JPH0666172B2 - Resistor trimming method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting a resistance value of a chip resistor and a trimming method for a thick film / thin film resistor element manufactured on a ceramic substrate or the like.

2. Description of the Related Art In recent years, with the miniaturization of devices, the mounting density of electronic components tends to be higher. One of the mounting methods is a hybrid IC (hereinafter referred to as HIC). In the method of manufacturing the resistor used in this HIC, after forming the resistor electrode and the wiring pattern on the ceramic substrate, the resistor is formed by printing or vapor deposition. However, the resistance value of the produced resistor varies depending on printing / firing or vapor deposition conditions. Therefore, in order to set the resistance value of the resistor to a desired value, the resistor is trimmed to increase the resistance value to obtain the desired resistance value. To adjust this resistance value, trimming the resistance value of the resistor itself to a specified value and operating the circuit, measuring the circuit characteristics (oscillation frequency etc.) and adjusting resistor to the specified value. Trimming function There are two types of trimming. recent years,
Since there is a trend toward higher density mounting of resistors and miniaturization of resistors, it is becoming more important to adjust the resistance value by trimming.

A conventional method of trimming a resistor will be described below with reference to the drawings. FIG. 6 is a block diagram for explaining a conventional method for trimming a resistor, in which 1 is a HIC substrate, 2 and 3 are printed resistors having resistance values R _o1 and R _o2 ,
4, 5, 6, and 7 are probes pressed against the resistor electrodes,
Reference numeral 8 is an initial resistance value measuring means for sequentially measuring the resistance values of the resistors 2 and 3, and 9 is an initial resistance value R _oi (i = 1, 2) of the resistor obtained by the initial resistance value measuring means 8 and the resistance. Geometrical dimensions (resistor width, resistor length) of the bodies 2 and 3 and desired resistance value R _ti (i =
Trim amount calculating means from 1, 2) to calculate the amount of trimming l _oi (i = 1,2), the trimming amount of the focal point 12 of the laser 11 on the resistor 2 and 3 10 l _oi (i = 1, 2)
It is a trimming means that moves only for trimming. A broken line portion A in FIG. 6 is a resistance value measurement positioning stage, and a broken line portion B is a trimming positioning stage.

The operation will be described below with reference to FIG. First, the HIC substrate 1 is positioned on the resistance value measuring stage A, and the probes 4, 5, 6, 7 as electrical connection means are pressed against the resistor electrode portions, and the initial resistance values R _{oi of the} resistors 2, 3 are set.
The initial resistance value measuring means 8 measures (i = 1, 2).
Next, after removing the probes 4, 5, 6, and 7, the HIC substrate 1
Is moved to the trimming stage B for positioning, and the trimming amount l _oi (i = 1, 2) is calculated by the trimming amount calculating means 9. The trimming amount l _oi can be calculated by the following equation as specified in Japanese Patent Application No. 59-76076.
Further, the resistor width is W _i (i = 1, 2) and the resistor length is L
_{Let i} (i = 1, 2).

However, π is a circular constant and i is an integer.

Hereinafter, the derivation of the trimming amount calculation formula shown in the formula will be described with reference to FIGS. 9 to 11. In FIG. 9, 21 is a rectangular printed resistor having a width W and a length L, and has electrodes 22 on both sides. Now, connect the central part of the resistor to the electrode 22.
Resistance value Rt when trimmed by x in the direction parallel to
Can be obtained by the following procedure.

Assuming that the distance x is trimmed in FIG. 9, the virtual electrode 24 is provided between the tip of the trimming groove and the edge of the resistor 21.
Can be considered to be. Therefore, as the resistance value, the resistance value between the virtual electrode 24 and the electrode 22 is obtained, and the resistance value Rt after trimming can be obtained by doubling the resistance value. In order to facilitate the calculation, two resistors between the virtual electrode 24 and the electrode 22 are connected in parallel and considered in the shape of FIG. As a matter of course, Rt may be obtained by multiplying the resistance value of the resistor shown in FIG. 10 by four. FIG. 11 (a) is a diagram in which the resistors of FIG. 10 are arranged on the Z plane. The figure shown in FIG. 11 (a) passes through the complex plane W shown in FIG. 11 (b),
It is possible to perform conformal conversion into the figure on the complex plane r shown in FIG. 11 (c). The conversion from the W plane to the Z plane is performed by the following Schwartz-Christoffel conversion formula.

However, 0 ≦ k ² ≦ 1 C ₁ and C ₃ are arbitrary constants. The conversion formula from the plane W to the r plane is the same as the formula (a),
It can be given by

However, if 0 ≦ k ² ≦ 1 C ₂ and C ₄ are conversion constants equal to or more than arbitrary constants, the resistance value of the resistor shown in FIG. Can be calculated by Therefore, the formula can be obtained by rearranging the formula (c).

Next, the trimming means 10 sets only the trimming amount l _o2 obtained by the above calculation for the laser focusing point 12 on the resistor 2 and
Move the trimming amount l _o2 on the resistor 3 respectively,
Trimming is complete. FIG. 7 shows an external view after trimming. 13a and 13b are electrodes added to the resistor, 1
Reference numeral 4 is a trimming groove, W is a resistor width, and L is a resistor length.

Problems to be Solved by the Invention However, in the method as described above, a constant shape value (resistor width, resistor length) is used to calculate the trimming amount for obtaining a desired resistance value. When a resistor is manufactured by the above method, the resistor has a shape as shown in FIG. 8a, and the resistor contour is not linear. Therefore, the shape value (resistor width, resistor length) of the resistor becomes unclear. Also, the shape value of the resistor depends on the printing conditions and HIC when the resistor is manufactured.
Variation occurs depending on the printing position and printing direction on the substrate. Moreover, in the conventional trimming method, it is considered that the resistor film thickness is constant as shown by the broken line in FIG. 8B, but the resistor produced by screen printing has a solid line. The distribution of the film thickness also varies depending on the printing conditions of the resistor, the printing position and the printing direction of the HIC substrate. For the above reason, the conventional method of calculating the trimming amount by regarding the film thickness and shape of the resistor as constant has a problem that a trimming error occurs and a resistance value error increases.

An object of the present invention is to provide a method for trimming a resistor that eliminates the conventional problems.

Means for Solving the Problems In order to solve the above problems, the resistor trimming method of the present invention is a trimming method in which a desired resistance value is obtained by trimming the resistor a plurality of times. In the first trimming, the trimming amount is calculated from the first target resistance value smaller than the initial resistance value of the resistor and the desired resistance value and the length and width of the resistor, and the trimming amount is applied to the resistor. Give. The trimming after the second time is performed by first correcting the length or width of the resistor from the resistance value after the previous trimming, the trimming amount of the previous time, and the initial resistance value, and then the shape value and the initial resistance value of the corrected resistor. Then, the trimming amount is calculated from the second target resistance value and the trimming amount is applied to the resistor.

Effect As described above, the present invention corrects the shape value of the resistor and obtains the trimming amount, so that highly accurate trimming can be performed.

Example A method of trimming a resistor according to an example of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram for explaining the method for trimming a resistor according to the present invention, in which 16 is a resistance value measuring means, and 17 is a trimming amount and a resistor correction value calculating means. FIG. 2 is an explanatory diagram of the method of trimming the resistor according to the present invention, in which the desired resistance value is obtained by trimming twice. Reference numeral 18 is a first trimming groove, and 19 is a second trimming groove. Point a is an edge point near the center of the resistor length, point b is the first trimming end position, and point c is the second trimming end position. In the following description, only the resistor 3 will be described for simplicity. First, the HIC substrate 1 is positioned on the resistance value measuring stage A, and the initial resistance value R _o is measured. Next, calculation means 17
Thus, the first trimming amount l ₁ is calculated and the HIC substrate is positioned on the trimming stage B.
This l ₁ can be obtained by the following equation if i = 1 in the following equation.

Here, π is a circular constant, 0 <x ≦ 1, i is an integer, W is a resistor width, L is a resistor length, and Rt is a desired resistance value. In addition,
The difference between the expression 'and the expression is that Rt is replaced by Rt.x. Rt is a desired resistance value (final target resistance value). Since the present invention obtains the final target resistance value by trimming a plurality of times, it is necessary to set the target resistance value for trimming other than the final trimming to the desired resistance value Rt or less. There is. Therefore, Rt is corrected by x.

In the equation ', a constant of about 0.9 is usually selected for x.
Then, l ₁ obtained by the equation 'is applied by the trimming means 10 in the direction perpendicular to the resistor length from the point a.
The external view at that time is shown in FIG. 2a. Next, a method of correcting the resistor shape value by the resistance value after the first trimming will be described. Here, a method of obtaining the resistance length L ′ as the correction value from the resistance value R ₁ after trimming, the initial resistance value R _0, and the resistance width W will be described. The correction value L'is called the effective resistor length L ', and is used when the next trimming amount is obtained. Now, position the HIC substrate after the first trimming on the resistance value measuring stage A, press the probes 6 and 7 onto the electrodes of the resistor, and set the resistance value to R.
_{If the value is 1} , the effective resistor length L ₁ ′ can be obtained by setting i = 1 in the following equation modified from the equation.

However, π is the circular constant, and i is the effective resistor length L ₁ ′ which is an integer or more.

Next, a method for obtaining the trimming amount for the second time by using L ₁ ′ obtained by the formula will be described. The HIC substrate again includes the resistance value measuring stage A to the trimming stage B.
Then, the calculating means 17 obtains the trimming amount l ₂ for the second time. This L ₂
Is x = 1 and i = 2 in the equation, and L is L ₁ ′
Is obtained by The L ₂ thus obtained is sent to the trimming means 10, and the trimming means 10 performs L ₂ amount trimming from the point a, and the trimming is completed. The completed diagram is shown in Figure 2b. here,
As described above, the resistor shape is not linear as shown in FIG. 8a, and therefore the resistor edge point a is naturally unclear, and the resistor positioning accuracy is not clear. Therefore, as shown in Fig. 4a, trimming may be performed from the position a'or a ', which is not correct. However, in the case of a resistor of 1 mm square or more, the deviation of the position a is ±. 100μm approximately is acceptable. showing the reason below. for example, if the distance l _o1 to true resistance edge point a when trimming l ₁ from the point a 'is decorated as shown in Figure 4 b Actually, it means that the resistor is trimmed by the amount of l ₁ −l _{o 1. If} the resistance value at that time is R ₁ ′,
This resistance value R ₁ ′ is smaller than the resistance value R ₁ when trimming of l ₁ amount is applied from the point a. Thus, _{R 1} in place of _{R 1} by the equation 'substitutes, "when seeking, resistor effective length _{L 1"} resistor the effective length _{L 1} the previous _{L 1'} is smaller than. Therefore, the trimming amount l ₂ ′ of the _second trimming can be obtained by setting x = 1.0 and L = L ₁ ″ in the equation, but the value is larger than the previous l _2. Therefore, the trimming amount l ₂ ′ of the _second trimming. Becomes longer than l _{2 and} the error of l _o1 is eliminated.Next, when the point a is the a ″ point of the inner part of the resistor as shown in Fig. _4b, the distance to the true edge is l _o2. It is assumed that the trimming amount of l ₁ has been applied from the point a ″. At this time, it is assumed that a trimming groove is formed between the points a and a ′.
The resistor is trimmed by l _o2 + l ₁ amount, and the resistance amount R ₁ ″ after trimming is larger than R ₁ when trimmed by l ₁ amount from point a. Therefore, by the formula, instead of R ₁ , R
By substituting ₁ ″, the resistor effective length L ₁ is calculated to be larger than the previous L ₁ ′. Therefore, the second trimming amount l ₂ ″ is x = 1.0, L = L _{1 in the} equation However, the value is smaller than l ₂ . Therefore, the trimming amount l ₂ ′ of the second time becomes shorter than L _{2 and} the error of L _o2 is canceled. By the above procedure, the correction value for obtaining the trimming amount l ₂ is obtained, and R _t can be obtained accurately. In FIG. 2, l ₁ and l ₂ are expressed at the same position, but l ₁ and l ₂ may be separated from each other as shown in FIG. Also l
_{Although 2} was performed from the point a, it is clear that the trimming of (l ₂ −l ₁ ) amount may be performed from the point b.
Moreover, when calculating l ₁ , x = 0.9 was set, but x = 0.9
The value is not limited to 0.9, and may be any value within the range of φ <x ≦ 1 as long as the obtained l ₁ is a constant that is inside the point a, that is, a trimming amount with which the resistor is sufficiently trimmed. Although only the resistor 3 has been described above, the same applies to the resistor 2, and even if many resistors are formed on the HIC substrate, the trimming can be performed by the same procedure. The above applies to the following description.

Next, a method of obtaining R _t by trimming three times will be described with reference to FIGS. 1 and 5. For simplicity, the following description will be limited to the resistor 3. FIG. 5 is an explanatory diagram for obtaining R _t by trimming three times, and 20 is the third
It is the trimming groove for the third trimming, and point d is the end point of the third trimming. First, the HIC substrate 1 is positioned on the resistance value measuring stage, the probes 6 and 7 are pressed against the electrodes of the resistor 3, and the initial resistance value R _o is measured. Next, calculation means 1
6, the first trimming amount l ₁ is calculated, and the HIC substrate is positioned on the trimming stage B. l ₁ can be obtained by the equation 'with i = 1 and x = 0.9. Next, l ₁ obtained by the expression 'is applied from the point a of the resistor 3 in a direction perpendicular to the resistor length, and an external view at that time is shown in FIG. 5a. Next, place the HIC substrate 1 on the stage A
Then, the probes 6 and 7 are brought into pressure contact with the electrodes of the resistor 3 again, and the resistance value thereof is R _1, and the effective resistor length L ₁ ′ of the correction value can be obtained by setting i = 1 in the equation. . Next, with reference to FIG. 4B, a method for obtaining a more appropriate correction value L ₂ ′ based on the resistance value after the second trimming will be described. FIG. 4b shows an external view of the resistor after the second trimming is completed. The second trimming amount l ₂ is '= 0.95, i = 2, L = L ₁ '
Can be asked as The above l ₂ is the calculation means 17
And the HIC substrate is positioned on the stage B. Next, the trimming means 10 trims from the point a by the amount of l ₂ . After trimming, HIC
The substrate is placed on the stage A, the probes 6 and 7 are pressed against the electrodes again, and the resistance value is measured. Now, the resistance value is R
_Set to ₂ . The correction value L ₂ ′ is obtained by setting i = 2 in the equation. Next, in equation ', i = 3, x = 1.0, L
= L ₂ ′, l ₃ is calculated by the calculating means 17, and the HIC substrate 1 is positioned on the stage B. The trimming means 10 completes the trimming by performing the trimming of l ₃ amount from the point a. As described above, L ₁ ′ is calculated and L
Trimming to find l ₂ using ₁ ′,
'Seek, _{L 2'} L ₂ by obtaining the _{l 3} using, it is possible to perform trimming precision. In the above description, when the first l ₁ is obtained,
x = 0.9 (assuming x is x ₁ ) and x ₂ was 0.95 (assuming x is x ₂ ) when the second l ₂ was obtained, but it is not limited to this constant and l ₁ is sufficient. Any value may be used as long as the resistor is trimmed and the relationship of O <X ₁ <X ₂ ≦ 1 is satisfied.

EFFECTS OF THE INVENTION As is apparent from the above description, at least two resistors are provided in the resistor.
A trimming method for obtaining a desired resistance value by performing trimming more than once, wherein the trimming amount is calculated from the shape value of the resistor, the initial resistance value, and the desired resistance value, and
The trimming amount after the second trimming is a resistor trimming method characterized in that the shape value of the resistor is corrected and calculated from the resistance value after the previous trimming, the initial resistance value, and the previous trimming amount. The shape and film thickness of the resistor may vary depending on the printing conditions and printing direction at the time of manufacturing, and the printing position of the HIC substrate of the resistor, which causes an error in the trimming amount to be calculated, resulting in a large resistance value error. There are no points, trimming can be performed with high precision, and the effect on productivity is great.

[Brief description of drawings]

FIG. 1 is a block diagram of a trimming method of a resistor of the present invention, FIGS. 2, 4, and 5 are explanatory views of the trimming method of the present invention, and FIG. 3 is a trimming method of the present invention applied to a resistor. Fig. 6 is an external view when the resistor is applied, Fig. 6 is a configuration diagram of a conventional trimming method, Fig. 7 is an external view when a conventional trimming method is applied to a resistor, and Fig. 8 is an external view and cross section of the resistor. FIG. 9, FIG. 10, FIG. 10 and FIG. 11 are explanatory diagrams for deriving the trimming amount calculation formula shown in the formula. 1 ... HIC substrate, 2,3 ... resistors, 4, 5, 6, 7
...... Probe, 8 …… Initial resistance value measuring means, 9 …… Trimming amount calculating means, 10 …… Trimming means, 11 ……
Laser light, 12 ... Laser condensing point, 13a, 13b ...
Electrode, 14 ... Trimming groove, 15 ... Resistor, 16 ...
... resistance value measuring means, 17 ... trimming amount / correction value calculating means, 18 ... first trimming groove, 19 ... second
Trimming groove of 20th time ... Trimming groove of 3rd time, 21 ... Resistor, 22 ... Electrode, 24 ... Virtual electrode

Claims (1)

[Claims] 1. A trimming method for obtaining a desired resistance value by trimming a resistor a plurality of times, wherein an electrical connection means is pressed against a resistor electrode portion and an initial resistance value of the resistor is measured. A first step, a first trimming amount is calculated from the length and width of the resistor, the measured initial resistance value and a first target resistance value smaller than a desired resistance value, and the electrical connection means is connected. A second step of applying the first trimming amount to the resistor in a state where it is removed from the resistor electrode portion; and a resistance value of the resistor by press-contacting an electrical connection means to the resistor electrode after the first trimming. And a third step of correcting at least one of the length and width of the resistor from the measured resistance value, initial resistance value, and first trimming amount, and the corrected shape value of the resistor. And initial resistance value and desired resistance value or before A fourth step of calculating a second trimming amount from a second target resistance value that is larger than the first target resistance value, and the second trimming amount with the electrical connection means removed from the resistor electrode portion. A method of trimming a resistor, which comprises performing a fifth step of applying to a resistor.