JP2002313928A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device in which initial resistance can be kept even if stress is applied by packaging and a conventionally required fuse is eliminated, a highly accurate breeder resistor circuit in which an accurate voltage division ratio can be kept, and a highly accurate semiconductor device using such a breeder resistor circuit, e.g. a voltage detector or a voltage regulator. SOLUTION: In a semiconductor device comprising a resistor, the resistor is formed by integrating a P type resistor formed of a P type semiconductor and an N type resistor formed of a N type semiconductor through an insulation film wherein the P type resistor is arranged on the low potential side and the N type resistor is arranged on the high potential side. The semiconductor device can be conducted by irradiating the insulation film with a laser beam thereby destroying insulation properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device, and more particularly to a semiconductor device having a resistor, a bleeder resistance circuit using a resistor, and a semiconductor device having the bleeder resistance circuit.

[0002]

2. Description of the Related Art Conventionally, a large number of resistors formed of a semiconductor thin film such as polysilicon and a bleeder resistor circuit using them have been used. What was formed by the thin film was known. In addition, there has been known a method of obtaining a desired voltage division ratio by cutting a polysilicon fuse by laser trimming and changing the connection of a bleeder resistance circuit. Then, ICs such as a voltage detector and a voltage regulator have been manufactured using these.

[0003]

However, the conventional thin-film resistor changes its resistance value when a stress is applied to the thin-film resistor such as a resin package.
The bleeder resistance circuit has a problem that the voltage division ratio often fluctuates after the resin package. Further, in the conventional laser trimming method, it is necessary to provide a fuse for trimming with a laser beam in addition to the bleeder resistance circuit.

An object of the present invention is to solve the above problems and obtain a high-precision bleeder resistance circuit capable of maintaining an initial resistance value even after packaging and maintaining an accurate voltage division ratio in a bleeder resistance circuit. It is an object of the present invention to provide a small and highly accurate semiconductor device, for example, a semiconductor device such as a voltage detector and a voltage regulator without installing a fuse which has been conventionally required.

[0005]

The first means adopted by the semiconductor device of the present invention to achieve the above object is that a resistor and a resistor of a bleeder resistor circuit using them are P-type semiconductors. The P-type resistor and the N-type resistor made of an N-type semiconductor are constituted. Further, in the bleeder resistance circuit, the resistance value as one unit is defined by a resistance value formed by combining a P-type resistor and an N-type resistor, so that a P-type resistor described below is provided. It is characterized in that a change in resistance value due to a piezo effect with an N-type resistor is offset each other.

The change in the resistance value due to the piezo effect and the effect on the bleeder resistance circuit will be described below.

When a stress is applied to the resistor, the resistance of the resistor changes due to the so-called piezo effect. However, the direction of the change in the resistance is different between the P-type resistor and the N-type resistor. Reverse. This has been confirmed by experiments performed by the present inventors. For example, the resistance value of the P-type resistor decreases, and the resistance value of the N-type resistor increases (the direction of the change depends on the direction of the stress).

[0008] When an IC is formed into a resin package, stress is generated, so that the resistance value of the resistor changes due to the piezo effect as described above. Although the bleeder resistance circuit is for obtaining an accurate voltage division ratio, the resistance value of each resistor changes, so that the voltage division ratio also fluctuates.

The resistor according to the present invention comprises a P-type resistor formed of a P-type semiconductor and an N-type resistor formed of an N-type semiconductor. The value can be prevented from changing. Also, in the bleeder resistance circuit, the resistance value as one unit is defined by the resistance value formed by combining the P-type resistor and the N-type resistor, so that even if stress is applied, The change in the resistance value of each resistor can be canceled out, and an accurate voltage division ratio can be maintained.

A second means adopted by the semiconductor device of the present invention to achieve the above object is that a P-type resistor is disposed on a low potential side, and the N-type resistor is disposed on a high potential side. And a laser beam is applied only to a necessary portion to the insulating film portion to break the insulating property to enable conduction. As a result, it is characterized in that the fuse which has been required conventionally is not required.

[0011]

The resistor of the semiconductor device according to the present invention is composed of a P-type resistor formed of a P-type semiconductor and an N-type resistor formed of an N-type semiconductor. Even when a stress is applied, for example, the change in the resistance value of each resistor can be canceled and the initial resistance value can be maintained.
In the bleeder resistance circuit, the resistance value as one unit is defined by a resistance value formed by combining a P-type resistor and an N-type resistor, so that an accurate voltage division ratio can be maintained. it can. In addition, the P-type resistor is disposed on the low potential side and the N-type resistor is disposed adjacent to the high potential side with an insulating film interposed therebetween. As a result, the fuse that has been required conventionally can be dispensed with.

By using such a bleeder resistance circuit, a small and highly accurate semiconductor device, for example, a semiconductor device such as a voltage detector or a voltage regulator can be obtained.

[0013]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view showing one embodiment of a polysilicon thin film resistor of a semiconductor device according to the present invention.

A first insulating film 10 is formed on a semiconductor substrate 101.
2 is formed, and a P-type polysilicon resistor 70 having a P-type high-resistance region 702 sandwiched between P-type low-resistance regions 701 containing a dense P-type impurity is formed on the first insulating film 102.
3 and an N-type low-resistance region 70 containing a dense N-type impurity
4 is an N-type polysilicon resistor 706 having an N-type high-resistance region 705 and one of the P-type low-resistance regions 701.
And one of the N-type low-resistance regions 704 has a thin insulating film 81.
The resistor 707 is integrally formed so as to be in contact with each other via the resistor 5. In the P-type low-resistance region 701 on the side not in contact with the N-type polysilicon resistor 706, a wiring 810 made of aluminum is provided, and on the N-type on the side not in contact with the P-type polysilicon resistor 703. Wiring 811 made of aluminum is connected to low-resistance region 704. Here, for example, the wiring 810 goes to the VSS side, and the wiring 811 goes to VD
The wiring 810 is connected to the D side so that the wiring 810 is connected to a lower potential than the wiring 811. Further, the resistor 7
07, a protective film 813 made of a silicon nitride film or the like.
Is a P-type low-resistance region 7 for irradiating a laser beam to damage the insulating film 815 and remove the insulating property.
01 and one of the N-type low-resistance regions 704 except for the area 814 where they are in contact.

Here, the resistance value of the resistor 707 obtained by combining the P-type polysilicon resistor 703 and the N-type polysilicon resistor 706 is equal to that of the P-type polysilicon resistor 703 even when a stress is applied due to resin packaging or the like. Polysilicon resistor 703
And the change in the resistance value of the N-type polysilicon resistor 706 can be offset each other, so that the initial resistance value can be maintained.

FIG. 1 shows only an example in which one P-type polysilicon resistor 703 and one N-type polysilicon resistor 706 are combined, but the bleeder resistor circuit is composed of a plurality of P-type polysilicon resistors. 703 and an N-type polysilicon resistor 706.

A resistor 707 obtained by combining the P-type polysilicon resistor 703 and the N-type polysilicon resistor 706 shown in FIG. 1 is defined as one unit of a bleeder circuit, and a plurality of resistors 707 are provided. When the entire bleeder circuit is formed by individually forming the bleeder circuit, an accurate voltage division ratio can be maintained even when a stress is applied due to resin packaging or the like. By using such a bleeder resistance circuit, a highly accurate semiconductor device such as a semiconductor device such as a voltage detector or a voltage regulator can be obtained.

FIG. 1 shows an example in which a polysilicon thin film resistor is used. However, the present invention is not limited to this. For example, a single crystal thin film resistor or a diffusion resistor formed in a silicon substrate may be used. For example, it is applicable if the P-type and N-type resistors can be integrally formed.

Further, according to the embodiment shown in FIG. 1, in order to obtain a desired voltage division ratio of the bleeder resistance circuit, the resistor 7
Since it is sufficient to perform laser trimming on 07, a fuse for cutting by a laser beam, which has been conventionally required, is not required. In the embodiment of FIG. 1, a protective film 813 made of a silicon nitride film or the like is provided on the resistor 707 to irradiate a laser beam to damage the insulating film 815 and remove the insulating property.
One of the P-type low-resistance regions 701 and the N-type low-resistance region 70
4 is formed except for an area 814 in contact with one of the P-type low-resistance regions 701 if the insulating property can be broken by a laser beam even when the protective film 813 exists. The protective film 813 may be formed also on an area 814 where one of the N-type and one of the N-type low-resistance regions 704 is in contact.

FIG. 2 is a block diagram of an embodiment of a voltage detector using a bleeder resistance circuit according to the present invention.

Although an example of a simple circuit is shown for simplicity, functions may be added to an actual product as needed.

The basic circuit components of the voltage detector are a current source 903, a reference voltage circuit 901, a bleeder resistance circuit 902, and an error amplifier 904. In addition, an inverter 906, N-type transistors 905 and 908, a P-type transistor 907, and the like. Has been added. A part of the operation will be briefly described below.

When VDD is equal to or higher than a predetermined release voltage, the N-type transistors 905 and 908 are turned off, the P-type transistor 907 is turned on, and VDD is output to the output OUT. At this time, the input voltage of the error amplifier 904 is (RB +
RC) / (RA + RB + RC) * VDD.

When VDD drops and becomes lower than the detection voltage, VSS is output to the output OUT. At this time, the N-type transistor 905 is ON, and the input voltage of the error amplifier 904 is R
B / (RA + RB) * VDD.

As described above, the basic operation is as follows: the reference voltage generated by the reference voltage circuit 901 and the bleeder resistance circuit 90
This is performed by comparing the voltage divided by 2 with the error amplifier 904. Therefore, the accuracy of the voltage divided by the bleeder resistance circuit 902 is extremely important. If the voltage division accuracy of the bleeder resistance circuit 902 is poor, the error amplifier 904
Input voltage varies, and a predetermined release or detection voltage cannot be obtained. By using the bleeder resistance circuit according to the present invention, high-precision voltage division is possible even after the IC is resin-packaged, so that the product yield as an IC can be improved or a more accurate voltage detector can be manufactured. Become.

FIG. 3 is a block diagram showing an embodiment of a voltage regulator using a bleeder resistance circuit according to the present invention.

Although an example of a simple circuit is shown for simplicity, functions may be added to an actual product as needed.

The basic circuit components of the voltage regulator include a current source 903, a reference voltage circuit 901, a bleeder resistance circuit 902, an error amplifier 904, and a P-type transistor 910 functioning as a current control transistor. A part of the operation will be briefly described below.

The error amplifier 904 compares the voltage divided by the bleeder resistance circuit 902 with the reference voltage generated by the reference voltage circuit 901, and outputs a constant output voltage VOUT which is not affected by the input voltage VIN or temperature change. The gate voltage required to obtain the voltage is supplied to the P-type transistor 910. Similar to the case of the voltage detector described with reference to FIG. 2, the basic operation of the voltage regulator is similar to that of the error detector 90 in which the reference voltage generated by the reference voltage circuit 901 and the voltage divided by the bleeder resistance circuit 902 are used.
This is done by comparison at 4. Therefore, the accuracy of the voltage divided by the bleeder resistance circuit 902 is extremely important. If the voltage division accuracy of the bleeder resistance circuit 902 is poor, the input voltage to the error amplifier 904 varies, and a predetermined output voltage VOUT cannot be obtained. By using the bleeder resistance circuit according to the present invention, high-precision voltage division is possible even after the IC is resin-packaged, so that the product yield as an IC can be improved and a more accurate voltage regulator can be manufactured. Become.

[0031]

As described above, the thin film resistor of the semiconductor device according to the present invention includes a P-type thin film resistor formed of a P-type semiconductor thin film and an N-type thin film resistor formed of an N-type semiconductor thin film. Since it is composed of a body, even if a stress is applied due to resin packaging or the like, it is possible to cancel the change in the resistance value of each resistor and maintain the initial resistance value. In the bleeder resistance circuit, the resistance value of one unit is P
Since the resistance is determined by the resistance value formed by combining the N-type thin film resistor and the N-type thin film resistor, an accurate voltage division ratio can be maintained. Also, the P-type resistor is disposed on the high potential side, and the N-type resistor is disposed on the low potential side. By irradiating a laser beam or the like to the insulating film portion, the insulating property is broken to enable conduction. As a result, the conventionally required fuse can be eliminated.

By using such a bleeder resistance circuit, there is an effect that a small and highly accurate semiconductor device, for example, a semiconductor device such as a voltage detector or a voltage regulator can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a semiconductor thin film resistor of a semiconductor device of the present invention.

FIG. 2 is a block diagram of an embodiment of a voltage detector using a bleeder resistance circuit according to the present invention.

FIG. 3 is a block diagram of an embodiment of a voltage regulator using a bleeder resistance circuit according to the present invention.

[Explanation of symbols]

Reference Signs List 101 semiconductor substrate 102 first insulating film 701 P-type low-resistance region 702 P-type high-resistance region 703 P-type polysilicon resistor 704 N-type low-resistance region 705 N-type high-resistance region 706 N-type polysilicon resistor Body 707 Resistor 801 Second insulating film 810 Wiring 811 Wiring 814 Area where one of P-type low-resistance regions 701 and one of N-type low-resistance regions 704 contact 815 Insulating film 901 Reference voltage circuit 902 Bleeder resistance circuit 903 Current source 904 Error amplifier 905 N-type transistor 906 Inverter 907 P-type transistor 908 N-type transistor 909 Parasitic diode 910 P-type transistor

Claims (5)

[Claims] 1. A semiconductor device having a resistor, wherein the resistor is a P-type resistor formed of a P-type semiconductor;
An N-type resistor formed of an N-type semiconductor is disposed adjacent to the N-type resistor via an insulating film, the P-type resistor is disposed on a low potential side, and the N-type resistor is disposed on a high potential side. A semiconductor device that irradiates a laser beam or the like to the insulating film portion to break the insulating property to enable conduction. 2. The semiconductor device according to claim 1, wherein said resistor is formed of polysilicon. 3. One of a P-type resistor formed of a P-type semiconductor and an N-type resistor formed of an N-type semiconductor constituting the resistor is provided in a single crystal silicon substrate. 2. The semiconductor device according to claim 1, wherein said semiconductor device is formed by said impurity diffusion resistance, and the other is formed by polysilicon. 4. The semiconductor device according to claim 1, wherein said semiconductor device is a voltage detector. 5. The semiconductor device according to claim 1, wherein said semiconductor device is a voltage regulator.