance and bias resistance of the second width segment are obtained respectively through the five-terminal circuit structure. The effective width is obtained by further calculating the invalid width using the first width, the second width, and the resistance and bias resistance of the first width segment and the second width segment.
8. The method for measuring the effective width of a resistance segment according to claim 7, characterized in that, The resistance and bias resistance of the first width segment obtained through the five-terminal circuit structure include: By applying current to the first width segment and the second width segment, and measuring the voltage between the first and third terminals and the voltage between the third and fifth terminals, the resistance is calculated using the voltage and current values. Then, the bias resistance is calculated using the resistance value and the length and width values.
9. The method for measuring the effective width of a resistance segment according to claim 8, characterized in that, The formula for calculating the bias resistance is: Where R represents resistance; W represents actual width; and L represents length.
10. The method for measuring the effective width of a resistance segment according to claim 7, characterized in that, The formula for calculating the effective width is: in, Effective width; This is the actual width; Invalid width; The length of the first width segment; This is the length of the second width segment; This is the actual width of the first width segment; This refers to the actual width of the second wide segment; The resistance of the first width segment; This is the resistance of the second width segment.