Method for testing service life of semiconductor device
By applying a test voltage higher than the operating voltage on the semiconductor device, analyzing the relationship between the percentage of saturation current change and voltage, the problem of long life evaluation time of complex structural devices is solved, and fast and accurate life testing is achieved, saving test resources.
Patent Information
- Application Number
- CN202310671614.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-07
- Publication Date
- 2024-12-10
AI Technical Summary
The prior art is difficult to quickly and accurately evaluate the lifetime of semiconductor devices with complex structures such as LDMOS and DEMOS, resulting in long test time and occupancy of large resources.
By applying at least two test voltages higher than the operating voltage, obtain the change curve of the percentage of saturation current change over time, analyze the relationship between the percentage of saturation current change and voltage, calculate the percentage of saturation current change at the operating voltage to determine the semiconductor device lifespan.
It achieves rapid and accurate testing of semiconductor devices, shortens the test time, and shortens the time from dozens to hundreds of times, saving testing resources.
Smart Images
Figure CN119104859A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and in particular to a life test method for a semiconductor device. Background Art
[0002] Hot Carrier Injection (HCI) is an important indicator for evaluating the reliability of semiconductor devices. For general CMOS, the evaluation method is the commonly used accelerated test, that is, the failure time of semiconductor devices under parameter degradation standards is obtained at different drain voltages. The test time is usually about 3 hours.
[0003] However, for some special devices, such as the commonly used drain-side high-voltage devices in the BCD (Bipolar CMOS DMOS) process, such as lateral diffused metal oxide semiconductor (LDMOS) or drain extension metal oxide semiconductor (DEMOS), due to the particularity of their structure and process, the failure mechanism is complex. The voltage of the drain side in the HCI is usually 1.1 times the working voltage, and a long-term test is performed to monitor the deviation of the corresponding electrical parameters. Due to the low stress voltage, the test time usually takes millions of seconds (more than 10 days), which is dozens or even hundreds of times the test time of conventional devices, and occupies a large amount of test resources. Therefore, a test method that can quickly predict the life is urgently needed. Summary of the invention
[0004] The present application provides a life test method for a semiconductor device, which can quickly and accurately test the life of the semiconductor device.
[0005] The present application provides a life test method for a semiconductor device, comprising: applying at least two test voltages higher than an operating voltage to the semiconductor device, respectively, to obtain a curve diagram of the change in saturation current percentage over time of the semiconductor device under different test voltages; obtaining, according to the curve diagram of the change in saturation current percentage over time, the time values when the saturation current percentage rises to a threshold percentage for the first time and the time when the saturation current percentage rises to the threshold percentage for the second time under different test voltages, and the peak value of the saturation current percentage change in between; obtaining a relationship diagram of the saturation current percentage change and the voltage value according to the relationship between the saturation current percentage change and the voltage value and the peak value of the saturation current percentage change corresponding to different test voltages; obtaining the saturation current percentage change under the operating voltage according to the relationship diagram of the saturation current percentage change and the voltage value; and obtaining the life of the semiconductor device according to the saturation current percentage change under the operating voltage.
[0006] In some embodiments of the present application, the method for obtaining the life of the semiconductor device based on the percentage change of the saturation current under the operating voltage includes: when the percentage change of the saturation current under the operating voltage is greater than the threshold percentage, obtaining a relationship graph between the voltage value and time when the percentage change of the saturation current is equal to the threshold percentage based on the relationship between the percentage change of the saturation current and the voltage value and time, as well as the time value when the percentage change of the saturation current rises to the threshold percentage for the first time under different test voltages and the corresponding test voltage, and obtaining the corresponding time value under the operating voltage based on the relationship graph between the voltage value and time when the percentage change of the saturation current is equal to the threshold percentage, and the corresponding time value under the operating voltage is the life of the semiconductor device; when the percentage change of the saturation current under the operating voltage is less than or equal to the threshold percentage, obtaining a relationship graph between the voltage value and time when the percentage change of the saturation current is equal to the threshold percentage based on the relationship between the percentage change of the saturation current and the voltage value and time, as well as the time value when the percentage change of the saturation current rises to the threshold percentage for the second time under different test voltages and the corresponding test voltage, and obtaining the corresponding time value under the operating voltage based on the relationship graph between the voltage value and time when the percentage change of the saturation current is equal to the threshold percentage, and the corresponding time value under the operating voltage is the life of the semiconductor device.
[0007] In some embodiments of the present application, the relationship between the saturation current change percentage and the voltage value and time is expressed as follows: Where ΔIdsat% is the percentage change of saturation current, A is a constant term under specific conditions of a fixed device, B is the voltage acceleration factor, Vd is the voltage value, t is the time, and n is the slope factor of degradation over time.
[0008] In some embodiments of the present application, a method for obtaining a relationship graph between the voltage value and time when the saturation current change percentage is equal to the threshold percentage based on the relationship between the saturation current change percentage and the voltage value and time, as well as the time value when the saturation current change percentage first rises to the threshold percentage under different test voltages and the corresponding test voltage includes: substituting any two test voltages and the time value when the saturation current change percentage first rises to the threshold percentage under the two test voltages and the threshold percentage into the voltage value, time and saturation current change percentage in the relationship formula between the saturation current change percentage and the voltage value and time, to obtain a voltage acceleration factor and a slope factor that degrades over time; obtaining a relationship graph between the voltage value and time when the saturation current change percentage is equal to the threshold percentage based on the relationship between the saturation current change percentage and the voltage value and time after supplementing with the voltage acceleration factor and the slope factor that degrades over time.
[0009] In some embodiments of the present application, a method for obtaining a relationship diagram between the voltage value and time when the saturation current change percentage is equal to the threshold percentage based on the relationship between the saturation current change percentage and the voltage value and time, as well as the time value when the saturation current change percentage rises to the threshold percentage for the second time under different test voltages and the corresponding test voltage includes: substituting any two test voltages and the time value when the saturation current change percentage rises to the threshold percentage for the second time under the two test voltages and the threshold percentage into the voltage value, time and saturation current change percentage in the relationship formula between the saturation current change percentage and the voltage value and time, to obtain a voltage acceleration factor and a slope factor that degrades over time; obtaining a relationship diagram between the voltage value and time when the saturation current change percentage is equal to the threshold percentage based on the relationship between the saturation current change percentage and the voltage value and time after supplementing with the voltage acceleration factor and the slope factor that degrades over time.
[0010] In some embodiments of the present application, the relationship between the saturation current change percentage and the voltage value is expressed as follows: Wherein, ΔIdsat% is the percentage change of saturation current, A is a constant term under specific conditions of a fixed device, B is the voltage acceleration factor, and Vd is the voltage value.
[0011] In some embodiments of the present application, a method for obtaining a relationship diagram between the saturation current change percentage and the voltage value based on the relationship between the saturation current change percentage and the voltage value and the saturation current change percentage peak values corresponding to different test voltages includes: substituting any test voltage and the corresponding saturation current change percentage peak value into the voltage value and the saturation current change percentage in the relationship formula between the saturation current change percentage and the voltage value to obtain a voltage acceleration factor; and obtaining a relationship diagram between the saturation current change percentage and the voltage value based on the relationship between the saturation current change percentage and the voltage value after the voltage acceleration factor is supplemented.
[0012] In some embodiments of the present application, the threshold percentage is 8% to 12%.
[0013] In some embodiments of the present application, a method for obtaining a curve graph showing a change in the saturation current percentage over time of the semiconductor device at different test voltages includes: obtaining an initial saturation current of the semiconductor device; recording a relationship between the saturation current and time of the semiconductor device at different test voltages; a ratio of the saturation current at different test voltages to the initial saturation current is the change in the saturation current percentage at the different test voltages, and obtaining a curve graph showing a change in the saturation current percentage over time of the semiconductor device at different test voltages based on the relationship between the saturation current and time of the semiconductor device at different test voltages.
[0014] In some embodiments of the present application, the method for obtaining the initial saturation current of the semiconductor device includes: applying an operating voltage of 0 volts and an operating voltage of 0 volts to the gate, source, drain and substrate of the semiconductor device respectively, and the measured drain current is the initial saturation current.
[0015] The present application provides a life test method for a semiconductor device, which can quickly and accurately test the life of the semiconductor device. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The following figures describe in detail the exemplary embodiments disclosed in this application. The same reference numerals represent similar structures in several views of the drawings. Those skilled in the art will understand that these embodiments are non-limiting, exemplary embodiments, and the drawings are only for the purpose of illustration and description, and are not intended to limit the scope of this application. Other embodiments may also accomplish the inventive intent in this application. It should be understood that the drawings are not drawn to scale.
[0017] in:
[0018] Figure 1 A flowchart of a life test method for a semiconductor device according to an embodiment of the present application;
[0019] Figure 2 It is a curve diagram showing the percentage change of saturation current of semiconductor devices under different test voltages over time;
[0020] Figure 3 It is a relationship diagram between the percentage change of saturation current and voltage value of semiconductor devices;
[0021] Figure 4 A relationship diagram between voltage value and time when the saturation current change percentage under the operating voltage is greater than the threshold percentage and the saturation current change percentage is equal to the threshold percentage;
[0022] Figure 5 It is a relationship diagram between voltage value and time when the saturation current change percentage under the operating voltage is less than or equal to the threshold percentage and when the saturation current change percentage is equal to the threshold percentage. DETAILED DESCRIPTION
[0023] The following description provides specific application scenarios and requirements of the present application, with the purpose of enabling those skilled in the art to make and use the content in the present application. It will be apparent to those skilled in the art that various local modifications to the disclosed embodiments are apparent, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present application. Therefore, the present application is not limited to the embodiments shown, but to the widest scope consistent with the claims.
[0024] The technical solution of the present invention is described in detail below in conjunction with the embodiments and drawings.
[0025] For LDMOS or DEMOS, under traditional high-voltage stress, electrical parameter drift often exceeds the failure standard in the early stage of testing. According to the general method, the failure time is the time when the electrical parameter drift first exceeds the failure standard. However, in practice, due to the involvement of multiple failure mechanisms, there is a maximum degradation saturation value related to the stress voltage in the early stage, and the early degradation may not exceed the failure standard.
[0026] Therefore, for this type of structure, the current practice is to directly apply 1.1 times the working voltage for a long time test. However, due to the absence of voltage acceleration, the test time is long, which is not conducive to timely and rapid judgment of the risk level.
[0027] Based on this, the present application provides a life test method for a semiconductor device, which can quickly and accurately test the life of a semiconductor device.
[0028] Figure 1 This is a flow chart of a life test method for a semiconductor device according to an embodiment of the present application.
[0029] The present application provides a semiconductor device life test method, referring to Figure 1 As shown, including:
[0030] Step S1: applying at least two test voltages higher than the operating voltage to the semiconductor device respectively, and obtaining a curve diagram of the change percentage of the saturation current of the semiconductor device under different test voltages over time;
[0031] Step S2: obtaining the time values when the saturation current change percentage rises to the threshold percentage for the first time and the second time under different test voltages and the saturation current change percentage peak value in between according to the curve diagram of the change of the saturation current change percentage over time;
[0032] Step S3: obtaining a relationship diagram between the saturation current change percentage and the voltage value according to the relationship between the saturation current change percentage and the voltage value and the saturation current change percentage peak values corresponding to different test voltages;
[0033] Step S4: obtaining the saturation current change percentage under the working voltage according to the relationship diagram between the saturation current change percentage and the voltage value;
[0034] Step S5: Obtaining the life of the semiconductor device according to the percentage change of the saturation current under the operating voltage.
[0035] The life test method of the semiconductor device described in the embodiment of the present application is described in detail below with reference to the accompanying drawings.
[0036] refer to Figure 1 As shown, step S1, at least two test voltages higher than the operating voltage (a first test voltage V1 and a second test voltage V2 in the embodiment of the present application) are applied to the semiconductor device (specifically the drain end of the semiconductor device), and a curve diagram (a first curve and a second curve) of the percentage change of the saturation current of the semiconductor device under different test voltages over time is obtained. Figure 2 This is a curve chart showing the percentage change of the saturation current of a semiconductor device at different test voltages over time.
[0037] It should be noted that the present embodiment only uses two different test voltages as examples. Figure 2 As shown, the curve graph obtained under the first test voltage V1 is the first curve, and the curve graph obtained under the second test voltage V2 is the second curve.
[0038] It should be noted that the present application only uses the percentage change of saturation current as a parameter for demonstration. In fact, other parameter change percentages can also be obtained, such as saturation current, linear current or threshold voltage, etc. The present application only uses saturation current as an example.
[0039] In some embodiments of the present application, a method for obtaining a curve diagram of the percentage change of the saturation current of the semiconductor device at different test voltages over time includes: obtaining the initial saturation current of the semiconductor device; recording the relationship between the saturation current and time of the semiconductor device at different test voltages; the ratio of the saturation current at different test voltages to the initial saturation current is the percentage change of the saturation current at the different test voltages, and obtaining a curve diagram of the percentage change of the saturation current of the semiconductor device at different test voltages over time based on the relationship between the saturation current and time of the semiconductor device at different test voltages. The saturation current of the semiconductor device at the test voltage can be directly measured, so the relationship of the saturation current over time can be obtained, and the ratio of the saturation current to the initial saturation current is the percentage change of the saturation current, so the relationship of the saturation current over time can be obtained based on the relationship of the saturation current over time.
[0040] In some embodiments of the present application, the method for obtaining the initial saturation current of the semiconductor device includes: applying an operating voltage of 0 volts and an operating voltage of 0 volts to the gate, source, drain and substrate of the semiconductor device respectively, and the measured drain current is the initial saturation current.
[0041] Continue to refer Figure 1 and Figure 2Step S2, according to the curve diagram of the saturation current change percentage over time, obtain the time value when the saturation current change percentage rises to the threshold percentage for the first time and the time value when the saturation current change percentage rises to the threshold percentage for the second time under different test voltages, as well as the saturation current change percentage peak value in between.
[0042] In some embodiments of the present application, the threshold percentage is 8% to 12%, for example, 9%, 10% or 11%.
[0043] Due to the complexity of the HCI degradation mechanism of LDMOS or DEMOS, the parameter value shows the characteristic of increasing first and then decreasing, which is reflected in the absolute value degradation percentage (saturation current change percentage), that is, the curve that increases first, then decreases, and then increases again. This means that a saturation current change percentage peak will appear in the early stage of the test. The larger the voltage, the larger the peak value, and the size of the peak value has nothing to do with time.
[0044] refer to Figure 2 As shown, the time when the first curve rises to the threshold percentage for the first time is T1, the time when it rises to the threshold percentage for the second time is T3, and the peak value of the first curve between T1 and T3 is a. The time when the second curve rises to the threshold percentage for the first time is T2, the time when it rises to the threshold percentage for the second time is T4, and the peak value of the second curve between T2 and T4 is b.
[0045] Continue to refer Figure 1 and Figure 2 As shown, in step S3, a relationship diagram between the saturation current change percentage and the voltage value is obtained according to the relationship between the saturation current change percentage and the voltage value and the saturation current change percentage peak values corresponding to different test voltages. Figure 3 This is a graph showing the relationship between the percentage change in saturation current and voltage value of a semiconductor device.
[0046] In some embodiments of the present application, the relationship between the saturation current change percentage and the voltage value is expressed as follows: Wherein, ΔIdsat% is the percentage change of saturation current, A is a constant term under specific conditions of a fixed device, B is the voltage acceleration factor, Vd is the voltage value, and e is the natural logarithm.
[0047] In some embodiments of the present application, a method for obtaining a relationship diagram between the saturation current change percentage and the voltage value based on the relationship between the saturation current change percentage and the voltage value and the saturation current change percentage peak values corresponding to different test voltages includes: substituting any test voltage (for example, V1 and V2) and the corresponding saturation current change percentage peak values (for example, a and b) into the voltage value and the saturation current change percentage in the relationship formula between the saturation current change percentage and the voltage value to obtain a voltage acceleration factor; and obtaining a relationship diagram between the saturation current change percentage and the voltage value based on the relationship between the saturation current change percentage and the voltage value after the voltage acceleration factor is supplemented.
[0048] The relationship between the percentage change of saturation current and the voltage value is given by the formula By substituting a and b obtained in step S2 and the corresponding V1 and V2, the values of A and B can be obtained, and then ΔIdsat% and The relationship between them can be drawn into a relationship diagram. Figure 3 The relationship diagram shown in FIG. 1 is shown in FIG. 1 , where the ordinate is the percentage change of the saturation current ΔIdsat%, and the abscissa is the inverse of the voltage
[0049] Continue to refer Figure 1 and Figure 3 Step S4, obtaining the saturation current change percentage under the working voltage according to the relationship diagram between the saturation current change percentage and the voltage value. Specifically, the working voltage is brought into Figure 3 The corresponding saturation current change percentage can be obtained from the relationship diagram. The operating voltage is, for example, 1.1 Vop.
[0050] Continue to refer Figure 1 As shown, in step S5, the life of the semiconductor device is obtained according to the percentage change of the saturation current under the operating voltage.
[0051] In some embodiments of the present application, the method for obtaining the life of the semiconductor device based on the percentage change of the saturation current under the operating voltage includes: when the percentage change of the saturation current under the operating voltage is greater than the threshold percentage, obtaining a relationship graph between the voltage value and time when the percentage change of the saturation current is equal to the threshold percentage based on the relationship between the percentage change of the saturation current and the voltage value and time, as well as the time value when the percentage change of the saturation current rises to the threshold percentage for the first time under different test voltages and the corresponding test voltage, and obtaining the corresponding time value under the operating voltage based on the relationship graph between the voltage value and time when the percentage change of the saturation current is equal to the threshold percentage, and the corresponding time value under the operating voltage is the life of the semiconductor device; when the percentage change of the saturation current under the operating voltage is less than or equal to the threshold percentage, obtaining a relationship graph between the voltage value and time when the percentage change of the saturation current is equal to the threshold percentage based on the relationship between the percentage change of the saturation current and the voltage value and time, as well as the time value when the percentage change of the saturation current rises to the threshold percentage for the second time under different test voltages and the corresponding test voltage, and obtaining the corresponding time value under the operating voltage based on the relationship graph between the voltage value and time when the percentage change of the saturation current is equal to the threshold percentage, and the corresponding time value under the operating voltage is the life of the semiconductor device.
[0052] Specifically, for example, when the percentage change of the saturation current under the working voltage is greater than the threshold percentage (indicating that it will fail under the dominance of the early degradation mechanism under working conditions, and the life estimation is applicable to failure times T1 and T2 to calculate the life), according to the relationship between the percentage change of the saturation current and the voltage value and time, and the time value (for example, T1 and T2) when the percentage change of the saturation current first rises to the threshold percentage under different test voltages and the corresponding test voltages (V1 and V2), a relationship graph between the voltage value and time when the percentage change of the saturation current is equal to the threshold percentage is obtained, and the corresponding time value under the working voltage is obtained according to the relationship graph between the voltage value and time when the percentage change of the saturation current is equal to the threshold percentage. The corresponding time value under the working voltage is the life of the semiconductor device. Figure 4 It is a relationship diagram between voltage value and time when the saturation current change percentage under the operating voltage is greater than the threshold percentage and when the saturation current change percentage is equal to the threshold percentage.
[0053] In some embodiments of the present application, the relationship between the saturation current change percentage and the voltage value and time is expressed as follows: Where ΔIdsat% is the percentage change of saturation current, A is a constant term under specific conditions of a fixed device, B is the voltage acceleration factor, Vd is the voltage value, t is the time, and n is the slope factor of degradation over time.
[0054] In some embodiments of the present application, a method for obtaining a relationship diagram between the voltage value and time when the saturation current change percentage is equal to the threshold percentage based on the relationship between the saturation current change percentage and the voltage value and time, and the time value when the saturation current change percentage rises to the threshold percentage for the first time under different test voltages and the corresponding test voltage includes: substituting any two test voltages (for example, V1 and V2) and the time value (T1 and T2) when the saturation current change percentage rises to the threshold percentage for the first time under the two test voltages, and the threshold percentage into the voltage value (Vd), time (t) and saturation current change percentage (ΔIdsat%) in the relationship formula between the saturation current change percentage and the voltage value and time, and obtaining a voltage acceleration factor (B) and a slope factor (n) that degrades over time; obtaining a relationship diagram (i.e., Vd) between the voltage value (Vd) and the time (t) when the saturation current change percentage is equal to the threshold percentage based on the relationship between the saturation current change percentage and the voltage value and time supplemented with the voltage acceleration factor and the slope factor that degrades over time. Figure 4 ).
[0055] Then, bring the operating voltage to Figure 4 A time value can be obtained, which is the life of the semiconductor device, that is, the life of the semiconductor device when working under the operating voltage.
[0056] Similarly, when the percentage change of the saturation current under the working voltage is less than or equal to the threshold percentage (indicating that its parameters will not fail under the early degradation mechanism under the working conditions, and the life estimation is applicable to the failure times T3 and T4 dominated by the subsequent degradation mechanism to calculate the life), the relationship diagram between the voltage value and the time when the percentage change of the saturation current is equal to the threshold percentage can also be obtained in a similar manner. Figure 5 It is a relationship diagram between voltage value and time when the saturation current change percentage under the operating voltage is less than or equal to the threshold percentage and when the saturation current change percentage is equal to the threshold percentage.
[0057] In some embodiments of the present application, a method for obtaining a relationship diagram between the voltage value and time when the saturation current change percentage is equal to the threshold percentage based on the relationship between the saturation current change percentage and the voltage value and time, and the time value when the saturation current change percentage rises to the threshold percentage for the second time under different test voltages and the corresponding test voltage includes: substituting any two test voltages (for example, V1 and V2) and the time values (T3 and T4) when the saturation current change percentage rises to the threshold percentage for the second time under the two test voltages, and the threshold percentage into the voltage value, time and saturation current change percentage in the relationship formula between the saturation current change percentage and the voltage value and time, respectively, to obtain a voltage acceleration factor and a slope factor that degrades over time; obtaining a relationship diagram between the voltage value and time when the saturation current change percentage is equal to the threshold percentage based on the relationship between the saturation current change percentage and the voltage value and time after the voltage acceleration factor and the slope factor that degrades over time are supplemented (i.e. Figure 5 ).
[0058] Then, bring the operating voltage to Figure 5 A time value can be obtained, which is the life of the semiconductor device, that is, the life of the semiconductor device when working under the operating voltage.
[0059] The technical solution of the present application mainly includes: measuring the initial value of the device parameter; applying at least two higher test voltages to the semiconductor device to obtain a parameter degradation percentage (saturation current change percentage) versus time curve (i.e. Figure 2 The curve shown in the figure); record the corresponding parameter degradation peak points under different test voltages (for example Figure 2 a and b in the figure), according to the corresponding formula (1), the maximum degradation value of the parameter under 1.1Vop before the parameter reversal is extrapolated; if this value is greater than the failure standard, the test time before the reversal to failure ( Figure 2 The T1 and T2 in the figure are extrapolated from the corresponding formula (2) to deduce the life under 1.1Vop; if this value is less than the failure standard, it means that the maximum degradation amount under the dominance of the previous mechanism under 1.1Vop will not reach the failure standard, and the test time to failure under the dominance of the subsequent mechanism can be calculated according to formula (2) ( Figure 2 Using this accelerated test and judgment method, the test time can be shortened from more than 10 days to a few hours, greatly improving efficiency.
[0060] The technical solution of the present application utilizes the relationship between the early peak point and the voltage that appears in the curve of parameter degradation over time under high-voltage conditions to obtain the maximum degradation value dominated by the early mechanism under the working voltage; compares this maximum degradation value with the failure standard to obtain the dominant failure mechanism; and infers the life span based on the failure time dominated by different failure mechanisms.
[0061] The technical solution of the present application can significantly reduce test time, save test resources, and improve efficiency; it does not change the failure mechanism; it performs wafer-level testing without the need for additional cutting and bonding, thus saving packaging consumption.
[0062] The present application provides a life test method for a semiconductor device, which can quickly and accurately test the life of the semiconductor device.
[0063] In summary, after reading the contents of this application, those skilled in the art will appreciate that the aforementioned application contents may be presented only in an exemplary manner and may not be restrictive. Although not explicitly stated herein, those skilled in the art will appreciate that this application is intended to encompass various reasonable changes, improvements and modifications to the embodiments. These changes, improvements and modifications are within the spirit and scope of the exemplary embodiments of this application.
[0064] It should be understood that the term "and / or" used in this embodiment includes any or all combinations of one or more of the associated listed items. It should also be understood that the terms "comprise", "comprising", "including" or "comprising", when used in this application document, indicate the existence of the recorded features, wholes, steps, operations, elements and / or components, but do not exclude the existence or addition of one or more other features, wholes, steps, operations, elements, components and / or their groups.
[0065] It should also be understood that although the terms first, second, third, etc. can be used to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Therefore, without departing from the teachings of the present application, the first element in some embodiments can be referred to as the second element in other embodiments. The same reference numerals or the same reference signs represent the same elements throughout the specification.
Claims
1. A semiconductor device life test method, characterized in that: include: Apply at least two test voltages higher than the operating voltage to the semiconductor device respectively, and obtain a curve diagram of the change percentage of the saturation current of the semiconductor device under different test voltages over time; According to the curve diagram of the change of the saturation current percentage over time, obtain the time value when the saturation current percentage rises to the threshold percentage for the first time and the time value when the saturation current percentage rises to the threshold percentage for the second time under different test voltages, and the peak value of the saturation current percentage change in between; According to the relationship between the saturation current change percentage and the voltage value and the saturation current change percentage peak value corresponding to different test voltages, a relationship diagram between the saturation current change percentage and the voltage value is obtained; Obtaining the saturation current change percentage under the operating voltage according to the relationship diagram between the saturation current change percentage and the voltage value; The life of the semiconductor device is obtained according to the percentage change of the saturation current under the operating voltage.
2. The life test method according to claim 1, characterized in that: The method for obtaining the life of the semiconductor device according to the percentage change of the saturation current under the operating voltage includes: When the saturation current change percentage under the operating voltage is greater than the threshold percentage, a relationship diagram between the voltage value and time when the saturation current change percentage is equal to the threshold percentage is obtained based on the relationship between the saturation current change percentage and the voltage value and time, as well as the time value when the saturation current change percentage first rises to the threshold percentage under different test voltages and the corresponding test voltage, and a corresponding time value under the operating voltage is obtained based on the relationship diagram between the voltage value and time when the saturation current change percentage is equal to the threshold percentage, and the corresponding time value under the operating voltage is the life of the semiconductor device; When the saturation current change percentage under the operating voltage is less than or equal to the threshold percentage, a relationship graph between the voltage value and time when the saturation current change percentage is equal to the threshold percentage is obtained based on the relationship between the saturation current change percentage and the voltage value and time, as well as the time value when the saturation current change percentage rises to the threshold percentage for the second time under different test voltages and the corresponding test voltage. According to the relationship graph between the voltage value and time when the saturation current change percentage is equal to the threshold percentage, the corresponding time value under the operating voltage is obtained, and the corresponding time value under the operating voltage is the life of the semiconductor device.
3. The life test method according to claim 2, characterized in that: The relationship between the percentage change of the saturation current and the voltage value and time is: Where ΔIdsat% is the percentage change of saturation current, A is a constant term under specific conditions of a fixed device, B is the voltage acceleration factor, Vd is the voltage value, t is the time, and n is the slope factor of degradation over time.
4. The life test method according to claim 3, characterized in that: A method for obtaining a relationship diagram between voltage value and time when the saturation current change percentage is equal to the threshold percentage according to the relationship between the saturation current change percentage and the voltage value and time, and the time value when the saturation current change percentage first rises to the threshold percentage under different test voltages and the corresponding test voltage, comprises: Substitute any two test voltages and the time value when the saturation current change percentage under the two test voltages first rises to the threshold percentage and the threshold percentage into the voltage value, time and saturation current change percentage in the relationship formula between the saturation current change percentage and the voltage value and time, respectively, to obtain the voltage acceleration factor and the slope factor that degrades over time; A relationship diagram between the voltage value and time when the saturation current change percentage is equal to the threshold percentage is obtained according to the relationship between the saturation current change percentage and the voltage value and time after the voltage acceleration factor and the slope factor degraded over time are supplemented.
5. The life test method according to claim 3, characterized in that: A method for obtaining a relationship diagram between voltage value and time when the saturation current change percentage is equal to the threshold percentage according to the relationship between the saturation current change percentage and the voltage value and time, and the time value when the saturation current change percentage rises to the threshold percentage for the second time under different test voltages and the corresponding test voltage, comprises: Substitute any two test voltages and the time value when the saturation current change percentage under the two test voltages rises to the threshold percentage for the second time and the threshold percentage into the voltage value, time and saturation current change percentage in the relationship formula between the saturation current change percentage and the voltage value and time, respectively, to obtain the voltage acceleration factor and the slope factor that degrades over time; A relationship diagram between the voltage value and time when the saturation current change percentage is equal to the threshold percentage is obtained according to the relationship between the saturation current change percentage and the voltage value and time after the voltage acceleration factor and the slope factor degraded over time are supplemented.
6. The life test method according to claim 1, characterized in that: The relationship between the saturation current change percentage and the voltage value is expressed as follows: Wherein, ΔIdsat% is the percentage change of saturation current, A is a constant term under specific conditions of a fixed device, B is the voltage acceleration factor, and Vd is the voltage value.
7. The life test method according to claim 6, characterized in that: A method for obtaining a relationship diagram of a saturation current change percentage and a voltage value according to the relationship between the saturation current change percentage and the voltage value and the saturation current change percentage peak value corresponding to different test voltages includes: Substituting any test voltage and the corresponding saturation current change percentage peak value into the voltage value and the saturation current change percentage in the relationship formula between the saturation current change percentage and the voltage value, respectively, to obtain a voltage acceleration factor; A relationship diagram between the saturation current change percentage and the voltage value is obtained based on the relationship between the saturation current change percentage and the voltage value after the voltage acceleration factor is supplemented.
8. The life test method according to claim 1, characterized in that: The threshold percentage is between 8% and 12%.
9. The life test method according to claim 1, characterized in that: The method for obtaining a curve diagram of the change percentage of the saturation current of the semiconductor device under different test voltages over time comprises: Obtaining an initial saturation current of the semiconductor device; Recording the relationship between the saturation current and time of the semiconductor device under different test voltages; The ratio of the saturation current under different test voltages to the initial saturation current is the percentage change of the saturation current under the different test voltages. According to the relationship between the saturation current and time of the semiconductor device under different test voltages, a curve graph of the percentage change of the saturation current of the semiconductor device under different test voltages versus time is obtained.
10. The life test method according to claim 9, characterized in that: The method for obtaining the initial saturation current of the semiconductor device includes: applying a working voltage of 0 volt to the gate, source, drain and substrate of the semiconductor device respectively, and the measured drain current is the initial saturation current.