KR102636299B1 - Method and apparatus for detecting initial defects in semiconductor - Google Patents

Abstract

A method and device for detecting initial defects in a semiconductor device are disclosed. A method for detecting initial defects in a semiconductor according to an embodiment includes generating a Weibull distribution equation based on the lifespan measured for a test semiconductor to which stress has been applied, and detecting an initial defect based on the Weibull distribution equation. It includes obtaining acceleration test conditions for the acceleration experiment, and applying stress according to the acceleration experiment conditions to the semiconductor device.

Description

Method and apparatus for detecting initial defects in semiconductor devices {METHOD AND APPARATUS FOR DETECTING INITIAL DEFECTS IN SEMICONDUCTOR}

The disclosure below relates to a method and device for detecting initial defects in semiconductor devices.

As microprocessing for semiconductor devices has developed, the thickness of the dielectric between the gate and channel, and between the gate and source or drain electrodes has become very short. However, as the dielectric thickness becomes thinner, the lifespan due to dielectric breakdown is shortened, and additional time-dependent traps are created, which may lead to performance degradation due to increased leakage current.

Since many products cannot be tested for a long period of time to detect initial defects in semiconductor devices, technology is required to detect early defects through accelerated lifespan experiments, such as giving a value greater than the actual driving voltage for a short period of time.

The definition of early defects may vary by company or product, such as 1 month, 6 months, or 1 year, and the statistical characteristics of time-dependent dielectric destruction may vary depending on the process and dielectric material, so it is necessary to detect early defects. Formal accelerated life test conditions have not been established.

The background technology described above is possessed or acquired by the inventor in the process of deriving the disclosure of the present application, and cannot necessarily be said to be known technology disclosed to the general public before this application.

The following embodiments can provide a technique for deriving test conditions corresponding to the target lifespan and operation scenario of a semiconductor device when detecting initial defects in a semiconductor device.

However, technical challenges are not limited to the above-mentioned technical challenges, and other technical challenges may exist.

A method for detecting initial defects in a semiconductor according to an embodiment includes generating a Weibull distribution equation based on the lifespan measured for a test semiconductor to which stress has been applied, and detecting an initial defect based on the Weibull distribution equation. It includes obtaining acceleration test conditions for the acceleration experiment, and applying stress according to the acceleration experiment conditions to the semiconductor device.

The generating step includes receiving lifespan data measured for a plurality of test semiconductors to which stress has been applied, and receiving lifespan data measured for test semiconductors to which stress has been applied with changed temperature and voltage conditions. and generating the Weibull distribution equation based on received lifespan data and stress conditions corresponding to the lifespan data.

The obtaining step may include inputting the lifespan of a semiconductor device defined as an initial defect by a user into the Weibull distribution equation.

The obtaining step may include applying the lifespan of the operation scenario of the semiconductor device input by the user to the Weibull distribution equation.

The stress may be a temperature and voltage condition applied to the semiconductor device.

The method for detecting initial defects in a semiconductor may further include determining whether to ship the semiconductor device when the semiconductor device to which the stress is applied operates normally.

A semiconductor initial defect detection device according to an embodiment includes a memory including instructions, and a processor for executing the instructions. When the instructions are executed by the processor, the processor performs a stress-applied test. Generate a Weibull distribution equation based on the lifespan measured for the semiconductor, obtain accelerated experiment conditions for detecting initial defects defined by the user based on the Weibull distribution equation, and calculate stress according to the acceleration experiment conditions. Applied to semiconductor devices.

The processor receives lifespan data measured for a plurality of test semiconductors to which stress has been applied, receives lifespan data measured for test semiconductors to which stress has been applied with changed temperature and voltage conditions, and receives the received lifespan data. The Weibull distribution equation can be generated based on the stress conditions corresponding to the data and the lifespan data.

The processor may input the lifespan of a semiconductor device defined as an initial defect by a user into the Weibull distribution equation.

The processor may apply the operation scenario of the semiconductor device input by the user to the lifespan of the Weibull distribution equation.

The stress may be a temperature and voltage condition applied to the semiconductor device.

The processor may determine shipment of the semiconductor device when the semiconductor device to which the stress is applied operates normally.

The device for detecting initial defects in a semiconductor may further include an inspection device that measures the lifespan by applying stress to the semiconductor device.

1 shows a semiconductor initial defect detection system according to an embodiment.
FIGS. 2A and 2B are diagrams for explaining dielectric breakdown within a semiconductor device.
Figure 3 shows a method for detecting initial defects in a semiconductor according to an embodiment.
Figure 4 shows an example of a Weibull distribution.
Figure 5 shows an example of a bathtub curve according to the probability of semiconductor failure.

Specific structural or functional descriptions of the embodiments are disclosed for illustrative purposes only and may be changed and implemented in various forms. Accordingly, the actual implementation form is not limited to the specific disclosed embodiments, and the scope of the present specification includes changes, equivalents, or substitutes included in the technical idea described in the embodiments.

Terms such as first or second may be used to describe various components, but these terms should be interpreted only for the purpose of distinguishing one component from another component. For example, a first component may be named a second component, and similarly, the second component may also be named a first component.

When a component is referred to as being “connected” to another component, it should be understood that it may be directly connected or connected to the other component, but that other components may exist in between.

Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to designate the presence of the described features, numbers, steps, operations, components, parts, or combinations thereof, and are intended to indicate the presence of one or more other features or numbers, It should be understood that this does not exclude in advance the possibility of the presence or addition of steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art. Terms as defined in commonly used dictionaries should be interpreted as having meanings consistent with the meanings they have in the context of the related technology, and unless clearly defined in this specification, should not be interpreted in an idealized or overly formal sense. No.

Hereinafter, embodiments will be described in detail with reference to the attached drawings. In the description with reference to the accompanying drawings, identical components will be assigned the same reference numerals regardless of the reference numerals, and overlapping descriptions thereof will be omitted.

1 shows a semiconductor initial defect detection system according to an embodiment.

The semiconductor initial failure detection system 10 can detect infant failure of a semiconductor device. The semiconductor initial defect detection system 10 derives accelerated life test conditions corresponding to the initial defect conditions defined by the user (for example, semiconductor devices with a lifespan of 6 months or less) and performs short-term testing in the micro-semiconductor process. It is possible to detect initial defects in semiconductor devices due to variations in the geometry of the dielectric due to process variations.

In semiconductor devices, a dielectric can serve as an insulator between a gate and a channel or between a gate and source/drain electrodes. A dielectric with an insulating function is located between the gate and channel of the semiconductor device, preventing current from flowing even when there is a voltage difference between the two ends. Additionally, the dielectric serves as an insulator that prevents current from flowing when voltage is applied between the gate, source, and/or drain of the semiconductor device.

When a semiconductor device is used for a long period of time and an electric field due to the voltage difference between the gate, source, and/or drain is continuously applied, dielectric breakdown (Time Dependent Dielectric Breakdown (TDDB)) within the semiconductor device may occur, as shown in FIG. 2A. You can. When the bonds between atoms forming a dielectric material are broken, a trap, which is an energy state in which electrons can exist, can be created within the dielectric material. The number of traps in the gate dielectric material can increase as the semiconductor device is used over a long period of time.

Traps can occur in random locations within the genetic material. When the traps are spatially continuous between the gate and both ends of the channel, electrons can easily move between the traps, creating a current path as shown in FIG. 2b. In other words, the dielectric material loses its insulation properties and current flows, which may cause electrical destruction within the semiconductor device. The lifespan of a semiconductor device, which is the operating time until a failure occurs that prevents the semiconductor device from performing the desired operation, may change due to dielectric breakdown, affecting reliability.

As semiconductor device processing technology develops, microprocessing becomes possible, and the thickness of the dielectric between the gate and channel, gate and source and/or drain electrodes can become very short. If the thickness of the dielectric becomes thin, the lifespan of the semiconductor device may be shortened due to dielectric breakdown, and as time-dependent traps are additionally created, the performance of the semiconductor device may decrease due to increased leakage current.

Process dispersion that may occur between device locations within the die of a wafer of a semiconductor device (inter die), between die of a wafer (intra die), and/or between wafers (wafer-to-wafer) causes geometrical fluctuations, causing dielectric thickness to increase. It can become thinner or thicker, and as the process becomes more refined, the thickness of the dielectric targeted in the process becomes thinner.

If the thickness of the dielectric that plays an insulating role becomes thicker due to process distribution, it is not a major issue, but if the thickness of the dielectric becomes thinner due to process distribution, time-dependent dielectric destruction causes the target lifespan (for example, 10 years). ) may not be reached and malfunction of the semiconductor device may occur, and initial defects that may cause malfunction within a short period of time (for example, 6 months) may be caused.

The semiconductor initial defect detection system 10 may include an inspection device 170 and an initial defect detection device 100. Although FIG. 1 illustrates that the inspector 170 is implemented separately from the initial defect detection device 100, the present invention is not limited thereto, and the inspector 170 may be implemented within the initial defect detection device 100.

The tester 170 may measure the lifespan of a semiconductor device by applying stress (eg, a specific temperature and a specific voltage) to the semiconductor device. The tester 170 may apply a set stress condition to the semiconductor device under the control of the initial defect detection device 100 and measure the lifespan of the semiconductor device under the applied stress condition. The tester 170 can measure the lifespan of a plurality of semiconductor devices under a plurality of stress conditions.

The initial defect detection device 100 may extract a Weibull distribution based on lifespan data collected through the inspection device 170. The initial defect detection apparatus 100 may generate a Weibull distribution equation including stress conditions based on the lifespan of a plurality of semiconductor devices for each stress condition.

The initial defect detection device 100 is based on the initial defect condition defined by the user (e.g., 6 months) and/or the operation scenario of the semiconductor device (e.g., the temperature and/or voltage at which the semiconductor device operates). Thus, accelerated experimental conditions for initial defect detection can be derived. The initial defect detection device 100 can apply stress to the semiconductor device according to the acceleration experiment conditions derived through the inspection device 170, and detects initial defects in the semiconductor device when the semiconductor device to which the stress has been applied does not operate normally. It can be detected.

The initial defect detection device 100 may include a processor 130 and a memory 150. The operation of the initial defect detection device 100 may be performed by the processor 130.

The memory 150 may store instructions (or programs) executable by the processor 130. For example, the instructions may include instructions for executing the operation of the processor and/or the operation of each component of the processor 130. The memory 150 may be implemented as a volatile memory device or a non-volatile memory device.

Volatile memory devices may be implemented as dynamic random access memory (DRAM), static random access memory (SRAM), thyristor RAM (T-RAM), zero capacitor RAM (Z-RAM), or twin transistor RAM (TTRAM).

Non-volatile memory devices include EEPROM (Electrically Erasable Programmable Read-Only Memory), flash memory, MRAM (Magnetic RAM), Spin-Transfer Torque (STT)-MRAM (MRAM), and Conductive Bridging RAM (CBRAM). , FeRAM (Ferroelectric RAM), PRAM (Phase change RAM), Resistive RAM (RRAM), Nanotube RRAM (Nanotube RRAM), Polymer RAM (PoRAM), Nano Floating Gate Memory (NFGM), holographic memory, molecular electronic memory device, or insulator resistance change memory.

The processor 130 may process data stored in the memory 150. The processor 130 may execute computer-readable code (eg, software) stored in the memory 150 and instructions triggered by the processor 130 .

The processor 130 may be a data processing device implemented in hardware that has a circuit with a physical structure for executing desired operations. For example, the intended operations may include code or instructions included in the program.

For example, data processing devices implemented in hardware include a central processing unit, graphics processing unit, neural processing unit, multi-core processor, It may include a multiprocessor, application-specific integrated circuit (ASIC), and field programmable gate array (FPGA).

Figure 3 shows a method for detecting initial defects in a semiconductor according to an embodiment.

The initial defect detection device 100 may extract a Weibull distribution based on the lifespan data of the semiconductor device for testing measured through the inspection device 170 (301). The tester 170 may apply a plurality of temperature and/or voltage stress conditions to a plurality of test semiconductor devices to measure the lifespan of the semiconductor devices (302). That is, the tester 170 can measure the lifespan of a plurality of test semiconductor devices by changing temperature and/or voltage stress conditions (303).

The initial defect detection device 100 may generate a Weibull distribution equation by reflecting a plurality of temperature and/or voltage stress conditions applied to measure the lifespan of a semiconductor device (304). Equation 1 may be a Weibull distribution equation that reflects a plurality of temperature and/or voltage stress conditions applied for life measurement.

[Equation 1]

Here, t is the time the stress is applied to the semiconductor device, V is the voltage, T is the temperature, β is the Weibull slope (e.g. a scale parameter that determines the form of the Weibull probability distribution), and B, C, and n are the voltage. , it can be a fitting parameter for describing lifespan characteristics according to temperature stress fluctuations. For example, the Weibull distribution equation can be expressed in a graph as shown in FIG. 4. As shown in FIG. 4, the lifespan of a semiconductor device to which a specific stress condition is applied can be obtained from the Weibull distribution equation.

The initial defect detection device 100 may receive input of the target lifespan and/or operation scenario of the semiconductor device due to the initial defect (305). For example, the user may provide the user-defined initial defect condition (e.g., 6 months) and/or operation scenario (e.g., temperature and/or voltage at which the semiconductor device operates) to the initial defect detection device 100. You can enter it.

The initial defect detection apparatus 100 may obtain conditions for the semiconductor device to satisfy the target lifespan and/or operation scenario due to the initial defect. The initial defect detection device 100 can analyze the conditions of the semiconductor device to satisfy the target lifespan and/or operation scenario due to the initial defect by dividing them into an initial defect area and a deterioration area based on the bathtub curve shown in FIG. 5. there is.

For example, the initial defect detection device 100 analyzes the initial defect area of the bathtub curve to determine a specific thickness (eg, 25 Å) and a specific area (eg, 1 ^e-4 cm2) of the device at room temperature. It is possible to obtain that the voltage condition of the accelerated life test to detect whether the MOSFET will have an initial defect within one year is 1.77V, and the initial defect detection device 100 analyzes the deterioration area of the bathtub curve, Assuming that the operating voltage is 20V, the thickness of the insulating material must be 35nm or more to guarantee a lifespan of 5 years when operated for 8 hours a day.

The initial defect detection apparatus 100 may extract acceleration test conditions for detecting initial defects in a specific user scenario and apply stress according to the acceleration test conditions to the semiconductor device through the inspection device 170 (306). Acceleration test conditions may be determined based on initial failure conditions defined by the user. The initial defect detection device 100 may determine whether a semiconductor device to which stress has been applied according to acceleration test conditions operates normally (307). The initial defect detection device 100 may decide to discard the semiconductor device if the semiconductor device does not operate normally (309), and may decide to ship the semiconductor device if the semiconductor device operates normally (308).

The embodiments described above may be implemented with hardware components, software components, and/or a combination of hardware components and software components. For example, the devices, methods, and components described in the embodiments may include, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, and a field programmable gate (FPGA). It may be implemented using a general-purpose computer or a special-purpose computer, such as an array, programmable logic unit (PLU), microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and software applications running on the operating system. Additionally, a processing device may access, store, manipulate, process, and generate data in response to the execution of software. For ease of understanding, a single processing device may be described as being used; however, those skilled in the art will understand that a processing device includes multiple processing elements and/or multiple types of processing elements. It can be seen that it may include. For example, a processing device may include multiple processors or one processor and one controller. Additionally, other processing configurations, such as parallel processors, are possible.

Software may include a computer program, code, instructions, or a combination of one or more of these, which may configure a processing unit to operate as desired, or may be processed independently or collectively. You can command the device. Software and/or data may be used on any type of machine, component, physical device, virtual equipment, computer storage medium or device to be interpreted by or to provide instructions or data to a processing device. , or may be permanently or temporarily embodied in a transmitted signal wave. Software may be distributed over networked computer systems and stored or executed in a distributed manner. Software and data may be stored on a computer-readable recording medium.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer-readable medium. A computer-readable medium may include program instructions, data files, data structures, etc., singly or in combination, and the program instructions recorded on the medium may be specially designed and constructed for the embodiment or may be known and available to those skilled in the art of computer software. It may be possible. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. -Includes optical media (magneto-optical media) and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, etc. Examples of program instructions include machine language code, such as that produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc.

The hardware devices described above may be configured to operate as one or multiple software modules to perform the operations of the embodiments, and vice versa.

As described above, although the embodiments have been described with limited drawings, those skilled in the art can apply various technical modifications and variations based on this. For example, the described techniques are performed in a different order than the described method, and/or components of the described system, structure, device, circuit, etc. are combined or combined in a different form than the described method, or other components are used. Alternatively, appropriate results may be achieved even if substituted or substituted by an equivalent.

Therefore, other implementations, other embodiments, and equivalents of the claims also fall within the scope of the claims described below.

Claims (14)

generating a Weibull distribution equation based on the lifespan measured for a test semiconductor to which stress is applied;
Obtaining accelerated experimental conditions for detecting initial defects based on the Weibull distribution equation; and
Applying stress according to the acceleration experiment conditions to the semiconductor device
Including,
The obtaining step is,
Entering the lifespan of a semiconductor device defined as an initial defect by the user into the Weibull distribution equation.
A method for detecting initial defects in a semiconductor, including a method.
According to paragraph 1,
The generating step is,
Receiving lifespan data measured for a plurality of test semiconductors to which stress has been applied;
Receiving lifespan data measured for a semiconductor for testing to which stress has been applied with changed temperature and voltage conditions;
Generating the Weibull distribution equation based on received life data and stress conditions corresponding to the life data.
A method for detecting initial defects in a semiconductor, including a method.
delete According to paragraph 1,
The obtaining step is,
Applying the lifespan of the operation scenario of the semiconductor device entered by the user to the Weibull distribution equation.
A method for detecting initial defects in a semiconductor, including a method.
According to paragraph 1,
The stress is
A method for detecting initial defects in a semiconductor, which is the temperature and voltage conditions applied to the semiconductor device.
According to paragraph 1,
If the semiconductor device to which the stress is applied operates normally, determining shipment of the semiconductor device
A method for detecting initial defects in a semiconductor, further comprising:
A computer program combined with hardware and stored in a computer-readable recording medium to execute the method of any one of claims 1, 2, and 4 to 6.
memory containing instructions; and
Processor for executing the instructions
Including,
When the instructions are executed by the processor, the processor:
Generate a Weibull distribution equation based on the lifespan measured for a test semiconductor to which stress is applied,
Obtain accelerated experimental conditions for detecting initial defects defined by the user based on the Weibull distribution equation,
Apply stress according to the acceleration experiment conditions to the semiconductor device,
The acceleration experiment conditions are,
Lifespan of a semiconductor device defined as an initial defect by the user in the Weibull distribution equation
A semiconductor initial defect detection device comprising:
According to clause 8,
The processor,
Receive measured lifespan data for a plurality of test semiconductors to which stress has been applied,
Receive measured lifespan data for test semiconductors to which stress has been applied with changed temperature and voltage conditions,
A semiconductor initial defect detection device that generates the Weibull distribution equation based on received lifespan data and stress conditions corresponding to the lifespan data.
delete According to clause 8,
The processor,
A semiconductor initial defect detection device that applies the lifespan of the operation scenario of the semiconductor device input by the user to the Weibull distribution equation.
According to clause 8,
The stress is,
A device for detecting initial defects in a semiconductor, which is a temperature and voltage condition applied to the semiconductor device.
According to clause 8,
The processor,
A semiconductor initial defect detection device that determines shipment of the semiconductor device when the semiconductor device to which the stress is applied operates normally.
According to clause 8,
An inspection device that measures the lifespan of semiconductor devices by applying stress to them.
A semiconductor initial defect detection device further comprising:

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