JP2004165384A - Semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device capable of applying a sufficient voltage and current stress to each contact for reliability evaluation and detecting a defect of electric isolation in a contact chain. <P>SOLUTION: In the semiconductor device having a circuit wherein a plurality of resistive elements are connected in series, both terminals of the resistive elements R1 to R12 to be measured among the resistive elements are respectively connected to terminals H, L via switching elements T1 to T13, control terminals of all the switching elements T1 to T13 are connected to a terminal G, the circuit is configured such that the resistive elements R1 to R12 to be measured are connected in parallel among common terminals in pairs by activating the switching elements T1 to T13 to electrically connect both the terminals of the resistive elements R1 to R12 to be measured to the common terminals in pairs respectively, and the semiconductor device is provided with a voltage application means for applying a voltage among the common terminals in pairs. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor device, and more particularly to a semiconductor device having a contact evaluation pattern.
[0002]
[Prior art]
In a semiconductor integrated circuit, various contacts including a semiconductor-metal contact are used. In a large-scale integrated circuit, hundreds of millions of contacts are formed on one chip. Therefore, variations in contact formation and contact resistance greatly affect the characteristics of the semiconductor integrated circuit. That is, the quality of the contact determines the reliability of the semiconductor integrated circuit.
[0003]
For this reason, in the development and manufacture of a semiconductor integrated circuit, an evaluation pattern called a contact chain is created and used to manage contact resistance and evaluate contact reliability against electric stress.
[0004]
FIG. 6 is a plan view showing a pattern of a conventional contact chain. The contact chain is formed by alternately connecting the plurality of diffusion layers 103 and the metal wires 102 via the contacts 101, so that the contacts 101 are connected in series. The contact 101 is for electrically connecting the diffusion layer 103 and the metal wiring 102, and usually has a constant resistance value. However, due to an abnormality in the manufacturing process, an electrical connection may not be obtained, or a manufacturing error such as extremely low resistance may occur.
[0005]
The determination of the electrical connection failure is made based on the resistance value of the contact chain obtained by measuring the value of the current flowing when a voltage is applied between the IN terminal and the OUT terminal at both ends of the contact chain.
[0006]
In addition, the reliability evaluation of the contact is determined by applying a voltage stress or the like between both terminals of the contact chain and then measuring a change in resistance value.
[0007]
[Patent Document 1]
JP-A-63-299358
[Problems to be solved by the invention]
A circuit diagram of a conventional contact chain has a configuration in which resistance elements 105 having a resistance value of R (Ω) are connected in series, as shown in FIG. Note that the resistance element 105 is a resistance due to the contact 101. If n resistance elements 105 are connected in series (where n is an integer of 2 or more), the total resistance value of this contact chain is n × R (Ω), and the voltage V (V ) Is applied, the current I (A) is I = V / (n × R) (A).
[0009]
As described above, the larger the n is, the larger the total resistance value is. Therefore, even when there is a defect due to abnormally low resistance of the contact 101, the amount of change in the measured current value is very small. Therefore, it is difficult to find such poor electrical separation. The same applies to the case where the metal wiring layers 102 are short-circuited or the diffusion layers 103 are short-circuited.
[0010]
Further, in a large-scale semiconductor integrated circuit in which the number of contacts 101 becomes extremely large, the resistance value n × R (Ω) of the contact chain becomes extremely high. Therefore, even when a voltage allowed on the semiconductor device is applied to the contact chain, the current I (A) flowing between the terminals is extremely small. Further, since the current flowing through each contact 101 is equal to the current I (A) flowing between the terminals, the voltage applied to each contact 101 is also small. Therefore, it is not possible to apply a sufficient voltage / current stress to each contact 101 required for evaluating the reliability of the contact 101.
[0011]
The present invention has been made in view of the problems of the related art, and it is possible to apply a sufficient voltage and current stress to each contact for reliability evaluation, and it is possible to provide an electric contact in a contact chain. An object of the present invention is to provide a semiconductor device capable of detecting separation failure.
[0012]
[Means for Solving the Problems]
The semiconductor device of the present invention is a semiconductor device having a circuit in which a plurality of resistance elements are connected in series. The control terminals of all of the switching elements are connected to a common control terminal, and the switching elements are operated, and both ends of each of the resistance elements to be measured form the pair of common terminals. Electrically connected to the pair of common terminals, the resistance element to be measured is connected in parallel, and voltage applying means for applying a voltage between the pair of common terminals is provided. Have.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the present invention, the resistance elements of the contact chain can be easily connected in series or in parallel using the switching elements. Therefore, it is possible to evaluate the reliability of the electrical connection and disconnection of the contact chain and the application of voltage / current stress.
[0014]
Further, the switching element may be a field effect transistor.
[0015]
Further, the resistance element includes at least one contact.
[0016]
Preferably, the circuit includes a metal wiring, a diffusion layer, and a contact, and the diffusion layer is connected to one of the paired common terminals, and is used for contact connection connected to the contact. Diffusion layers and transistor diffusion layers forming a part of the switching element, which is a field-effect transistor, are alternately arranged in the longitudinal direction of the diffusion layer, and the metal wiring and the contact connection are formed. The diffusion layers are alternately connected in series via the contacts, and when the switching element operates, the transistor diffusion layer and the contact connection diffusion layer are connected to form the pair of common terminals. So that a parallel connection is established between them. Thereby, a contact failure between the metal wiring and the diffusion layer can be detected. Further, the switching element can be easily formed.
[0017]
Preferably, the circuit includes a lower metal wiring, an upper metal wiring, a diffusion layer, and a contact formed in different layers, and the diffusion layer is connected to one of the paired common terminals. A contact connection diffusion layer connected to the contact, and a transistor diffusion layer forming a part of the switching element, which is a field effect transistor, are alternately arranged in the longitudinal direction of the diffusion layer. Wherein the lower metal wiring and the upper metal wiring are alternately connected in series via the contacts, and are connected to the respective different contact connection diffusion layers, and the switching element operates. And the transistor diffusion layer and the contact connection diffusion layer are connected to form a parallel connection between the pair of common terminals. Unisuru. Thus, a contact failure between the first metal wiring and the second metal wiring can be detected. Further, the switching element can be easily formed.
[0018]
Hereinafter, more specific embodiments of the present invention will be described with reference to the drawings.
[0019]
(Embodiment 1)
First Embodiment A semiconductor device according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a circuit diagram of a contact chain in the semiconductor device according to the first embodiment.
[0020]
The resistance due to the contact is represented by twelve resistance elements R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12. The resistance elements R1 to R12 are connected in series between the IN terminal and the OUT terminal in order to form a contact chain. Further, between the IN terminal and the resistance element R1, between each of the resistance elements R1 to R12, and between the resistance element R12 and the OUT terminal, as switching elements, 13 transistors T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, and T13 are connected. The switching element may be any element that can switch between conduction and non-conduction, and here, the field effect transistors T1 to T13 are used. A field-effect transistor can be used as a switch because conduction and non-conduction between a source and a drain can be controlled by a voltage of a gate. Note that ON indicates conduction and OFF indicates non-conduction.
[0021]
As described above, the nodes between the IN terminal, each of the resistance elements R1 to R12, and the OUT terminal are connected to the sources of the transistors T1 to T13, and their drains are alternately paired terminals. H terminal and L terminal are connected. Specifically, the node between the IN terminal and the resistor R1 is connected to the source of the transistor T1, and the drain of the transistor T1 is connected to the H terminal. The node between the resistor R1 and the resistor R2 is connected to the source of the transistor T2, and the drain of the transistor T2 is connected to the L terminal. Similarly, each node is connected to the source of each transistor, and the drain is alternately connected to the H terminal and the L terminal for each transistor. That is, the drains of the transistors T1, T3, T5, T7, T9, T11, T13 are connected to the H terminal, and the drains of the transistors T2, T4, T6, T8, T10, T12 are connected to the L terminal. The gate nodes of all the transistors T1 to T13 are all connected to a G terminal which is a control terminal.
[0022]
In such a circuit configuration, all the transistors T1 to T13 can be turned off or on by controlling the voltage of the G terminal. When all the transistors T1 to T13 are turned off, both ends of each of the resistance elements R1 to R12 and the H terminal and the L terminal are in a non-conductive state. Therefore, the resistance elements R1 to R12 are all connected in series between the IN terminal and the OUT terminal, and a circuit similar to the conventional contact chain shown in FIG. 7 is obtained. In this state, the total resistance of the contact chain can be measured by applying a voltage to the IN terminal and the OUT terminal and measuring the flowing current in the same manner as in the conventional method. By dividing, the average resistance value of each resistance element can be obtained. Therefore, the electrical connection failure of the contact chain can be detected by this measurement.
[0023]
Next, when the G terminal is controlled to turn on all the transistors T1 to T13, one terminal of each of the resistance elements R1 to R12 is all connected to the H terminal, and the other terminal is all connected to the L terminal. Will be. That is, all the resistance elements R1 to R12 are connected in parallel between the H terminal and the L terminal.
[0024]
Although not shown, the semiconductor device of the first embodiment includes a voltage source that is a voltage applying unit that can apply a voltage between the H terminal and the L terminal. Can be applied.
[0025]
When a voltage is applied between the H terminal and the L terminal by turning on the transistors T1 to T13, one of the resistance elements R1 to R12 has been extremely reduced in resistance due to an abnormality such as a short circuit because of being connected in parallel. In this case, the resistance between the H terminal and the L terminal is significantly reduced. As a result, it is possible to detect the electrical separation failure of the contact chain.
[0026]
Also, since the resistance elements R1 to R12 are connected in parallel, the voltage applied to each of the resistance elements R1 to R12 is the same as the voltage applied between the terminals. Therefore, even if the voltage between the H terminal and the L terminal is a voltage allowed in the semiconductor device, sufficient voltage and current stress for reliability evaluation can be applied to the individual contacts (resistance elements R1 to R12). it can. Further, even if the number of contacts increases, the voltage applied to each contact is equal to the voltage applied between the H terminal and the L terminal, so that measurement can be performed even when the number of contacts further increases.
[0027]
As described above, according to the semiconductor device of the first embodiment, by controlling the transistors T1 to T13 to be OFF, it is possible to determine the electrical connection failure of the contact chain, and to control the transistors T1 to T13 to be ON. Thus, it is possible to determine the reliability of the contact chain due to the electrical separation failure and the voltage / current stress.
[0028]
Although the resistance element is a resistance based on a contact, a similar effect can be obtained with a similar configuration using a resistance based on a diffusion layer as a resistance element.
[0029]
(Embodiment 2)
Second Embodiment A semiconductor device according to a second embodiment of the present invention will be described with reference to the drawings. In a second embodiment, an example of a specific configuration of a contact chain in a circuit of the semiconductor device according to the first embodiment will be described. FIG. 2 is a plan view showing a configuration of the semiconductor device according to the second embodiment. FIG. 3 is a sectional view taken along line AA 'of FIG.
[0030]
FIG. 2 is a plan view showing a contact chain of the semiconductor device shown in the circuit diagram of FIG. A metal wiring 2 is formed on the two contacts 1 formed on the contact connection diffusion layer 3a. Between the IN terminal and the OUT terminal, the metal wiring 2 and the contact connection diffusion layer 3a are alternately connected in series via the contact 1 to form a contact chain.
[0031]
As shown in FIG. 3, the diffusion layer 3 includes a contact connection diffusion layer 3a and a transistor diffusion layer 3b, which are alternately arranged in the longitudinal direction of the diffusion layer 3. An MOS transistor 6 is formed by sequentially stacking an oxide film 5 and a gate electrode 4 on the transistor diffusion layer 3b. Further, as shown in FIG. 2, the diffusion layer 3 is connected to either the metal wiring 21 or the metal wiring 22.
[0032]
The diffusion layer 3 is an N-type diffusion layer in which an N-type impurity such as arsenic (As) commonly used in a semiconductor process is diffused, or a P-type impurity in which a P-type impurity such as boron (B) is diffused. It is possible to use a diffusion layer. In addition, materials such as aluminum (Al), tungsten (W), or copper (Cu) can be used for the metal wirings 2, 21, 22.
[0033]
In a conventional semiconductor device, for example, as shown in FIG. 8 which is a cross-sectional view taken along the line CC ′ in FIG. 6, an oxide film layer 114 having a thickness is formed between the diffusion layers 103. The diffusion layers 103 are completely separated from each other, and electrical separation is performed. However, in the second embodiment, the contact connection diffusion layers 3a are separated from each other by the MOS transistor 6. Therefore, by controlling the voltage of the gate electrode 4 of the MOS transistor 6, the contact connection diffusion layer 3a Diffusion layers 3a can be electrically separated or connected to each other.
[0034]
The diffusion layer 3 is connected to an H terminal or an L terminal via a metal wiring 21 and a metal wiring 22, respectively. The gate electrodes 4 of the MOS transistors 6 are all connected to the G terminal.
[0035]
The MOS transistor 6 can be easily manufactured because it is formed only by stacking the oxide film 5 and the gate electrode 4 on the diffusion layer 3. Note that another field effect transistor may be formed instead of the MOS transistor 6.
[0036]
All the MOS transistors 6 can be simultaneously turned on and off by the voltage of the G terminal, whereby the circuit configuration of the contact chain can be changed. More specifically, when the voltage of the G terminal is controlled and the MOS transistor 6 is OFF, the respective contact connection diffusion layers 3a in the same diffusion layer 3 are electrically separated from each other. Therefore, a circuit configuration is obtained in which a resistance element by the contact 1 is connected in series between the IN terminal and the OUT terminal. In this case, as described in the first embodiment, it is possible to determine a poor electrical connection.
[0037]
Further, by controlling the voltage of the G terminal and turning on the MOS transistor 6, all the contact connection diffusion layers 3a of the same diffusion layer 3 are connected. Further, since the diffusion layer 3 is connected to the H terminal or the L terminal via the metal wiring 21 or the metal wiring 22, the resistance element formed by the contact 1 is connected in parallel between the H terminal and the L terminal. Circuit configuration. In this case, as described in the first embodiment, it is possible to determine the electrical isolation failure and the reliability based on the voltage / current stress.
[0038]
In FIG. 2, among the metal wirings 2, metal wirings 23 disposed at the upper and lower ends and connected to the U-shaped metal wiring 23 and the IN terminal and the OUT terminal extending over the contact connection diffusion layer 3a in the adjacent column. The contact 1 provided at 24 is not an object to be measured during the above-described parallel connection, and no current flows.
[0039]
As described above, according to the semiconductor device according to the second embodiment, the circuit configuration of the first embodiment is provided, so that the electrical connection failure of the contact connecting the metal-diffusion layer and the electrical isolation failure occur. In addition, it is possible to easily realize a semiconductor device capable of determining reliability evaluation based on voltage / current stress.
[0040]
(Embodiment 3)
Third Embodiment A semiconductor device according to a third embodiment of the present invention will be described with reference to the drawings. In the third embodiment, an example (another example) of a specific configuration of a contact chain in a circuit of the semiconductor device according to the first embodiment will be described. FIG. 4 is a plan view showing the configuration of the semiconductor device according to the third embodiment, and FIG. 5 is a sectional view taken along the line BB 'in FIG.
[0041]
FIG. 4 is a plan view showing a contact chain of the semiconductor device represented by the circuit diagram of FIG. As in the second embodiment, the diffusion layer 3 includes a contact connection diffusion layer 3a and a transistor diffusion layer 3b in which the MOS transistor 6 is formed. These are alternately arranged in the longitudinal direction of the diffusion layer 3. Are located. As shown in FIG. 5, in the semiconductor device according to the third embodiment, the contact connection diffusion layer 3a, the lower metal wiring 2a, and the upper metal wiring 2b are formed in different layers, respectively. The layer 3a is at the bottom, the lower metal wiring 2a is disposed thereon, and the upper metal wiring 2b is further disposed thereon. The lower metal wiring 2a and the upper metal wiring 2b are connected by a contact 1a, the lower metal wiring 2a and the contact connection diffusion layer 3a are connected by a contact 1b, and the upper metal wiring 2b and the contact connection diffusion layer 3a. Are connected by a contact 1c.
[0042]
In the third embodiment, a lower-layer metal wiring 2a and an upper-layer metal wiring 2b are alternately connected in series via a contact 1a between an IN terminal and an OUT terminal to form a contact chain. Further, diffusion layer 3 including contact connection diffusion layer 3a connected to lower metal interconnection 2a is connected to H terminal via metal interconnection 21 and includes contact connection diffusion layer 3a connected to upper metal interconnection 2b. The diffusion layer 3 is connected to the L terminal via the metal wiring 22.
[0043]
Note that, of the lower metal wires 2a, the U-shaped lower metal wires 23a, which are arranged at the upper and lower ends of the contact chain and extend over the contact connection diffusion layer 3a in the adjacent column, and the lower layers connected to the IN terminal and the OUT terminal. The metal wiring 24a is not connected to the contact connection diffusion layer 3a.
[0044]
In such a circuit, by controlling the voltage of the G terminal and turning off the MOS transistor 6, the lower metal wiring 2a and the upper metal wiring 2b alternate between the IN terminal and the OUT terminal via the contact 1a. , And a circuit configuration in which the resistance element by the contact 1a is connected in series. In this case, as described in the first embodiment, it is possible to determine a poor electrical connection.
[0045]
Further, by controlling the voltage to the G terminal and turning on all the MOS transistors 6, the resistance element by the contact 1a connecting the lower metal wiring 2a and the upper metal wiring 2b between the H terminal and the L terminal. Are connected in parallel. In this case, as described in the first embodiment, it is possible to determine the electrical isolation failure and the reliability based on the voltage / current stress.
[0046]
As described above, according to the semiconductor device of the third embodiment, it is possible to judge the reliability evaluation based on the electrical connection failure of the metal-to-metal contact, the electrical isolation failure, and the voltage / current stress. .
[0047]
【The invention's effect】
According to the semiconductor device of the present invention, it is possible to switch a contact chain in which each resistance element is connected in series to a parallel connection. Therefore, it is possible to determine not only the electrical connection failure of the contact chain but also the reliability evaluation based on the electrical isolation failure and the voltage / current stress, thereby improving the reliability of the contacts of the semiconductor device with increased integration. be able to.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a contact chain in a semiconductor device according to a first embodiment of the present invention; FIG. 2 is a plan view showing a configuration of a contact chain in a semiconductor device according to a second embodiment of the present invention; FIG. 4 is a cross-sectional view taken along line AA ′ of FIG. 4. FIG. 4 is a plan view showing a configuration of a contact chain in a semiconductor device according to a third embodiment of the present invention. FIG. 5 is a cross-sectional view taken along line BB ′ of FIG. FIG. 6 is a plan view showing a configuration of a contact chain in a conventional semiconductor device. FIG. 7 is a circuit diagram of a contact chain in a conventional semiconductor device. FIG. 8 is a cross-sectional view taken along the line CC ′ of FIG.
1, 1a, 1b, 1c, 101 Contact 2, 21, 22, 23, 24, 102 Metal wiring 2a, 23a, 24a Lower metal wiring 2b Upper metal wiring 3 Diffusion layer 3a Diffusion layer 3b for contact connection Diffusion layer 4 for transistor Gate electrode 5 Oxide film 6 MOS transistor 114 Insulating film R1 to R12 Resistance element T1 to T13 Transistor

Claims (5)

In a semiconductor device having a circuit in which a plurality of resistance elements are connected in series,
Both ends of each of the resistance elements to be measured among the resistance elements are connected to a pair of common terminals via a switching element,
The control terminals of all the switching elements are connected to a common control terminal,
By operating the switching element, both ends of each of the resistance elements to be measured are each electrically connected to the common terminal to be paired, so that the resistance to be measured is between the common terminals to be paired. Elements are connected in parallel,
A semiconductor device, comprising: voltage applying means for applying a voltage between the pair of common terminals. The semiconductor device according to claim 1, wherein the switching element is a field effect transistor. The semiconductor device according to claim 1, wherein the resistance element includes at least one contact. The circuit includes a metal wiring, a diffusion layer, and a contact,
The diffusion layer is connected to one of the paired common terminals, and a diffusion layer for contact connection connected to the contact, and a transistor constituting a part of the switching element which is a field-effect transistor For the diffusion layer, in the longitudinal direction of the diffusion layer, is configured alternately arranged,
The metal wiring and the contact connection diffusion layer are alternately connected in series via the contact,
2. The transistor according to claim 1, wherein the switching element operates to connect the transistor diffusion layer and the contact connection diffusion layer, thereby forming a parallel connection between the paired common terminals. 3. Semiconductor device. The circuit includes a lower metal wiring, an upper metal wiring, a diffusion layer, and a contact formed in different layers,
The diffusion layer is connected to one of the paired common terminals, and a diffusion layer for contact connection connected to the contact, and a transistor constituting a part of the switching element which is a field-effect transistor For the diffusion layer, in the longitudinal direction of the diffusion layer, is configured alternately arranged,
The lower metal wiring and the upper metal wiring are alternately connected in series via the contacts, and are connected to the different contact connection diffusion layers, respectively.
2. The transistor according to claim 1, wherein the switching element operates to connect the transistor diffusion layer and the contact connection diffusion layer, thereby forming a parallel connection between the paired common terminals. 3. Semiconductor device.

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