Semiconductor device manufacturing method
11071212 · 2021-07-20
Assignee
Inventors
Cpc classification
H01L2924/19105
ELECTRICITY
Y02P70/50
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H01L21/4853
ELECTRICITY
H01L2924/00012
ELECTRICITY
H01L2224/48096
ELECTRICITY
H01L2224/49111
ELECTRICITY
H01L2224/32225
ELECTRICITY
H01L2224/0603
ELECTRICITY
H01L2224/32225
ELECTRICITY
H01L2224/29101
ELECTRICITY
H01L2924/00
ELECTRICITY
H01L25/16
ELECTRICITY
H01L2224/48139
ELECTRICITY
H01L2924/00
ELECTRICITY
H05K3/4015
ELECTRICITY
B23K3/087
PERFORMING OPERATIONS; TRANSPORTING
H01L2924/00014
ELECTRICITY
H05K2203/0278
ELECTRICITY
H05K2201/0367
ELECTRICITY
H01L2224/48139
ELECTRICITY
H01L25/50
ELECTRICITY
H01L2224/48096
ELECTRICITY
H01L2224/29101
ELECTRICITY
H01L2224/49111
ELECTRICITY
H01L2924/00014
ELECTRICITY
H01L2224/83192
ELECTRICITY
H01L2924/00012
ELECTRICITY
H01L2224/92247
ELECTRICITY
H01L2224/92247
ELECTRICITY
H01L23/49811
ELECTRICITY
B23K1/0016
PERFORMING OPERATIONS; TRANSPORTING
H01L24/73
ELECTRICITY
H01L23/3735
ELECTRICITY
International classification
H01R12/00
ELECTRICITY
H01L25/07
ELECTRICITY
H01L23/498
ELECTRICITY
H05K3/30
ELECTRICITY
Abstract
A pressing area set on a main surface of a plate-shaped holding jig is arranged on contact parts. The contact parts are pressed against a multilayer board while heating the multilayer board and the pressing area of the holding jig is inclined with a warp of the multilayer board. In this way, when pressing for bonding the contact parts is performed, even if the multilayer board is warped by the heating and the contact parts are shifted, the contact parts are pressed against the multilayer board without fail.
Claims
1. A semiconductor device manufacturing method; comprising: preparing a multilayer board and a plurality of contact parts, the multilayer board including an insulating layer; a circuit pattern layer formed on a front surface of the insulating layer, and a metal layer formed on a rear surface of the insulating layer and having an area larger than an area of the circuit pattern layer in a plan view of the multilayer board; arranging each of the plurality of contact parts on the circuit pattern layer of the multilayer board via a bonding material; arranging a pressing area of a main surface of a plate-shaped holding jig on the plurality of contact parts; and while heating the multilayer board, pressing the plurality of contact parts against the multilayer board by inclining the pressing area of the holding jig to conform to a warp of the multilayer board.
2. The semiconductor device manufacturing method according to claim 1, wherein the holding jig includes a plurality of pressing blocks, each of which includes a pressing surface; and the pressing surfaces are planarly engaged with one another to form the pressing area.
3. The semiconductor device manufacturing method according to claim 2, wherein the arranging of the pressing area includes supporting each of the plurality of contact parts by a corresponding one of the plurality of pressing surfaces of the holding jig, and wherein the pressing of the plurality of contact parts includes pressing the plurality of contact parts against the multilayer board by moving the plurality of pressing surfaces with movements of the plurality of contact parts due to the warp of the multilayer board.
4. The semiconductor device manufacturing method according to claim 2, wherein a boundary line between any adjacent two of the plurality of pressing surfaces of the holding jig is shifted from a midpoint of the pressing area in a predetermined direction.
5. The semiconductor device manufacturing method according to claim 2, wherein the pressing area has a rectangular shape having side faces facing in a first direction and side faces facing in a second direction orthogonal to the first direction, a boundary between any adjacent two of the plurality of pressing blocks of the holding jig is located apart from one of first and second center lines, and is parallel to the one of the first and second center lines, the first center line being a line passing through a center of the pressing area in a direction parallel to the first direction, the second center line being a line passing through the center of the pressing area in a direction parallel to the second direction.
6. The semiconductor device manufacturing method according to claim 2, wherein the holding jig includes the plurality of pressing blocks and a frame portion provided with the plurality of pressing blocks.
7. The semiconductor device manufacturing method according to claim 6, wherein supporting portions supported by the frame portion are formed on peripheral portions of surfaces respectively opposite to the pressing surfaces of the pressing blocks.
8. The semiconductor device manufacturing method according to claim wherein each supporting portion has a width larger than a gap between any adjacent two of the plurality of pressing blocks.
9. The semiconductor device manufacturing method according to claim 8, wherein a largest pressing block among the plurality of pressing blocks having a largest pressing surface among the plurality of pressing surfaces area has a first surface, and an adjacent pressing block that is adjacent to the largest pressing block has a second surface facing the first surface, one of the first and second surfaces including a concave portion, the other one of the first and second surfaces including a convex portion that is fitted with the concave portion.
10. The semiconductor device manufacturing method according to claim 1, further comprising, after bonding the plurality of contact parts to the circuit pattern layer by the bonding material, removing the holding jig from the multilayer board.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
(17) Hereinafter, a semiconductor device manufacturing method according to a first embodiment will be described with reference to
(18) First, a multilayer board 1 and a plurality of contact parts 2a to 2c are prepared. The multilayer board 1 includes an insulating layer 1a, circuit pattern layers 1b1 and 1b2 that are formed on a front surface of the insulating layer 1a, and a metal layer 1c that is formed on a rear surface of the insulating layer 1a and that has a larger area than those of the circuit pattern layers 1b1 and 1b2. The insulating layer 1a, the circuit pattern layers 1b1 and 1b2, and the metal layer 1c of the multilayer board 1 have different thermal expansion rates. In addition, for example, each of the contact parts 2a to 2c has a cylindrical shape, and a through-hole is formed therein. A pin external connection terminal (not illustrated) is inserted into each of these contact parts 2a to 2c.
(19) Bonding material 3a to 3c is applied onto the circuit pattern layers 1b1 and 1b2 of the multilayer board 1, and the contact parts 2a to 2c are arranged on the bonding material 3a to 3c, respectively (
(20) Next, as a pre-pressing step, a pressing area 4a set on a main surface of a plate-shaped holding jig 4 is arranged on the contact parts 2a to 2c arranged on the circuit pattern layers 1b1 and 1b2 of the multilayer board 1 (
(21) Next, in this state, the holding jig 4 is pressed against the multilayer board 1 while being heated as a pressing step. When heated, the multilayer board 1 is warped in a downward convex shape (in the direction of the gravitational force) due to the difference among the thermal expansion rates of the insulating layer 1a, the circuit pattern layers 1b1 and 1b2, and the metal layer 1c. The pressing area 4a of the holding jig 4 is also inclined with the warp of the multilayer board 1. In this way, even when the contact parts 2a to 2c arranged on the warped multilayer board 1 are shifted, since the pressing area 4a moves with the warp of the multilayer board 1, the holding jig 4 is able to appropriately press the contact parts 2a to 2c against the multilayer board 1 (
(22) The following description will be made on a case in which the pressing step is performed without moving the pressing area 4a of the holding jig 4 with the warp of the multilayer board 1. As illustrated in
(23) As described above, according to the semiconductor device manufacturing method, first, there are prepared: the multilayer board 1 including the insulating layer 1a, the circuit pattern layers 1b1 and 1b2 that are formed on the front surface of the insulating layer 1a, and the metal layer 1c that is formed on the rear surface of the insulating layer 1a and that has a larger area than those of the circuit pattern layers 1b1 and 1b2; and the plurality of contact parts 2a to 2c. Next, the contact parts 2a to 2c are arranged on the circuit pattern layers 1b1 and 1b2 of the multilayer board 1 via the bonding material 3a to 3c. Next, the pressing area 4a set on the main surface of the plate-shaped holding jig 4 is arranged on the contact parts 2a to 2c. Next, while being heated, the pressing area 4a of the holding jig 4 is inclined with the warp of the multilayer board 1, and the contact parts 2a to 2c are pressed against the multilayer board 1. As a result, when the pressing for the bonding of the contact parts 2a to 2c is performed, even if the multilayer board 1 is warped by the heating and the contact parts 2a to 2c are shifted, the contact parts 2a to 2c are pressed against the multilayer board 1 without fail.
Second Embodiment
(24) In a second embodiment, the semiconductor device manufacturing method according to the first embodiment will be described in more detail. First, a semiconductor device 50 will be described with reference to
(25) As illustrated in
(26) The ceramic circuit board 10 includes an insulating layer 11, the plurality of circuit pattern layers 12 formed on a front surface of the insulating layer 11, and a metal layer 13 formed on a rear surface of the insulating layer 11. The insulating layer 11 is made of ceramic material having high thermal conductivity, such as aluminum oxide, aluminum nitride, or silicon nitride having excellent thermal conductivity. The plurality of circuit pattern layers 12 are made of material having excellent electrical conductivity. For example, the circuit pattern layers 12 are made of silver, copper, nickel, or an alloy containing at least one kind of these elements. The metal layer 13 is made of metal material having excellent thermal conductivity, such as aluminum, iron, silver, copper, or an alloy containing at least one kind of these elements.
(27) For example, a direct copper bonding (DCB) board or an active metal brazed (AMB) board may be used as the ceramic circuit board 10 having the above configuration. The heat radiation performance may be improved by attaching a cooler (not illustrated) to the metal layer 13 of the ceramic circuit board 10 via thermal grease such as silicone mixed with metal oxide filler. In this case, for example, the cooler is made of material having excellent thermal conductivity, such as aluminum, iron, silver, copper, or an alloy containing at least one kind of these elements. In addition, a fin, a heatsink including a plurality of fins, a water-cooling cooling device, or the like may be used as the cooler. In addition, a heat radiation board may be formed integrally with the cooler. In this case, the heat radiation board is made of material having excellent thermal conductivity, such as aluminum, iron, silver, copper, or an alloy containing at least one kind of these elements. In addition, for example, material such as nickel may be formed on a surface of the heat radiation board integrally formed with the cooler by plate processing or the like, to improve the corrosion resistance. Specifically, other than nickel, a nickel-phosphorus alloy, a nickel-boron alloy, or the like may be used as the material.
(28) For example, the insulating layer 11 has a rectangular shape in a planar view. The metal layer 13 also has a rectangular shape in a planar view and has an area smaller than that of the insulating layer 11 and larger than the total area of the circuit pattern layers 12. Namely, the ceramic circuit board 10 has a rectangular shape, for example.
(29) For example, the semiconductor elements include switching elements such as IGBTs or power MOSFETs made of silicon or silicon carbide. An individual semiconductor element 20 includes, for example, a drain electrode (or a collector electrode) as a main electrode on its rear surface and a gate electrode and a source electrode (or an emitter electrode) as main electrodes on its front surface. In addition, an individual semiconductor element 20 includes, as needed, a diode such as a Schottky barrier diode (SBD) or a freewheeling diode (FWD). An individual semiconductor element 20 includes a cathode electrode as a main electrode on its rear surface and an anode electrode as a main electrode on its front surface. The rear surface of the individual semiconductor element 20 is bonded to a predetermined circuit pattern layer (not illustrated). The semiconductor elements 20 are bonded to the circuit pattern layers 12 via solder (not illustrated). The solder will be described below. While not illustrated, for example, lead frames, external connection terminals (pin terminals, contact parts, or the like), electronic parts (thermistors, current sensors), or the like may be arranged in place of the semiconductor elements 20, as needed.
(30) The bonding wires 35 are made of material having excellent electrical conductivity. For example, the bonding wires 35 are made of gold, silver, copper, aluminum, or an alloy containing at least one kind of these elements. In addition, the diameter of each of the bonding wires 35 that electrically connect the gate electrodes of the semiconductor elements 20 and the circuit pattern layers 12 is 110 μm or more and 130 μm or less, and the average is 125 μm, for example. The diameter of each of the other bonding wires 35 is 350 μm or more and 450 μm or less, and the average is 400 μm, for example.
(31) The sealing material 45 includes, for example, thermoset resin such as maleimide-modified epoxy resin, maleimide-modified phenolic resin, or maleimide resin and filler contained in the thermoset resin. For example, the sealing material 45 includes epoxy resin and material such as silicon dioxide, aluminum oxide, boron nitride, or aluminum nitride included in the epoxy resin as filler.
(32) Next, a manufacturing method of the semiconductor device 50 will be described in accordance with a flowchart illustrated in
(33)
(34)
(35)
(36)
(37) The semiconductor device 50 is manufactured in accordance with the following manufacturing steps (flowchart). The following manufacturing steps are performed manually or a manufacturing apparatus, as needed.
(38) [Step S10] The semiconductor elements 20, the ceramic circuit board 10, and the contact parts 30 are prepared. Other than the above parts, parts needed to manufacture the semiconductor device 50 are prepared.
(39) [Step S11] As illustrated in
(40) [Step S12] As illustrated in
(41) In addition, for example, the solder 31 is lead-free solder including at least one of a tin-silver-copper alloy, a tin-zinc-bismuth alloy, a tin-copper alloy, and a tin-silver-indium-bismuth alloy as a main component. In addition to the alloy, the solder 31 includes flux that removes oxides on the circuit pattern layers 12. For example, the flux contains epoxy resin, carboxylic acid, rosin resin, activator, or solvent and may additionally contain other components, as needed. An additive such as nickel, germanium, cobalt, or silicon may be contained additionally in the solder 31.
(42) [Step S13] As illustrated in
(43) [Step S14] As illustrated in
(44) [Step S15] As illustrated in
(45) The pressing blocks 84 to 87 have flat pressing surfaces 84a to 87a, respectively, which are planarly engaged with each other to form the flat pressing area 83. When the holding jig 80 is set on the part positioning jig 70, the pressing surfaces 84a to 87a of the pressing blocks 84 to 87 serve as the rear surface of the holding jig 80 and face the part positioning jig 70. The opposite side of the rear surface of the holding jig 80 is the front surface of the holding jig 80. When the holding jig 80 is set on the part positioning jig 70, the pressing blocks 84 to 87 are engaged with each other with a gap T in the pressing area 83 of the holding jig 80. The pressing blocks 84 to 87 are formed in such a manner that the boundary lines thereof do not correspond to the cross line indicated by a dashed line in
(46) Around peripheral portions of the front surfaces of the pressing blocks 84 to 87, supporting portions 84b to 87b are formed in parallel with a lateral direction of the holding jig 80. The widths of the supporting portions 84b to 87b (in a direction perpendicular to the lateral direction) are set to be larger than the gap T. In addition, around peripheral portions of the front surfaces of the pressing blocks 84 to 87, supporting portions 84c to 87c are formed in parallel with a longitudinal direction of the holding jig 80. The widths of the supporting portions 84c to 87c (in a direction perpendicular to the longitudinal direction) are set to be larger than the gap T. The locations, the number, and the shapes of the supporting portions 84b to 87b and 84c to 87c formed on the pressing surfaces 84a to 87a of the pressing blocks 84 to 87 are not limited to those illustrated in
(47) In addition, the pressing surfaces 84a to 87a of the pressing blocks 84 to 87 have pressing portions 84d to 87d (in
(48) [Step S16] After the holding jig 80 is set in step S15, the ceramic circuit board 10 is brought into a reflow oven and is heated at a reflow processing temperature under reduced pressure in the oven (reflow soldering step). For example, the reflow processing temperature is 250° C. or more and 300° C. or less.
(49) Under this temperature, the ceramic circuit board 10 is warped in a downward convex shape (in the direction of the gravitational force) due to the difference among the thermal expansion rates of the insulating layer 11, the circuit pattern layers 12, and the metal layer 13. If the ceramic circuit board 10 is warped, the pressing blocks 84 to 87 of the holding jig 80 that are supported by the contact parts 30 from the rear surface drop in the direction of the part positioning jig 70. The peripheral portions, namely, the supporting portions 84b to 87b and 84c to 87c, of the pressing blocks 84 to 87 are supported by the frame portion 81. In particular, the widths of the supporting portions 84b to 87b and 84c to 87c are set to be larger than the gap T at the individual boundary line. In addition, the boundary lines of the pressing blocks 84 to 87 do not correspond to the cross line in
(50) In contrast, the pressing surfaces 86a and 87a of the pressing blocks 86 and 87 are engaged with each other to form a key shape. Thus, while the pressing blocks 86 and 87 are designed to drop easily from the boundary line thereof in the direction of the part positioning jig 70, the pressing blocks 86 and 87 are not easily detached from each other. In this way, for example, when the holding jig 80 is removed, the holding jig 80 is easily handled.
(51) As described above, the pressing area 83 of the holding jig 80 is inclined with the warp of the ceramic circuit board 10. In this way, even when the contact parts arranged on the warped ceramic circuit board 10 are shifted, since the pressing area 83 moves with the warp of the ceramic circuit board 10, the holding jig 80 appropriately presses the contact parts 30 against the ceramic circuit board 10.
(52) Consequently, when the solder 31 is melted, the circuit pattern layers 12, the semiconductor elements 20, and the contact parts 30 are electrically connected to each other.
(53) Next, when the melted solder 31 is solidified, the semiconductor elements 20 and the contact parts 30 are bonded to the circuit pattern layers 12.
(54) [Step S17] The board positioning jig 60, the part positioning jig 70, and the holding jig 80 are removed from the ceramic circuit board 10 having the circuit pattern layers 12 to which the semiconductor elements 20 and the contact parts 30 have been bonded. Next, the semiconductor elements 20 are electrically connected to predetermined areas of the circuit pattern layers 12 of the ceramic circuit board 10 by bonding wires by using a ultrasonic bonding tool (not illustrated). After connecting the bonding wires 35, external connection terminals (not illustrated) are pressed into the contact parts 30.
(55) [Step S18] The semiconductor elements 20, the contact parts 30, and the bonding wires 35, etc. on the ceramic circuit board 10 are sealed by the sealing material 45.
(56) As described above, the board positioning jig 60, the part positioning jig 70, and the holding jig 80 are used in steps S11, S13, and S15, respectively. The semiconductor device 50 illustrated in
(57) As described above, in the manufacturing method of the above semiconductor device 50, first, the ceramic circuit board 10 and the plurality of contact parts 30 are prepared, the ceramic circuit board 10 including the insulating layer 11, the circuit pattern layers 12 that are formed on the front surface of the insulating layer 11, and the metal layer 13 that is formed on the rear surface of the insulating layer and that has a larger area than those of the circuit pattern layers 12. Next, the contact parts 30 are arranged on the circuit pattern layers 12 of the ceramic circuit board 10 via the solder 31. Next, the pressing blocks 84 to 87 constituting the pressing area 83 of the plate-shaped holding jig 80 are arranged on the contact parts 30. The contact parts 30 are pressed against the ceramic circuit board 10 while heat being applied and the pressing blocks 84 to 87 constituting the pressing area 83 of the holding jig 80 are being inclined with a warp of the ceramic circuit board 10. In this way, when pressing is performed for bonding of the contact parts 30, even if the ceramic circuit board 10 is warped by heating and the contact parts 30 are consequently shifted, the contact parts 30 are pressed against the ceramic circuit board 10 without fail.
(58) According to the embodiments, there is provided a semiconductor device manufacturing method that enables bonding of contact parts without fail even when a multilayer board is warped by heating at the time of the bonding and that prevents reduction of the quality of the semiconductor device.
(59) All examples and conditional language provided herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.