JPS61287201A - Electronic apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a technology that is particularly effective when applied to thin film resistor technology and ladder resistors, such as A/D converters or D/D converters that are implemented as semiconductor integrated circuit devices. The present invention relates to technology that is effective for use in A converters.

[Background technology]

For example, in a parallel processing type A/D converter, the analog input voltage is commonly applied to one input of each of a large number of voltage comparators, while the analog input voltage is applied to the other input of each of the large number of voltage comparators in stages. Give each one a different reference voltage. Then, a digital output corresponding to the input voltage is obtained from the comparison output side of each voltage comparator.

In this case, the accuracy of the conversion depends on the relative accuracy of the reference voltages respectively applied to each voltage comparator. This reference voltage is divided using a ladder resistor formed by connecting a large number of resistors in series. Therefore, particularly high specific accuracy is required for the resistors that constitute the ladder resistance.

FIG. 9 shows an example of the configuration of the parallel processing type A/D converter described above.

The A/D converter shown in the figure consists of a ladder resistor 10° comparison circuit array 2. and an encoder 3.

The ladder resistor 10 includes a large number of resistors R1, R1, . . . R1, R3, R1, .
R2, R1,...R1'! & are connected in series, and both ends thereof are connected to a constant potential reference voltage source v8 and a reference potential (ground potential).

As a result, a large number of stepwise different reference voltages are divided from the connection points of the respective resistors constituting the ladder resistor 10. A large number of divided reference voltages are applied to the comparison circuit array 2.

The comparison circuit array 2 is an arrangement of a large number of voltage comparison circuits, and simultaneously performs comparison processing using the analog input voltage Vin'fr: the above-mentioned large number of reference voltages.

The encoder 3 converts the comparison output of the comparison circuit array into, for example, 2
It is organized into digital data encoded in a hexadecimal code. Dou
t indicates its digital output.

As described above, high-speed A/D conversion operation is performed by parallel processing.

Here, for example, when the above-mentioned A/D converter is formed in a semiconductor integrated circuit device, the ladder resistor 10 is formed by a thin film resistor made of evaporated aluminum or the like. The ladder resistor is formed by connecting a large number of thin film resistors in series within a semiconductor integrated circuit device.

In this case, it is desirable that each thin film resistor be formed in the same planar shape to ensure its relative accuracy.

However, in order to form a ladder resistor consisting of a large number of thin film resistors connected in series, for example, on a limited layout surface within a semiconductor integrated circuit device, the ladder resistor 10 must be placed in the middle as shown in the same section. have to turn around. Therefore, the planar shape of the thin film resistors R3 and R2 in the folded portions must be different from that of the thin film resistor R1 in the other non-folded portions. Therefore, the resistors R3, R2 of the folded portions must be formed so that their resistance values are the same as those of the other non-folded portions due to their different planar shapes.

However, for thin film resistors having different planar shapes, the effect of, for example, a difference in pieces at the manufacturing stage appears differently depending on the shape of the thin film resistor. For this reason, even if the resistance values t of thin film resistors with different planar shapes can be made to match each other in calculations at the design stage, the actually completed product will have different resistances depending on the planar shape. It ends up having a value. In particular, since the thin film resistors in the folded portions of large wires have a large degree of difference in planar shape, it is difficult to match their resistance values with high accuracy from the beginning to those of the thin film resistors in other non-folded portions. is almost impossible. For this reason, in the past, at least the thin film resistor in the folded portion had to be trimmed and corrected using a laser or the like.

Regarding parallel processing type A/D converters that use ladder resistors, see, for example, "Integrated Circuit Application Handbook" published by Shokusho Shoten, June 30, 1981, 222, 22.
An overview is provided on page 3.

[Purpose of the invention]

An object of the present invention is to improve the ratio accuracy and reproducibility between the thin film resistance in the folded part and the thin film resistance in the non-folded part of a folded ladder resistor by a relatively simple modification of the structure. The goal is to provide technology that enables

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief description of typical inventions disclosed in this application is as follows.

In other words, in a folded ladder resistor, by forming the thin film resistance at the folded portion and the thin film resistance at the non-folded portion to be the same only in the planar shape of each folded portion, υ is reduced. To improve the ratio accuracy between the thin film resistance in the folded part and the thin film resistance in the non-folded part of a folded ladder resistor with a simple configuration of just changing the pattern shape of the resistor, with good reproducibility. This goal is achieved.

〔Example〕

Hereinafter, typical embodiments of the present invention will be described with reference to the drawings.

In the drawings, the same reference numerals indicate the same or corresponding parts.

First, FIG. 5 shows an embodiment of a parallel processing type A/D converter to which the technology according to the present invention is applied.

The parallel processing type A/D converter shown in the figure is formed within a semiconductor integrated circuit device, and is basically the same as that described above. That is, a large number of voltage comparators CPI~
Analog input voltage Vin is applied to each one input (to) of CPn.
'e common and its multiple voltage comparators CP
Stepwise different reference voltages Vsl-Van are applied to the other inputs (→) of I to CPn. As a result, a digital output circuit corresponding to the input voltage Vln is output from the comparison output side of each voltage comparator CP1 to CPn. In this case, the comparison outputs of each comparator CPI to CPn are "1" and "1", respectively.
0" logic level. Each comparison output is converted into an alternative selection signal XI to Xn by logic Gl to Gn provided for each comparator CPI to CPn. This selection signal X1 to Xn are assembled into a binary code string of a predetermined number of digits (for example, 8 bits) by the encoder 3.The assembled binary code string becomes the digital output Dout.

FIG. 6 shows the circuit of the A/D converter shown in FIG. 5 in correspondence with its planar arrangement.

The A/D converter shown in the same figure is similar in circuit to that shown in FIG. 5, and has a comparison circuit array 2. 2. 2 along with ladder resistance 10
is formed. Each comparison circuit row 2 has a fifth
A large number of pairs of voltage comparators and logic gates shown in the figure are arranged. The ladder resistor 10 is connected to each comparison circuit column 2.
2. It is folded back to sew between the two. One end thereof is connected to a reference voltage source Vg, and the other end is connected to ground potential. Each comparison circuit row 2. 2. The logic output from encoder 2 is input to encoder 3 after being subjected to preliminary encoding processing using wired logic for each block. Then, the encoder 3 outputs a digital output Dout of a binary code string.

FIG. 7 shows in detail a portion of the circuit of the A/D converter shown in FIG.

As shown in the figure, the comparison circuit array 2 shown in FIG. 6 includes a large number of comparison circuit units) 2X to 1, 2x.

2x+1. It is composed of... Part comparison circuit unit) 2x is voltage comparator CP x s latch circuit 2
1° phase division circuit 22. and a gate buffer 23. The voltage comparator CPX compares the reference voltage vax divided by the ladder resistor 1° with the commonly applied analog input voltage Vinae.

For example, in the Xth comparator circuit unit) 2x, when the input voltage Vin becomes higher than the reference voltage Va After being temporarily held in the circuit 21, the phase dividing circuit 22 divides the signal into positive logic "1" and negative logic "O".

Then, the positive logic output "1" of the phase division circuit 22 is
After the inhibit signal EL from the upper stage side (x+1st) unit 2x+1 and the wired logic (OR) k are taken, it is output to the outside via the buffer 23, and a. On the other hand, the negative logic output "O" of the phase division circuit 22 is given to the lower stage (x-1st) unit 2 at -1 as the inhibition signal EL. As a result, one of the comparison circuit units is selected depending on the magnitude of the input voltage Vin, and only the output of the selected comparison circuit unit is activated. for example,
The input voltage Vin is the reference voltage Vax of the X-th comparison circuit unit 2x and the x+1st comparison circuit unit) 2x+1
When the reference voltage is between Vsx+1, then DVsx
Only the output Xx of -1 (Win (when Vsx is 11, the・Xx -1, Xx+1... become inactive.Such a comparison circuit unit... -CPX-1
, CPX, CPX+1. . . . For the upper side, the parallel processing type A/D converter shown in FIG. 6 is constructed.

Here, the ladder resistor 10 is, as shown in FIG.
There is a linear portion along the side of the comparison circuit row 2, a small turn-back portion that is folded back to back, and a large turn-back portion that straddles the end of the comparison circuit row 2. A large number of thin film resistors R1 having a planar pattern shape as shown in FIG. 2 are connected in series in the linear portion, that is, the non-folded portion. A thin film resistor R2 having a planar pattern shape as shown in FIG. 4 is arranged in the folded portion of the small turn.

A thin film resistor R3 having a planar pattern shape as shown in FIG. 1 is arranged at the six-fold folded portion.

The thin film resistors R1, R2, and R3 of each portion are all formed by photoetching a metal resistor 1 made of aluminum or the like within a semiconductor integrated circuit device.

FIGS. 2 and 3 show the planar pattern shape of the thin film resistor R1 formed in the non-folded portion.

As shown in the figure, the thin film resistance R1 of the non-folded portion is
Because the planar pattern shape has a large resistance value,
It is formed in a zigzag shape in which bent portions a and straight portions are alternately connected. At the same time, each corner IA, 1B of the pattern is formed at an obtuse angle (approximately 125 degrees).

By forming each corner IA and IBe at an obtuse angle in this way, as shown in the partially enlarged view of FIG. They appear in the width direction and are separated from each other. That is, one inner corner and one outer corner IB
The dimensional variations ΔWA and ΔWB in the width direction can be kept small. As a result, the variation in resistance value in the relevant portion is reduced, and as a result, the specific accuracy of each thin film resistor R1 is not affected by the etching accuracy limit or the outline brushing of the mask pattern, and the reproducibility is improved. It can be improved well.

FIG. 4 shows the planar pattern shape of the thin film resistor R2 formed in the folded portion of the small turn 9. FIG.

As shown in the figure, the thin film resistor R2 formed in the folded portion of the small turn has a bent planar pattern shape, similar to the resistor in the non-bent portion 9, and the bent portion The corners are formed at obtuse angles. The thin film resistor R2 in the folded part of this small turn and the thin film resistor R1 in the non-folded part are designed to connect the resistors R1 and R1 lined up on the same side of the two non-folded parts to each other.
The bending directions are different from each other. However, their width and length are aligned with each other. Furthermore, the thin film resistor R2 in the folded portion of the small turn and the thin film resistor R1 in the non-folded portion are partially different in their bending directions, but the bending direction is partially different from that in the υ portion a1.
The numbers and angles of ~a8 are aligned to be the same.

Only the shape of the tab υ and the bent part itself is the same. This allows even if slight errors occur in the photoetching process, such as in mask alignment,
The change in resistance value due to this error appears in the same way in both the thin film resistor R1 in the non-folded portion and the resistor R2 in the short folded portion. Therefore, the thin film resistor R2 in the small folded portion can have a very high relative accuracy or ratio accuracy with respect to the thin film resistor R1 in the non-folded portion without any trimming correction.

FIG. 1 shows the planar pattern shape of the thin film resistor R3 formed in the six-fold folded portion.

As shown in the figure, the thin film resistor R3 formed in the folded part of the large turn has a thin film bent part a of the non-folded part, and the partial resistance value at the folded part a and the part other than the folded part a. It is formed in a planar shape such that the sum of the partial resistance values at the points becomes a predetermined value.

In this case, the thin film resistor R3 of the folded portion includes resistor portions R31, R31 having the same bent loop shape as the thin film resistor R1 of the folded portion, and resistors R1, R1? which are lined up at the same side ends of the two non-folded portions. and a rectangular resistance portion R32 formed for connection to each other.

The resistance portion R31 includes a thin film resistance R at the non-folded portion.
1, a bent portion a and a straight portion b2 are formed. The planar shape at the bent portion a is the same as that at the bent portion a of the thin film resistor R1 in the non-folded portion. On the other hand, the length L of the resistor portion R32 is determined to be a size necessary to straddle the end of the comparison circuit array (FIG. 6). Along with this, its resistance value Δr
The width W3 is ensured to be large so that the width W3 is sufficiently small.

Here, the length R2 of the straight portion b2 of the resistance portion R31 is also set to be slightly shorter than the length L1 of the straight portion bl of the thin film resistor R1 in the non-folded portion. The difference ΔL is set to a length corresponding to producing the same resistance value (Δr) as the resistance value Δr of the resistance portion 32. Thereby, the resistance value of the thin film resistor R3 in the folded portion of the six-fold turn can be made equal to the resistance value of the thin film resistor R1 in the non-folded portion. Although the resistors R1 and R3 have partially different planar shapes and dimensions, their shapes at the bent portions a are the same, so errors in the photoetching process, such as mask position, may occur. Even if a slight error occurs in alignment, the change in resistance value due to the error appears in the same way in both the thin film resistor R1 in the non-folded portion and the resistor R3 in the six-fold folded portion. Therefore, the thin film resistor R3 of the six-fold folded portion can have very high relative accuracy or ratio accuracy with respect to the thin film resistor R1 of the non-folded portion without trimming correction.

FIG. 8 shows an example of application to the ladder resistor 10'i D/A converter.

The D/A converter shown in the figure includes a decoder 4 that converts a digital input Din into alternative selection signals XI-Xn, and analog switches 81-Sn that are individually controlled to open and close by the selection signals X1-Xn. and a ladder resistor 10 that equally divides the reference voltage source v3 and applies it to each end of the analog switch. The other ends of the analog switches Sl to Sn are commonly connected, and from this common connection point, the digital human power D
An analog voltage Vout corresponding to in is output. By configuring the ladder resistor 10i as described above, a D/A converter with very high linear accuracy of conversion characteristics can be obtained.

As described above, by simply changing the pattern shape of the thin film resistor, the relative accuracy of each resistance value of the thin film resistor in the folded part and the thin film resistor in the non-folded part of the folded ladder resistor can be easily reproducible. You will be able to improve it well. This makes it possible to construct, for example, a highly accurate parallel processing mA/D converter or D/A converter at low cost.

〔effect〕

(1) In a nine-fold folded ladder resistor, by forming the thin film resistance at the folded portion and the thin film resistance at the non-folded portion to be the same only in the planar shape of each folded portion, By simply changing the pattern shape of the thin film resistor, it is possible to improve the ratio accuracy between the thin film resistance in the folded part and the thin film resistance in the non-folded part of the folded ladder resistor with good reproducibility. The effect is that it becomes.

Although the invention made by the present inventor has been specifically explained above based on examples, it should be noted that this invention is not limited to the above-mentioned examples and can be modified in various ways without departing from the gist thereof. Nor. For example, the material of the thin film resistor may be a metal other than aluminum or a semiconductor.

[Application field]

As mentioned above, the invention made by the present inventor is applicable to the parallel processing type A/D converter or D/D converter, which is the application field for which the invention was made.
Although the case where the present invention is applied to an A converter has been described, the present invention is not limited thereto, and can also be applied to, for example, a high-precision resistance attenuator.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the folded portion of the dog loop υ of the ladder resistor according to the present invention, Fig. 2 is a plan view showing the shape of the thin film resistor in the non-folded portion, and Fig. 3 is a partial enlargement of Fig. 2. 4 is a plan view showing the folded part of the small turntable, and FIG. 5 is a plan view showing the folded part of the small turntable.
Figure 4 is a circuit diagram showing a configuration example of an A/D converter using the ladder resistor shown in Figure 6. Figure 6 is a circuit diagram showing the A/D converter in Figure 5 according to its layout arrangement. Figure 6 is a circuit diagram showing a part of the A/D converter in detail, Figure 8 is a circuit diagram showing an example of the configuration of a D/A converter using ladder resistance sound, and Figure M9 is a parallel processing type A. FIG. 2 is a circuit diagram showing a configuration example of a /D converter. 1... Resistor, 10... Ladder resistance, R1... Thin film resistance of the non-folded part, R2... Thin film resistance of the folded part of the small turn, R3... Resistance of the folded part of the dog turn, a ...Bending part, b, bl, b2... Straight part. Figure 1 2vA

Claims (1)

[Claims] 1. A large number of thin film resistors bent in the same planar shape are connected in series, and a thin film resistor with a planar shape different from the above thin film resistors is inserted in the middle of the connected resistor string. The thin film resistor in the non-folded part has a planar shape in which folded parts and straight parts are connected alternately, while the thin film resistor in the folded part has a folded part. It has a bent portion having the same shape as the bent portion in the thin film resistor, and the sum of the partial resistance value at the bent portion and the partial resistance value outside the bent portion is a predetermined value. 1. An electronic device comprising a ladder resistor formed in a planar shape. 2. The thin film resistor in the folded portion of the ladder resistor has a bent portion and a straight portion, and the bent portion has the same planar shape as that of the bent portion in the thin film resistor in the non-folded portion. Claims characterized in that only the length of the portion is adjusted so that the partial resistance value at the portion other than the folded portion is the same as that in the straight portion of the thin film resistor in the non-folded portion. The electronic device according to item 1.