Metallic via resistance in a multilayer metal structure

Abstract

The application discloses a metal hole resistance of a multilayer metal structure, comprising: at least i columns of vertical structure metal via hole resistance structures, each column of the vertical structure metal via hole resistance structures being connected in series through top metal lines or bottom metal lines; each column of the vertical structure metal via hole resistance structures comprising at least j layers of via holes, each layer of the via holes being distributed above and below, and the symmetry centers of each layer of the via holes being located on the same vertical center axis, and each two adjacent layers of the via holes being electrically connected through an intermediate metal layer; wherein, the value range of i is i>=2, and the value range of j is j>=2. The application has a larger square resistance value than a single hole resistance, can realize a larger resistance value under the same area, occupies a smaller layout area under the same target resistance value, can better realize the resistance function of an analog circuit, reduce the manufacturing cost, and is suitable for manufacturing a resistance with a smaller target resistance value but much larger than the square value of a metal resistance.

Description

Technical Field

[0001] This utility model belongs to the field of analog circuit technology, and specifically relates to a metal hole resistor with a multilayer metal structure. Background Technology

[0002] Resistors provide a defined or controllable resistance value in a circuit and are commonly used for functions such as voltage division and current limiting. They are important components in analog circuits. Analog circuits typically contain multiple resistors, and the selection of resistor materials and space planning are crucial issues when designing the circuit layout.

[0003] Currently, the market offers a variety of resistors made from different materials for different applications. Metal resistors are made of aluminum, and their resistance is affected by the thickness of the metal layer and the temperature coefficient. In multilayer metal processes, resistors can be made with any metal layer. The upper metal conductor can be placed above the lower metal resistor, but the lower metal or silicon conductor cannot be placed below the upper metal resistor because it would cause non-planarity of the resistor. Compared with other resistors, metal resistors have stable physical properties and good conductivity, but metal resistors have a small sheet resistance and are not suitable for making high-resistance resistors.

[0004] Polycrystalline silicon resistors are made of polycrystalline silicon material, and their sheet resistance can be changed by doping. Heavily doped polycrystalline silicon resistors have a sheet resistance of about 25 to 50 ohms per square, while lightly doped polycrystalline silicon resistors have a sheet resistance of about several hundred to several thousand ohms per square. Compared with other resistors, polycrystalline silicon resistors are compatible with integrated circuit processes, have a larger sheet resistance, flexible and controllable resistance, and better stability. However, polycrystalline silicon resistors can cause local overheating under excessive power consumption, making it difficult to achieve megaohm-level resistances, and the cost is high when manufacturing resistors with smaller target resistance values.

[0005] A via (VIA) is a conductive structure in a multi-layer metal structure that connects adjacent metal layers by creating openings in an insulating layer and filling them with metal. The metal layers are isolated from each other by the insulating layer, and vertical interconnection is achieved by surrounding the corresponding vias. Vias connecting different metal layers can be stacked on the same vertical line. The sheet resistance of a via is greater than that of a metal wire, approximately 5 ohms per square block. Utility Model Content

[0006] To address at least one of the above problems, this utility model proposes a multilayer metal via resistor. Compared to ordinary resistors, the metal via resistor provided in this application combines the characteristics of metal resistors and via resistors, possessing a larger sheet resistance value than a single via resistor. It achieves a larger resistance value in the same area and occupies a smaller layout area for the same target resistance value. This allows for better realization of the resistive function of analog circuits and reduces manufacturing costs. It is suitable for manufacturing resistors with a target resistance value that is small but much larger than the sheet resistance value of metal resistors.

[0007] The technical solution adopted in this utility model is as follows:

[0008] This application discloses a multilayer metal via resistor for use in analog circuits. The metal via resistor includes at least i vertically arranged metal-via resistor structures, with each column of the vertically arranged metal-via resistor structures connected in series via a top-layer metal line or a bottom-layer metal line. Each column of the vertically arranged metal-via resistor structures includes at least j layers of vias, with each layer of vias distributed vertically, and the center of symmetry of each layer of vias located on the same vertical central axis. Adjacent layers of vias are electrically connected through an intermediate metal layer. The value of i is in the range of i≥2, and the value of j is in the range of j≥2.

[0009] As an optional technical solution, when i=2 and j=2, the metal via resistor includes two columns of vertically structured metal-via resistor structures. Each column of vertically structured metal-via resistor structures includes a first layer of vias and a second layer of vias. The first layer of vias and the second layer of vias in the same column are electrically connected through an intermediate metal layer. The first layer of vias in the first column and the first layer of vias in the second column are electrically connected through the bottom metal wire.

[0010] As an optional technical solution, when i=4 and j=3, the metal via resistor includes four columns of vertically structured metal-via resistor structures. Each column of vertically structured metal-via resistor structures includes a first layer of vias, a second layer of vias, and a third layer of vias. The first, second, and third layer vias in the same column are electrically connected through an intermediate metal layer. The first layer vias in the first column are electrically connected to the first layer vias in the second column through a bottom metal wire. The third layer vias in the second column are electrically connected to the third layer vias in the third column through a top metal wire. The first layer vias in the third column are electrically connected to the first layer vias in the fourth column through a bottom metal wire.

[0011] As an optional technical solution, when i=6 and j=4, the metal via resistor includes six columns of vertically structured metal-via resistor structures. Each column of vertically structured metal-via resistor structures includes a first layer via, a second layer via, a third layer via, and a fourth layer via. The first, second, third, and fourth layer vias in the same column are electrically connected through an intermediate metal layer. The first layer vias in the first column are electrically connected to the first layer vias in the second column through a bottom layer metal wire. The fourth layer vias in the second column are electrically connected to the fourth layer vias in the third column through a top layer metal wire. The first layer vias in the third column are electrically connected to the first layer vias in the fourth column through a bottom layer metal wire. The fourth layer vias in the fourth column are electrically connected to the fourth layer vias in the fifth column through a top layer metal wire. The first layer vias in the fifth column are electrically connected to the first layer vias in the sixth column through a bottom layer metal wire.

[0012] The beneficial effects of this utility model are as follows: This application is based on metal resistors and via resistors, and increases the total resistance value by adding vias; compared with ordinary metal resistors, this application utilizes the characteristics of vias and the vertical area of ​​the chip, and increases the number of vias connected in series on the same vertical line to achieve a larger sheet resistance value than a single-via resistor, achieving a larger total resistance value with a smaller layout area, which has an absolute advantage in terms of cost; compared with a single-via resistor, this application has a larger sheet resistance value, and the sheet resistance value can be flexibly adjusted; when designing resistors with a target resistance value that is small but much larger than the sheet resistance value of metal resistors, it can effectively save layout area and reduce manufacturing costs; this application cleverly utilizes common metal lines and via structures, and the resistor structure can be adjusted according to the target resistance value required by the design, which has good portability and flexibility. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a single vertical metal-via resistor structure in an exemplary embodiment.

[0014] Figure 2 This is a schematic diagram of a metal hole resistor in a multilayer metal structure in an exemplary embodiment.

[0015] Figure 3 This is a schematic diagram of the metal hole resistance of a multilayer metal structure when i=2 and j=2 in an exemplary embodiment.

[0016] Figure 4 This is a schematic diagram of the metal hole resistance of a multilayer metal structure when i=4 and j=3 in an exemplary embodiment.

[0017] Figure 5 This is a schematic diagram of a metal hole resistor in a multilayer metal structure with i=6 and j=4 in an exemplary embodiment. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. The components of the embodiments of this utility model described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to illustrate selected embodiments of the utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0020] Example

[0021] To address the shortcomings of existing process technologies, this embodiment provides a multilayer metal via resistor. Utilizing the vertical distribution of vias, multiple vias and metal layers are vertically connected in series to form a vertical metal-via resistor structure. This vertical metal-via resistor structure is then horizontally connected in series. Compared to a single-via resistor, it has a larger sheet resistance value, solving the problem of small resistance values ​​in ordinary metal resistors within a limited area. This achieves a larger resistance value in a smaller layout area, occupies a smaller layout area for the same target resistance value, and provides a well-matched resistor.

[0022] First, the metal-via resistor structure of a single vertical structure will be explained, taking a 4-layer via as an example, refer to... Figure 1 It comprises a five-layer metal structure and four vias. The bottom metal line M1 and the top metal line M5 connect adjacent vertical metal-via resistor structures. The second, third, and fourth metal layers M2, M3, and M4 are intermediate metal layers. The top metal line M5, the first via VIA1, the second via M2, the second via VIA2, the third via M3, the third via VIA3, the fourth via M4, the fourth via VIA4, and the top metal line M5 are connected in series to form the total resistance of the vertical metal-via resistor structure. In the layout, the resistance of vias is much greater than that of metals. Since vias are vertical interconnect channels, within the same area of ​​the layout, the more metal layers and the more vias connected in series, the greater the block resistance of the metal-via resistor structure. The resistance value of the vertical metal-via resistor structure can be controlled by designing the number of vias and metal layers.

[0023] Where the layout area allows, multiple vertical metal-via resistor structures can be connected in series laterally to increase the resistance value and thus meet the required design resistance. In other words, this embodiment allows for vertical (i.e., increasing the number of vias and metal layers) or horizontal (i.e., increasing the number of columns of the vertical metal-via resistor structure) expansion of the metal-via structure based on the layout area and the required design resistance value, offering flexible and convenient design options.

[0024] Specifically, such as Figure 2 As shown, this embodiment discloses a multilayer metal via resistor applied to analog circuits. The metal via resistor includes: at least i vertically arranged metal-via resistor structures, with each column of the vertically arranged metal-via resistor structures connected in series via a top-layer metal line or a bottom-layer metal line; each column of the vertically arranged metal-via resistor structure includes at least j layers of vias, with each layer of vias distributed vertically, and the center of symmetry of each layer of vias located on the same vertical central axis L, with adjacent layers of vias electrically connected through an intermediate metal layer; wherein, the value of i is in the range of i≥2, and the value of j is in the range of j≥2.

[0025] As an optional implementation, the metal hole resistance of the multilayer metal structure in this embodiment will be described below with i=2 and j=2. For example... Figure 3 As shown, the metal via resistor includes two vertically structured metal-via resistor structures. Each vertically structured metal-via resistor structure includes a first via VIA1 and a second via VIA2. The first via VIA1 and the second via VIA2 in the same column are electrically connected by an intermediate metal layer M2. The first via VIA1 in the first column and the first via VIA1 in the second column are electrically connected by a bottom metal line M1.

[0026] As an optional implementation, the metal hole resistance of the multilayer metal structure in this embodiment will be described below with i=4 and j=3. Figure 4 As shown, the metal via resistor includes four vertically arranged metal-via resistor structures. Each vertically arranged metal-via resistor structure includes a first layer via VIA1, a second layer via VIA2, and a third layer via VIA3. The first layer via VIA1, the second layer via VIA2, and the third layer via VIA3 located in the same column are electrically connected through an intermediate metal layer (M2, M3). The first layer via VIA1 located in the first column is electrically connected to the first layer via VIA1 located in the second column through a bottom metal line M1. The third layer via VIA3 located in the second column is electrically connected to the third layer via VIA3 located in the third column through a top metal line M4. The first layer via VIA1 located in the third column is electrically connected to the first layer via VIA1 located in the fourth column through a bottom metal line M1.

[0027] As an optional implementation, the metal hole resistance of the multilayer metal structure in this embodiment will be described below with i=6 and j=4. Figure 5 As shown, the metal via resistor comprises six vertically arranged metal-via resistor structures. Each vertically arranged metal-via resistor structure includes a first via VIA1, a second via VIA2, a third via VIA3, and a fourth via VIA4. The first via VIA1, second via VIA2, third via VIA3, and fourth via VIA4 located in the same column are sequentially electrically connected through intermediate metal layers (M2, M3, M4). The first via VIA1 in the first column is connected to the first via VIA1 in the second column. The fourth via VIA4 in the second column and the fourth via VIA4 in the third column are electrically connected via the bottom metal line M1. The first via VIA1 in the third column and the first via VIA1 in the fourth column are electrically connected via the bottom metal line M1. The fourth via VIA4 in the fourth column and the fourth via VIA4 in the fifth column are electrically connected via the top metal line M5. The first via VIA1 in the fifth column and the first via VIA1 in the sixth column are electrically connected via the bottom metal line M1.

[0028] It should be noted that the value of j (i.e., the number of vias and metal layers) is determined based on the size of the sheet resistor described in the actual design, and the value of i is determined based on the actual layout area, the required resistance value in the design, and the value of j.

[0029] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. All technical solutions that fall within the scope of the claims of this utility model are within the scope of protection of this utility model.

Claims

1. A multilayer metal via resistor, used in analog circuits, characterized in that, The metal via resistor includes: at least i vertically arranged metal-via resistor structures, with each column of the vertically arranged metal-via resistor structures connected in series via a top-layer metal line or a bottom-layer metal line; each column of the vertically arranged metal-via resistor structure includes at least j layers of vias, with each layer of vias distributed vertically, and the center of symmetry of each layer of vias located on the same vertical central axis, and adjacent layers of vias electrically connected through an intermediate metal layer; wherein, the value of i is i≥2, and the value of j is j≥2.

2. The metal via resistance of the multilayer metal structure according to claim 1, characterized in that: When i=2 and j=2, the metal via resistor includes two columns of vertical metal-via resistor structures. Each column of vertical metal-via resistor structures includes a first layer of vias and a second layer of vias. The first layer of vias and the second layer of vias in the same column are electrically connected through an intermediate metal layer. The first layer of vias in the first column and the first layer of vias in the second column are electrically connected through the bottom metal wire.

3. The metal hole resistance of the multilayer metal structure according to claim 1, characterized in that: When i=4 and j=3, the metal via resistor includes four columns of vertically structured metal-via resistor structures. Each column of vertically structured metal-via resistor structures includes a first layer of vias, a second layer of vias, and a third layer of vias. The first, second, and third layer vias in the same column are electrically connected through an intermediate metal layer. The first layer vias in the first column are electrically connected to the first layer vias in the second column through a bottom layer of metal wire. The third layer vias in the second column are electrically connected to the third layer vias in the third column through a top layer of metal wire. The first layer vias in the third column are electrically connected to the first layer vias in the fourth column through a bottom layer of metal wire.

4. The metal hole resistance of the multilayer metal structure according to claim 1, characterized in that: When i=6 and j=4, the metal via resistor includes six columns of vertically structured metal-via resistor structures. Each column of vertically structured metal-via resistor structures includes a first layer via, a second layer via, a third layer via, and a fourth layer via. The first, second, third, and fourth layer vias in the same column are electrically connected through an intermediate metal layer. The first layer via in the first column is electrically connected to the first layer via in the second column through a bottom metal wire. The fourth layer via in the second column is electrically connected to the fourth layer via in the third column through a top metal wire. The first layer via in the third column is electrically connected to the first layer via in the fourth column through a bottom metal wire. The fourth layer via in the fourth column is electrically connected to the fourth layer via in the fifth column through a top metal wire. The first layer via in the fifth column is electrically connected to the first layer via in the sixth column through a bottom metal wire.

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