JP6659463B2 - Wedge bonding parts - Google Patents

Description

  The present disclosure relates to a wedge bonding component used in a wedge bonding apparatus for bonding a wire to a member to be bonded.

  Conventionally, a wedge bonding apparatus has been used for connecting a wire to a member to be joined. For example, Patent Document 1 discloses an example of a component (component for wedge bonding) used in a wedge bonding apparatus. In the example described in Patent Document 1, the tip of the tool that presses the conductive wire is made of at least one type of ceramic sintered body selected from silicon nitride, zirconia, sialon, silicon carbide, and alumina.

JP-A-4-225543

  In recent years, there has been an increasing demand for connecting copper wires to semiconductor elements. However, copper wires have a higher melting point and work hardening index than conventional aluminum wires and gold wires. There was a problem that increased. In particular, in a wedge bonding apparatus, since high-output ultrasonic vibration is applied to the tool tip, breakage and shedding of the tool tip are likely to occur. With the miniaturization of semiconductor devices, the size of problematic particles has become very small (even fine particles have become a problem), and the shedding at the time of wedge bonding has become more problematic than ever.

  An object of the present disclosure is to provide a component for wedge bonding with less occurrence of shedding and high durability.

The component for wedge bonding, the portion in contact with at least wires, see contains aluminum oxide as a main component, carbonitride titanium and a titanium compound selected from at least one of borides of titanium as a sub-component The content of the titanium compound is 15% by mass or more and 40% by mass or less, the average crystal grain size of the titanium compound is 0.1 μm or less, and the volume resistivity is 2.6 × 10 ⁻³ Ω · m or less. A wedge bonding component characterized by comprising a ceramic sintered body having the above conductivity .

  The wedge bonding component according to the present disclosure is less likely to shatter and has high durability.

It is a typical side view showing an example of the schematic structure of the wedge bonding device provided with the wedge bonding parts of this embodiment. FIG. 2 is a schematic side view illustrating a main part of a schematic configuration of the wedge bonding component illustrated in FIG. 1. It is a perspective view which shows an example of the component for wedge bonding of this embodiment. It is a perspective view which shows the other example of the component for wedge bonding of this embodiment.

Hereinafter, an embodiment of a wedge bonding component of the present disclosure (hereinafter, referred to as the present embodiment) will be described in detail with reference to the drawings.

  FIG. 1 is a schematic side view showing an example of a schematic configuration of a wedge bonding apparatus 10 provided with a wedge bonding component. FIG. 2 is a schematic side view showing a main part of a schematic configuration of the wedge bonding apparatus 10 shown in FIG. 1 and 2, a cross section is partially shown, and a portion showing the cross section is hatched.

  A wedge bonding apparatus 10 shown in FIGS. 1 and 2 includes a bonding tool 2 that presses a wire 1, a wire feed mechanism 3 that supplies the wire 1 to the bonding tool 2, and a vibration transmission mechanism that applies ultrasonic vibration to the bonding tool 2. 4 and a pressing mechanism (not shown) for applying a load to the bonding tool 2 and pressing the bonding portion 1 a of the wire 1. The wire feed mechanism 3 is disposed between the drum 31 that supplies the wire 1, the drum 31 and the tip of the bonding tool 2, and includes a first wire guide 32 and a first wire guide 32 that are sequentially disposed along the movement path of the wire 1. And a second wire guide 33. The wire 1 is made of, for example, copper or aluminum having a diameter of 30 μm or more and 3 mm or less. Each of the first wire guide 32 and the second wire guide 33 has a through hole through which the wire 1 is inserted, and the wire 1 contacts at least one of the entrance, the inside, and the exit of the through hole.

  The wedge bonding apparatus 10 includes a bonding tool 2, a first wire guide 32, and a second wire guide 33 as an embodiment of a wedge bonding component.

  Above the bonding tool 2, a support table 34 configured to be movable integrally with the bonding tool 2 is arranged. Above the support table 34, a drum 31 for supplying the wire 1 is mounted. . Further, a first wire guide 32 through which the wire 1 is inserted is attached to a side portion of the support base 34.

  The vibration transmission mechanism 4 includes an ultrasonic oscillator 41, a bolted Langevin type vibrator (hereinafter, referred to as a BLT vibrator) 42, a cone 43, and a horn 44, and the bonding tool 2 is fixed to the horn 44. The electrical signal oscillated from the ultrasonic oscillator 41 is converted into longitudinal ultrasonic vibration by the BLT vibrator 42, and the ultrasonic vibration is converted into bending vibration of the bonding tool 2 via the cone 43 and the horn 44. Then, the tip of the bonding tool 2 is ultrasonically vibrated.

  The second wire guide 33 is held on the side of the horn 44. Further, a wire clamp 35 for fixing the wire 1 when cutting the wire 1 is attached to the horn 44 along the axial direction of the bonding tool 2.

  The bonding tool 2 and the second wire guide 33 can be moved to desired positions by an actuator (not shown) or the like.

  The wire 1 supplied from the drum 31 is inserted through the first wire guide 32 and the second wire guide 33, and is guided near the tip of the bonding tool 2.

  The bonding tool 2 presses the bonding portion 1a of the wire 1 to apply a load received from a pressing mechanism (not shown) and an ultrasonic vibration received from the vibration transmitting mechanism 4 to apply the wire 1 to a circuit board (not shown). Can be joined to the member 5 to be joined, such as an electrode, formed on the main surface of.

  As shown in FIGS. 1 and 2, the bonding tool 2 may include a through hole 2a for stably supplying the wire 1 to the distal end.

  FIG. 3 is a perspective view showing an example of the wedge bonding component of the present embodiment. The wedge bonding component shown in FIG. 3 is a bonding tool 2 for pressing a wire, and has a groove 2b for pressing the wire 1 on the distal end side. FIG. 4 is a perspective view showing a first wire guide 32 and a second wire guide 33 as another example of the wedge bonding component of the present embodiment. The first wire guide 32 and the second wire guide 33 have a similar shape, and each wire guide is shown in the same drawing. The first wire guide 32 has a through hole 32a, and the second wire guide 33 has a through hole 33a.

  In the wedge bonding component of the present embodiment, at least a portion in contact with the wire 1 is mainly composed of aluminum oxide, and is a titanium compound selected from at least one of titanium nitride, titanium carbonitride, and titanium boride. Is a ceramic sintered body containing as an auxiliary component. The portion that contacts the wire 1 is, for example, the inner surface of the groove 2 b of the bonding tool 2 (the lower surface in the figure), the inner surface of the through hole 32 a of the second wire guide 32, and the inner surface of the through hole 33 a of the third wire guide 33. And so on.

  Such a ceramic sintered body has high hardness, rigidity and mechanical strength among ceramic sintered bodies. In the wedge bonding component according to the present embodiment, for example, in a portion that comes into contact with the wire 1, wear and shedding due to sliding of the wire 1 are suppressed. Also, shedding and breakage due to vibration during wedge bonding are suppressed. The wedge bonding component of the present embodiment has high durability and the frequency of replacement when used repeatedly over a long period of time is low. When replacing wedge bonding components, it is necessary to adjust the relative position of the components.However, the frequency of replacement is low, so the frequency of adjusting the relative position is low. The time required can be reduced.

  Further, when the wedge bonding component is the above-mentioned ceramic sintered body, since it is non-magnetic, it is difficult to adsorb magnetic dust, so that damage to the wire 1 by the dust hardly occurs. In addition, since such a ceramic sintered body has high hardness and is hard to be shattered during joining, it is possible to suppress a failure in a bonding operation due to shedding and an influence on a portion to be joined due to shedding. For example, in the case where the degranulated particles have conductivity, and when the bonding target is a device on which a current flows, such as a semiconductor circuit board, or a substrate on which wiring is provided, the current is short-circuited by the degranulated particles (so-called, Short) can be suppressed.

  Further, since the ceramic sintered body can easily have higher conductivity than, for example, a silicon carbide sintered body known to exhibit semi-conductivity, it is easily processed into a complicated shape by electric discharge machining. be able to. In recent years, with the miniaturization of the bonding size, miniaturization and complicated shapes of wedge bonding components have been progressing. Generally, it is relatively difficult to process a small and complicated shape of a ceramic sintered body. However, in the present embodiment, since the ceramic sintered body has high conductivity, the ceramic sintered body can be easily formed into a complicated shape by electric discharge machining. Can be processed. Further, a bonding component having a complicated shape can be manufactured at low cost.

  In the present embodiment, the entire bonding tool 2, the entire first wire guide 32, and the entire second wire guide 33 each include aluminum oxide as a main component, titanium nitride, titanium carbonitride. And a ceramic sintered body containing, as an auxiliary component, a titanium compound selected from at least one of titanium borides. Thus, the entire wedge bonding component is not limited to the above-described ceramic sintered body.

  Here, the main component in the ceramic sintered body refers to a component having a content of 50% by mass or more among the components constituting the ceramic sintered body. In the wedge bonding component of this embodiment, the content of the aluminum oxide is, for example, 50% by mass or more and 86% by mass or less, and the content of the titanium compound is more than 14% by mass and less than 50% by mass.

The titanium nitride is, for example, titanium nitride whose composition formula is shown as TiN. The titanium carbonitride is, for example, titanium carbonitride whose composition formula is shown as TiCN. The boride of titanium is, for example, titanium nitride whose composition formula is shown as TiB ₂ .

  When the ceramic sintered body contains a nitride of titanium, it may further contain aluminum titanium oxynitride.

  In addition, when the content of the titanium compound is 15% by mass or more and 40% by mass or less, the ceramic sintered body constituting the wedge bonding component of the present embodiment is less likely to shatter and has high chipping resistance. Can be obtained. Specifically, when the above configuration is satisfied, generation of minute pores (for example, pores having a diameter of 100 nm to 500 nm) in the ceramic sintered body can be suppressed in the sintering step. Therefore, degranulation hardly occurs in processing after sintering, for example, cutting or polishing. In addition, when the above configuration is satisfied, a ceramic sintered body having high conductivity is obtained, and electric discharge machining such as wire electric discharge machining and single-sinking electric discharge machining can be easily performed. Parts can be manufactured with less labor.

  Further, the ceramic sintered body constituting the wedge bonding component of the present embodiment may further contain ytterbium. When ytterbium is contained in an amount of 0.01% by mass or more and 1% by mass or less in terms of oxide, the density is increased by the sintering promoting action, so that the mechanical strength is increased. Further, when the content of ytterbium is 0.06% by mass or more and 0.2% by mass or less in terms of oxide, the mechanical strength can be further increased. In addition, ytterbium is unlikely to segregate, and the risk of shedding due to this segregation is suppressed, so that fracture resistance is increased.

Here, the composition of the components contained in the ceramic sintered body can be identified using an X-ray diffractometer. The amount of each element contained in the ceramic sintered body can be determined by a fluorescent X-ray analyzer or an ICP (Inductively Coupled Plasma) emission spectrometer. When the components identified by the X-ray diffractometer are aluminum oxide and a titanium compound, the aluminum determined by a fluorescent X-ray analyzer or an ICP (Inductively Coupled Plasma) emission spectrometer is an oxide (Al ₂ O ₃ ). In addition, titanium may be converted into a compound whose composition is identified by an X-ray diffractometer.

  Further, when the average crystal grain size of the ceramic sintered body constituting the wedge bonding component of the present embodiment is 0.1 μm or more and 0.9 μm or less, large shedding hardly occurs even when machining is performed, and Since the number of phases is reduced and the thermal conductivity is improved, the wire 1 can be efficiently connected to the member 5 to be joined.

  Further, when the average crystal grain size of the titanium compound in the ceramic sintered body constituting the wedge bonding component of the present embodiment is 0.1 μm or less, a titanium compound having a low volume resistivity and a high hardness is mixed with the ceramic sintered body. Since components can be arranged with good dispersibility, components having a complicated shape and high accuracy can be easily obtained, and the wear resistance can be improved.

  Here, in order to determine the average crystal grain size of the ceramic sintered body, first, an arbitrary surface of the ceramic sintered body is polished to a mirror surface using diamond abrasive grains, and then this surface is subjected to several tens of phosphoric acid. Etch for about a second. Next, using a scanning electron microscope (SEM), an arbitrary place was selected from the etched surface, and an image in a range of 5 μm × 8 μm photographed at a magnification of about 10,000 to 13000 times (hereinafter, this image is referred to as SEM image). Image processing is performed on the SEM image using free software called Jtrim. More specifically, the SEM image is converted to gray scale, and then a “5 × 5 Gaussian” filter (a type of noise filter) is applied twice on the entire surface to remove fine noise and obtain the contrast of the SEM image. . Next, the histogram of the contrast is equalized (a type of averaging process) to correct the contrast, and then the SEM image is binarized. The image obtained by this process is, for example, “Image-Pro Plus” By using image analysis software (manufactured by Media Cybernetics Inc.), the average crystal grain size of the ceramic sintered body can be obtained.

  Here, when aluminum oxide is a main component, and a titanium compound selected from at least one of titanium nitride, titanium carbonitride and titanium boride has a total of subcomponents exceeding 99% by mass, The crystal on which the average crystal grain size of the ceramic sintered body is measured is a crystal of aluminum oxide and a titanium compound. In addition, the binarization processing refers to processing for converting the density of an image into two values of white or black. In this binarization processing, aluminum oxide crystals are treated as black and titanium compound crystals are treated as white, This correspondence can be supported by elemental analysis of the SEM image using an X-ray microanalyzer (EPMA). Then, when calculating the average crystal grain size of the titanium compound crystals, the particles observed as white may be targeted. When calculating the average crystal grain size of the aluminum oxide crystal grains, the crystal grains observed in black may be targeted.

  Further, the wedge bonding component of the present embodiment has a through hole through which a wire is inserted, and on the inner peripheral surface of the through hole, the average crystal grain size of aluminum oxide crystal grains is larger than that of titanium compound crystal grains, and The aluminum crystal grains may protrude more than the titanium compound crystal grains. When the through-holes have such a configuration, that is, when the crystal grains protrude on the inner peripheral surface, the crystal grains of aluminum oxide protruding on the inner peripheral surface are more likely to be caught in the minute concave portions present on the surface of the wire, and Since the runout is reduced, the wire can be supplied smoothly. In addition, since aluminum oxide crystal particles have lower hardness than titanium compound crystal particles, the wire is less likely to be damaged. The average crystal grain size of the aluminum oxide crystal grains is, for example, 1.1 times or more and 2 times or less the average crystal grain size of the titanium carbide crystal grains.

  The average crystal grain size of the titanium compound crystal grains and the average crystal grain size of the aluminum oxide crystal grains may be compared by the above-described method. The state in which the aluminum oxide crystal particles protrude from the titanium compound crystal particles may be confirmed by using an SEM and an energy dispersive analyzer (EDS). Specifically, the wedge bonding component is cut along the through-hole, the elements constituting the crystal grains located on the inner periphery of the cut surface are identified by EDS, and the state of projection of the crystal grains is SEM, for example. The observation may be performed with a magnification of 1000 to 2000 times.

  Next, an example of a method for manufacturing the wedge bonding component of the present embodiment will be described.

  First, an aluminum oxide powder and a titanium compound powder selected from at least one of a nitride, a carbonitride, and a boride of titanium are prepared, and the ratio of each powder in a total of 100% by mass of these powders is oxidized. Aluminum is 50% by mass or more and 86% by mass or less, and the remainder is a titanium compound. Instead of the titanium carbonitride powder, a titanium carbide powder and a titanium nitride powder may be used. The nitride, carbide, carbonitride and boride of titanium are, for example, titanium nitride, titanium carbide, titanium carbonitride and titanium boride.

Further, in order to make the ceramic sintered body more dense, a powder obtained by adding at least one powder of ytterbium oxide, yttrium oxide, and magnesium oxide in an amount of 0.06% by mass or more and 0.2% by mass or less may be used. These powders are wet-mixed using a barrel mill, a rotary mill, a vibration mill, a colloid mill, a bead mill, an attritor, a high-speed mixer, or the like, and pulverized into a slurry. In order to obtain a ceramic sintered body containing ytterbium and having a content of 0.06% by mass or more and 0.2% by mass or less in terms of oxide, powder of ytterbium oxide is used at 0.06% by mass or more and 0.2% by mass or less. % Or less. The wet mixing and pulverization of the powder are preferably performed, for example, by charging pulverizing beads having a diameter of 2 mm or less into a bead mill.

  Here, in order to obtain a wedge bonding component in which the average crystal grain size of the aluminum oxide and the titanium compound is 0.1 μm or more and 0.9 μm or less, for example, the average particle size of the powder after pulverization is 0. Raw material powder having a diameter of not less than 08 μm and not more than 0.59 μm) may be used. To obtain such a relatively small raw material powder, grinding beads having a diameter of not less than 0.4 mm and not more than 1.5 mm may be used. Also, on the inner peripheral surface of the through-hole, the crystal grains of aluminum oxide are larger in average crystal grain size than the crystal grains of titanium compound, and the crystal grains of aluminum oxide are more protruding than the crystal grains of titanium compound for wedge bonding. In order to obtain a part, grinding beads having a diameter of 0.5 mm or less may be used.

  In order to obtain a wedge bonding component having an average crystal grain size of the titanium compound of 0.1 μm or less, a powder of a titanium compound having an average particle size of 0.08 μm or less before pulverization is used.

  The average particle size of the pulverized powder can be determined by a liquid phase sedimentation method, a centrifugal sedimentation light transmission method, a laser diffraction scattering method, a laser Doppler method, or the like.

  Then, after adding and mixing a molding aid such as a binder and a dispersant to the pulverized powder, for example, granulating using a tumbling granulator, a spray drier or a compression granulator, Get.

  In particular, when obtaining a wedge bonding component having an average crystal grain size of the titanium compound of 0.1 μm or less, it is preferable to use a dispersant to suppress aggregation of the titanium compound.

  Next, after filling the obtained granules into a molding die, pressure sintering is performed at a temperature of 1400 to 1700 ° C. and a pressure of 30 MPa or more in an atmosphere such as argon, helium, neon, nitrogen, or vacuum. Thus, a columnar or plate-shaped ceramic sintered body can be obtained. Here, when the subcomponent is at least one of a nitride and a boride of titanium, the temperature is set to 1400 to 1600 ° C, and when the subcomponent is a boride of titanium, the temperature is set to 1550 to 1650 ° C. In addition, it is possible to suppress abnormal grain growth of the titanium compound crystal particles while appropriately dispersing the titanium compound crystal particles without insufficient sintering. Further, when the pressing force in the pressure sintering is set to 30 MPa or more, the densification of the ceramic sintered body is promoted, and the mechanical strength required as a wedge bonding component can be obtained.

  In addition, if a shielding material containing a carbonaceous material is placed around the molded body and sintered under pressure, oxidation of the titanium compound can be prevented and a ceramic sintered body having excellent mechanical properties can be obtained.

  After the pressure sintering, hot isostatic pressing (HIP) may be performed as necessary. By performing hot isostatic pressing (HIP), the three-point bending strength of the ceramic sintered body can be made 800 MPa or more. The hot isostatic pressing sintering (HIP) may be subjected to annealing as needed.

Then, the ceramic sintered body is processed into a desired shape by using electric discharge machining such as wire electric discharge machining or single-sinking electric discharge machining, and the surface is buff-polished with diamond powder or the like to obtain a wedge bonding component.

  Hereinafter, examples of the ceramic sintered body used for the wedge bonding component of the present invention will be specifically described, but the ceramic used for the wedge bonding component of the present invention is not limited to these examples.

  First, powders of aluminum oxide, titanium nitride, titanium carbonitride, titanium boride, and ytterbium oxide are prepared, and the powders are blended so that the content of each component in the ceramic sintered body becomes a value shown in Table 1. These powders were wet-mixed using a bead mill having a diameter of 1.5 mm with a bead mill and pulverized to obtain a slurry.

  Then, molding aids such as a binder and a dispersant were added to the ground powder, mixed, and then granulated using a spray dryer to obtain granules.

  Next, after filling the obtained granules into a molding die, in a vacuum atmosphere, the temperature is as shown in Table 1, the pressure is 40 MPa, the heating rate is 10 ° C./min, and the holding time is 1 hour. By pressure sintering, a prism-shaped ceramic sintered body having a width of 4 mm, a thickness of 3 mm, and a height of 40 mm, and a disk-shaped ceramic sintered body having a diameter of 152.4 mm and a thickness of 3 mm are obtained. Was.

  Further, as a comparative example, a ceramic sintered body having the above-mentioned shape and dimensions whose main components were silicon nitride, zirconia, sialon and aluminum oxide, respectively, was produced.

  The composition of the components constituting each sample was identified using an X-ray diffractometer. In addition, the amounts of the elements in each sample were determined by an ICP (Inductively Coupled Plasma) emission spectrometer, and the components identified by the X-ray diffractometer were used in the compound and in the X-ray diffractometer where the amounts of the elements were small. Components not identified by were converted to oxides, respectively. Table 1 shows the composition and amount of each component.

  The Vickers hardness and the volume resistivity of each sample were measured in accordance with JIS R 1610: 2003 (ISO14705: 2000 (MOD)) and JIS C 2141: 1992, respectively. Table 1 shows these measured values.

In addition, the sample No. Regarding the fracture resistance of 1 to 33, ten strip-shaped samples 70 mm long, 3 mm wide and 2 mm thick from the center of the disc-shaped ceramic sintered body were sliced with a slicing machine equipped with a diamond blade. The cutout was cut out, and the length of chipping generated on the cut surface was measured at 400 times magnification using an optical microscope, and the maximum value was shown in Table 1. In this case, SD1200 was used as the diamond blade, and the diamond blade was cut at a rotation speed of 10,000 rpm, a feed speed of 100 mm / min, and a single cut amount of 2 mm.

  As shown in Table 1, the sample No. Since ceramics 1 to 33 are made of a ceramic sintered body containing aluminum oxide as a main component and a titanium compound selected from at least one of titanium nitride, carbonitride and boride as an auxiliary component, other ceramics Since the hardness is higher than that of the sample made of a sintered body, it is possible to obtain a wedge bonding component having high durability and low replacement frequency. In addition, the sample No. Since Nos. 1-33 have high conductivity, they can be wedge bonding parts having a complicated shape.

  In addition, in Sample No. 2 having the same titanium nitride content. Sample Nos. 1 to 11 were compared. Sample Nos. 2 to 10 in which the content of the titanium nitride in the ceramic sintered body is 15% by mass or more and 40% by mass or less, the sample No. 2 in which the content of the titanium nitride is less than 15% by mass. Sample No. 1 having higher conductivity than that of Sample No. 1 and having a titanium nitride content of more than 40% by mass. 11 has higher fracture resistance. From this, it can be seen that Sample No. 2 to 10 can be said to have both high conductivity and high fracture resistance.

1: Wire 2: Bonding tool 3: Wire feed mechanism 4: Vibration transmission mechanism 5: Member 31: Drum 32: First wire guide 33: Second wire guide 34: Support 35: Wire clamp 41: Ultrasonic oscillator 42: bolted Langevin type vibrator 43: cone 44: horn

Claims (4)

The component for wedge bonding, the portion in contact with at least wires, see contains aluminum oxide as a main component, carbonitride titanium and a titanium compound selected from at least one of borides of titanium as a sub-component The content of the titanium compound is 15% by mass or more and 40% by mass or less, the average crystal grain size of the titanium compound is 0.1 μm or less, and the volume resistivity is 2.6 × 10 ⁻³ Ω · m or less. A wedge bonding component comprising a ceramic sintered body having the following conductivity . 2. The wedge bonding component according to claim 1, wherein the ceramic sintered body further contains ytterbium, and the content thereof is 0.06% by mass or more and 0.2% by mass or less in terms of oxide. 3. The wedge bonding component according to claim 1, wherein the ceramic sintered body has an average crystal grain size of 0.1 μm or more and 0.9 μm or less. 4. A through-hole through which the wire is inserted, wherein, on the inner peripheral surface of the through-hole, the average crystal grain size of the aluminum oxide crystal grains is larger than the titanium compound crystal grains, and the aluminum oxide crystal grains are titanium compound crystal grains. The wedge bonding component according to any one of claims 1 to 3 , wherein the wedge bonding component is more protruding than the wedge bonding component.

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