Semiconductor Devices

Abstract

To provide a semiconductor device capable of reducing variation in a resistance value generated in a resistance element of a bleeder resistance circuit and simplifying a configuration.SOLUTION: A semiconductor device comprises: a first circuit comprising a plurality of fixed resistance elements; a second circuit connected in series to the first circuit and including a plurality of variable resistance elements connected in series; a first cover part provided on the upper layer side of the first circuit and covering the first circuit; and a second cover part provided on the upper layer side of the second circuit and covering the second circuit. The first cover part includes two or more first metal films per unit including any number of fixed resistance elements. The second cover part includes a second metal film electrically connected to the plurality of variable resistance elements.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor device. [Background technology]

[0002] Conventionally, semiconductor devices have been commonly used that have a bleeder resistor circuit in which multiple polycrystalline silicon resistors are connected in series. During the manufacturing process of the bleeder resistor circuit, hydrogen may enter the resistors, causing variations in the resistance values ​​of the resistors. To reduce the effects of hydrogen, the resistors are covered with a metal film or the like. However, after manufacturing the bleeder resistor circuit, variations in the resistance values ​​of the resistors may occur due to a potential difference generated between the resistors and the metal film.

[0003] Patent Document 1 describes a bleeder resistor circuit having a plurality of fixed resistance elements connected in series and a plurality of metal wirings covering the plurality of fixed resistance elements on the upper layer side of the plurality of fixed resistance elements. This bleeder resistor circuit electrically connects a plurality of metal wirings that are individually divided to the plurality of fixed resistance elements, thereby eliminating the potential difference between each fixed resistance element and the metal wirings and reducing the variation in the resistance value of each fixed resistance element.

[0004] Patent Document 2 describes a bleeder resistance circuit having a plurality of fixed resistance elements connected in series, a plurality of first metal wirings covering the plurality of fixed resistance elements above the plurality of fixed resistance elements, and a second metal wiring covering the plurality of first metal wirings upstream of the plurality of first metal wirings. This bleeder resistance circuit electrically connects a plurality of divided first metal wirings individually to the plurality of fixed resistance elements, and electrically connects a seamless second metal wiring covering the plurality of metal wirings above the plurality of first metal wirings to the plurality of fixed elements, thereby eliminating the potential difference between each fixed resistance element and the first metal wiring and reducing variations in the resistance value of each fixed resistance element. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-321229 [Patent Document 2] Japanese Patent Application Publication No. 2018-152545 Summary of the Invention [Problem to be solved by the invention]

[0006] In the bleeder resistor circuit described in Patent Document 1, after manufacturing, hydrogen may enter through gaps between the metal wiring divided corresponding to all fixed resistance elements, which may cause variations in resistance value.In the bleeder resistor circuit described in Patent Document 2, the provision of second metal wiring may complicate the configuration and manufacturing process.

[0007] One aspect of the present invention has been made in consideration of the above situation, and aims to provide a semiconductor device that can reduce the variation in resistance value that occurs in the resistance elements in a bleeder resistance circuit and can simplify the configuration. [Means for solving the problem]

[0008] A series-connected semiconductor device according to one embodiment of the present invention comprises a first circuit having a plurality of fixed resistance elements, a second circuit connected in series to the first circuit and having a plurality of variable resistance elements connected in series, a first cover portion provided on the upper side of the first circuit and covering the first circuit, and a second cover portion provided on the upper side of the second circuit and covering the second circuit, wherein the first cover portion comprises two or more first metal films electrically connected to each unit including any number of the fixed resistance elements, and the second cover portion comprises second metal films electrically connected to a plurality of the variable resistance elements. [Effects of the Invention]

[0009] According to one aspect of the present invention, it is possible to reduce variations in resistance values ​​occurring in resistor elements in a bleeder resistor circuit and to simplify the configuration. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating a configuration of a semiconductor device according to an embodiment; [Figure 2] FIG. 10 is a diagram showing a configuration of a semiconductor device according to a modified example. [Figure 3] FIG. 10 is a diagram showing a configuration of a semiconductor device according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a semiconductor device according to an embodiment will be described with reference to the drawings. In the following description, the Z axis is defined, and the +Z direction is referred to as the upper layer side, and the −Z direction is referred to as the lower layer side, etc.

[0012] As shown in FIG. 1, the semiconductor device 1 includes a bleeder resistor circuit including a first circuit S1 and a second circuit S2 connected in series to the first circuit S1. The first circuit S1 and the second circuit S2 are formed, for example, on one side of a substrate (not shown). An insulating film (not shown) is formed between the substrate and the first circuit S1 and the second circuit S2. The first circuit S1 includes a plurality of fixed resistor elements Rn (n is a natural number) connected in series. The fixed resistor elements Rn are formed, for example, of polycrystalline silicon resistors exhibiting a desired resistance value. The fixed resistor elements Rn are connected to each other by a plurality of electrical connections Cn. The upstream side of the first circuit S1 is connected, for example, to a first electrode C0 on the high-potential side of the circuit. The first electrode C0 is, for example, a positive power supply (VDD) of a circuit configured with field-effect transistors.

[0013] A first cover part K1 that covers the first circuit S1 is formed on the upper side of the first circuit S1. The first cover part K1 includes, for example, a plurality of first metal films Bn that are individually provided for each fixed resistance element Rn. Each first metal film Bn is formed, for example, of an Al-Si-Cu laminated film, an Al-Cu laminated film, or the like. Adjacent first metal films Bn are spaced apart from each other. An insulating film (not shown) is formed between the first circuit S1 and the first cover part K1. An insulating layer (not shown) is formed on the upper side of the first metal films Bn.

[0014] The first metal films Bn are electrically connected in parallel to the upstream electrical connection portion Cn-1 by electrical wiring Wn. As a result, each first metal film Bn is electrically connected to each fixed resistance element Rn so as to be at an equipotential. With the above configuration, the first circuit S1 is provided with a first metal film Bn individually for each fixed resistance element Rn, thereby maintaining an equipotential between each fixed resistance element Rn and each first metal film Bn, and preventing variations in resistance value for each fixed resistance element Rn.

[0015] The second circuit S2 is connected in series downstream of the first circuit S1. The second circuit S2 includes a plurality of variable resistance elements Vm (m is a natural number) connected in series. The downstream side of the second circuit S2 is connected to a second electrode Cx on the low potential side of the circuit. The second electrode Cx is, for example, a negative power supply (VSS) of a circuit configured with a field effect transistor. The voltage value of the negative power supply can be any value. The downstream side of the second circuit S2 is connected to the ground side.

[0016] The variable resistance element Vm is formed of a material such as a polycrystalline silicon resistor. The variable resistance element Vm is configured to be reversibly changeable between a low resistance state and a high resistance state based on an input voltage. A second cover part K2 that covers the second circuit S2 is provided on the upper layer side of the second circuit S2. The second cover part K2 is formed in the same layer as the first cover part K1. The second cover part K2 includes a second metal film D that is electrically connected in parallel to the multiple variable resistance elements Vm. An insulating film (not shown) is formed between the second circuit S2 and the second metal film D. An insulating layer (not shown) is formed on the upper layer side of the second metal film D.

[0017] The second metal film D is electrically connected in parallel to the downstream second electrode Cx by the electrical wiring WE. As a result, the second metal film D is electrically connected to the second circuit S2 so as to be at the same potential. The second metal film D is formed, for example, of an Al-Si-Cu laminated film, an Al-Cu laminated film, or the like. Since the second circuit S2 is seamlessly covered by the second metal film D, it is possible to prevent hydrogen from penetrating during the manufacturing process. The second circuit S2 is connected to the second electrode Cx so as to be at the same potential as the substrate.

[0018] The second metal film D is connected to the second electrode Cx so as to be at the same potential as the substrate, thereby electrically connecting the second circuit S2 and the second metal film D to be at the same potential. The second circuit S2 is seamlessly covered by the second metal film D, which prevents hydrogen from entering and suppresses deterioration in the accuracy of the resistance value of the variable resistance element Vm.

[0019] An output electrode Q is connected to the electrical connection Cn-1 of the first circuit S1, and outputs an output voltage Vout divided at the electrical connection Cn-1. The output voltage Vout can be adjusted by adjusting the resistance value of the variable resistance element Vm in the second circuit S2. The output electrode Q may be connected to an electrical connection at any position among a plurality of electrical connections connecting a plurality of fixed resistance elements in the first circuit S1, and output the output voltage. With the above configuration, when different power supply voltages VDD and VSS (VDD > VSS) are input to the upper side of the first circuit S1 and the downstream side of the second circuit S2, respectively, and a potential difference is generated, an equipotential is established between the first circuit S1 and the plurality of first metal films Bn, and an equipotential is established between the second circuit S2 and the second metal film D.

[0020] As described above, according to the semiconductor device 1, since the plurality of first metal films Bn are electrically connected to the plurality of fixed resistance elements Rn individually in the first circuit S1, it is possible to reduce variations occurring in the plurality of fixed resistance elements Rn. According to the semiconductor device 1, in the second circuit S2 which is more affected by hydrogen penetration than the first circuit S1, the second metal film D covering all of the plurality of variable resistance elements Vm is electrically connected, thereby preventing hydrogen penetration and suppressing deterioration in the accuracy of the resistance value of the variable resistance elements Vm.

[0021] According to the semiconductor device 1, the configuration of the first cover part K1 and the second cover part K2 is changed depending on the type of resistive element that constitutes the first circuit S1 and the second circuit S2, thereby simplifying the configuration and manufacturing process while reducing the variation in resistance value due to hydrogen penetration.

[0022] [Variations] The following describes modified examples of the semiconductor device 1. In the following description, the same components as those in the above embodiment are designated by the same names and reference numerals, and redundant description will be omitted as appropriate.

[0023] 2, in the semiconductor device 1A according to the modification, each first metal film Bn may be connected to an electrical connection portion Cn downstream of the corresponding fixed resistance element Rn, thereby making it possible to equipotentially connect each fixed resistance element Rn to the corresponding first metal film Bn and reduce variations in the resistance value of each fixed resistance element Rn.

[0024] 3, in the first circuit S1, the first cover part K1 may include two or more first metal films Bf electrically connected to each unit Uf (f is a natural number) including any number of fixed resistance elements Rn. The number of fixed resistance elements Rn included in each unit Uf may or may not be equal. Therefore, at least two first metal films Bf are provided. By providing a first metal film Bf for each unit Uf, the number of electrical wirings Wf electrically connecting the first metal films Bf and the units Uf can be reduced compared to when a first metal film Bn is provided for each fixed resistance element Rn, thereby simplifying the device configuration and manufacturing process.

[0025] Alternatively, the second circuit S2 may be connected not only in series downstream of the first circuit S1 but also upstream to the VDD side. The second circuit S2 may be connected at any position of the electrical connection Cn between the multiple fixed resistor elements Rn. Furthermore, the connection position of the second circuit S2 may be changed depending on the output voltage.

[0026] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be modified as appropriate without departing from the spirit of the present invention. Furthermore, within the spirit of the present invention, the components in the above embodiment can be replaced with well-known components as appropriate, and the above-described modified examples can be combined as appropriate. [Explanation of symbols]

[0027] 1, 1A Semiconductor Device Bf, Bn first metal film C0 1st electrode Cn Electrical Connection Cx 2nd electrode D Second metal film K1 First cover part K2 Second cover part Rn fixed resistor element S1 1st circuit S2 2nd circuit Uf unit Vm variable resistance element

Claims

1. a first circuit including a plurality of fixed resistance elements connected in series; a second circuit connected in series to the first circuit and including a plurality of variable resistance elements connected in series; a first cover portion provided on an upper layer side of the first circuit and covering the first circuit; a second cover portion provided on an upper layer side of the second circuit and covering the second circuit, the first cover portion includes two or more first metal films electrically connected to each unit including any number of the fixed resistance elements, the second cover portion includes a second metal film electrically connected to the plurality of variable resistance elements; Semiconductor device.

2. the first cover portion includes a plurality of the first metal films provided for each of the fixed resistance elements; The semiconductor device according to claim 1 .

3. the second metal film is connected to have an equipotential with the substrate; 3. The semiconductor device according to claim 1.

4. the first circuit is connected to a first electrode on a high potential side; the second circuit is connected to a second electrode on the low potential side; The semiconductor device according to claim 1 .

5. The second circuit is connected to the ground side. The semiconductor device according to claim 1 .

6. an output voltage is output from an electrical connection portion at an arbitrary position among a plurality of electrical connection portions that connect the plurality of fixed resistance elements in the first circuit; The semiconductor device according to claim 1 .

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