KR20180120465A - Apparatus for distinguishing of identification key availability - Google Patents

Abstract

The present invention provides an apparatus for distinguishing the availability of an identification key which comprises: a plurality of identification key generation apparatuses for generating a digital value by reading whether a unit cell is disconnected in a circuit of a semiconductor manufacturing process, and selecting a part of the generated digital values to generate an identification key; a determination unit for determining at least one of randomness and reliability of the identification key generated by the identification key generation apparatus; and a deactivation unit for only selecting one or a part of the identification key generation apparatus to operate, and permanently deactivating the remaining unselected identification key generation apparatus according to a determination result.

Description

[0001] APPARATUS FOR DISTINGUISHING OF IDENTIFICATION KEY AVAILABILITY [0002]

And more particularly to security of electronic devices, embedded system security, System on Chip (SoC) security, smart card security, and USIM (Universal Subscriber Identity Module) security. And an identification key usability discrimination device for discriminating the usability of a generated identification key used for digital signatures and the like.

As the information society becomes more sophisticated, there is a growing need for privacy protection, and technology for building a security system that encrypts, decrypts, and transmits information securely becomes an important technology.

In an advanced information society, the use of embedded systems or system-on-chip (SoC) -based computing devices is rapidly increasing, in addition to high-performance computers. For example, computing devices such as Radio Frequency Identification (RFID), Smart Card, Universal Subscriber Identity Module (USIM), and One Time Password (OTP) are widely used.

In order to construct a security system in such a computing device, a cryptographic key or a unique ID used in an encryption and decryption algorithm is used. Hereinafter, a cryptographic key or a unique ID is referred to as an identification key do. The identification key is generated externally from a cryptographically secure PRN (Pseudo Random Number) externally and stored in a nonvolatile memory such as a flash memory or an EEPROM (Electrically Erasable Programmable Read-Only Memory) Is the most commonly used method.

In recent years, various attacks such as a side channel attack and a reverse engineering attack have been performed on an identification key stored in a computing device. PUF (Physical Unclonable Function) technology is being developed as a method for securely generating and storing an identification key against such an attack.

Physically Unclonable Function (PUF) is a technique for generating or storing an identification key using a difference in physical characteristics existing in an electronic system, and is also called a hardware fingerprint.

In order to use the PUF as the identification key, firstly, the generated random key of the generated identification key must be sufficiently secured, and second, the value should be maintained unchanged with respect to the change of the time flow or the usage environment.

In the patents with guaranteed value invariance over the existing time, there is a problem that the bit generation probability is remarkably distant from the value of 50% or the like, and the usefulness of the manufactured PUF is lost or the security is lowered.

This can be seen in the via / metal line PUF. For example, the etching characteristics may vary with the location of the wafer, the date and time of the process, and the connectivity / disconnection probabilities of via and metal / poly lines are very sensitive thereto.

Therefore, it is necessary to distinguish between good and defective products according to the distribution and average value of the generated values. To extract the internal bits and to judge this from the outside, there is a problem of security that the PUF value is leaked. Therefore, in this case, there is a contradiction between good and bad product discrimination and security.

It is an object of the present invention to ensure the usefulness and security of the produced PUF by making the bit generation probability far from 50% or the like.

Another object of the present invention is to provide an internal device capable of distinguishing good products and defective products based on the distribution and the average value of the generated identification key values while preventing the generated identification key values from being leaked.

It is another object of the present invention to provide a PUF that is constructed by using different elements or different sizes of vias or metal lines of different thicknesses in a chip to select a PUF with the most random distribution and average, And to provide a device that enables the device to be used.

In order to solve the above-mentioned problem, the identification key availability discriminating apparatus of the present invention reads out whether a unit cell is short-circuited in a circuit of a semiconductor manufacturing process to generate a digital value, selects a part of the generated digital values, A plurality of identification key generating apparatuses A determination unit determining at least one of randomness and reliability of the identification key generated by the identification key generation apparatus; And an inactive unit for selecting only one or a part of the identification key generating apparatus to operate only as a result of the determination, and for permanently deactivating the remaining remaining unselected identification key generating apparatuses.

The identification key availability determination device of the present invention may further include a storage unit configured to store a value generated by one or a plurality of identification key generation devices as a result of the determination.

The randomness may include at least one of average, distribution, and variance.

The reliability may include at least one of operational stability and time invariance.

The identification key generation device includes: a plurality of unit cells provided in a circuit in a semiconductor manufacturing process; A reading unit configured to read the short circuit of each of the unit cells; A digital value generation unit which makes it possible to stably determine whether or not each of the unit cells is short-circuited and generates a digital value of each of the unit cells based on a short circuit read out from the reading unit; And a selection unit configured to select at least one of the plurality of unit cells, wherein the identification key can be generated from a combination of digital values generated in each unit cell selected by the selection unit.

Wherein each of the plurality of unit cells comprises: a conductive layer of a pair of semiconductors; And a contact or via disposed between the pair of conductive layers and configured to short or open the conductive layer.

The reading unit may read whether the contact or via shorts between the conductive layers and read whether or not each of the unit cells is short-circuited.

The contact or via may have an etching property such that the short circuit is determined stochastically in the semiconductor manufacturing process.

The etching characteristics may include at least one of an etching type, an etching rate, and an etching time.

The etching rate may be 3.0 to 3.5 [mu] m / s, and the time may be 5s to 7s.

The contact or via may be sized such that the contact or via formed between the conductive layers of the semiconductor is within a predetermined tolerance of the difference between the probability of shorting the conductive layer and the probability of not shorting Lt; / RTI >

The digital value generator may have an etching characteristic such that the contact or via has an etching property such that a difference between a probability of shorting the conductive layer or a probability of not shorting the conductive layer is within a predetermined error range.

The digital value generating unit may include N (N is a natural number) unit structures for generating a 1-bit digital value by using a pair of conductive layers and one contact or via (unit cell) , So that an N-bit identification key can be generated through the N unit structures.

The identification key availability determination device of the present invention may further include a digital value processing unit configured to receive and process the N bits of the digital value read by the read unit and to process the digital value, Bit and the second bit to determine a digital value representative of the first bit and the second bit to be 1 when the first bit value is greater than the second bit value, And a digital value representative of the first bit and the second bit may be set to 0 when the second bit value is smaller than the second bit value.

Wherein the digital value processing unit determines a digital value representative of the first bit and the second bit to be either 1 or 0 if the first bit value is equal to the second bit value, And the digital value representing the second bit may not be determined.

The identification key usability discrimination apparatus of the present invention is characterized in that the discrimination key usability discrimination apparatus of the present invention comprises a discrimination key generation apparatus, The usability and security of the PUF can be secured.

In addition, the identification key usability determination apparatus of the present invention can distinguish good and defective products based on the distribution and the average value of the generated identification key values while preventing the identification key values generated using the determination unit from being leaked.

On the other hand, the identification key availability determination apparatus of the present invention is characterized in that, in a PUF configured by using different elements or different sizes of vias or metal lines of different thicknesses in a chip, a PUF having the most random distribution and average is selected, .

1 is a block diagram showing an identification key usability discriminating apparatus of the present invention.
Fig. 2 is a block diagram showing an identification key generating apparatus of the identification key availability discriminating apparatus of Fig. 1; Fig.
FIG. 3A is a conceptual diagram showing short-circuiting and opening of a unit cell of the present invention, and thus digital values generated; FIG.
FIG. 3B is a conceptual diagram showing a metal line of the present invention. FIG.
3C is a conceptual diagram showing connection or disconnection of metal lines of the present invention;
4 is a graph showing the etch rate, the short circuit probability of a unit cell with time;
5 is a conceptual diagram showing whether or not a metal line is short-circuited according to an interval.
6 is a graph showing the short circuit probability of a unit cell according to via size.
FIG. 7 is a conceptual diagram showing the short-circuiting and opening of a unit cell according to the via size of the present invention, and thus the resulting digital value; FIG.
8 is a conceptual diagram showing an arrangement of unit cells in an identification key generating apparatus;
9 is a specific circuit configuration of a digital value generation unit according to an embodiment of the present invention.
10 is a conceptual diagram for explaining a process of processing a digital value by a digital value processing unit according to an embodiment of the present invention.
11 is a flowchart showing a method of generating an identification key according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like or similar elements are denoted by the same or similar reference numerals, and a duplicate description thereof will be omitted. The suffix "part" for the constituent elements used in the following description is to be given or mixed with consideration only for ease of specification, and does not have a meaning or role that distinguishes itself. In the following description of the embodiments of the present invention, a detailed description of related arts will be omitted when it is determined that the gist of the embodiments disclosed herein may be blurred. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. , ≪ / RTI > equivalents, and alternatives.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another.

It is to be understood that when an element is referred to as being "connected" to another element, it may be directly connected or connected to the other element, although other elements may be present in between.

The singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Referring to FIG. 1, an identification key availability discrimination apparatus 1000 of the present invention includes a plurality of identification key generation apparatuses 100, a determination unit 200, and an inactive unit 300.

In the circuit of the semiconductor manufacturing process, the identification key generating apparatus 100 reads out whether a unit cell is short-circuited, generates a digital value, and selects a part of the generated digital values to generate an identification key.

The determination unit 200 is configured to evaluate, compare, and determine at least one of the randomness and the reliability of the identification key generated in the identification key generation apparatus 100. The randomness determined by the determination unit 200 may include at least one of average, distribution, and variance. The reliability determined by the determination unit 200 may include at least one of operational stability and time invariance.

The determination unit 200 may be a circuit connected to the identification key generation apparatus 100. [

The inactivity unit 300 selects only one or a part of the identification key generating apparatuses 100 to operate only in accordance with the determination result by the determining unit 200 and permanently deactivates the remaining remaining unselected identification key generating apparatuses 100 .

The inactive unit 300 may be a circuit connected to the identification key generating apparatus 100. [

The identification key availability determination apparatus 1000 of the present invention may further include a storage unit 400.

The storage unit 400 is configured to store the values generated by one or a part of the identification key generating apparatus 100 as a result of the evaluation, comparison, and determination.

For example, the identification key usability determining apparatus 1000 is configured to select only one or a part of the PUFs to operate according to a result of the comparison and determination performed by the determination unit 200, Is stored for the first time by the controller 400 and can be made to inactivate the remaining or the entire PUF permanently by the inactivity portion 300.

2, the identification key generating apparatus 100 includes a plurality of unit cells 110, a reading unit 120, a digital value generating unit 130, and a selecting unit 140. [ On the other hand, the identification key generating apparatus 100 may be an identification key generating unit as a subordinate configuration of the identification key usability discriminating apparatus 1000.

A plurality of unit cells 110 are provided in a circuit in a semiconductor manufacturing process. In one example, each of the plurality of unit cells 110 includes a contact or via (not shown) disposed between conductive layers 201, 202 of the pair of semiconductors and the conductive layers 201, , 203). The contacts or vias 203 short-circuit or open the conductive layers 201, 202 to enable the generation of digital values, as described below, whereby the identification key is generated by a combination of digital values.

The contact or via 203 is designed to connect between the conductive layers 201 and 202 so that the size of the contact or via 203 is typically determined to short the conductive layers 201 and 202. And etches to a sufficient etch rate, time, so as to short-circuit between the conductive layers 201, 202 in a typical semiconductor process to form a contact or via 203. In the present invention, the etching rate may be an etching rate.

However, in the implementation of the digital value generation unit 130 according to an embodiment of the present invention, the etching rate is made slow and the time is shortened for the production of the contact or via 203, so that some of the contacts or vias 203 Will short circuit between the conductive layers 201 and 202 and some of the contacts or vias 203 will not short circuit between the conductive layers 201 and 202 and this shorting will be determined stochastically . For this purpose, the kind or concentration of the etching material may be different. In the present invention, the etching rate can be set at a rate of 40 to 60% of the etching rate used in semiconductor fabrication, and the etching time can be 40 to 60% of the etching time used in semiconductor fabrication.

For example, in the test examples described below, the etching rate may be 3.0 to 3.5 mu m / s or 2.5 to 3.1 mu m / s. The etching time may also be 6 s or 11 s.

The meaning of being determined stochastically in the present invention may mean that it is determined randomly. Also, the meaning of being determined stochastically in the present invention may include the meaning of 50% probability or 45% to 55% probability.

In the conventional semiconductor process, if the contact or via 203 fails to short-circuit between the conductive layers 201 and 202, the process is unsuccessful. In the present invention, however, a short circuit is intentionally made and used for random key generation .

The setting of the etching characteristics for the fabrication of the contact or via 203 according to this embodiment will be described in more detail below with reference to Figures 3A-4.

According to another embodiment of the present invention, the vias 203 for connecting the two conductive layers 201 and 202, which are separated from the contacts or vias 203 for the purpose of generating the identification key, And may be provided with separate design rules, respectively.

According to another embodiment of the present invention, in the semiconductor manufacturing process, the identification key generating apparatus 100 may determine the short-circuiting probability among the conductive lines by adjusting the interval and the etching characteristic of the wiring, And generates an identification key having randomness.

This embodiment is also a departure from the process of ensuring openness between the conductive lines in a conventional semiconductor manufacturing process to produce a random identification key. A description of the conductive metal line according to the above embodiment will be described later in detail with reference to FIG.

According to another embodiment of the present invention, a conductive layer 201 for isolating two conductive layers 201 and 202 distinguished from a gap of the conductive layers 201 and 202 for the purpose of generating the identification key 201 , 202 may be provided with separate design rules, respectively, to be distinguished.

The digital value generation unit 130 electrically generates the identification key generated according to the above embodiments. Whether the contact or via 203 is shorting between the conductive layers 201, 202, or between the conductive lines, can be identified using a read transistor, Will be described later in more detail.

On the other hand, in an embodiment that utilizes the process for fabricating the contact or via 203 described above, the process characteristic for the fabrication of the contact or via 203 may be adjusted to provide a shorting between the conductive layers 201, Even if the ratio of the via 203 to the non-viable 203 is adjusted so as to have the same probability as 1/2, it is possible to prevent a short circuit (for example, a digital value 0) May not be guaranteed to be completely equal in probability.

That is, as the etching for forming the contact or via 203 is strong and the etching is performed for a long time, the probability that the two conductive layers 201 and 202 are short-circuited increases. Conversely, (The probability of being opened) becomes large. If the probability of being short-circuited or short-circuited is increased, the randomness of the generated identification key is deteriorated.

This problem is also true in the embodiment in which the spacing of the conductive lines or the characteristics of the etching are adjusted with respect to the spacing between the conductive lines.

The readout unit 120 reads out whether each of the unit cells 110 is short-circuited.

In the present invention, the term " read " may be to detect or detect the short-circuit of each unit cell. The reading unit may be a detecting unit or a sensing unit. When the reading unit is the detecting unit or the sensing unit, the detecting unit or the sensing unit may be one of various kinds of sensors.

The reading unit 120 may be connected to the unit cell 110. In one example, the readout 120 can read via the via 203 that the conductive layers 201, 202 are shorted or open. The reading unit 120 may also store an identification key generated by a combination of a digital value or a digital value generated by the digital value generating unit 130, which will be described later.

In one example, the read unit 120 may be a logic gate, an amplifier, a register, or a flip flop. However, the reading unit 120 is not limited to a register or a flip-flop, but can be understood as a broad concept of reading a short circuit or open state of the conductive layers 201 and 202 and storing a digital value and an identification key .

The digital value generation unit 130 can stably determine whether each of the unit cells is short-circuited and generates a digital value of each of the unit cells 110 based on whether or not the short-circuit is read out from the reading unit 120 .

The selection unit 140 is configured to select at least one of the plurality of unit cells 110. An identification key is generated by combining the digital values generated in the unit cells 110 selected by the selection unit 140. [

Therefore, according to an embodiment of the present invention, the identification key generation apparatus 100 includes a digital value processing unit (hereinafter referred to as " digital value processing unit ") for processing digital values so as to receive and process information about short- 130). For reference, the term " processing " or " digital value processing unit " is used in this specification, but it should not be construed that the generated digital value is processed by a separate technique or algorithm, It should be understood that this means a series of configurations that perform balancing between 0 and 1 to ensure randomness (randomness) to generate an identification key as a digital value.

With reference to this digital value processing unit 130, it will be described later in more detail with reference to FIG.

FIG. 3A is a conceptual diagram showing short-circuiting and opening of the unit cell 110 of the present invention, and thus generated digital values.

The formation of the vias 203 between the conductive layer 1 202 and the conductive layer 201 in the semiconductor manufacturing process has been shown.

In the first etch group 210 where the etch rate is sufficiently high and the etch time is long during fabrication of the vias 203, all the vias 203 are shorting the conductive layer 1 202 and the conductive layer 2 201, If it is expressed as a digital value, it is all zero.

On the other hand, in the third etching group 230 in which the etching rate is low and the etching time is too short in the fabrication of the vias 203, all the vias 203 can not short-circuit the conductive layer 202 and the conductive layer 201 . Therefore, if a short circuit is represented by a digital value, it becomes 1.

In the second etching group 220 in which the rate and time of etching are set between the group 210 and the group 230 in the fabrication of the vias 203, a part of the vias 203 are electrically connected to the conductive layer 1 202 and the conductive layer 2 201 and some of the vias 203 fail to short the conductive layer 1 202 and the conductive layer 2 201. [

The identification key generation apparatus 100 according to the embodiment of the present invention is configured such that a part of the vias 203 short-circuit the conductive layer 1 202 and the conductive layer 2 201, as in the second etching group 220 And another portion of the vias 203 are formed by setting the etching characteristics in the fabrication of the vias 203 so as not to short the conductive layer 202 and the conductive layer 201. [

Referring to FIGS. 3B and 2C, in the metal or poly line etching method, the etching rate and time are required such that the connection probability of A and B is 50%. FIG. 3C shows an example in which a metal or poly line etching is formed where A and B are connected or disconnected with a random probability.

The probability of a short circuit between the two conductive layers 201, 202 in making the contact or via 203 is proportional to the rate and time of the etch. It is ideal that the probability distribution of the short circuit has a short-circuit probability of 50%, and the identification key generating apparatus 100 according to the embodiment of the present invention sets the etching process characteristic as close as 50% . The characteristics of this etching process can be determined experimentally and can be adjusted during the process.

4 is a graph showing the etch rate, the short circuit probability of the unit cell 110 with time.

It can be seen that as the rate of etching is high and the time is long in the graph, the probability of shorting of the contact or via 203 is close to 100%.

The embedded system EM is a characteristic of an etching process in which the short circuit probability of the two conductive layers 201 and 202 is theoretically 50%. As described above, the values are different according to the process, , But it is difficult to find an accurate embedded system.

Accordingly, in the digital value generator 130 according to the embodiment of the present invention, whether the short circuit between the conductive layers 201 and 202 is within a range of Ex1 and Ex2 having a predetermined tolerance at a probability of 50% (Ex1 and Ex2 are regions not shown separately but having a certain margin near the Ex shown in the figure).

5 is a conceptual diagram showing whether or not the metal lines are short-circuited according to intervals.

As described above, according to another embodiment of the present invention, it is possible to stably determine whether the metal lines are short-circuited by adjusting the intervals and etching characteristics (rate and time) of the metal lines. In group 1 (410) where the interval of the metal lines was extended, the metal lines were short-circuited in all cases.

In the third group 430 where the intervals of the metal lines were shortened, the metal lines were not short-circuited in all cases.

In the digital value generation unit 130 according to an exemplary embodiment of the present invention, as in the case of the group 420, the digital value generation unit 130 sets intervals of metal lines in which a short-circuit occurs stochastically so that some of the metal lines are short- do.

Though not shown in the drawing, the etching rate may be lowered or the etching time may be shortened in the metal line so that the short circuit may be stochastically determined.

Metal lines are short-circuited in all cases in group 1 where the etching rate of the metal line is increased or the etching time is increased.

In the third group 430, in which the intervals of the metal lines are made thin, the etching rate is made low, and the time is long, the conductive lines are not short-circuited in all cases.

In the digital value generation unit 130 according to the embodiment of the present invention, as in the case of the second group 420, the digital value generation unit 130 generates the digital value of the metal line, which is short-circuited stochastically such that some of the metal lines are short- Set the rate and time.

In Fig. 5, irregularities are generated at the edges of the metal lines, which can be understood to be due to limitations and randomness of patterning accuracy by etching.

Referring to FIGS. 6 and 7, the contact or via may be formed such that the difference between the probability that the contact or via formed between the conductive layers of the semiconductor short-circuits the conductive layer and the short- In the range of the error.

Referring to FIG. 7, vias are formed between a metal 1 layer 302 and a metal 2 layer 301 in a semiconductor manufacturing process.

In the group 310 where the via size is sufficiently large according to the design rule, all the vias short-circuit the metal 1 layer 302 and the metal 2 layer 301, In Fig. 7, a digital value is represented by 0 in a short-circuited state and a digital value is represented by 1 in an open state. However, the digital value is not necessarily limited to 1, The digital value may be represented by zero.

On the other hand, in the group 330 in which the via size is too small, all the vias can not short-circuit the metal 1 layer 302 and the metal 2 layer 301. Therefore, if a short circuit is represented by a digital value, it becomes 1.

In the group 320 where the via size is between the group 310 and the group 330, some vias short-circuit the metal 1 layer 302 and the metal 2 layer 301, The layer 302 and the metal 2 layer 301 can not be short-circuited.

The identification key generation unit 110 according to the embodiment of the present invention may be configured such that the vias of the metal 1 layer 302 and the metal 2 layer 301 are short circuited in the same way as the group 320 having the b- , And the other vias are formed by setting the via size so as not to short-circuit the metal 1 layer 302 and the metal 2 layer 301. The design rule for the via size differs depending on the semiconductor manufacturing process. For example, if the design rule of the via in the CMOS (Complementary Metal Oxide Semiconductor) process of 0.18 micron (um) is set to 0.25 micron, The size of the vias is set to 0.19 microns in the identification key generating unit 110 according to the present invention so that the shortage among the metal layers is stochastically distributed.

It is ideal to have a short-circuit probability of 50% or less, and the identification-key generator 110 according to an embodiment of the present invention sets the via-size to a probability distribution as close as 50% do. In such a via size setting, the via size can be determined by the experiment according to the process.

Also, referring to FIG. 6, it can be seen that as the size of the via increases in the graph, the probability of short circuit between the metal layers is close to 1. The via size according to the design rule is Sd, which is a value at which a short circuit between the metal layers is sufficiently ensured. The SM is theoretically a via size in which the short circuit probability of the metal layer is 0.5. As described above, the values are different according to the process, and it is possible to find a value as close as possible by the experiment, but it is difficult to find the exact SM.

Therefore, in the identification key generating unit 110 according to the embodiment of the present invention, it is determined that the short-circuit between the metal layers is within the range of Sx1 and Sx2 (the Sx1 and Sx2 are separately Which is not shown, but having a certain margin near the Sx shown in the figure).

8 is a conceptual diagram showing the arrangement of the unit cells 110 in the identification key generating apparatus 100. As shown in Fig.

A total of M * N unit cells 110 are arranged on a semiconductor substrate in a matrix of M width and N length (where M and N are natural numbers).

The digital value generation unit 130 may determine whether the M * N vias 203 are short-circuited (digital value 0) or short-circuited (digital value 1) between the conductive layers 201 and 202 , And M * N bits.

The M * N bit digital value thus generated is selected by the selection unit 140 as the unit cell 110 and the digital value generated by the unit cell 110 selected by the selection unit 140 An identification key is generated from the combination.

9 shows a specific circuit configuration of the digital value generation unit 130 according to an embodiment of the present invention.

According to an embodiment of the present invention, the digital value generator 130 checks whether a short circuit exists between the power supply voltage VDD and the ground using a read transistor.

In the example of FIG. 9 composed of a pull-down circuit (the description of the pull-down circuit is obviously extended to an example constituted by a pull-up circuit, and a separate description is omitted) When the individual vias 203 in the conductive layer 130 short-circuit the conductive layers 201 and 202, the output value becomes 0; otherwise, the output value becomes 1. Conversely, if the individual vias 203 in the digital value generation unit 130 short-circuit the conductive layers 201 and 202, the output value becomes 1, otherwise the output value may be zero. Through this process, the digital value generation unit 130 generates a digital value, and the selection key 140 generates an identification key.

Of course, in an embodiment that utilizes a short between the conductive lines, the same identification key is generated.

However, the configuration of the digital value generation unit 130 of FIG. 9 according to an embodiment of the present invention is only one embodiment, and the present invention is not construed to be limited by these embodiments.

Therefore, if the digital value generation unit 130 is configured to check whether there is a short circuit between the conductive layers 201 and 202 or between the metal lines, a digital value can be generated, and other variations can be made without departing from the spirit of the present invention. And such a configuration is not excluded from the scope of the present invention.

Meanwhile, the identification key generated by the digital value generation unit 130 is transferred to and stored in an identification key storage unit (not shown). The identification key storage unit includes a register or flip- (Not shown).

In the following description, not only a register or a flip-flop for reading and storing the generated identification key, but also other configurations having an equivalent role can be understood as an identification key storage unit.

10 is a conceptual diagram for explaining a process of processing a digital value by the digital value processing unit according to an embodiment of the present invention.

According to an embodiment of the present invention, the digital value processing unit 130 selects and compares two of the M * N-bit digital values generated by the digital value generation unit 130.

In this specification, two of the digital values generated by the digital value generation unit 130 are conceptually described with reference to FIG. 10, but this is merely an exemplary embodiment, and a register or a flip-flop It is sufficiently possible to select two of the bits stored in the register or flip-flops in the identification key reading unit 120 constituted, and it can be applied without any difficulties to those of ordinary skill in the art, Should not be interpreted as deviating from the scope of the present invention.

In the example of FIG. 10, two bits among the plurality of bits generated by the digital value generation unit 130 are selected.

The digital value processor compares the magnitudes of the digital values generated by the first bit 710 and the second bit 720, respectively. If the digital value of the first bit 710 is greater than the digital value of the second bit 720, the digital value representative of the first bit 710 and the second bit 720 is determined as one.

Conversely, if the digital value of the first bit 710 is less than the digital value of the second bit 720, the digital value representative of the first bit 710 and the second bit 720 is determined to be zero.

Of course, if the digital value of the first bit 720 is greater than the digital value of the second bit 710, the representative digital value may be determined to be one.

If the digital value of the first bit 710 is the same as the digital value of the second bit 720, the representative digital value may be determined to be 1 or 0, or the representative value may not be determined.

In this manner, the third bit 730 and the fourth bit 740 are compared with each other to generate a representative digital value, a digital value is selected and used by the selection unit 140, and the combination key finally determines the identification key .

This process can be understood as an identification key process for increasing the randomness of the identification key.

In the digital value generation unit 130, the short-circuiting ratio (digital value 0) and the short-circuiting ratio (digital value 1) are different from each other, so that the balancing between 0 and 1 may not be matched. , The probability that 1 and 0 will be generated in each bit is equal to the probability that any one of the two bits will have a larger digital value than the other (because the two bits are equal to each other, even if the probability is not 50% Is 50%. Therefore, it can be understood that the probabilistic balancing of 0 and 1 is matched through the above process.

On the other hand, if the originally generated identification key is M * N bits, the identification key finally determined by the identification key processing unit 130 in FIG. 10 is (M * N / 2) bits. Since a new 1-bit digital value is determined using a 2-bit digital value.

In addition, the grouping of the identification key processing unit 130 and the process of the identification key process described above are only one embodiment of the present invention, and the process of processing the identification key for maintaining the balancing of the digital values 0 and 1, It can be changed as much as it does not deviate.

The new identification key generated by the digital value generation unit 130 and determined by the identification key processing unit 130 has a random value and becomes a reliable value that theoretically does not change permanently once it is generated.

Therefore, according to the embodiments of the present invention, a reliable identification key having a random number characteristic whose value does not change with time can be easily manufactured without a large manufacturing cost.

In addition, since the random identification key is generated during the semiconductor manufacturing process, and the identification key is unchanged even after the completion of the manufacturing process, there is no need to write the identification key from the outside into the separate nonvolatile memory as in the conventional method. Therefore, even if the design drawing of the semiconductor chip is leaked, the identification key is generated and can not be duplicated due to the difference in the physical characteristics in the manufacturing process, so that the security is remarkably excellent. In addition, since the nonvolatile memory manufacturing process is not required, the manufacturing cost can also be reduced.

11 is a flowchart showing a method of generating an identification key according to an embodiment of the present invention.

Hereinafter, a method of generating an identification key will be described. Hereinafter, description will be made mainly on the methodical contents of the present invention.

The identification key generating method includes: (S10) reading whether each of the plurality of unit cells 110 provided in the semiconductor manufacturing process circuit is short-circuited; (S20) adjusting the vertical spacing of the conductive layers (201, 202) and the etching characteristics of the patterning in a semiconductor manufacturing process; Generating (S30) a digital value from each of the unit cells 110 by making it possible to stochastically determine whether or not the unit cell 110 (node) constituting the circuit is short-circuited; Selecting at least one of the plurality of unit cells 110 (S40); And generating an identification key by a combination of the digital values of the selected unit cells 110 (S50).

According to the embodiment of the present invention, the readout unit 120 reads the short-circuit state of each of the plurality of unit cells 110 (S10). In one example, the readout 120 causes the pair of conductive layers 201 and 202 to read whether the semiconductor is shorted, as described above, when the contact or via 203 is in contact with the conductive layers 201 and 202, Is short-circuited.

The vertical spacing of the conductive layers 201 and 202 and the step of adjusting the etching characteristics of the patterning S20 adjust the probability that the conductive layers 201 and 202 are shorted or opened by the contact or via 203.

Here, by controlling the etching characteristics, the roughness of the surface of the conductive layers 201 and 202 is adjusted so that the coupling rate between the conductive layers 201 and 202 and the contact or via 203 is adjusted.

(S30) of generating a digital value from each of the unit cells 110 by stochastically determining whether or not the unit cells 110 constituting the circuit are short-circuited is performed by setting a value 0 Or a digital value of 1 is generated.

The digital value generation step S30 may include a digital value processing step S33. The digital value processing step S33 receives and processes the N-bit digital value read by the reading unit 120. [

For example, the digital value processing step S33 compares the first and second bits of the input N bits of digital values, and when the first bit value is greater than the second bit value, The digital value representative of the first bit and the second bit is determined as 0 when the first bit value is smaller than the second bit value.

In the digital value processing step S33, if the first bit value is equal to the second bit value, the digital value representative of the first bit and the second bit is selectively set to either 1 or 0 according to the setting Or does not determine a digital value representative of the first bit and the second bit.

At least one of the plurality of unit cells 110 is selected by the selection unit 140 (S40), and an identification key is generated by combining the selected digital values (S50).

According to the embodiment of the present invention, whether or not a short between nodes generated in the semiconductor manufacturing process is randomized by controlling the vertical intervals of the conductive layers 201 and 202 and the etching characteristics of the patterning, In addition, since the short-circuit characteristic between nodes does not change physically, the once generated identification key is not changed.

According to one embodiment of the present invention, the digital value generation unit 130 may generate a digital value according to whether a contact or a via formed between the conductive layers 201 and 202 (metal layers) The digital value is generated, and the digital value is combined by the selection unit 140 to generate an identification key. The etching property setting of the contact or via 203 manufacturing process according to the embodiment is described with reference to FIGS. 3A to 5 As described above.

According to another embodiment of the present invention, the vias 203 for connecting the two conductive layers 201 and 202, which are separated from the contacts or vias 203 for the purpose of generating the identification key, And may be provided with separate design rules, respectively.

According to another embodiment of the present invention, the digital value generation unit 130 adjusts the gap and the etching property of the conductive layers 201 and 202 in the process of forming the conductive lines in the semiconductor manufacturing process, Some of them are short-circuited and some of them are not short-circuited, thereby generating an identification key having randomness. This embodiment is as described above with reference to Figs.

According to another embodiment of the present invention, a conductive layer 201 for isolating two conductive layers 201 and 202 distinguished from a gap of the conductive layers 201 and 202 for the purpose of generating the identification key 201 , 202 may be provided with separate design rules, respectively, to be distinguished.

The identification key storage unit stores and stores the digital key or the identification key generated according to the above embodiments through a register or a flip-flop. Whether the contact or via 203 is shorting between the conductive layers 201, 202 during the generation and reading of the identification key, or whether the conductive lines are short-circuited can be identified using a read transistor have.

Also, the identification key processing unit 130 processes the digital value generated by the digital value generation unit 130 to ensure randomness.

The finally generated identification key is provided to the user through the output unit.

In an experiment related to the present invention relating to an identification key generating apparatus and a generating method, for example, the etching pressure is 26 mTorr, the gas used for etching is SF ₆ , the flow rate is 130 SCCM, 600 W, and the bias (Bias) may be 20 W. In particular, the etching time may be 5 s to 7 s and the etch rate may be 3.0 to 3.5 μm / s.

In another example, the etching pressure may be 20 mTorr, the gas used for etching may be SF6, the flow rate may be 130 SCCM, the source may be 600 W, and the bias may be 15 W. [ In particular, the etch time may be 10 s to 12 s and the etch rate may be 2.5 to 3.1 μm / s.

As a result of performing the experiments 10,000 times each by the above etching characteristics, the unit cells were short-circuited at a probability of 45% to 55%.

The identification key generating apparatus 100 and the identification key generating method S100 described above are not limited to the configurations and the methods of the embodiments described above, but the embodiments may be applied to all or some of the embodiments May be selectively combined.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

The identification key availability determination apparatus 1000 described above is not limited to the configurations and methods of the embodiments described above, but the embodiments may be configured such that all or some of the embodiments are selectively combined so that various modifications can be made It is possible.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

1000: identification key availability determination device
100: Identification key generating device
110: a plurality of unit cells
120: Reading section
130:
140:
201, 202: Conductive layer
203: contact or via
200:
300: inert portion
400:

Claims (15)

A plurality of identification key generation devices for reading out whether a unit cell is short-circuited in a circuit of a semiconductor manufacturing process to generate a digital value and selecting a part of the generated digital values to generate an identification key;
A determination unit determining at least one of randomness and reliability of the identification key generated by the identification key generation apparatus; And
And an inactive unit for selecting only one or a part of the identification key generating apparatus to operate only as a result of the determination and for permanently deactivating the remaining remaining unauthenticated identification key generating apparatuses.
The method according to claim 1,
Further comprising a storage unit configured to store a value generated by one or a plurality of identification key generating devices as a result of the determination.
The method according to claim 1,
Wherein the randomness includes at least one of an average, a distribution, and a variance.
The method according to claim 1,
Wherein the reliability comprises at least one of operational stability and time invariance.
The method according to claim 1,
Wherein the identification key generation device comprises:
A plurality of unit cells provided in a circuit in a semiconductor manufacturing process;
A reading unit configured to read the short circuit of each of the unit cells;
A digital value generation unit which makes it possible to stably determine whether or not each of the unit cells is short-circuited and generates a digital value of each of the unit cells based on a short circuit read out from the reading unit; And
And a selection unit configured to select at least one of the plurality of unit cells,
And generates an identification key from a combination of digital values generated in each unit cell selected by the selection unit.
6. The method of claim 5,
Wherein each of the plurality of unit cells includes:
A conductive layer of a pair of semiconductors; And
And a contact or via disposed between the pair of conductive layers and configured to short or open the conductive layer.
The method according to claim 6,
Wherein the reading unit reads whether the contact or via shorts between the conductive layers and reads out whether each of the unit cells is short-circuited.
The method according to claim 6,
Wherein the etching characteristic is set such that the contact or via is determined stochastically in the semiconductor manufacturing process.
9. The method of claim 8,
Wherein the etching characteristic includes at least one of an etching type, an etching rate, and an etching time.
10. The method of claim 9,
Wherein the etching rate is 3.0 to 3.5 占 퐉 / s and the time is 5s to 7s.
The method according to claim 6,
The contact or via may be sized such that the contact or via formed between the conductive layers of the semiconductor is within a predetermined tolerance of the difference between the probability of shorting the conductive layer and the probability of not shorting And the identification key usability determination device.
The method according to claim 6,
Wherein the digital value generator has an etching characteristic such that the contact or via has an etching characteristic such that a difference between a probability of shorting the conductive layer by the contact or via and a probability of not shorting the conductive layer is within a predetermined error range. Device.
The method according to claim 6,
The digital value generation unit includes N (N is a natural number) unit structures for generating a 1-bit digital value by using a pair of conductive layers and one contact or via connecting therebetween, and the N Wherein the identification key generating unit generates the N-bit identification key through the unit structure.
14. The method of claim 13,
Further comprising a digital value processing unit configured to receive and process N-bit digital values read out by said readout unit,
Wherein the digital value processor comprises:
Comparing a first bit and a second bit of the input N bits of digital values and outputting a digital value representative of the first bit and the second bit when the first bit value is greater than the second bit value 1,
And determines a digital value representing the first bit and the second bit to be 0 when the first bit value is smaller than the second bit value.
15. The method of claim 14,
Wherein the digital value processor comprises:
If the first bit value is equal to the second bit value, a digital value representative of the first bit and the second bit is determined to be either 1 or 0, or the first bit and the second bit And does not determine a representative digital value.

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