Resistor

Abstract

This resistor comprises a die pad and a circuit body disposed on the die pad, wherein the circuit body includes 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 to insulate the first circuit element and the second circuit element, and the die pad and the circuit body are covered with an insulating resin.

Description

resistor

[0001] The present invention relates to a resistor.

[0002] JP2023-042044A discloses a semiconductor device that has a resistor and can widen the output voltage range with a simple configuration.

[0003] As described above, in semiconductor devices in which multiple chips are formed on one die pad in order to achieve miniaturization, measures to prevent short circuits between the multiple chips are essential, particularly under operating conditions in which high voltages are applied.

[0004] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a resistor that includes a plurality of circuit elements and is sealed with resin, and to improve the insulation between the circuit elements while achieving miniaturization.

[0005] According to one aspect of the present invention, there is provided a resistor comprising a die pad and a circuit body arranged on the die pad, the circuit body having 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.

[0006] According to one aspect of the present invention, in a resistor that includes multiple circuit elements and is resin-encapsulated, an insulating portion is provided between a first circuit element and a second circuit element, thereby enabling miniaturization while improving insulation between the circuit elements.

[0007] FIG. 1 is a plan view of the resistor viewed from the top surface side, illustrating the structure of the resistor according to this embodiment. FIG. 2 is a cross-sectional view of the resistor taken along line II-II in FIG. 1. FIG. 3 is a circuit diagram illustrating a general voltage divider circuit. FIG. 4 is a plan view of the resistor viewed from the top surface side, illustrating the structure of the resistor according to a first modified example. FIG. 5 is a plan view of the resistor viewed from the top surface side, illustrating the structure of the resistor according to a second modified example.

[0008] [Embodiment] <Resistor> The structure of a resistor according to the present embodiment will be described with reference to the drawings. In this specification, the same or equivalent elements are designated by the same reference numerals throughout.

[0009] The resistor is, for example, a thin-film chip resistor connected to a circuit board as a power module for processing high-voltage and large-current signals. In this embodiment, the resistor functions as a voltage divider circuit that divides a high voltage of several hundred volts or more applied to the circuit board into a low voltage of several volts for detection.

[0010] Fig. 1 is a plan view of the resistor 1 as seen from the top side, illustrating the structure of the resistor 1 according to this embodiment. For ease of understanding, the insulating resin (mold resin) covering the top surface of the resistor 1 is not shown in Fig. 1. Fig. 2 is a cross-sectional view of the resistor 1 taken along line II-II in Fig. 1.

[0011] 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 .

[0012] The resistor 1 has lead terminals 12 (plurality of lead terminals 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h). The die pad 11 and the lead terminals 12 form a lead frame 10. In this embodiment, when the lead terminals are not to be distinguished from one another, they are represented by the letters omitting the letters, such as lead terminal 12.

[0013] The die pad 11 and lead terminals 12 that constitute the lead frame 10 are formed from thin plates of metal materials such as copper, copper alloys, and iron-nickel alloys, which have excellent mechanical strength, electrical conductivity, thermal conductivity, corrosion resistance, etc. The die pad 11 and lead terminals 12 are obtained from these thin metal films by processing such as punching (pressing) and etching.

[0014] The lead terminal 12 has an inner lead portion 121 electrically connected to the electrode connection portion (hereinafter referred to as the pad portion P) of the first circuit element 22 and the second circuit element 23 formed in the circuit main body 20, and an outer lead portion 122 connected to external wiring not shown.

[0015] In this embodiment, the circuit body 20 includes an insulating substrate 21 , a first circuit element 22 , a second circuit element 23 , and an insulating portion 24 disposed between the first circuit element 22 and the second circuit element 23 .

[0016] In this embodiment, the insulating substrate 21 includes 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.

[0017] The first insulating substrate 211 and the second insulating substrate 212 are made of an insulating material. In this embodiment, for example, the insulating substrate 21 is made of alumina (Al ２ O ３ The insulating substrate 21 may be an alumina substrate, a thermal oxide film obtained by modifying the surface of a silicon substrate into an oxide film, or a silicon oxide film or silicon nitride film formed by CVD or the like.

[0018] 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 forming a film by sputtering, plasma CVD, or the like using a material capable of forming a circuit pattern, and then by photolithography or the like.

[0019] Examples of metal materials that can be used to form the thin film circuit pattern include copper, chromium (Cr), metal materials mainly made of chromium (Cr), nickel-chromium (Ni-Cr), metal materials mainly made of nickel-chromium (Ni-Cr), metal oxide materials, etc. The metal material can be appropriately selected depending on the application of the resistor 1 from materials that can provide high-precision resistance tolerance and temperature characteristics, materials that are highly resistant to high voltages and surges, materials that have good TCR characteristics, etc.

[0020] In this embodiment, a chromium (Cr) alloy or a nickel-chromium (Ni-Cr) alloy can be suitably used as an example of a material that can form a circuit pattern.

[0021] After the circuit patterns of the first circuit element 22 and the second circuit element 23 are formed, a conductive material is used to form a film of the pad portion P. In this embodiment, the pad portion P is formed by sputtering an Al alloy, for example.

[0022] The first circuit element 22 is formed in a predetermined circuit pattern shape on the first insulating substrate 211. In this embodiment, the first circuit element 22 has a first resistor 221 and a second resistor 222 as the circuit pattern shape.

[0023] The first resistor 221 is set to a meandering shape with a predetermined line width, meandering amplitude, and meandering number so as to have a resistance value R1, while the second resistor 222 is set to a meandering shape with a predetermined line width, meandering amplitude, and meandering number so as to have a resistance value R2.

[0024] The second circuit element 23 is formed in a predetermined circuit pattern shape on the second insulating substrate 212. In the present embodiment, the second circuit element 23 has a third resistor 231 and a fourth resistor 232 as the circuit pattern.

[0025] The third resistor 231 is set to a meandering shape with a predetermined line width, meandering amplitude, and meandering number so as to have a resistance value R3, and the fourth resistor 232 is set to a meandering shape with a predetermined line width, meandering amplitude, and meandering number so as to have a resistance value R4.

[0026] In this 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. In the resistor 1, the first circuit element 22 and the second circuit element 23 having the same circuit pattern shape are arranged side by side.

[0027] FIG. 3 is a circuit diagram illustrating a typical voltage divider circuit.

[0028] The voltage divider circuit shown in FIG. 3 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 condition: R2 / R1=R4 / R3

[0029] Furthermore, when extracting a potential difference smaller than the input potential difference, the voltage divider circuit is designed to satisfy R1>R2, forming a step-down circuit in which the output voltage Vout is smaller than the input potential difference.

[0030] In this embodiment, the resistance value R1 of the first resistor 221 formed in the first circuit element 22, the resistance value R2 of the second resistor 222, the resistance value R3 of the third resistor 231 formed in the second circuit element 23, and the resistance value R4 of the fourth resistor 232 are configured to satisfy the following condition: R2 / R1=R4 / R3, where R1>R2.

[0031] That is, the circuit body 20 in the resistor 1 constitutes a pressure reducing circuit.

[0032] The insulating portion 24 is disposed between the first circuit element 22 and the second circuit element 23, and physically shields the first circuit element 22 from the second circuit element 23 while electrically insulating the first circuit element 22 from the second circuit element 23.

[0033] The insulating material that constitutes the insulating portion 24 may be an inorganic material or a resin that has insulating properties.

[0034] Examples of insulating inorganic materials that can be used include glass fiber materials formed by mixing silicon dioxide, aluminum oxide, calcium oxide, magnesium oxide, boron oxide, etc. Also usable are inorganic materials such as aluminum nitride and magnesium oxide, and minerals such as mica.

[0035] The insulating resin may be a thermosetting resin such as an epoxy resin, a silicone resin, a urethane resin, a phenolic resin, etc. By mixing a filler such as a silicon dioxide filler or a curing agent into the thermosetting resin, 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.

[0036] It is preferable to arrange the first circuit element 22 and the second circuit element 23, and the first insulating substrate 211 and the second insulating substrate 212 as widely spaced as possible within the area of ​​the die pad 11 of the resistor 1 in order to prevent short circuits between the first circuit element 22 and the second circuit element 23 and to ensure a volume of the insulating portion 24 that will provide sufficient insulation effect.

[0037] As shown in FIG. 1, the first circuit element 22 and the second circuit element 23 of the resistor 1 are connected to inner lead portions 121 by bonding wires W at predetermined pad portions P.

[0038] Under high temperature and pressure conditions, Au (gold) can form an intermetallic compound with Al (aluminum) that provides a highly reliable connection. Utilizing this property, the pad portions P of the first circuit element 22 and the second circuit element 23 are bonded to the inner lead portions 121 with Au wires using ultrasonic vibration. Cu (copper) wires can also be used instead of Au wires. In wire bonding, bonding wires with a diameter of 10 μm to 100 μm are generally formed.

[0039] 3, when reducing a voltage from a high voltage to a low voltage, a high voltage is applied to the input terminals (Vin-, Vin+). For this reason, it is preferable to arrange the input terminals corresponding to the input voltage Vin- and input voltage Vin+ in FIG. 3 far apart in resistor 1.

[0040] Therefore, in this embodiment, the lead terminals 12a and 12d are used as input terminals, which makes it possible to prevent short circuits between the lead terminals 12.

[0041] In this embodiment, the lead terminals 12f and 12g are connected to an operational amplifier (not shown). The lead terminals 12b and 12c are not electrically connected to external wiring, but function as joints for joining to a circuit board (not shown). This increases the mounting strength when the resistor 1 is mounted on the circuit board.

[0042] The resistor 1 is sealed with an insulating resin 30 in a state in which the pad portions P of the first circuit element 22 and the second circuit element 23 are wire-bonded to the inner lead portions 121 .

[0043] Thermosetting resins such as epoxy resin, silicone resin, urethane resin, and phenol resin can be used as insulating resin 30. By mixing a filler such as silicon dioxide filler or a curing agent into these thermosetting resins, the thermal expansion coefficient of the insulating resin is set to a value close to the thermal expansion coefficients of first circuit element 22, second circuit element 23, first insulating substrate 211, and second insulating substrate 212.

[0044] In this embodiment, it is preferable that the insulating resin 30 be the same resin as the insulating resin used for the insulating portion 24 from the viewpoint of affinity.

[0045] By sealing the lead frame 10 and the circuit body 20 with insulating resin 30, the lead frame 10 and the circuit body 20 are protected from scratches due to external impacts, dust adhesion, moisture, etc., and the performance of the resistor 1 can be maintained for a long period of time.

[0046] The resistor 1 configured as above is mounted by soldering the outer lead portion 122 to a connection terminal provided at a predetermined position on wiring (external wiring) of a circuit board (not shown).

[0047] <Method of Manufacturing Circuit Body> A method of manufacturing the circuit body 20 of the resistor 1 according to this embodiment will be described.

[0048] Cleaning of the insulating substrate The insulating substrate 21 that constitutes the circuit body 20 is cleaned.

[0049] Deposition of Metal Thin Films Metal thin films are formed for the first circuit element 22 and the second circuit element 23. In the present embodiment, as an example, a metal thin film that constitutes the first circuit element 22 and the second circuit element 23 is formed on the surface of the insulating substrate 21 (first insulating substrate 211, second insulating substrate 212) by sputtering using a chromium (Cr)-based alloy or a nickel-chromium (Ni—Cr)-based alloy as the metal material.

[0050] Patterning Circuit patterns that function as the first resistor 221, the second resistor 222, the third resistor 231, and the fourth resistor 232 are formed on the deposited metal thin film by photolithography.

[0051] Formation of Pads In this embodiment, pads P are formed at predetermined locations on the formed circuit pattern by sputtering using an Al alloy.

[0052] Dividing the Circuit Body After the pad portions P are formed, the slits are divided to cut out the circuit body 20. Through the above steps, the circuit body 20 can be manufactured.

[0053] <Manufacturing Method of Resistor> Next, a manufacturing method of the resistor 1 according to this embodiment will be described.

[0054] Die Bonding: An adhesive is used to bond the circuit body 20 to the lead frame 10. As an example of the adhesive, a silver paste adhesive can be used.

[0055] Wire Bonding The pad portions P of the first circuit element 22 and the second circuit element 23 formed on the circuit body 20 are wire-bonded to the lead terminals 12 of the lead frame 10 .

[0056] Molding The lead frame 10 to which the circuit body 20 is connected by wire bonding is covered (molded) with insulating resin 30. Before the molding step, 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.

[0057] Plating Formation As an example, Sn plating is formed on the outer lead portion 122 .

[0058] Forming: The lead frame 10 is cut from the lead frame body. Then, a press process 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.

[0059] [Effects of the embodiment] In the resistor 1 according to the first embodiment, the circuit body 20 includes the die pad 11, a first insulating substrate 211 and a second insulating substrate 212 arranged on the die pad 11, a first circuit element 22 arranged on the first insulating substrate 211, a second circuit element 23 arranged on the second insulating substrate 212, and an insulating portion 24 arranged between the first circuit element 22 and the second circuit element 23 to insulate the first circuit element 22 from the second circuit element 23. The lead frame 10 and the circuit body 20 are covered with an insulating resin 30.

[0060] The resistor 1 according to the first embodiment includes a first circuit element 22 and a second circuit element 23 to achieve miniaturization, and is provided with an insulating portion 24 that insulates the first circuit element 22 from the second circuit element 23, and is sealed with insulating resin 30.

[0061] Therefore, the resistor 1 can be made smaller and have better insulation between the first circuit element 22 and the second circuit element 23 than a typical resistor in which the first circuit element 22 and the second circuit element 23 are separately sealed with the insulating resin 30. Therefore, a compact resistor can be realized that can reliably prevent short circuits between the circuit elements.

[0062] 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 in one circuit body 20 while maintaining insulation between the first circuit element 22 and the second circuit element 23. Therefore, the resistor 1 can avoid short circuits between the circuit elements while meeting the demand for miniaturization, even in an environment where a high voltage is applied.

[0063] 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.

[0064] When a resistor is used for high voltage applications, if the circuit elements contained therein contain defects such as minute dirt, dust, or impurities, the greater the difference in potentials applied to each circuit element, the more likely it is that electrolytic corrosion will spread from the defect.

[0065] In contrast, in resistor 1, because first insulating substrate 211 and second insulating substrate 212 are separated, electrolytic corrosion due to a potential difference applied between first circuit element 22 formed on first insulating substrate 211 and second circuit element 23 formed on second insulating substrate 212 is less likely to occur. Furthermore, because the insulating substrates are separated, electrolytic corrosion can be prevented from spreading between first circuit element 22 and second circuit element 23.

[0066] Furthermore, in the resistor 1, by positioning 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 more easily dispersed over the entire surface of the insulating resin 30 covering the resistor 1, thereby improving the heat dissipation effect.

[0067] In the resistor 1, the circuit pattern shape of the first circuit element 22 is the same as the circuit pattern shape of the second circuit element 23. This can reduce variations in the performance of the resistor 1. In addition, the manufacturing cost of the resistor 1 can be reduced.

[0068] In this embodiment, the first circuit element 22 has a circuit pattern including a first resistor having a resistance value R1 and a second resistor having a resistance value R2, while the second circuit element 23 has a circuit pattern including a third resistor having a resistance value R3 and a fourth resistor having a resistance value R4.

[0069] When the circuit pattern is formed as described above, the first circuit element 22 and the second circuit element 23 have the same circuit pattern shape, so that variations in performance of each resistor element can be suppressed.

[0070] Furthermore, when a voltage divider circuit is formed in which 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 are R2 / R1=R4 / R3, the variation in each resistor element can be suppressed, and therefore a highly accurate voltage divider circuit can be constructed.

[0071] 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. This allows the resistor 1 to be miniaturized.

[0072] Furthermore, 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 one of the plurality of lead terminals 12. By wire bonding, an intermetallic compound is formed between the pad portions P of the first circuit element 22 and the second circuit element 23 and the lead terminals 12, thereby achieving high connection reliability.

[0073] As shown in Fig. 2, in the resistor 1 according to the embodiment, the surface of the die pad 11 is formed so as to be lower than the inner lead portion 121 of the lead terminal 12. This reduces 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. This allows the trajectory of the capillary used for wire bonding to be lowered when wire bonding the first circuit element 22 to the inner lead portion 121. This allows the bonding wire W to be formed along an ideal trajectory. This prevents errors in wire bonding.

[0074] [Modifications] <First Modification> Fig. 4 is a plan view of a resistor 2 as a first modification, seen from the top side of the resistor 2. To make the description easier to understand, Fig. 4 does not show the insulating resin 30 that covers the top surface of the resistor 2. Furthermore, components having the same functions and effects as those of the resistor 1 shown in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0075] In the first modification, both the first circuit element 22 and the second circuit element 23 are formed on a single insulating substrate 200 disposed on the die pad 11 .

[0076] In the case of the resistor 2 according to the first variant, both the first circuit element 22 and the second circuit element 23 are arranged within the area of ​​the insulating substrate 200, so that the dimensions of the first circuit element 22 and the second circuit element 23 in the arrangement direction can be shortened.

[0077] This makes it possible to reduce the mounting area of ​​the circuit body 20 within the lead frame 10 of the resistor 2. Therefore, it is possible to meet the demand for miniaturization of the resistor 2.

[0078] <Second Modification> Fig. 5 is a plan view of a resistor 3 as a second modification, seen from the top side of the resistor 3. To make the explanation easier to understand, Fig. 5 does not show the insulating resin 30 that covers the top surface of the resistor 3. Furthermore, components having the same functions and effects as those of the resistor 1 shown in Fig. 1 are denoted by the same reference numerals, and detailed explanations thereof will be omitted.

[0079] 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 the insulating portion 24 arranged between the first circuit element 22 and the second circuit element 23.

[0080] By making the first circuit element 22 and the second circuit element 23 symmetrical with respect to an axis, when connecting to the lead terminal 12 by wire bonding, the length of the bonding wire W from the pad portion P of the first circuit element 22 and the second circuit element 23 to the lead terminal 12 to which it is connected can be made equal.

[0081] Furthermore, the length of the bonding wire W can be made shorter than that of resistors 1 arranged side by side with the same circuit pattern shape.

[0082] [Other Embodiments] The present embodiment has been described above, but the above embodiment merely shows one application example 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.

[0083] The circuit pattern shapes of the first circuit element 22 and the second circuit element 23 shown in the resistor 1 in this embodiment, the resistor 2 in the first modified example, and the resistor 3 in the second modified example are not limited to those shown in Figures 1, 4, and 5.

[0084] Furthermore, the circuits formed in the first circuit element 22 and the second circuit element 23 are not limited to resistors.

[0085] The first circuit element 22 and the second circuit element 23 can be formed on the insulating substrate 21 by plating, vacuum deposition, ion plating, sputtering, vapor phase growth, cold spraying, or the like.

[0086] This application claims priority based on Japanese Patent Application No. 2024-8204, filed with the Japan Patent Office on January 23, 2024, the entire contents of which are incorporated herein by reference.

[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 resistor comprising a die pad and a circuit body disposed on the die pad, wherein the circuit body includes 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 for insulating the first circuit element and the second circuit element, and wherein the die pad and the circuit body are covered with an insulating resin.

2. The resistor according to claim 1, wherein the circuit pattern shapes of the first circuit element and the second circuit element are the same.

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

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

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 one of the plurality of lead terminals by wire bonding.

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

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