JP2011204925A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device including a bleeder resistor circuit of superior accuracy capable of varying voltage dividing ratio by trimming so that desired voltage dividing ratio can be obtained.SOLUTION: The bleeder resistor circuit is constituted by resistance circuit parts in two or more steps connected in series, and, as resistance elements of these resistance circuit parts, basic resistance wirings of the same material, the same length, the same width and the same thickness are formed in a form where at least two or more of them are connected. The basic resistance wirings constituting the bleeder resistor circuit are aligned in one region in the semiconductor device while all of them are aggregated, and the basic resistance wirings of the resistance circuit parts are divided into at least two pieces, respectively, and arranged while sandwiching the basic resistance wiring of another resistance circuit part, thereby difference in resistance value due to variation in manufacture of the basic resistance wirings arranged separately is dispersed to each of resistance circuit parts.

Description

  The present invention relates to a semiconductor device including a bleeder resistance circuit with high accuracy that can change a voltage dividing ratio by trimming and obtain a desired voltage dividing ratio.

  Currently, a bleeder resistance circuit that can change a voltage dividing ratio by trimming used in a semiconductor integrated circuit is composed of a high-resistance wiring region and a trimming fuse region. A high resistance material is formed in a wiring pattern of the same shape having the same length and the same width, and a plurality of such high resistance materials are arranged, and a desired resistance value is obtained by connecting these wirings in series or in parallel. One of the same-shaped wiring patterns is referred to as a basic resistance wiring in the following description. The bleeder resistor is composed of a series connection of a plurality of resistance circuit units for obtaining a reference resistance voltage dividing ratio and a trimming fuse. The resistor circuit can also be classified into a fixed resistor circuit portion having a fixed resistance value that is not trimmed and a correction resistor portion that can correct the resistance by fuse trimming. As the trimming correction bit of the correction resistor section, one basic resistor wiring, two wires, four wires,... N 2 power resistors connected in series, two wires, four wires,. In general, a method of forming a correction circuit for 2n + 1 bits using basic resistance wirings connected in parallel to the nth power of n is adopted. The advantage of this configuration is that the number of fuses to be trimmed is small, the range of the desired resistance value to be trimmed is large, and resistance correction is possible with high resolution in units of 2 n parallel connection resistance values of the basic resistance wiring It is a thing. Furthermore, a 2n + 1-bit correction circuit can be created with (2 ^ (n + 2) -3) basic resistance wires, and the circuit layout area can be designed to be relatively small. The resistance circuit of each bit connected in series and in parallel is formed by connecting adjacent basic resistance wirings. This is because the area of the layout of the connection wiring between the basic resistance wirings is minimized and consideration is made to prevent a difference in electric field or stress applied to the basic resistance in the same bit.

  However, in this bleeder resistor circuit configuration, the resistance value, which should be the basic resistance wiring with the same characteristics, varies, so the difference between the target partial voltage value after trimming calculated from the circuit constants and the actual partial voltage value after trimming is different. Including problems that occur. It has been found that the basic resistance wiring connected in series or in parallel has a slight difference between the resistance value calculated from each circuit constant and the actual resistance value.

  Therefore, as a method for solving such a problem, it is considered that the fact that the neighboring potential is different from the operating point potential of each basic resistance wiring is the main cause that the desired resistance value cannot be obtained, and the lower and upper layers of each basic resistance wiring A method is disclosed in which an adjacent electrode potential is fixed to an operating point potential of a resistor by forming an electrode on the substrate and connecting it to a basic resistance wiring. (For example, refer to Patent Document 1 and Patent Document 2).

  As another method, by utilizing the fact that the resistance value of the resistance material changes depending on the amount of hydrogen annealing, a metal electrode is arranged on the basic resistance wiring, and the position of the basic resistance wiring and the metal electrode is gradually changed and adjusted. A method of obtaining a desired resistance value by adjusting the amount of hydrogen reaching each basic resistance wiring in the hydrogen annealing process is disclosed. (For example, refer to Patent Document 3).

JP 2002-762281 A JP 2003-234405 A JP 2006-49581 A

  However, the above-mentioned Patent Documents 1, 2, and 3 do not disclose countermeasures against variations in the manufacturing process causing the basic resistance wirings to vary. In view of the variation of each basic resistance wiring, there is almost no difference in resistance value between adjacent basic resistance wirings, but there is a tendency that the difference in resistance value between basic resistances tends to occur as the distance increases. As the cause of variation, the film thickness variation of the high resistance wiring material itself. When using the implanter to introduce impurities, the micro uniformity effect, the resist film thickness difference in the photolithographic process, the line width difference caused by the focus shift, the dry etching process There are various items such as loading effect, in-plane variation of heat and atmosphere of the thermal process, stress difference after product completion, etc. The difference in resistance value tends to increase as the basic resistance wirings are separated.

  Since the constituent elements of each resistance circuit block of the bleeder resistance circuit are configured by using adjacent basic resistance wiring, the distance between the basic resistance wirings between the circuit blocks is set apart. Is affected as a resistance value difference between circuit blocks. There is also a resistance circuit unit in which a certain resistance circuit unit has a high resistance value and conversely a low resistance value. As a result, the difference between the desired partial pressure value calculated from the circuit constant by trimming and the actual partial pressure value is likely to occur.

  In addition, since 2n + 1-bit correction circuits are created with (2 ^ (n + 2) -3) basic resistance wirings, a circuit that requires high accuracy, that is, the number of basic resistance wirings increases as the number of bits increases. As a result, the distance between the circuit blocks of the respective correction bit resistors is greatly increased, and a difference between the desired correction bit resistance value and the actual correction bit resistance value is likely to occur. It is conceivable that the more accurate the multi-bit correction circuit is, the more inconsistent it becomes.

  Therefore, in the present invention, in a semiconductor device including a bleeder resistance circuit capable of changing a voltage dividing ratio by trimming, the bleeder resistance circuit is configured by two or more stages of series-connected resistance circuit sections, and the resistance elements of these resistance circuit sections Are formed in a form in which at least two basic resistance wirings of the same material, the same length, the same width and the same thickness are connected, and all the basic resistance wirings constituting the bleeder resistance circuit are gathered in one region in the semiconductor device. The basic resistance wirings of the respective resistance circuit sections are divided into at least two parts and arranged with the basic wiring resistances of the other resistance circuit sections sandwiched between them, so that the resistance value difference between the separated basic resistance wirings The configuration is such that each resistor circuit portion is affected in a distributed manner.

  Although the layout area required for connection of the basic resistance wiring increases, the layout area does not become so large by using the multilayer wiring technique.

  In addition, in the resistor circuit portion constituted by the basic resistor wiring which is not numerous, that is, a correction bit resistor circuit with one basic resistor, a correction bit resistor circuit in which two basic resistors are connected in parallel or in series, etc. On the other hand, by using the n-stage series connection and the n-stage parallel connection together to form a circuit using n ^ 2 times the number of basic resistance wirings, the configuration of the basic resistance wiring of each resistance circuit section The number was increased and distributed as described above.

  By this method, it becomes possible to disperse the resistance value difference between the separated basic resistors with respect to the entire resistance circuit portion. As a result, even if there is a difference in the resistance values of the separated basic resistance wires, the respective resistance circuit portions are similarly affected, and a desired bleeder voltage dividing ratio can be accurately obtained.

  According to the present invention, it is possible to provide a semiconductor device including a bleeder resistance circuit that can be trimmed to a stable and accurate voltage dividing ratio.

It is a resistor layout schematic diagram showing an example of a bleeder resistance circuit in the present invention. It is a circuit diagram which shows one example of the bleeder resistance circuit in this invention. It is a resistance layout schematic diagram of a conventional bleeder resistance circuit. It is a circuit diagram of the conventional bleeder resistance circuit.

  DESCRIPTION OF EMBODIMENTS Embodiments for carrying out the present invention will be described with reference to the drawings.

  Hereinafter, an embodiment relating to a semiconductor device will be described by taking a bleeder circuit having a simple 5-bit trimming correction circuit as an example.

  FIG. 1 is a schematic diagram of a resistance layout showing an example of a bleeder resistance circuit according to the present invention. FIG. 2 is a circuit diagram of the resistor layout schematic diagram of FIG. Twenty pieces of the same high resistance material having the same length and width and having the same shape are formed and arranged, and this same shape wiring pattern is referred to as a basic resistance wiring. The 20 basic resistor wirings ideally have the same resistance value, and each resistor is connected in series or in parallel to form a bleeder resistance circuit having a 5-bit trimming correction circuit. A corrected first bit resistor circuit unit 100 in which a resistor in which four basic resistor wires 101, 102, 103, and 104 are connected in series and a trimming fuse 105 are connected in parallel, and two basic resistor wires 201 and 202 are provided. A correction second bit resistance circuit unit 200 in which a basic resistance wiring is connected in series and a trimming fuse 205 are connected in parallel, and four basic resistance wirings 301, 302, 303, and 304 are connected in parallel. In addition, the trimming fuse 405 includes a correction third-bit resistance circuit unit 300 in which two stages of resistors connected in series and the trimming fuse 305 are connected in parallel, and a resistor in which two basic resistance wires 401 and 402 are connected in parallel. The corrected fourth bit resistor circuit unit 400 connected in parallel and the four basic resistor wires 501, 502, 503, and 504 A correction fifth bit resistor circuit unit 500 in which a resistor connected in parallel with this resistor wire and a trimming fuse 505 are connected in parallel and two basic resistor wires 601, 602, 603, and 604 are connected in parallel. Furthermore, it consists of six resistance circuit parts of the fixed resistance circuit part 600 of resistors connected in series in two stages. One voltage input terminal 1001 is connected to the corrected first bit resistor circuit unit 100, and the corrected second bit resistor circuit unit 200, the corrected third bit resistor circuit unit 300, the corrected fourth bit resistor unit 400, the corrected fifth bit resistor unit 100 in this order. The bit resistor unit 500, the voltage output terminal 1002, the fixed resistor circuit unit 600, and the other voltage input terminal 1003 are connected in series.

  In the bleeder resistance circuit shown in FIG. 1 and FIG. 2 as an example of the present invention, the resistance of the cut circuit block is added to the circuit by cutting the trimming fuse. The fuse cutting method has 5 bits, that is, 32 kinds, and the voltage applied between the voltage input terminal 1001 and the voltage input terminal 1003 is 11.4286% to 100% between the voltage output terminal 1002 and the voltage input terminal 1003. Output voltage can be obtained.

  FIG. 3 is a schematic diagram of a resistance layout of a conventional bleeder resistor circuit, and FIG. 4 is a circuit diagram of the conventional resistor layout diagram of FIG. Embodiments of the Present Invention In FIGS. 1 and 2, the number of basic resistance wires is 20, whereas in the conventional method of FIGS. 3 and 4, it is 14. The corrected third bit resistor circuit unit 300 and the fixed resistor circuit unit 600 are composed of one basic resistor wiring in the conventional method of FIGS. 3 and 4, and are configured by the basic resistor wiring 301 and the basic resistor wiring 601. Yes. On the other hand, the embodiment of the present invention is constructed by using four basic resistors in FIGS. In addition, according to the schematic layout of FIG. 1, the basic resistances of the components of each of the six resistance circuit units are arranged adjacent to the basic resistance wiring of different resistance circuit units, and the respective resistance circuit units are confused and distributed. . In the conventional layout schematic diagram of FIG. 3, the basic resistance wiring in the same resistance circuit portion is arranged adjacent to each resistance circuit portion.

  Considering the variation of each basic resistance wiring, there is almost no difference in the resistance value between adjacent basic resistance wirings, but it is already that the difference in resistance value between the basic resistance wirings tends to occur as the distance increases. As stated. If there is in-plane variation, a difference is likely to occur in the resistance values of the basic resistance wires that are separated from each other. As the cause of variation, the film thickness variation of the high resistance wiring material itself. When using the implanter to introduce impurities, the micro uniformity effect. There are various items such as loading effect, in-plane variation of heat and atmosphere in the thermal process, stress difference after product completion.

  In each circuit block of the conventional bleeder resistance circuit of FIG. 3 and FIG. 4, it is arranged for each resistance circuit section, and the basic resistance wiring between each resistance circuit section is separated, and the resistance value difference of the basic resistance is It is easily affected by the difference in resistance between the resistance circuit parts. There may be a resistance circuit portion in which a resistance value of a certain resistance circuit portion is high, and conversely, a resistance value is low. As a result, the difference between the desired partial pressure value calculated from the circuit constant and the actual partial pressure value after trimming tends to occur. On the other hand, in the bleeder resistance circuit shown in FIG. 1 and FIG. 2 as an example of the present invention, the basic resistance wiring as the constituent elements of the resistance circuit section is arranged in a distributed manner in which all the resistance circuit sections are disturbed. The parts are affected by the same degree of variation.

  If the basic resistance wiring 101 arranged at the uppermost end of FIG. 1 has a resistance value of 1000Ω, the basic resistance wiring 202 is 1001Ω and the basic resistance wiring 301 is 1002Ω. ..If the basic resistance wiring 602 at the lowermost end is 1019Ω, and there is a manufacturing variation in which the adjacent resistance value increases by 1Ω, which is approximately 0.1% of the resistance value, the output voltage after trimming and all the basic resistance wiring The deviation from the ideal output voltage with no variation in the resistance value is obtained by performing 32 trimmings, and the maximum deviation is 0.40%. In addition, regarding the conventional method of FIG. 3, as the same variation, 32 basic trimmings were performed when the basic resistance wiring 101 was 1000Ω, the basic resistance wiring 102 was 1001Ω, and the lowest basic resistance wiring 601 was 1013Ω. The maximum deviation is 0.92%. Even if the layout becomes large and the variation range between the basic resistance wirings becomes large, the adverse effect due to the manufacturing variation can be reduced by using the method of the present invention, and a bleeder resistor with high accuracy can be provided. The actual manufacturing variation does not always indicate a value that regularly increases as described above, but the difference in the resistance value of the basic resistance tends to increase as the distance increases. By using this method, a bleeder resistance with high accuracy can be provided.

  In addition, even if the resistance circuit units are not arranged in order in a regular manner as shown in FIG. 1, the basic resistance wiring, which is a constituent element of all resistance circuit units of the bleeder resistor, is distributed and distributed for each resistance circuit unit. This effect can be obtained.

  Depending on the resistance circuit part, the number of basic resistance wirings is small, so it may not be possible to distribute them. In such a case, by using a combination of n stages of series connections and n stages of parallel connections, the configuration is changed to a circuit that uses basic resistance wiring composed of n ^ 2 times the total number. It is possible to increase the number and distribute them. In the example of FIGS. 1 and 2, the basic resistance wirings 301, 302, 303, 304 and 601, 602, 603, 604 are the same as the basic resistance wirings 301, 601 in FIG. 3 and FIG. This is an example of increasing the number by four.

100 corrected first bit resistance circuit unit 101, 102, 103, 104 basic resistance wiring 105 trimming fuse 200 corrected second bit resistance circuit unit 201, 202 basic resistance wiring 205 trimming fuse 300 corrected third bit resistance circuit unit 301, 302, 303, 304 Basic resistance wiring 305 Trimming fuse 400 Correction fourth bit resistance circuit section 401, 402 Basic resistance wiring 405 Trimming fuse 500 Correction fifth bit resistance circuit section 501, 502, 503, 504 Basic resistance wiring 505 Trimming fuse 600 Fixed resistance Circuit unit 601, 602, 603, 604 Basic resistance wiring 1001 Voltage input terminal 1002 Voltage output terminal 1003 Voltage input terminal

Claims (2)

A semiconductor device including a bleeder resistance circuit capable of changing a voltage division ratio by trimming,
The bleeder resistance circuit is composed of two or more stages of resistance circuit units connected in series,
Each of the resistance circuit portions is formed of a resistance element formed by connecting at least two basic resistance wires having the same material, the same length, the same width, and the same thickness,
The basic resistance wirings constituting the bleeder resistance circuit are all arranged and aligned in one region in the semiconductor device,
2. The semiconductor device according to claim 1, wherein the basic resistance wiring constituting each of the resistance circuit portions is divided into at least two parts and arranged with the basic wiring resistance of the other resistance circuit portions interposed therebetween.   2. The semiconductor device according to claim 1, wherein a part of the basic resistance wiring is constituted by n series connection of the basic resistance wiring and n parallel connection of the basic resistance wiring.

Images