JP6733410B2 - Trimming circuit and trimming method - Google Patents

Description

The present invention relates to a trimming circuit and a trimming method.

A trimming circuit is used to correct variations in circuit characteristics due to manufacturing variations in semiconductor integrated circuits. As a trimming circuit, a circuit including a fuse resistor formed of a polysilicon layer is known (for example, Patent Document 1). The trimming circuit corrects the electrical characteristics of the element to be adjusted by cutting the fuse resistor and changing the terminals of the fuse resistor from the short state to the open state.

In the trimming circuit, if the fuse resistance is blown, the original state cannot be restored. Therefore, before cutting the fuse resistance, virtual cutting is performed to confirm the electrical characteristics of the adjusted element after cutting the fuse resistance. Regarding the virtual cutting technique, a technique using a resistance bypass circuit including a transistor connected in series with a fuse resistor is known (for example, Patent Document 2). Further, a trimming circuit is known in which external terminals dedicated to trimming are provided at both ends of a fuse resistor (for example, Patent Document 3).
[Prior Art Document]
[Patent Document]
[Patent Document 1] JP-A-2014-207413 [Patent Document 2] JP-A-2002-26131 [Patent Document 3] JP-A-2000-340656

However, when the resistance bypass circuit is added, a resistance bypass circuit capable of withstanding a large current for blowing the fuse resistance is required, which increases the circuit area. Also, the circuit area becomes large when external terminals dedicated to trimming are provided at both ends of the fuse resistor. Further, the increase in the number of terminals increases the scale of the package that houses the semiconductor integrated circuit and the external circuit.

In a first aspect of the invention, a trimming circuit is provided. The trimming circuit may adjust the electrical characteristics of the adjusted element depending on whether or not the fuse resistor is blown. The trimming circuit may include a fuse resistor, a trimming pad, and a diode. The fuse resistor may be formed by a polysilicon layer. The polysilicon layer may be arranged on the semiconductor substrate of the first conductivity type with an insulating film interposed therebetween. The trimming pad may be connected to one end of the fuse resistor. The diode may have a second conductivity type semiconductor region formed in the semiconductor substrate. The diode may have one end connected to the other end of the fuse resistor.

The trimming circuit may further include a first resistance element. One end of the first resistance element may be connected to a connection point between the fuse resistance and the diode. The other end of the first resistance element may be connected to the first potential.

The trimming circuit may further include a protection diode. The protection diode may be connected between one end of the first resistance element and the other end of the first resistance element.

The trimming circuit may further include a second resistance element. One end of the second resistance element may be connected to a connection point between one end of the fuse resistor and the pad. The other end of the second resistance element may be connected to the second potential.

The diode may be a vertical diode. The other end of the diode may be connected to the substrate electrode of the semiconductor substrate.

The trimming circuit may further include a MOS transistor. The MOS transistor may be formed on the semiconductor substrate. The gate of the MOS transistor may be connected to the connection point of the fuse resistor and the diode.

The first conductivity type may be n-type. The second conductivity type may be p-type. The other end of the fuse resistor and the anode of the diode may be connected. The trimming circuit may include a first resistance element and a second resistance element. One end of the first resistance element may be connected to a connection point between the fuse resistance and the anode of the diode. The other end of the first resistance element may be connected to the ground wiring. One end of the second resistance element may be connected to a connection point between the fuse resistance and the pad. The other end of the second resistance element may be connected to a high potential wiring such as a power supply wiring.

The first conductivity type may be p-type. The second conductivity type may be n-type. The other end of the fuse resistor and the cathode of the diode may be connected. The trimming circuit may include a first resistance element and a second resistance element. One end of the first resistance element may be connected to a connection point between the fuse resistance and the cathode of the diode. The other end of the first resistance element may be connected to the high potential wiring. One end of the second resistance element may be connected to a connection point between the fuse resistance and the pad. The other end of the second resistance element may be connected to the ground wiring.

The second-conductivity-type semiconductor region and the fuse resistor may be stacked so as to overlap at least a part of the region with the insulating film interposed therebetween. The fuse resistor, the metal wiring layer connected to the fuse resistor, and the second-conductivity-type semiconductor region may be stacked so as to overlap each other in at least a part of the region.

According to a second aspect of the present invention, there is provided a trimming method for adjusting the electrical characteristics of an element to be adjusted using the above trimming circuit. The trimming method includes adjusting a potential of a semiconductor substrate and a voltage applied to a pad so that a forward current flows through a diode, and cutting the fuse resistance by allowing the forward current to flow through the fuse resistance. You can

The trimming method is a step of applying a voltage corresponding to the voltage at the other end of the fuse resistor to the pad before the step of applying a forward current to the diode to generate a state in which the fuse resistor is virtually cut. May be further provided.

Note that the above summary of the invention does not enumerate all the necessary features of the present invention. Further, a sub-combination of these feature groups can also be an invention.

It is a figure which shows schematic structure of the trimming circuit 100 which concerns on one Embodiment of this invention. 3 is a circuit diagram showing an example of a main body unit 20 in the trimming circuit 100. FIG. It is a flowchart which shows an example of a trimming method. 6 is a circuit diagram showing another example of the main body section 20 in the trimming circuit 100. FIG. 3 is a plan view showing a configuration example of a main body section 20. FIG. 3 is a cross-sectional view showing a configuration example of a main body section 20. FIG. It is a circuit diagram showing an example of main part 20 using a p-type semiconductor substrate. FIG. 6 is a plan view showing another configuration example of the main body section 20. It is sectional drawing which shows the other structural example of the main-body part 20.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Further, not all of the combinations of features described in the embodiments are essential to the solving means of the invention.

FIG. 1 is a diagram showing a schematic configuration of a trimming circuit 100 according to an embodiment of the present invention. The trimming circuit 100 adjusts the resistance value between the internal terminals T1 and T2. A resistor is connected as the element to be adjusted 2 between the internal terminals T1 and T2. A plurality of adjusted elements 2 may be connected in series. The trimming circuit 100 adjusts the resistance value between the internal terminals T1 and T2 by short-circuiting both ends of the adjusted element 2. The number of the elements to be adjusted 2 and the resistance value may be appropriately changed. Further, the element to be adjusted 2 is not limited to the resistor and may be another element such as MOSFET. In this case, the trimming circuit 100 adjusts the electrical characteristics of a series MOSFET circuit in which MOSFETs are connected in series, for example.

The trimming circuit 100 includes a main body section 20 and a transistor section 10. The trimming circuit 100 may include a plurality of sets of main body section 20 and transistor section 10. The numbers of the main body section 20 and the transistor section 10 may be appropriately changed. As the numbers of the main body section 20 and the transistor section 10 increase, the electrical characteristics such as the current between the terminals T1 and T2 can be finely adjusted, and the adjustment accuracy can be improved.

The transistor unit 10 may be a MOS transistor. For example, the transistor unit 10 shown in FIG. 1 is an n-channel MOSFET. The adjusted element 2 is provided between the drain 12 and the source 13 of the transistor unit 10. That is, the element to be adjusted 2 whose electric characteristics such as current are to be adjusted and the transistor section 10 are connected in parallel. The gate 11 of the transistor unit 10 may be connected to the output terminal OUT of the body unit 20.

In this example, when the output terminal OUT of the main body unit 20 becomes the _Lo level (low level), the transistor unit 10 is turned off. As a result, both ends of the corresponding adjusted element 2 are not short-circuited. On the other hand, when the output terminal OUT of the main body unit 20 becomes the H _i level (high level), the transistor unit 10 is turned on. When the transistor section 10 is turned on, both ends of the corresponding adjusted element 2 are short-circuited. However, the present invention is not limited to this case. When the output terminal OUT of the main body unit 20 becomes Lo level, the transistor unit 10 is turned on, and when the output terminal OUT of the main body unit 20 becomes _Hi level, the transistor unit 10 is turned off. The part 10 may be configured.

FIG. 2 is a circuit diagram showing an example of the main body 20 in the trimming circuit 100. The trimming circuit 100 of this example includes a fuse resistor 22, a pad 24 for trimming, and a first diode D1. The trimming circuit 100 changes the voltage _So applied to the output terminal OUT to determine the on/off of the transistor unit 10 as described above. That is, the voltage _So is changed depending on whether the fuse resistor 22 is blown or not. Further, when the virtual cutting to produce a state where the fuse resistor 22 is over virtually cut is executed, the trimming circuit 100 changes the voltage S _o.

One end of the fuse resistor 22 is connected to the pad 24. The other end of the fuse resistor 22 is connected to one end of the first diode D1. In this example, the other end of the fuse resistor 22 is connected to the anode of the first diode D1.

The trimming circuit 100 may include a first resistance element R1, a second resistance element R2, and a protection diode D2. One end of the first resistance element R1 is connected to a connection point 28 between the fuse resistor 22 and the anode of the first diode D1. On the other hand, the other end of the first resistance element R1 is connected to the first potential. The connection point 28 is connected to the gate 11 of the transistor unit 10, which is a MOS transistor, via the output terminal OUT.

One end of the second resistance element R2 is connected to a connection point 27 between one end of the fuse resistor 22 and the pad 24. On the other hand, the other end of the second resistance element R2 is connected to the second potential. That is, one end of the fuse resistor 22 is connected to the second potential via the second resistance element R2.

In this example, the second potential may be higher than the first potential. In this example, the first potential corresponds to the potential of the ground wiring GND (ground potential), and the second potential corresponds to the potential of the high potential wiring VDD. The first potential may be a _Lo level that is approximately equal to the ground potential, and the second potential may be a H _i level that is approximately equal to the potential of the high potential wiring VDD. The other end of the first resistance element R1 may be connected to the ground wiring GND, and one end of the fuse resistor 22 may be connected to the high potential wiring VDD via the second resistance element R2.

The protection diode D2 is connected between one end of the first resistance element R1 and the other end of the first resistance element R1. In this example, the anode of the protection diode D2 is connected to the ground wiring GND having the first potential, and the cathode of the protection diode D2 is connected to the output terminal OUT and the connection point 28.

The fuse resistor 22, the pad 24 for trimming, the first diode D1, the first resistance element R1, the second resistance element R2, and the protection diode D2 may be formed on a semiconductor substrate. The transistor unit 10 shown in FIG. 1 may also be formed on the same semiconductor substrate. The fuse resistor 22 is a polysilicon fuse formed of a polysilicon layer. The first diode D1 has a second conductivity type semiconductor region on a first conductivity type semiconductor substrate. In one example, the first conductivity type is n-type and the second conductivity type is p-type.

One end of the first diode D1 may be connected to the substrate electrode 26 of the semiconductor substrate. The substrate electrode 26 is an electrode that fixes the potential of the first conductivity type semiconductor substrate. The substrate electrode 26 may be a back surface electrode arranged on the back surface of the semiconductor substrate or may be an electrode arranged on the front side.

The first resistance element R1 is a pull-down resistance for pulling down the output terminal OUT to the ground potential when the fuse resistance 22 is cut. On the other hand, the second resistance element R2 is a pull-up resistor for pulling up the output terminal OUT to the potential of the high-potential wiring VDD and also flows to the fuse resistor 22 when the trimming circuit 100 is not performing trimming. It is also a current limiting resistor that limits the current. Regarding the resistance values of the first resistance element R1 and the second resistance element R2, the voltage _So applied to the output terminal OUT turns on the transistor unit 10 in a state where the trimming is not performed and the fuse resistor 22 is not cut. You may adjust it to a level.

[When not trimming]
When the trimming circuit 100 is not performing trimming, the potential of the substrate electrode 26 of the semiconductor substrate may be adjusted so that a reverse voltage that causes the first diode D1 to have a high impedance is applied. As an example, a voltage higher than the voltage applied to the high potential wiring VDD is applied to the substrate electrode 26 of the semiconductor substrate. For example, a voltage of 12V is applied to the substrate electrode 26 of the semiconductor substrate. In this way, since the voltage is applied so that the first diode D1 is reverse biased, no current flows from the high potential wiring VDD through the first diode D1. Therefore, it is possible to prevent unnecessary current from flowing through the fuse resistor 22.

During operation of a semiconductor device such as a semiconductor integrated circuit that does not need to be trimmed or has been trimmed, a voltage may be applied to the semiconductor substrate so that the first diode D1 has a reverse bias. Since the voltage is applied to the semiconductor substrate so that the first diode D1 is reverse-biased, the influence of the addition of the first diode D1 on the semiconductor integrated circuit is reduced.

The voltage applied to the high potential wiring VDD is divided by the first resistance element R1 and the second resistance element R2. For example, if the voltage applied to the high potential wiring VDD is 5V, and the electric resistance values of the first resistance element R1, the second resistance element R2, and the fuse resistance 22 are 100 kΩ, 10 kΩ, and 100 Ω, respectively. A voltage of about 4.5V is applied to the output terminal OUT. That is, the output terminal OUT is applied with the voltage S _{o at} the H _i level (a voltage higher than the threshold voltage of the transistor included in the transistor unit 10 ). As a result, the transistor section 10 which is a MOSFET for current adjustment is turned on, and both ends of the corresponding element to be adjusted 2 are kept in a short-circuited state.

FIG. 3 is a flowchart showing an example of the trimming method. Virtual disconnection and normal disconnection will be described with reference to FIG.

[Virtual disconnection]
The trimming circuit 100 can perform virtual cutting in order to confirm the electrical characteristics of the adjusted element 2 after cutting the fuse resistor 22. The trimming circuit 100 generates a state in which the fuse resistor 22 is virtually cut. When the trimming circuit 100 executes virtual cutting (step S100: YES), the voltage S _p applied to the trimming pad 24 and the voltage S _c applied to the substrate electrode 26 of the semiconductor substrate are adjusted. May be done.

In the trimming circuit 100, the external voltage source or the internal voltage source applies the voltage S _p corresponding to the voltage at the other end of the fuse resistor 22 to the pad 24 for trimming (step S101). The voltage corresponding to the voltage at the other end of the fuse resistor 22 is a high potential at which the end of the fuse resistor 22 located on the opposite side of the end to which the pad 24 is connected is connected (via a resistor). It means the voltage of the wiring (for example, VDD voltage) or the voltage of the ground wiring (for example, 0V voltage) described in another embodiment described later. In this example, the other end of the fuse resistor 22 via a first resistor element R1, since they are connected to the ground line, the pad 24 for trimming, voltage S _p of 0V is applied.

The voltage S _{p of} 0 V is applied to the trimming pad 24, so that the voltage S _o at the L _o level is applied to the output terminal OUT, as in the case where the fuse resistor 22 is blown. Since the voltage S _p of the pad 24 for trimming ground wiring and the same potential, no no potential difference across the fuse resistor 22. As a result, the transistor section 10, which is a current adjusting MOSFET, is turned off, and both ends of the corresponding element to be adjusted 2 are not short-circuited. That is, virtual disconnection is realized. At this stage, the characteristic of the adjustment target is measured, and the cutting result of the target fuse resistor 22 is evaluated. If the evaluation result does not satisfy the target and another trimming state can be set, the process branches to the No side in step S102.

The transistor section 10, the fuse resistor 22, and the trimming pad 24 may be prepared for each of the plurality of adjusted elements 2 and provided in parallel. Also in this case, each fuse resistor 22 can be individually cut virtually. In this case, it is desirable to adjust the potential of the substrate electrode 26 of the semiconductor substrate so that the first diode D1 has a high impedance, as in the case of non-trimming.

For example, in a state in which a voltage applied to the high potential wiring VDD or a voltage higher than that is applied to the substrate electrode 26, the substrate electrode 26 is connected to the fuse resistor 22 of the plurality of pads 24, which is desired to be selectively cut off virtually. The voltage S _p of 0 V is applied to the pad 24. This prevents a current from flowing from the high-potential wiring VDD to the ground wiring GND through the first diode D1, so that a large current that would cut the fuse resistor 22 does not flow.

[When cutting normally]
Whether or not to perform the trimming may be determined based on the result obtained by the virtual cutting (step S102). For example, the fuse resistor 22 that is selectively disconnected from the plurality of fuse resistors 22 is determined so that the current value between the terminals T1 and T2 falls within the target range.

When trimming is performed (step S102: YES), the potential of the first conductivity type semiconductor substrate and the voltage applied to the pad 24 are adjusted so that the forward current flows through the first diode D1 (step S103). In this example, the substrate electrode 26 of the semiconductor substrate is set to the ground potential. Then, a voltage higher than the voltage applied to the high potential wiring VDD may be applied to the trimming pad 24 by an external voltage source or an internal voltage source.

For example, a voltage of 10 V or more and 30 V or less is applied to the pad 24 by an external voltage source or an internal voltage source. As a result, a current flows through the fuse resistor 22 and the fuse resistor 22 is blown by Joule heat (step S104). Since the first diode D1 is connected in the forward direction, a forward current flows to the substrate electrode 26 through the fuse resistor 22 and the first diode D1. Therefore, a sufficient current for cutting the fuse resistor 22 can be passed without being affected by the first resistance element R1.

After trimming, the trimming circuit 100 is in a state in which the fuse resistor 22 is cut off. In the state where the fuse resistor 22 is cut off, the first resistance element R1 pulls down the output terminal OUT to the ground potential. Therefore, the output terminal OUT, _{L o} level voltage _{S o} is applied. As a result, the transistor section 10 which is a current adjusting MOSFET is turned off, and both ends of the corresponding element to be adjusted 2 are changed to a state in which they are not short-circuited.

The protection diode D2 can be omitted. FIG. 4 is a circuit diagram showing another example of the main body 20 in the trimming circuit 100. The body portion 20 shown in FIG. 4 has the same structure as the body portion 20 shown in FIG. 2 except that the protection diode D2 is omitted.

FIG. 5 is a plan view showing a configuration example of the main body section 20. FIG. 6 is a cross-sectional view showing a configuration example of the main body section 20. FIG. 6 shows a cross section of the main body portion 20 along the line AA′ in FIG. 5 and 6, the transistor section 10, the first resistance element R1, the second resistance element R2, and the second diode D2 are omitted for convenience of description. The transistor portion 10, the first resistance element R1, the second resistance element R2, and the second diode D2 may be formed on the semiconductor substrate 30 of the embodiment.

As shown in FIG. 5, in the trimming circuit 100, the first diode D1 and the fuse resistor 22 are formed on the semiconductor substrate 30. The semiconductor substrate 30 is a semiconductor substrate 30 of the first conductivity type. In this example, the semiconductor substrate 30 is an n-type semiconductor substrate 30. As shown in FIG. 6, a second conductivity type first semiconductor region 42 is formed on the front surface side of the semiconductor substrate 30. In one example, the first semiconductor region 42 is a p-type diffusion layer formed on the n-type semiconductor substrate 30. A PN junction is formed by the first semiconductor region 42 and the semiconductor substrate 30. This PN junction functions as the first diode D1.

The first diode D1 may be a vertical diode. In the present specification, the vertical diode refers to a diode in which a current flows in the thickness direction of the semiconductor substrate 30. In this example, the anode is arranged on the front surface side of the semiconductor substrate 30, and the cathode is arranged on the rear surface side of the semiconductor substrate 30. The substrate electrode 26 is connected to the cathode. However, even in the case of a vertical diode, the substrate electrode 26 may be provided on the front surface side of the semiconductor substrate 30 as long as the potential of the semiconductor substrate 30 is fixed.

A second semiconductor region 44 of the second conductivity type may be formed in a part of the first semiconductor region 42. The second semiconductor region 44 is a contact region to which the contact portion 34 is connected. The second semiconductor region 44 has a higher impurity concentration than the first semiconductor region 42. In one example, the second semiconductor region 44 is a p+ diffusion layer. In this example, the edges of the first semiconductor region 42 are formed in a rectangular shape, and the second semiconductor regions 44 are formed separately along the two sides of the rectangle that face each other. Therefore, in this example, in the first semiconductor region 42, a plurality of second semiconductor regions 44 facing each other are formed.

The insulating film 46 is partially provided on the semiconductor substrate 30. The insulating film 46 may be a LOCOS oxide film. The polysilicon layer 32 is provided on the semiconductor substrate 30 via the insulating film 46. The fuse resistor 22 is formed of a polysilicon layer 32. The fuse resistor 22 has a narrow width W in the central portion so that it can be easily cut.

One end of the fuse resistor 22 is connected to the metal wiring 36 via the contact portion 34. In the region of the first diode D1 in which the second semiconductor region 44 is formed, the insulating film 46 is partially removed, and the second semiconductor region 44 is partially exposed. The second semiconductor region 44 is connected to the metal wiring 36 via the contact portion 34. The metal wiring 36 and the contact portion 34 electrically connect the anode of the first diode D1 and the fuse resistor 22 and function as the connection point 28 shown in FIGS. 2 and 4.

The other end of the fuse resistor 22 is connected to the metal wiring 37 via the contact portion 34. The metal wiring 37 may have a connecting portion 38 that connects to the pad 24 for trimming. The metal wiring 37 functions as a connection point 27 that connects the fuse resistor 22 to the pad 24 and the resistor R2. An interlayer insulating film 47 may be formed between the polysilicon layer 32, the second semiconductor region 44, the insulating film 46 and the metal wirings 36 and 37. That is, the metal wiring 36 and the metal wiring 37 may be formed on the interlayer insulating film 47. In this case, the contact portion 34 is formed so as to penetrate the opening in the interlayer insulating film 47.

According to the structure of this example, the first semiconductor region 42 of the first diode D1 and the fuse resistor 22 are stacked so as to overlap each other with the insulating film 46 interposed therebetween in at least a part of the region. Further, the metal wiring 36 connected to the fuse resistor 22, the first semiconductor region 42, and the fuse resistor 22 are laminated so as to overlap at least in a part of the region.

In this example, the central portion and the other end portion of the fuse resistor 22 are overlapped with the first semiconductor region 42 except for one end portion where another metal wiring 37 is provided for connecting to the trimming pad 24. It is formed. The metal wiring 36 overlaps the first semiconductor region 42 in most regions. Therefore, as compared with the case where the fuse resistor 22 and the first semiconductor region 42 are formed in different regions on the semiconductor substrate 30 so as not to be laminated, the circuit area of the trimming circuit 100 is reduced and the trimming circuit 100 is downsized. be able to.

According to the trimming circuit 100 of this example, virtual cutting for confirming the electrical characteristics of the adjusted element after cutting the fuse resistor 22 can be realized before cutting the fuse resistor 22. Also in this example, the trimming pad 24 connected to one end of the fuse resistor 22 is required, but as the terminal on the other end side of the fuse resistor 22, the existing substrate electrode 26 such as the back surface electrode can be used. Therefore, it is not necessary to provide an external terminal exclusively for trimming. Further, there is no need to provide a resistance bypass circuit capable of withstanding a large current that fuses the fuse resistor 22. Therefore, it is possible to realize the trimming circuit 100 that achieves both the downsizing and the virtual disconnection function as compared with the related art.

According to the trimming circuit 100 of the present example, the first diode D1 has the second conductivity type first semiconductor region 42 formed in the first conductivity type semiconductor substrate 30. In this example, the first diode D1 may not be formed of the polysilicon layer 32 but may be formed of an impurity diffusion layer formed in the semiconductor substrate 30. Therefore, since the fuse resistor 22 and the first diode D1 are not formed in the same layer, they can be formed by stacking. As a result, the area of the trimming circuit 100 can be reduced by effectively utilizing the region on the semiconductor substrate 30.

In the above example, the case where the main body portion 20 of the trimming circuit 100 is configured using the n-type semiconductor substrate 30 has been described. However, even if the p-type semiconductor substrate 30 is used as the semiconductor substrate 30, the trimming circuit 100 can be realized. FIG. 7 is a circuit diagram showing an example of the main body 20 using the p-type semiconductor substrate 30.

In this example, the first conductivity type is p-type and the second conductivity type is n-type. Therefore, in the main body 20 of this example, in the configuration shown in FIGS. 5 and 6, the n-type semiconductor substrate 30 is the p-type semiconductor substrate 30, the p-type first semiconductor region 42 is the n-type semiconductor region, and p+ The second type semiconductor region 44 is an n+ type second semiconductor region 44. Due to the orientation of the PN junction, the substrate electrode 26 side serves as an anode. Other configurations are similar to those shown in FIGS. 5 and 6.

The trimming circuit 100 of this example includes a fuse resistor 22, a trimming pad 24, a first diode D1, a first resistance element R1, a second resistance element R2, and a protection diode D2. Although the protection diode D2 is omitted in FIG. 7, the protection diode D2 may be provided in parallel with the resistors R1 and/or R2 in this example as well. One end of the fuse resistor 22 is connected to the pad 24. The other end of the fuse resistor 22 is connected to one end of the first diode D1. In this example, the other end of the fuse resistor 22 is connected to the cathode of the first diode D1.

One end of the first resistance element R1 is connected to a connection point 28 between the fuse resistor 22 and the cathode of the first diode D1. On the other hand, the other end of the first resistance element R1 is connected to the first potential. In this example, the first potential may be the potential of the high potential wiring VDD. The connection point 28 is connected to the gate 11 of the transistor unit 10, which is a MOS transistor, via the output terminal OUT. One end of the second resistance element R2 is connected to a connection point 27 between one end of the fuse resistor 22 and the pad 24. On the other hand, the other end of the second resistance element R2 is connected to the second potential. In this example, the second potential may be the ground potential.

[When not trimming]
The potential of the semiconductor substrate 30 may be adjusted so that a reverse voltage is applied so that the first diode D1 has a high impedance when the trimming circuit 100 is not performing the trimming. As an example, a ground potential or a negative voltage may be applied to the substrate electrode 26 of the semiconductor substrate 30. Since the voltage is applied so that the first diode D1 is reverse-biased in this manner, a current is prevented from flowing through the fuse resistor 22 through the first diode D1.

Assuming that the voltage applied to the high-potential wiring VDD is 5V and the electric resistance values of the first resistance element R1, the second resistance element R2, and the fuse resistance 22 are 100 kΩ, 10 kΩ, and 100 Ω, respectively, the output terminal A voltage of about 0.5 V is applied to OUT. That is, the output terminal OUT, _{L o} level voltage _{S o} is applied. As a result, the transistor section 10 which is a MOSFET for current adjustment is turned off, and both ends of the corresponding element to be adjusted 2 are maintained in a non-short-circuited state.

[Virtual disconnection]
When the trimming circuit 100 performs virtual cutting, the voltage S _p applied to the pad 24 for trimming and the voltage S _c applied to the substrate electrode 26 of the semiconductor substrate 30 may be adjusted. In the trimming circuit 100, the external voltage source or the internal voltage source applies the voltage S _p corresponding to the voltage at the other end of the fuse resistor 22 to the pad 24 for trimming.

In this example, the other end of the fuse resistor 22 is connected to the high-potential wiring VDD (for example, 5V voltage) via the first resistance element R1, so the trimming pad 24 is connected to the high-potential wiring VDD. The voltage _Sp is applied. Therefore, as in the case where the fuse resistor 22 is cut, the H _i level voltage S _o is applied to the output terminal OUT. As a result, the transistor section 10 which is a current adjusting MOSFET is turned on, and both ends of the corresponding element to be adjusted 2 are short-circuited. That is, virtual disconnection is realized. At this stage, the characteristic of the adjustment target is measured, and the cutting result of the target fuse resistor 22 is evaluated. If the evaluation result does not meet the target and another trimming state can be set, the process branches to the No side in step S102 of FIG.

The transistor section 10, the fuse resistor 22, and the trimming pad 24 may be prepared for each of the plurality of adjusted elements 2 and provided in parallel. In this case, it is desirable to adjust the potential of the substrate electrode 26 of the semiconductor substrate 30 so that the first diode D1 has a high impedance, as in the case of non-trimming. For example, in terms of 0V or a negative voltage is applied to the substrate electrode 26, among the plurality of pads 24, the voltage S _p of the high potential wiring VDD is applied to the pad 24 to be performed selectively imaginary cutting.

[When cutting normally]
During trimming, the potential of the first conductivity type semiconductor substrate 30 and the voltage applied to the pad 24 are adjusted so that a forward current flows through the first diode D1. For example, the substrate electrode 26 of the semiconductor substrate 30 is set to the ground potential. Then, for example, a negative voltage of -30 V or more and -10 V or less is applied to the trimming pad 24 by an external voltage source or an internal voltage source. As a result, a current flows through the fuse resistor 22 and the fuse resistor 22 is cut by Joule heat.

Since the first diode D1 is connected in the forward direction, the forward current flows to the pad 24 through the substrate electrode 26, the first diode D1 and the fuse resistor 22. Therefore, a sufficient current for cutting the fuse resistor 22 can be passed without being affected by the first resistance element R1.

After trimming, the fuse resistor 22 is cut off. In the state where the fuse resistor 22 is cut off, the first resistance element R1 pulls up the output terminal OUT to the high potential wiring VDD. Therefore, the H _i level voltage S _o is applied to the output terminal OUT. As a result, the transistor section 10 which is a MOSFET for current adjustment is turned on, and both ends of the corresponding element to be adjusted 2 are changed to a short circuit state.

The structure of the trimming circuit 100 of the present invention is not limited to the structures shown in FIGS. FIG. 8 is a plan view showing another configuration example of the main body section 20. FIG. 9 is a cross-sectional view showing another configuration example of the main body section 20. FIG. 9 shows a cross section of the main body portion 20 along the line AA′ in FIG. Note that the transistor section 10, the first resistance element R1, the second resistance element R2, and the second diode D2 are omitted in FIG. 8 for the sake of simplicity of explanation, and in FIG. 9, only electrical connection relationships are shown by circuit symbols. ing. Note that the transistor portion 10, the first resistance element R1, the second resistance element R2, and the second diode D2 may be formed on the semiconductor substrate 30 of the embodiment.

Also in this example, the first diode D1 may be a vertical diode. However, in this example, the first semiconductor region 42 of the first diode D1 and the fuse resistor 22 are not arranged so as to overlap with each other. One second semiconductor region 44 is formed in the first semiconductor region 42. Therefore, the area of the first diode D1 itself is smaller than that in the case where the plurality of second semiconductor regions 44 are formed in the first semiconductor region 42 in a spaced manner.

One end of the polysilicon layer 32 forming the fuse resistor 22 is connected to the metal wiring 36 via the contact portion 34. In the second semiconductor region 44 of the first diode D1, the insulating film 46 is partially removed, and the second semiconductor region 44 is partially exposed. The second semiconductor region 44 is connected to the metal wiring 36 via the contact portion 34.

The metal wiring 36 and the contact portion 34 connected to the metal wiring 36 function as a connection point 28 that electrically connects the anode of the first diode D1 and the fuse resistor 22. One end of the protection diode D2 and one end of the first resistance element R1 may be connected to the metal wiring 36. Therefore, the anode of the first diode is connected to the ground wiring GND via the first resistance element R1.

The other end of the polysilicon layer 32 forming the fuse resistor 22 is connected to the metal wiring 37 via the contact portion 34. The output terminal OUT and one end of the second resistance element R2 may be connected to the metal wiring 37. Therefore, the other end of the fuse resistor 22 (polysilicon layer 32) is connected to the high potential wiring VDD via the second resistance element R2.

Also by the trimming circuit 100 of this example, virtual cutting for confirming the electrical characteristics of the element to be adjusted after cutting the fuse resistor 22 can be realized before cutting the fuse resistor 22. An existing substrate electrode 26 such as a back surface electrode can be used as a control terminal of the fuse resistor 22, and the number of external terminals dedicated for trimming can be reduced. Further, it is not necessary to provide a resistance bypass circuit capable of withstanding a large current that fuses the fuse resistor 22. Therefore, it is possible to realize the trimming circuit 100 that has a small circuit area and can be virtually cut.

Although the present invention has been described using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is apparent to those skilled in the art that various modifications and improvements can be added to the above-described embodiment. It is clear from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

The execution order of each process such as the operation, procedure, step, and step in the devices, systems, programs, and methods shown in the claims, the specification, and the drawings is "preceding" or "prior to". It should be noted that the output of the previous process can be realized in any order unless the output of the previous process is used in the subsequent process. The operation flow in the claims, the specification, and the drawings is described by using “first,” “next,” and the like for the sake of convenience, but it is essential that the operations are performed in this order. Not a thing.

10... Transistor part, 11... Gate, 12... Drain, 13... Source, 20... Main body part, 22... Fuse resistor, 24... Pad, 26... Substrate Electrode, 27... Connection point, 28... Connection point, 30... Semiconductor substrate, 32... Polysilicon layer, 34... Contact part, 36... Metal wiring, 37... Metal Wiring, 38... Connection part, 42... First semiconductor region, 44... Second semiconductor region, 46... Insulating film, 47... Interlayer insulating film, 100... Trimming circuit

Claims (17)

A trimming circuit that adjusts the electrical characteristics of the element to be adjusted according to whether or not the fuse resistor is cut,
A fuse resistor formed of a polysilicon layer arranged on the first conductivity type semiconductor substrate via an insulating film;
A trimming pad connected to one end of the fuse resistor,
A diode having a second conductivity type semiconductor region formed on the semiconductor substrate, one end of which is connected to the other end of the fuse resistor;
A first resistance element having one end connected to a connection point between the fuse resistor and the diode and the other end connected to a first potential;
A protection diode connected between one end of the first resistance element and the other end of the first resistance element;
Trimming circuit with. A trimming circuit that adjusts the electrical characteristics of the element to be adjusted according to whether or not the fuse resistor is cut,
A fuse resistor formed of a polysilicon layer arranged on the first conductivity type semiconductor substrate via an insulating film;
A trimming pad connected to one end of the fuse resistor,
A diode having a second conductivity type semiconductor region formed on the semiconductor substrate, one end of which is connected to the other end of the fuse resistor;
A first resistance element having one end connected to a connection point between the fuse resistor and the diode and the other end connected to a first potential;
A second resistance element, one end of which is connected to a connection point between one end of the fuse resistor and the pad, and the other end of which is connected to a second potential;
Trimming circuit with. The trimming circuit according to claim 1 , further comprising a second resistance element having one end connected to a connection point between one end of the fuse resistor and the pad and the other end connected to a second potential. The diode is a vertical diode,
The trimming circuit according to claim 1, wherein the other end of the diode is connected to a substrate electrode of the semiconductor substrate. A trimming circuit that adjusts the electrical characteristics of the element to be adjusted according to whether or not the fuse resistor is cut,
A fuse resistor formed of a polysilicon layer arranged on the first conductivity type semiconductor substrate via an insulating film;
A trimming pad connected to one end of the fuse resistor,
A diode having a second conductivity type semiconductor region formed on the semiconductor substrate, one end of which is connected to the other end of the fuse resistor;
A MOS transistor formed on the semiconductor substrate and having a gate connected to a connection point between the fuse resistor and the diode;
Trimming circuit with. A trimming circuit that adjusts the electrical characteristics of the element to be adjusted according to whether or not the fuse resistor is cut,
A fuse resistor formed of a polysilicon layer arranged on the first conductivity type semiconductor substrate via an insulating film;
A trimming pad connected to one end of the fuse resistor,
A diode having a second conductivity type semiconductor region formed on the semiconductor substrate, one end of which is connected to the other end of the fuse resistor;
A first resistance element having one end connected to a connection point between the fuse resistor and the diode and the other end connected to a first potential;
A MOS transistor formed on the semiconductor substrate and having a gate connected to a connection point between the fuse resistor and the diode;
Trimming circuit with. A MOS transistor formed on the semiconductor substrate and having a gate connected to a connection point between the fuse resistor and the diode;
Trimming circuit according to claim 1, any one of 4, further comprising a. A trimming circuit that adjusts the electrical characteristics of the element to be adjusted according to whether or not the fuse resistor is cut,
A fuse resistor formed of a polysilicon layer arranged on the first conductivity type semiconductor substrate via an insulating film;
A trimming pad connected to one end of the fuse resistor,
A diode having a second conductivity type semiconductor region formed on the semiconductor substrate, one end of which is connected to the other end of the fuse resistor;
Bei to give a,
The first conductivity type is n-type, the second conductivity type is p-type,
The other end of the fuse resistor and the anode of the diode are connected,
A first resistance element having one end connected to a connection point between the fuse resistor and the anode of the diode, and the other end connected to a ground wiring;
A second resistance element, one end of which is connected to a connection point between the fuse resistor and the pad, and the other end of which is connected to a high potential wiring;
Trimming circuit with. A trimming circuit that adjusts the electrical characteristics of the element to be adjusted according to whether or not the fuse resistor is cut,
A fuse resistor formed of a polysilicon layer arranged on the first conductivity type semiconductor substrate via an insulating film;
A trimming pad connected to one end of the fuse resistor,
A diode having a second conductivity type semiconductor region formed on the semiconductor substrate, one end of which is connected to the other end of the fuse resistor;
A first resistance element having one end connected to a connection point between the fuse resistor and the diode and the other end connected to a first potential;
Equipped with
The first conductivity type is n-type, the second conductivity type is p-type,
The other end of the fuse resistor and the anode of the diode are connected,
A first resistance element having one end connected to a connection point between the fuse resistor and the anode of the diode, and the other end connected to a ground wiring;
A second resistance element, one end of which is connected to a connection point between the fuse resistor and the pad, and the other end of which is connected to a high potential wiring;
Trimming circuit with. The first conductivity type is n-type, the second conductivity type is p-type,
The other end of the fuse resistor and the anode of the diode are connected,
A first resistance element having one end connected to a connection point between the fuse resistor and the anode of the diode, and the other end connected to a ground wiring;
A second resistance element, one end of which is connected to a connection point between the fuse resistor and the pad, and the other end of which is connected to a high potential wiring;
Trimming circuit according to any one of claims 1 7 comprising a. A trimming circuit that adjusts the electrical characteristics of the element to be adjusted according to whether or not the fuse resistor is cut,
A fuse resistor formed of a polysilicon layer arranged on the first conductivity type semiconductor substrate via an insulating film;
A trimming pad connected to one end of the fuse resistor,
A diode having a second conductivity type semiconductor region formed on the semiconductor substrate, one end of which is connected to the other end of the fuse resistor;
Equipped with
The first conductivity type is p-type, the second conductivity type is n-type,
The other end of the fuse resistor and the cathode of the diode are connected,
A first resistance element having one end connected to a connection point between the fuse resistor and the cathode of the diode, and the other end connected to a high potential wiring;
A second resistance element, one end of which is connected to a connection point between the fuse resistor and the pad, and the other end of which is connected to a ground wiring;
Trimming circuit with. A trimming circuit that adjusts the electrical characteristics of the element to be adjusted according to whether or not the fuse resistor is cut,
A fuse resistor formed of a polysilicon layer arranged on the first conductivity type semiconductor substrate via an insulating film;
A trimming pad connected to one end of the fuse resistor,
A diode having a second conductivity type semiconductor region formed on the semiconductor substrate, one end of which is connected to the other end of the fuse resistor;
A first resistance element having one end connected to a connection point between the fuse resistor and the diode and the other end connected to a first potential;
Equipped with
The first conductivity type is p-type, the second conductivity type is n-type,
The other end of the fuse resistor and the cathode of the diode are connected,
A first resistance element having one end connected to a connection point between the fuse resistor and the cathode of the diode, and the other end connected to a high potential wiring;
A second resistance element, one end of which is connected to a connection point between the fuse resistor and the pad, and the other end of which is connected to a ground wiring;
Trimming circuit comprising a. The first conductivity type is p-type, the second conductivity type is n-type,
The other end of the fuse resistor and the cathode of the diode are connected,
A first resistance element having one end connected to a connection point between the fuse resistor and the cathode of the diode, and the other end connected to a high potential wiring;
A second resistance element, one end of which is connected to a connection point between the fuse resistor and the pad, and the other end of which is connected to a ground wiring;
Trimming circuit according to claim 1, any one of 10 with a. The second-conductivity-type semiconductor region and the fuse resistor are laminated so as to overlap with each other in at least a part of the region via the insulating film,
And the fuse resistor, the metal wiring layer connected to the fuse resistor, any one of the second conductivity type semiconductor region and from claim 11 are stacked so as to overlap at least part of the region 13 The trimming circuit described in. A trimming circuit that adjusts the electrical characteristics of the element to be adjusted according to whether or not the fuse resistor is cut,
A fuse resistor formed of a polysilicon layer arranged on the first conductivity type semiconductor substrate via an insulating film;
A trimming pad connected to one end of the fuse resistor,
A diode having a second conductivity type semiconductor region formed on the semiconductor substrate, one end of which is connected to the other end of the fuse resistor;
Bei to give a,
The second-conductivity-type semiconductor region and the fuse resistor are laminated so as to overlap with each other in at least a part of the region via the insulating film,
A trimming circuit in which the fuse resistor, a metal wiring layer connected to the fuse resistor, and the second-conductivity-type semiconductor region are stacked so as to overlap each other in at least a part of the region . Using trimming circuit according to any one of claims 1 to 15, a trimming method for adjusting the electrical characteristics of the adjusting element,
Adjusting the potential of the semiconductor substrate and the voltage applied to the pad so that a forward current flows through the diode;
Blowing the fuse resistor by causing the forward current to flow through the fuse resistor;
Trimming method with. Generating a state in which the fuse resistor is virtually cut off by applying a voltage corresponding to the voltage at the other end of the fuse resistor to the pad before the forward current is applied to the diode. The trimming method according to claim 16 , further comprising:

Images