Resistor

Abstract

To improve the insulation between circuit elements while achieving miniaturization in a resin-encapsulated resistor that includes a plurality of circuit elements.SOLUTION: A resistor includes a die pad and a circuit body arranged on the die pad, the circuit body includes an insulating substrate, a first circuit element and a second circuit element arranged on the insulating substrate, and an insulating portion arranged between the first circuit element and the second circuit element to insulate the first circuit element from the second circuit element, and the die pad and the circuit body are covered with an insulating resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a resistor.

Background Art

[0002] Patent Document 1 discloses a semiconductor device having a resistor and capable of expanding the output voltage range with a simple configuration.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, in a semiconductor device in which a plurality of chips are formed on one die pad in order to achieve miniaturization, particularly under usage conditions where a high voltage is applied, measures against short circuits between the plurality of chips are essential.

[0005] Therefore, an object of the present invention is to enhance the insulation between circuit elements while achieving miniaturization in a resistor including a plurality of circuit elements and resin-sealed.

Means for Solving the Problems

[0006] According to an aspect of the present invention, there is provided a resistor including a die pad and a circuit body disposed on the die pad, the circuit body including an insulating substrate, a first circuit element and a second circuit element disposed on the insulating substrate, and an insulating portion disposed between the first circuit element and the second circuit element and insulating the first circuit element and the second circuit element, wherein the die pad and the circuit body are covered with an insulating resin.

Effects of the Invention

[0007] According to an aspect of the present invention, in a resistor including a plurality of circuit elements and resin-sealed, an insulating portion is provided between the first circuit element and the second circuit element, so that while miniaturization is achieved, the insulation between the circuit elements can be enhanced.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0009] [Embodiment] <Resistor> The structure of the resistor of the present embodiment will be described with reference to the drawings. In this specification, throughout, the same or equivalent elements are denoted by the same reference numerals.

[0010] The resistor is, for example, a thin film chip resistor connected to a circuit board as a power module where high voltage and large current signal processing is performed. In the present embodiment, the resistor functions as a voltage dividing circuit that divides a high voltage of several hundred volts or more applied to the circuit board to a low voltage of several volts for detection.

[0011] FIG. 1 is a plan view of the resistor 1 according to the present embodiment, as viewed from the upper surface side of the resistor 1, for explaining the structure of the resistor 1. For clarity of explanation, the insulating resin (mold resin) covering the upper surface of the resistor 1 is not shown in FIG. 1. FIG. 2 is a cross-sectional view of the resistor 1 taken along the line II-II in FIG. 1.

[0012] The resistor 1 includes a die pad 11 and a circuit body 20 disposed on the die pad 11, and the die pad 11 and the circuit body 20 are covered with an insulating resin 30.

[0013] The resistor 1 has lead terminals 12 (a plurality of lead terminals 12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h). The die pad 11 and the lead terminals 12 constitute a lead frame 10. In the present embodiment, when the lead terminals are not distinguished, they are denoted without the alphabet like the lead terminal 12.

[0014] The die pad 11 and the lead terminals 12 constituting the lead frame 10 are formed from thin plates of metal materials such as copper, copper alloy, and iron-nickel alloy, which are excellent in mechanical strength, electrical conductivity, thermal conductivity, corrosion resistance, etc. The die pad 11 and the lead terminals 12 are obtained by performing processing such as punching (pressing) and etching on these metal thin films.

[0015] The lead terminal 12 has an inner lead portion 121 that is electrically connected to electrode connection portions (hereinafter referred to as pad portions P) in a first circuit element 22 and a second circuit element 23 formed on the circuit body 20, and an outer lead portion 122 that is connected to an external wiring (not shown).

[0016] In the present embodiment, the circuit body 20 has an insulating substrate 21, a first circuit element 22 and a second circuit element 23, and an insulating portion 24 disposed between the first circuit element 22 and the second circuit element 23.

[0017] In the present embodiment, the insulating substrate 21 has a first insulating substrate 211 and a second insulating substrate 212, and the first insulating substrate 211 and the second insulating substrate 212 are separated from each other.

[0018] The first insulating substrate 211 and the second insulating substrate 212 are formed of an insulating material. In this embodiment, as an example, the insulating substrate 21 is an alumina (Al2O3) substrate. In addition to the alumina substrate, the insulating substrate 21 can be applied with a thermal oxide film obtained by modifying the surface of a silicon substrate into an oxide film, a silicon oxide film or a silicon nitride film formed by CVD or the like.

[0019] Also, in this embodiment, the first circuit element 22 is formed on the first insulating substrate 211, and the second circuit element 23 is formed on the second insulating substrate 212. The first circuit element 22 and the second circuit element 23 are thin film circuit patterns formed by photolithography or the like after film formation by sputtering, plasma CVD or the like using a material capable of forming a circuit pattern.

[0020] Examples of the metal material capable of forming the thin film circuit pattern include copper, chromium (Cr), a metal material mainly composed of chromium (Cr), nickel-chromium (Ni-Cr), a metal material mainly composed of nickel-chromium (Ni-Cr), and a metal oxide material. The metal material can be appropriately selected according to the use of the resistor 1 from materials having a high-precision resistance value tolerance and temperature characteristics, materials having strong high voltage and surge resistance, materials having good TCR characteristics, and the like.

[0021] In this embodiment, as an example of the material capable of forming the circuit pattern, a chromium (Cr) alloy or a nickel-chromium (Ni-Cr) alloy can be preferably used.

[0022] After the circuit patterns of the first circuit element 22 and the second circuit element 23 are formed, the pad portion P is formed by film deposition using a conductive material. In this embodiment, the pad portion P is formed by sputtering using an Al alloy as an example.

[0023] The first circuit element 22 is formed on the first insulating substrate 211 in a predetermined circuit pattern shape. In this embodiment, the first circuit element 22 has a first resistor 221 and a second resistor 222 as the circuit pattern shape.

[0024] The first resistor 221 is set to a meander shape having a predetermined line width, meander amplitude, and number of meanders such that the resistance value becomes R1. Further, the second resistor 222 is set to a meander shape having a predetermined line width, meander amplitude, and number of meanders such that the resistance value becomes R2.

[0025] The second circuit element 23 is formed on the second insulating substrate 212 in a predetermined circuit pattern shape. In the present embodiment, the second circuit element 23 has a third resistor 231 and a fourth resistor 232 as circuit patterns.

[0026] The third resistor 231 is set to a meander shape having a predetermined line width, meander amplitude, and number of meanders such that the resistance value becomes R3. Further, the fourth resistor 232 is set to a meander shape having a predetermined line width, meander amplitude, and number of meanders such that the resistance value becomes R4.

[0027] In the present embodiment, the circuit pattern shape of the first circuit element 22 formed on the first insulating substrate 211 is the same as the circuit pattern shape of the second circuit element 23 formed on the second insulating substrate 212. The resistor 1 has the first circuit element 22 and the second circuit element 23 having the same circuit pattern shape arranged side by side.

[0028] FIG. 3 is a circuit diagram for explaining a general voltage dividing circuit.

[0029] The voltage dividing circuit shown in FIG. 3 is a circuit that amplifies the potential difference between the input voltage Vin- input to the inverting input terminal and the input voltage Vin+ input to the non-inverting input terminal, and outputs the amplified potential difference as the output voltage Vout, and is designed to satisfy the following conditions. R2 / R1 = R4 / R3

[0030] Further, when the voltage dividing circuit extracts a potential difference smaller than the input potential difference, it is designed to satisfy R1 > R2. At this time, a step-down circuit in which the output voltage Vout is smaller than the input potential difference is configured.

[0031] In this embodiment, the resistance value R1 of the first resistor 221 formed on the first circuit element 22, the resistance value R2 of the second resistor 222, the resistance value R3 of the third resistor 231 formed on the second circuit element 23, and the resistance value R4 of the fourth resistor 232 are configured to satisfy the following conditions. R2 / R1 = R4 / R3, provided that R1 > R2

[0032] That is, the circuit body 20 in the resistor 1 constitutes a step-down circuit.

[0033] The insulating portion 24 is disposed between the first circuit element 22 and the second circuit element 23, physically shields the first circuit element 22 and the second circuit element 23, and electrically insulates the first circuit element 22 and the second circuit element 23.

[0034] As the insulating material constituting the insulating portion 24, an inorganic material or a resin having insulating properties can be used.

[0035] As the insulating inorganic material, a glass fiber material formed by mixing silicon dioxide, aluminum oxide, calcium oxide, magnesium oxide, boron oxide, etc. can be used. Also, inorganic materials such as aluminum nitride and magnesium oxide, and minerals such as mica can be used.

[0036] As the insulating resin, thermosetting resins such as epoxy resin, silicone resin, urethane resin, and phenol resin can be applied. By mixing fillers such as silicon dioxide fillers and curing agents with these thermosetting resins, the thermal expansion coefficient of the insulating resin is set to a value close to the thermal expansion coefficients of the first circuit element 22, the second circuit element 23, the first insulating substrate 211, and the second insulating substrate 212.

[0037] The first circuit element 22, the second circuit element 23, the first insulating substrate 211, and the second insulating substrate 212 are preferably arranged with as wide a spacing as possible within the region of the die pad 11 of the resistor 1 from the viewpoint of preventing a short circuit between the first circuit element 22 and the second circuit element 23 and from the viewpoint of ensuring the volume of the insulating portion 24 that can obtain a sufficient insulating effect.

[0038] As shown in FIG. 1, the first circuit element 22 and the second circuit element 23 of the resistor 1 are connected by an inner lead portion 121 and a bonding wire W at a predetermined pad portion P.

[0039] Au (gold) can form an intermetallic compound with high connection reliability with Al (aluminum) under high temperature and high pressure conditions. Utilizing this property, the pad portions P of the first circuit element 22 and the second circuit element 23 and the inner lead portion 121 are joined with an Au wire by ultrasonic vibration. A Cu (copper) wire can also be used instead of the Au wire. In wire bonding, generally, a bonding wire with a diameter of 10 μm to 100 μm is formed.

[0040] In the voltage dividing circuit shown in FIG. 3, when reducing the voltage from a high voltage to a low voltage, a high voltage is applied to the input side terminals (Vin-, Vin+). For this reason, in the resistor 1, it is preferable to arrange the input terminals corresponding to the input voltage Vin- and the input voltage Vin+ in FIG. 3 at a distance.

[0041] Therefore, in the present embodiment, the lead terminals 12a and 12d are used as the input terminals. Thereby, a short circuit between the lead terminals 12 can be prevented.

[0042] Also, in the present embodiment, the lead terminal 12f and the lead terminal 12g are connected to an operational amplifier (not shown). The lead terminals 12b and 12c are not electrically connected to the external wiring, but function as a bonding portion for bonding to a circuit board (not shown). Thereby, the mounting strength when mounting the resistor 1 on the circuit board is enhanced.

[0043] The resistor 1 is encapsulated with an insulating resin 30 in a state where the pad portions P of the first circuit element 22 and the second circuit element 23 and the inner lead portions 121 are wire-bonded.

[0044] As the insulating resin 30, thermosetting resins such as epoxy resin, silicone resin, urethane resin, and phenol resin can be applied. By mixing fillers such as silicon dioxide filler and curing agents into these thermosetting resins, the coefficient of thermal expansion of the insulating resin is set to a value close to the coefficients of thermal expansion of the first circuit element 22, the second circuit element 23, the first insulating substrate 211, and the second insulating substrate 212.

[0045] In the present embodiment, from the viewpoint of affinity, it is preferable to apply the same resin as the insulating resin applied to the insulating portion 24 to the insulating resin 30.

[0046] By encapsulating the lead frame 10 and the circuit body 20 with the insulating resin 30, the lead frame 10 and the circuit body 20 can be protected from damage due to external impacts, adhesion of dust, moisture, etc., and the performance of the resistor 1 can be maintained over a long period.

[0047] The resistor 1 configured as described above is mounted by soldering to connection terminals provided at predetermined positions of wirings (external wirings) of a circuit board (not shown) at the outer lead portion 122.

[0048] <Manufacturing method of the circuit body> A manufacturing method of the circuit body 20 in the resistor 1 according to the present embodiment will be described.

[0049] · Cleaning of the insulating substrate The insulating substrate 21 constituting the circuit body 20 is cleaned.

[0050] · Film formation of the metal thin film A metal thin film for the first circuit element 22 and the second circuit element 23 is formed. In the present embodiment, as an example, a metal thin film constituting the first circuit element 22 and the second circuit element 23 is formed on the surface of the insulating substrate 21 (the first insulating substrate 211 and the second insulating substrate 212) by sputtering using a chromium (Cr)-based alloy or a nickel-chromium (Ni-Cr)-based alloy as the metal material.

[0051] ·Patterning Circuit patterns that respectively function as the first resistor 221, the second resistor 222, the third resistor 231, and the fourth resistor 232 are formed on the formed metal thin film by photolithography.

[0052] ·Formation of pad portions In the present embodiment, pad portions P are formed by sputtering using an Al alloy at predetermined locations having the formed circuit pattern shape.

[0053] ·Division of circuit body After the pad portions P are formed, the circuit body 20 is cut out by dividing the slit. The circuit body 20 can be manufactured by the above steps.

[0054] <Manufacturing method of resistor> Subsequently, the manufacturing method of the resistor 1 according to the present embodiment will be described.

[0055] ·Die bonding The circuit body 20 is joined to the lead frame 10 using an adhesive. As an example of the adhesive, a silver paste adhesive can be used.

[0056] ·Wire bonding Wire bonding is performed between the pad portions P of the first circuit element 22 and the second circuit element 23 formed on the circuit body 20 and the lead terminals 12 on the lead frame 10.

[0057] ·Molding The circuit body 20 covers (molds) the lead frame 10 connected by wire bonding with an insulating resin 30. Before the molding process, a protective film may be formed on the resistors of the first circuit element 22 and the second circuit element 23 of the circuit body 20.

[0058] ·Plating formation As an example, Sn plating is formed on the outer lead portion 122.

[0059] ·Forming The lead frame 10 is cut from the lead frame body. Further, press working is performed using a mold to adjust the shape of the outer lead portion 122 (forming). Through the above steps, the resistor 1 can be manufactured.

[0060] [Effect according to the embodiment] In the resistor 1 according to the first embodiment, the circuit body 20 includes a die pad 11, a first insulating substrate 211 and a second insulating substrate 212 disposed on the die pad 11, a first circuit element 22 disposed on the first insulating substrate 211, a second circuit element 23 disposed on the second insulating substrate 212, and an insulating portion 24 disposed between the first circuit element 22 and the second circuit element 23 and insulating the first circuit element 22 and the second circuit element 23. The lead frame 10 and the circuit body 20 are covered with an insulating resin 30.

[0061] The resistor 1 according to the first embodiment includes the first circuit element 22 and the second circuit element 23 for miniaturization, and includes an insulating portion 24 for insulating the first circuit element 22 and the second circuit element 23, and is sealed with an insulating resin 30.

[0062] Therefore, compared with a general resistor in which the first circuit element 22 and the second circuit element 23 are separately sealed with an insulating resin 30, the resistor 1 can increase the insulation between the first circuit element 22 and the second circuit element 23 while achieving miniaturization. Therefore, a compact resistor that can reliably prevent a short circuit between circuit elements can be realized.

[0063] For example, even when the resistor 1 is used in an environment where a high voltage is applied, the first circuit element 22 and the second circuit element 23 can be arranged side by side within a single circuit body 20 while maintaining insulation between them. Therefore, even in an environment where a high voltage is applied, the resistor 1 can meet the requirement of miniaturization while avoiding a short circuit between circuit elements.

[0064] In the resistor 1, the insulating substrate 21 includes a first insulating substrate 211 on which the first circuit element 22 is formed, and a second insulating substrate 212 on which the second circuit element 23 is formed and which is separated from the first insulating substrate 211. That is, the first insulating substrate 211 on which the first circuit element 22 is formed and the second insulating substrate 212 on which the second circuit element 23 is formed are separated from each other.

[0065] When the resistor is used for high-voltage applications, if the circuit elements contained therein include defective parts such as fine dirt, dust, impurities, etc., the greater the difference in potential applied to each circuit element, the easier it is for electrolytic corrosion to spread from the defective parts.

[0066] In contrast, in the resistor 1, since the first insulating substrate 211 and the second insulating substrate 212 are separated, electrolytic corrosion due to the potential difference applied between the first circuit element 22 formed on the first insulating substrate 211 and the second circuit element 23 formed on the second insulating substrate 212 is less likely to occur. Also, since the insulating substrate is separated, it is possible to prevent the spread of electrolytic corrosion between the first circuit element 22 and the second circuit element 23.

[0067] Further, in the resistor 1, by arranging the first insulating substrate 211 on which the first circuit element 22 is formed and the second insulating substrate 212 on which the second circuit element 23 is formed as far apart as possible, the heat generated from the circuit body 20 can be easily dispersed over the entire surface of the insulating resin 30 covering the resistor 1, so that the heat dissipation effect can be enhanced.

[0068] The resistor 1 has the same circuit pattern shape for the first circuit element 22 and the second circuit element 23. Therefore, variations in the performance of the resistor 1 can be suppressed. Also, the manufacturing cost of the resistor 1 can be reduced.

[0069] In this embodiment, in the first circuit element 22, a first resistor having a resistance value R1 and a second resistor having a resistance value R2 are formed as the circuit pattern. Also, in the second circuit element 23, a third resistor having a resistance value R3 and a fourth resistor having a resistance value R4 are formed as the circuit pattern.

[0070] When the circuit pattern is formed as described above, since the first circuit element 22 and the second circuit element 23 have the same circuit pattern shape, variations in the performance of each resistor element can be suppressed.

[0071] Also, when a voltage dividing circuit is formed such that the resistance value R1 of the first resistor 221, the resistance value R2 of the second resistor 222, the resistance value R3 of the third resistor 231, and the resistance value R4 of the fourth resistor 232 satisfy R2 / R1 = R4 / R3, variations in each resistor element can be suppressed, and thus a high-precision voltage dividing circuit can be configured.

[0072] The first insulating substrate 211, the second insulating substrate 212, the first circuit element 22, and the second circuit element 23 are all formed as thin films. That is, the circuit body 20 is a circuit formed as a thin film. Therefore, the resistor 1 can be miniaturized.

[0073] Also, since the circuit body 20 is formed as a thin film, the first circuit element 22 and the second circuit element 23 can each be wire-bonded to any of the plurality of lead terminals 12. According to wire bonding, an intermetallic compound is formed between the pad portion P and the lead terminal 12 in the first circuit element 22 and the second circuit element 23, so high connection reliability can be obtained.

[0074] As shown in Fig. 2, for the resistor 1 according to the embodiment, the surface of the die pad 11 is formed to be lower than the inner lead portion 121 of the lead terminal 12. Thereby, the height difference between the inner lead portion 121 and the surface of the first circuit element 22 formed on the first insulating substrate 211 can be reduced. Thereby, when wire bonding the first circuit element 22 and the inner lead portion 121, the trajectory of the capillary for performing wire bonding can be lowered. Thereby, the bonding wire W can be formed by an ideal trajectory. Therefore, errors in wire bonding can be prevented.

[0075] [Modification Example] [First Modification Example] Fig. 4 is a plan view of the resistor 2 as a first modification example, as viewed from the upper surface side of the resistor 2. In Fig. 4, for the sake of clarity of explanation, the insulating resin 30 covering the upper surface of the resistor 2 is not shown. Also, components having the same effects as those of the resistor 1 shown in Fig. 1 are denoted by the same reference numerals and detailed description thereof is omitted.

[0076] In the first modification example, both the first circuit element 22 and the second circuit element 23 are formed on one insulating substrate 200 disposed on the die pad 11.

[0077] In the case of the resistor 2 according to the first modification example, since both the first circuit element 22 and the second circuit element 23 are disposed within the region of the insulating substrate 200, the dimensions in the arrangement direction of the first circuit element 22 and the second circuit element 23 can be shortened.

[0078] Thereby, the mounting area of the circuit body 20 within the lead frame 10 of the resistor 2 can be reduced. Therefore, the requirement for miniaturization of the resistor 2 can be met.

[0079] [Second Modification Example] FIG. 5 is a plan view of the resistor 3 as a second modification, as seen from the upper surface side of the resistor 3. In FIG. 5, for the sake of clarity of explanation, the insulating resin 30 covering the upper surface of the resistor 3 is not shown. Also, components having the same operational effects as those of the resistor 1 shown in FIG. 1 are given the same reference numerals and detailed descriptions thereof are omitted.

[0080] As shown in FIG. 5, in the resistor 3 according to the second modification, the first circuit element 22 and the second circuit element 23 are formed symmetrically with respect to a virtual line L that crosses an insulating portion 24 disposed between the first circuit element 22 and the second circuit element 23.

[0081] By making the first circuit element 22 and the second circuit element 23 line-symmetrical, when connecting to the lead terminal 12 by wire bonding, the lengths of the bonding wires W from the pad portions P of the first circuit element 22 and the second circuit element 23 to the lead terminal 12 as the connection destination can be made equal.

[0082] Also, as the same circuit pattern shape, the length of the bonding wire W can be made shorter compared to the resistors 1 arranged side by side.

[0083] [Other Embodiments] Although the present embodiment has been described above, the above embodiment merely shows one example of the application of the present invention, and is not intended to limit the technical scope of the present invention to the specific configuration of the above embodiment.

[0084] The circuit pattern shapes of the first circuit element 22 and the second circuit element 23 shown in the resistor 1 in the present embodiment, the resistor 2 in the first modification, and the resistor 3 in the second modification are not limited to those illustrated in FIGS. 1, 4, and 5.

[0085] Also, the circuits formed in the first circuit element 22 and the second circuit element 23 are not limited to resistors.

[0086] As a method for forming the first circuit element 22 and the second circuit element 23 on the insulating substrate 21, a plating method, a vacuum evaporation method, an ion plating method, a sputtering method, a vapor growth method, a cold spray method, or the like can be used.

Explanation of Signs

[0087] 1, 2, 3 Resistor 10 Lead Frame 11 Die Pad 12 (12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h) Lead Terminal 20 Circuit Body 21 Insulating Substrate 22 First Circuit Element 23 Second Circuit Element 24 Insulating Portion 30 Insulating Resin 121 Inner Lead Portion 122 Outer Lead Portion 200 Insulating Substrate 211, 212 Insulating Substrate 221 First Resistor 222 Second Resistor 231 Third Resistor 232 Fourth Resistor P Pad Portion R1, R2, R3, R4 Resistance Value L Virtual Line W Bonding Wire

Claims

1. A die pad, a circuit body disposed on the die pad, and comprising: The circuit body includes: an insulating substrate, a first circuit element and a second circuit element disposed on the insulating substrate, an insulating portion disposed between the first circuit element and the second circuit element and insulating the first circuit element and the second circuit element, and having: The die pad and the circuit body are covered with an insulating resin, a resistor.

2. The resistor according to claim 1, wherein a circuit pattern shape of the first circuit element is the same as a circuit pattern shape of the second circuit element, a resistor.

3. The resistor according to claim 1 or 2, wherein the first circuit element has a first resistor with a resistance value R1 and a second resistor with a resistance value R2, the second circuit element has a third resistor with a resistance value R3 and a fourth resistor with a resistance value R4, and is configured such that R2 / R1 = R4 / R3, a resistor.

4. The resistor according to claim 1, wherein the circuit body is a circuit formed by thin film formation, a resistor.

5. The resistor according to claim 4, wherein the circuit body includes a plurality of lead terminals connected to external wiring, and the first circuit element and the second circuit element are each connected to any one of the plurality of lead terminals by wire bonding, a resistor.

6. The resistor according to claim 1, wherein the insulating substrate includes: a first insulating substrate on which the first circuit element is formed, a second insulating substrate on which the second circuit element is formed and which is separated from the first insulating substrate, and comprising: a resistor. ​

Images