JPH07202122A - Semiconductor integrated circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] When trimming is attempted after packaging, including the characteristic variation due to the stress generated by resin casting during packaging, the number of lead wires drawn to the trimming terminals outside the package increases, and the package Solve the problem of large size. [Structure] The resistors to be trimmed are divided into those with a large resistance value and those with a small resistance value, and the resistors with a large resistance value are trimmed before packaging to make a rough adjustment. Trimming a small resistor to adjust the characteristics with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor integrated circuit which undergoes on-chip trimming for adjusting electrical characteristics on a chip during a manufacturing process.

[0002]

2. Description of the Related Art As a method for on-chip trimming of an IC
Laser is used to partially remove the thin film resistor formed in the chip.
To adjust the resistance value continuously by cutting the
Or connect multiple resistors in parallel and cut the wiring if necessary.
There is a method of cutting off and adjusting resistance discretely. Discrete key
The adjustment method is to electrically short the Zener diode.
And the zener zapping that adjusts the resistance value
There is also a method called. Wiring cut and Zener diode
To short circuit, use expensive equipment such as laser
Since there is no need to
Is a commonly used method. Fig. 2 Zena Zapping
An example of a partial circuit is shown. Resistance ΔR₁, ΔR ², ΔR₃
Zener diode Z connected to both ends of₁, Z
₂, Z₃Trimming terminals (pads) 21 and 2 for each
2, 23, 24 are provided, and this electrode is externally
Touch the probe and let the Zener diode have its breakdown voltage.
By applying the above voltage, the Zener diode
Adjust the resistance value by breaking or short-circuiting.

[0003]

When the IC chip whose resistance is adjusted by the above-mentioned method is packaged by resin casting, the resistance value is increased due to the piezo effect due to the stress generated in the IC chip by the resin. It is known that there is a fluctuation. Therefore, even if the resistance value inside the IC is precisely adjusted, there is a problem that the expected characteristics cannot be obtained due to the characteristic variation after the package, and this problem becomes more remarkable as the required accuracy becomes stricter. In order to solve this, there is also a method in which a trimming electrode is connected to a package lead of an IC and electrically trimmed after packaging. However, this method has a big problem that the package becomes large when the number of trimming leads is large. It is desired to solve this problem from the viewpoint of high precision and miniaturization of characteristics required for ICs in recent years. A similar problem also exists when adjusting the characteristics by inserting a resistor in series and increasing the resistance value.

An object of the present invention is to solve the above-mentioned problems and to provide a semiconductor integrated circuit which enables on-chip trimming after packaging while suppressing an increase in the size of the package.

[0005]

In order to achieve the above object, the present invention provides a semiconductor integrated circuit having a plurality of discrete or insertable adjusting resistors for adjusting electrical characteristics, wherein the adjusting resistors have a resistance value. The adjustment resistor having a small resistance value is connected to the trimming terminal outside the package by lead wires. It is preferable that the Zener diode is connected in parallel to each of the adjustment resistors, and the adjustment resistors can be separated from the circuit by short-circuiting the Zener diodes by applying a voltage via the trimming terminal. Fuses are connected in parallel to the adjustment resistors, respectively, and the fuses are blown by energization through the trimming terminals.
It is also possible that the adjusting resistor can be inserted in the circuit.

[0006]

[Function] For the adjusting resistor having a large resistance value, the characteristics on the chip are roughly trimmed by the electrodes on the chip to roughly adjust the characteristic against a large initial variation generated in manufacturing.
The final characteristic adjustment, including small characteristic fluctuations that occur during packaging, is performed by discrete or inserting adjustment resistors with small resistance values by trimming terminals outside the package. As a result, the number of lead wires is reduced, and the size of the package is minimized.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit diagram of an IC of an embodiment of the present invention.
An example of a circuit of a ping part is shown. In this case, they are connected in series.
The adjusted resistance has a large resistance value, for example, several tens of KΩ.
ΔR₁₁, ΔR₁₂, ΔR₁₃, ΔR₁₄And the resistance value is
A few KΩ and small ΔR_{twenty one}, ΔR_{twenty two}Consists of. And each tone
Zener diode Z in parallel with each resistance₁, Z ₂,
Z₃, Z_Four, Z_Five, Z₆Is connected to both ends of the adjustment resistor.
And the intermediate points are trimming terminals 1, 2, 3, 4, 5,
6 and 7 are connected. Of these, the trimming terminal
Only 5, 6, and 7 are outside the package 9 using the lead wire 8.
Will be sent to. Therefore, the resistance ΔR₁₁, ΔR₁₂, Δ
R₁₃Or ΔR₁₄Discrete is a tri
Selective with Mming terminals 1, 2, 3, 4 or 5
Zener diode Z₁, Z₂, Z₃
Or Z_FourIt can be done by shorting the
Therefore, a rough characteristic adjustment is performed. Packaging
After that, use the trimming terminals 5, 6 and 7 to reduce the resistance.
I ΔR_{twenty one}, ΔR_{twenty two}By selectively shorting and
Due to the stress generated by resin casting during packaging
Make precise adjustments, including slight variations in characteristics.

In this embodiment, zena zapping is used.
As an example, for ICs that use other trimming methods,
However, it can be implemented in the same manner. For example, the Tuena Daio in Figure 1
De Z ₁Through Z₆Insert the fuse at the position of Trimin
Select fuse by energizing using terminals 1 to 7
Adjustment resistor R that has a large resistance value₁₁Through R₁₄,
Adjustment resistor R with small resistance_{twenty one}, R_{twenty two}Directly to the circuit
By inserting it in a row and increasing the resistance, various characteristics of the IC
It can also be adjusted.

[0009]

According to the present invention, the adjustment resistors for obtaining the semiconductor integrated circuit having the desired characteristics are divided into those having a large resistance value for rough adjustment and those having a small resistance value for high precision adjustment. By pulling out only the trimming terminal connected to the high-accuracy adjustment resistor to the outside of the package, high-accuracy characteristics can be achieved without excessively increasing the package pin count or increasing the package size. In addition, it is possible to prevent a decrease in the non-defective rate due to manufacturing variations.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a zenerzapping portion of a semiconductor integrated circuit according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a zenerzapping portion of a conventional semiconductor integrated circuit.

[Explanation of symbols]

1, 2, 3, 4, 5, 6, 7 Trimming terminal 8 Lead wire 9 Package ΔR ₁₁ , ΔR ₁₂ , ΔR ₁₃ , ΔR ₁₄ High resistance adjustment resistance ΔR ₂₁ , ΔR ₂₂ Low resistance adjustment resistance

Claims (3)

[Claims] 1. An adjusting resistor having a plurality of adjusting resistors that are discrete or insertable for adjusting an electrical characteristic, wherein the adjusting resistor has a large resistance value and a small resistance value, and both ends of the adjusting resistance having a small resistance value are A semiconductor integrated circuit, which is connected to a trimming terminal outside a package by a lead wire. 2. The semiconductor device according to claim 1, wherein a zener diode is connected in parallel to each of the adjusting resistors, and the adjusting resistors are discrete from the circuit by short-circuiting the zener diodes by applying a voltage via a trimming terminal. Integrated circuit. 3. The semiconductor integrated circuit according to claim 1, wherein parallel fuses are respectively connected to the adjusting resistors, and the adjusting resistors can be inserted into the circuit by blowing the fuses by energizing the trimming terminals.