Thermosonic bonding of gold wire onto a copper pad with titanium thin-film deposition

A novel thermosonic (TS) bonding process for gold wire bonded onto chips with copper interconnects was successfully developed by depositing a thin, titanium passivation layer on a copper pad. The copper pad oxidizes easily at elevated temperature during TS wire bonding. The bondability and bonding strength of the Au ball onto copper pads are significantly deteriorated if a copper-oxide film exists. To overcome this intrinsic drawback of the copper pad, a titanium thin film was deposited onto the copper pad to improve the bondability and bonding strength. The thickness of the titanium passivation layer is crucial to bondability and bonding strength. An appropriate, titanium film thickness of 3.7 nm is proposed in this work. One hundred percent bondability and high bonding strength was achieved. A thicker titanium film results in poor bond-ability and lower bonding strength, because the thicker titanium film cannot be removed by an appropriate range of ultrasonic power during TS bonding. The protective mechanism of the titanium passivation layer was interpreted by the results of field-emission Auger electron spectroscopy (FEAES) and electron spectroscopy for chemical analysis (ESCA). Titanium dioxide (TiO₂), formed during the die-saw and die-mount processes, plays an important role in preventing the copper pad from oxidizing. Reliability of the high-temperature storage (HTS) test for a gold ball bonded on the copper pad with a 3.7-nm titanium passivation layer was verified. The bonding strength did not degrade after prolonged storage at elevated temperature. This novel process could be applied to chips with copper interconnect packaging in the TS wire-bonding process.     

Increasing bondability and bonding strength of gold stud bumps onto copper pads with a deposited titanium barrier layer

A flip-chip assembly is an attractive scheme for use in high performance and miniaturized microelectronics packaging. Wafer bumping is essential before chips can be flip-bonded to a substrate. Wafer bumping can be used for mechanical-single point stud bump bonding (SBB), and is based on conventional thermosonic wire bonding. This work proposes depositing a titanium barrier layer between the copper film and the silver bonding layer to achieve perfect bondability and sufficiently strong thermosonic bonding between a stud bump and the copper pad.A titanium layer was deposited on the copper pads to prevent copper atoms from out-diffusing during thermosonic stud bump bonding. A silver film was then deposited on the surface of the titanium film as a bonding layer to increase the bondability and bonding strength for stud bumps onto copper pads. The integration of the silver bonding layer with a diffusion barrier layer of titanium on the copper pads yielded 100% bondability between the stud bump and pads. The strength of bonding between the gold bumps on the copper pads significantly exceeds the minimum average values in JEDEC specifications. The diffusion barrier layer of titanium effectively prevents copper atoms from out-diffusing to the silver bonding layer surface during thermosonic bonding, which fact can be interpreted with reference to the experimental results of energy dispersive spectrometry (EDS) and analyses of Auger depth profiles. This diffusion barrier layer of titanium efficiently provides perfect bondability and sufficiently strong bonding between a stud bump and copper pads with a silver bonding layer.     

Development of a thermosonic wire-bonding process for gold wire bonding to copper pads using argon shielding

To improve the bondability and ensure the reliability of Au/Cu ball bonds of the thermosonic (TS) wire-bonding process, an argon-shielding atmosphere was applied to prevent the copper pad from oxidizing. With argon shielding in the TS wire-bonding process, 100% gold wire attached on a copper pad can be achieved at the bonding temperature of 180°C and above. The ball-shear and wire-pull forces far exceed the minimum requirements specified in the related industrial codes. In a suitable range of bonding parameters, increasing bonding parameters resulted in greater bonding strength. However, if bonding parameters exceed the suitable range, the bonding strength is deteriorated. The reliability of the high-temperature storage (HTS) test for Au/Cu ball bonds was verified in this study. The bonding strength of Au/Cu ball bonds increases slightly with prolonged storage duration because of diffusion between the gold ball and copper pad during the HTS test. As a whole, argon shielding is a successful way to ensure the Au/Cu ball bond in the TS wire-bonding process applied for packaging of chips with copper interconnects.     

Oxidation of copper pads and its influence on the quality of Au/Cu bonds during thermosonic wire bonding process

To understand the copper oxide effect on the bondability of gold wire onto a copper pad, thermosonic gold wire bonding to a copper pad was conducted at 90–200 °C under an air atmosphere. The bondability and bonding strength of the Au/Cu bonds were investigated. The bondability and bonding strength were far below the minimum requirements stated in industrial codes. At elevated bonding temperature of 200 °C, the bondability and bonding strength deteriorated mainly due to hydroxide and copper oxide formation on the copper pad. Oxide formation occurred if no appropriate oxide preventive schemes were applied. At lower bonding temperature, 90 °C, poor bondability and low bonding strength were mainly attributed to insufficient thermal energy for atomic inter-diffusion between the gold ball and copper pad.Copper pad oxidation was investigated using an electron spectroscopy for chemical analysis (ESCA) and thermogravimetric analysis (TGA). An activation energy of 35 kJ/mol for copper pad oxidation was obtained from TGA. This implies that different mechanisms govern the oxidation of copper pad and bulk copper. Hydroxide and copper oxide were identified based on the shifted binding energy. Cu(OH)₂ forms mainly on the top surface of copper pads and the underlying layer consists mainly of CuO. The hydroxide concentration increased with increasing the heating temperatures. After heating at 200 °C, the hydroxide concentration on the copper pad surface was approximately six times that at 90 °C. Protective measures such as passivation layer deposition or using shielding gas are critical for thermosonic wire bonding on chips with copper interconnects.     

Gold Stud Bumps Flip-Chip Bonded onto Copper Electrodes with Titanium and Silver Layers

The purpose of this study was to develop the thermosonic flip-chip bonding process for gold stud bumps bonded onto copper electrodes on an alumina substrate. Copper electrodes were deposited with silver as the bonding layer and with titanium as the diffusion barrier layer. Deposition of these layers on copper electrodes improves the bonding quality between the gold stud bumps and copper electrodes. With appropriate bonding parameters, 100% bondability was achieved. Bonding strength between the gold stud bumps and copper electrodes was much higher than the value converted from the standards of the Joint Electron Device Engineering Council (JEDEC). The effects of process parameters, including bonding force, ultrasonic power, and bonding time, on bonding strength were also investigated. Experimental results indicate that bonding strength increased as bonding force and ultrasonic power increased and did not deteriorate after prolonged storage at elevated temperatures. Thus, the reliability of the high-temperature storage (HTS) test for gold stud bumps flip-chip bonded onto a silver bonding layer and titanium diffusion barrier layer is not a concern. Deposition of these two layers on copper electrodes is an effective and direct method for thermosonic flip-chip bonding of gold stud bumps to a substrate, and ensures excellent bond quality. Applications such as flip-chip bonding of chips with low pin counts or light-emitting diode (LED) packaging are appropriate.     

Direct gold and copper wires bonding on copper

The key to bonding to copper die is to ensure bond pad cleanliness and minimum oxidation during wire bonding process. This has been achieved by applying a organic coating layer to protect the copper bond pad from oxidation. During the wire bonding process, the organic coating layer is removed and a metal to metal weld is formed. This organic layer is a self-assembled monolayer. Both gold and copper wires have been wire-bonded successfully to the copper die even without prior plasma cleaning. The ball diameter for both wires are 60 μm on a 100 μm fine pitch bond pad. The effectiveness of the protection of the organic coating layer starts from the wafer dicing process up to the wire bonding process and is able to protect the bond pad for an extended period after the first round of wire bond process. In this study, oxidization of copper bond pad at different packaging processing stages, dicing and die attach curing, have been explored. The ball shear strength for both gold and copper ball bonds achieved are 5 and 6 g/mil² respectively. When subjected to high temperature storage test at 150 °C, the ball bonds formed by both gold and copper wire bond on the organic coated copper bondpad are thermally stable in ball shear strength up to a period of 1440 h. The encapsulated daisy chain test vehicle with both gold and copper wires bonding have passed 1000 cycles of thermal cycling test (−65 to 150 °C). It has been demonstrated that orientation imaging microscopy technique is able to detect early levels of oxidation on the copper bond pad. This is extremely important in characterization of the bondability of the copper bond pad surface.     

Increasing bondability and ball-shear force of gold balls thermosonic bonding to flex substrates by depositing a nickel layer

To improve the bondability and ball-shear force of gold balls that are thermosonically bonded to copper electrodes over flex substrates, a nickel layer was deposited on the surface of the copper electrodes to increase their rigidity. A silver layer was then deposited on the nickel layer to prevent oxidation of the copper electrodes during the thermosonic bonding process. This nickel layer was expected to enhance the rigidity of copper electrodes over the flex substrates, increasing the thermosonic bonding efficiency of gold balls to copper electrodes over the flex substrates.Deposition the nickel layer on the copper electrodes improved the elastic modulus of the flex substrates, indicating that the nickel layer is effective in enhancing the rigidity of copper electrodes over the flex substrates. The bondability and ball-shear force of gold balls that are thermosonically bonded to copper electrodes increases with the thickness of the nickel layer given fixed bonding parameters. One hundred percent bondability and high ball-shear force can be achieved when gold balls are thermosonically bonded to copper electrodes with the deposition of a 0.5 μm-thick nickel layer. Herein, the ball-shear force was higher than that specified in JEDEC standards. Furthermore, gold balls that were thermosonically bonded to copper electrodes with a nickel layer had a large bonded area with an extensive scrape, while gold balls that were thermosonically bonded to copper electrodes without a nickel layer had a blank surface morphology. This experimental result was similar to that of tests of the elastic modulus of flex substrates, similarity can be used to explain that the effectiveness of the nickel layer in increasing the rigidity of copper electrodes, increasing the bonding efficiency at the bonding interface between gold balls and copper electrodes during thermosonic bonding process. After ball-shear test, a layer that was stuck on the ball bond was observed at the location of fracture of the ball bonds for gold balls they were thermosonically boned on copper electrodes with 0.5 μm-thick nickel layer. This observation implies that the ball-shear force of the gold balls that were bonded on the copper electrodes exceeded even the adhesive force of the layers that were deposited on the copper electrodes.The deposition of a 0.5 μm-thick nickel layer on copper electrodes over flex substrates improved the rigidity of the copper electrodes; the ultrasonic power could be propagated to the bonding interface between the gold balls and the copper electrodes, increasing the bondability and ball-shear force.     

Reliability of assembly of chips and flex substrates using thermosonic flip-chip bonding process with a non-conductive paste

This study investigates the reliability of the assembly of chips and flex substrates using the thermosonic flip-chip bonding process with non-conductive paste (NCP). The high-temperature storage (HTS) test, the temperature cycling test (TCT), the pressure cooker test (PCT) and the high-temperature/high-humidity (HT/HH) test were conducted to examine the reliability of chips that are bonded on flex substrates. The environmental parameters used in the various reliability tests were consistent with the JEDEC standards. After the reliability tests, a peeling test was performed and the microstructure of the tested specimen observed to evaluate further the reliability.The bonding strength increased with the storage period in the HTS test. After the peeling test, a layer of copper electrodes was observed to be stuck on gold bumps over the fractured morphology of the chips when the chips and flex substrates were assembled using an ultrasonic power of 14.46 W, indicating that the bonding strength between the gold bumps and the copper electrodes was even higher than the adhesive strength of the layers that were deposited on the flex substrates. The HTS test yielded sufficient thermal energy to promote atomic interdiffusion between gold bumps and copper electrodes. Metallurgical bonding between the gold bump and the copper electrode occurred, improving the bonding strength. In the assembly of chips and flex substrates without the application of ultrasonic power in bonding process, the adhesive strength of NCP was highly reliable after HTS test, because the bonding strength was maintained after HTS test for various storage periods. The typical failure mode of PCT was interfacial delamination between NCP and flex substrates. Approximately 80% of the specimens exhibited full separation after PCT at 336 h when chips and flex substrates were assembled without applied ultrasonic power to the bonding process, revealing that the NCP cannot withstand the PCT and lost its adhesive strength. Applying an adequate ultrasonic power of 14.46 W in the bonding process not only improved the bonding strength, but also enabled the bonding strength to be maintained at high level after PCT. The high bonding strength was attributable to the strong bonding of the gold bumps on the copper electrodes after PCT for various storage periods. This experimental result demonstrates that ultrasonic power can increase the reliability of PCT on chips and flex substrates that were assembled with the NCP. The bonding strength of the gold bumps on the flex substrates did not change significantly after the TCT, revealing the great reliability of TCT on chips and flex substrates that were assembled using the thermosonic flip-chip bonding process with the NCP. The bonding strength of chips bonded to flex substrates increased with the storage periods of the HT/HH test if ultrasonic power was applied to bonding process. Neither delamination nor any defect at the bonding interface was observed. The reliability of the HT/HH test for chips bonded on flex substrates using the thermosonic flip-chip process with the NCP fulfills the requirements stated in the JEDEC standards.According to the experimental findings of various reliability tests, the chips that were bonded to flex substrates using the thermosonic bonding process with NCP met the JEDEC specifications; with the exception of the adhesive strength of NCP under PCT which must be improved.     

Process windows for low-temperature Au wire bonding

The process windows are presented for low-temperature Au wire bonding on Au/Ni/Cu bond pads of varying Au-layer thicknesses metallized on an organic FR-4 printed circuit board (PCB). Three different plating techniques were used to deposit the Au layers: electrolytic plating, immersion plating, and immersion plating followed by electrolytic plating. Wide ranges of wire bond force, bond power, and bond-pad temperature were used to identify the combination of these processing parameters that can produce good wire bonds, allowing the construction of process windows. The criterion for successful bonds is no peel off for all 20 wires tested. The wire pull strengths and wire deformation ratios are measured to evaluate the bond quality after a successful wire bond. Elemental and surface characterization techniques were used to evaluate the bond-pad surfaces and are correlated to wire bondability and wire pull strength. Based on the process windows along with the pull strength data, the bond-pad metallization and bonding conditions can be further optimized for improved wire bondability and product yields. The wire bondability of the electrolytic bond pad increased with Au-layer thickness. The bond pad with an Au-layer thickness of 0.7 μm displayed the highest bondability for all bonding conditions used. The bondability of immersion bond pads was comparable to electrolytic bond pads with a similar Au thickness. Although a high temperature was beneficial to wire bondability with a wide process window, it did not improve the bond quality as measured by wire pull strength.     

Thermosonic gold wire bonding to laminate substrates with palladiumsurface finishes

As the laminate substrate industry moves from hot air solder level (HASL) finishes, alternate plating finishes are being proposed such as immersion gold/electroless nickel, electroless palladium, and electroless silver. This paper presents results of an evaluation of the thermosonic gold ball wire bondability of electroless palladium. Two palladium thicknesses, with and without a nickel underlayer, were evaluated from two vendors. In each case, a thin gold passivation layer was deposited by immersion plating over the palladium. The initial evaluation criteria included bondability (number of missed bonds and flame off errors), wire pull strength, standard deviation, bond failure mode, and visual inspection. The bonding window was determined by independently varying force (four levels), power (four levels), and time (two levels). The stage temperature was maintained at 150°C, compatible with BT laminate material. Different preconditioning environments such as a solder reflow cycle, high temperature storage (125°C) and humidity storage (85%RH/85°C) on initial bondability were also considered. Rutherford backscattering and Auger analysis were used to examine the surface finishes. The stability of the bonds was investigated by high temperature storage (125°C) with periodic electrical resistance and pull strength testing     

Effect of the direct current on microstructure,tensile property and bonding strength of pure silver wires

In the microelectronics assembly and packaging industry, the wire bonding has become an important process to connect lead frames and pads. In the past, gold and copper were the main materials of wire bonding. However, the cost of gold wires is getting higher nowadays and yet wire bonding cannot be wholly replaced by copper wire; thus silver wires become a novel bonding material in recent years. The reliability test of wires was a static method; this study leads electrical current into the wires to estimate the structural changing and interface properties of Al pads (positive and negative pad). After leading 90% critical fusing current density (CFCD) into a 23 μm silver wire, some grains of silver wire had grown up and formed into equal-diameter grains (EDG). After the current test, the fracture position of bonded wires moved from heat affect zone (HAZ) of electric flame-off (EFO) to the neck of HAZ. Otherwise, the current test would reduce the tensile strength of wire. The bonding strength of the positive pad was lower than that of the negative pad. The intermetallic compound (IMC) of bonding interface was AgAl₂.     

The effect of thin film structure and properties on gold ball bonding

The gold ball bonding process is widely used for making interconnections between integrated circuit chips and package lead frames, yet the relationships between the wire/substrate materials properties and the bond formation processes are not yet well understood. While the creation of a metallurgical bond at the interface between the wire and substrate is required, the deformation of the wire and substrate also play an important role in bond formation. Bonding to thin film substrates is of particular interest, since thin films often exhibit mechanical behavior distinctly different from bulk materials. In the present study, a systematic investigation has been conducted to understand the effects of the structure and properties of aluminum thin films on the quality of gold ball bonds. A series of aluminum thin films was fabricated with systematic variations in hardness, roughness, thickness, and composition. Gold wires were ball bonded to these substrates, and the bondability and bond shear strengths were assessed. Metallographic sections of several of these specimens were made and examined in the scanning electron microscope. The results show that the film thickness has the most dominant effect on the bondability and bond strength; films that were 0.5 μm thick often exhibited low strength or poor bondability. Very hard films also gave poor results. Ultimately, these results can be used to predict the wire bond reliability expected from various types of thin film metallization.     

Effects of Cu/Al intermetallic compound (IMC) on copper wire and aluminum pad bondability

Copper wire bonding is an alternative interconnection technology that serves as a viable, and cost saving alternative to gold wire bonding. Its excellent mechanical and electrical characteristics attract the high-speed, power management devices and fine-pitch applications. Copper wire bonding can be a potentially alternative interconnection technology along with flip chip interconnection. However, the growth of Cu/Al intermetallic compound (IMC) at the copper wire and aluminum interface can induce a mechanical failure and increase a potential contact resistance. In this study, the copper wire bonded chip samples were annealed at the temperature range from 150/spl deg/C to 300/spl deg/C for 2 to 250 h, respectively. The formation of Cu/Al IMC was observed and the activation energy of Cu/Al IMC growth was obtained from an Arrhenius plot (ln (growth rate) versus 1/T). The obtained activation energy was 26Kcal/mol and the behavior of IMC growth was very sensitive to the annealing temperature. To investigate the effects of IMC formation on the copper wire bondability on Al pad, ball shear tests were performed on annealed samples. For as-bonded samples, ball shear strength ranged from 240-260gf, and ball shear strength changed as a function of annealing times. For annealed samples, fracture mode changed from adhesive failure at Cu/Al interface to IMC layer or Cu wire itself. The IMC growth and the diffusion rate of aluminum and copper were closely related to failure mode changes. Micro-XRD was performed on fractured pads and balls to identify the phases of IMC and their effects on the ball bonding strength. From XRD results, it was confirmed that the major IMC was /spl gamma/-Cu/sub 9/Al/sub 4/ and it provided a strong bondability.     

Nickel-palladium bond pads for copper wire bonding

The semiconductor packaging industry is undergoing a step-change transition from gold to copper wire bonding brought on by a quadrupling of gold cost over the last 8 years. The transition has been exceptionally rapid over the last 3 years and virtually all companies in the industry now have significant copper wire bonding production. Among the challenges to copper wire bonding is the damage to bond pads that had been engineered for wire bonding with the softer gold wire. This paper presents an extensive evaluation of electroless NiPd and NiPdAu bond pads that offer a much more robust alternative to the standard Al pad finish. These NiPd(Au) bond are shown to outperform Al in virtually all respects: bond strength, bond parameter window, lack of pad damage and reliability.     

Effects of metallization characteristics on gold wire bondability of organic printed circuit boards

Organic printed circuit boards (PCBs) with Au/Ni plates on bond pads are widely used in chip-on-board (COB), ball grid array (BGA), and chip-scale packages. These packages are interconnected using thermosonic gold wire bonding. The wire bond yield relies on the bondability of the Ni/Au pads. Several metallization parameters, including elemental composition, thickness, hardness, roughness, and surface contamination, affect the success of the solid state joining process. In this study, various characterization and mechanical testing techniques are employed to evaluate these parameters for different metallization schemes with varying Ni and Au layer thicknesses. The pull force of Au wires is measured as a function of plasma treatment applied before wire bonding to clean the bond pads. Close correlations are established between metallization characteristics and wire bond quality.     

Increasing the bonding strength of chips on flex substrates using thermosonic flip-chip bonding process with nonconductive paste

Thermosonic flip-chip bonding process with a nonconductive paste (NCP) was employed to improve the processability and bonding strength of the flip-chip onto flex substrates (FCOF). A non-conductive paste was deposited on the surface of the copper electrodes over the flex substrate, and a chip with eight gold bumps bonded onto the copper electrodes by the thermosonic flip-chip bonding process.For the chips and flex substrates assembly, ultrasonic power is important in the removal of some of the non-conductive paste on the surface of copper electrodes during thermosonic bonding. Accordingly, gold stud bumps in this study were directly bonded onto copper electrodes to form successful electrical paths between chips and the flex substrate. A particular ultrasonic power resulted in some metallurgical bonding between the gold bumps and the copper electrodes, increasing the bonding strength. The ultrasonic power was not only to remove the NCP from the copper electrodes, but also formed metallurgical bonds during the thermosonic flip-chip bonding process with NCP.In this study, the parameters of the bonding of chips onto flex substrates using thermosonic flip-chip bonding process with NCP were a bonding force of 4.9 N, a curing time of 40 s, a curing temperature of 140 °C and an ultrasonic power of 14.46 W. The processability and bonding strength of flip-chips on flex substrates using thermosonic bonding process with NCP was verified in this study. This process has great potential to be applied to the packaging of consumed electronic products.     

Reliability evaluation of BOAC and normal pad stacked-chip packaging using low-K wafers

This work evaluates the wire bondability and the reliability tests for the stacked-chip TFBGA wire bond packaging with the Sn–4.0Ag–0.5Cu lead-free solder ball. The bonding-over-active-circuit (BOAC) pad is the top test chip and the normal pad is the bottom test chip and is combined in the stacked-chip packaging. Both test chips are 90 nm low-K dielectric with five copper layers and one layer aluminum pad and a background ranging from 775 μm to 150 μm. According to the simulation results, the maximum normal stress of low-K layer for the BOAC pad is higher than that of the normal pad by 146.4%. However, the maximum shear stress of Cu metal layer for the BOAC pad is lower than that of the normal pad by 64.2%. To compare the bonding pad strength for the BOAC and normal pad low-K wafers, this work uses the simplified two-layer model to extract the effective mechanical properties of the two bonding pad structures. The effective average Young’s modulus of the normal pad and the BOAC pad are 86 GPa and 69 GPa, respectively. The test results indicate that the effective Young’s modulus of the normal pad exceeds that of the BOAC pad by 17 GPa. The wire bondability test of the ball shear and the wire pull test results are superior to the specification by 80% and 83.75%, respectively. All stacked-chip TFBGA packaging samples underwent reliability tests, including HAST, TCT, and HTST. All the wire bondability and reliability tests passed the specification for the BOAC pad and the normal pad low-K structures. Accordingly, this work shows that the proposed stacked-chip TFBGA packaging passes the wire bondability and the reliability tests. The proposed packaging improves the electrical performance, enhances the utility of the active chip area and saves chip area through the use of low-K and BOAC chips. Furthermore, the results show that the equivalent stiffness of the bonding pad structure can be used as the bondability and reliability test index for the chip.     

Effect of plasma treatment of Au-Ni-Cu bond pads on process windows of Au wire bonding

The wire bondability of Au-Ni-Cu bond pads with different Au plating schemes, including electrolytic and immersion plates, are evaluated after plasma treatment. The plasma cleaning conditions, such as cleaning power and time, are optimized based on the process window and wire pull strength measurements for different bond pad temperatures. Difference in the efficiency of plasma treatment in improving the wire bondability for different Au plates is identified. The plasma-cleaned bond pads are exposed to air to evaluate the recontamination process and the corresponding degradation of wire pull strength. The changes in bond pad surface characteristics, such as surface free energy and polar functionality, with exposure time are correlated to the wire pull strength, which in turn provides practical information about the shelf life of wire bonding after plasma cleaning.     

Investigation of Thermosonic Wire Bonding Resistance of Gold Wire Onto Copper Pad

This paper discusses the electric performance for thermosonic wire bonding of gold wire onto copper pads. Various methods normally used to improve bondability were investigated including the bare copper pads with argon shielding gas and the copper pads with cupric oxide film, cuprous oxide film, and silver film. The micro-contact theory was used to determine the effective contact area. The circuit contact resistance was measured for each sample and was presented in terms of ultrasound power and effective contact area. The results show that the increase in the effective contact area leads to a lower circuit contact resistance before reaching a minimum value, and further increase in the effective contact area would not have noticeable effect on the resistance.      

IC键合铜线材料的显微力学性能研究

用于IC(集成电路)的键合铜线材料具有低成本、优良的导电和导热性等优点,但其高硬度容易对铝垫和芯片造成损伤,因此对其硬度的测量是一项关键技术。纳米压痕测量技术可以方便、准确地测量铜线材料的显微硬度值和其他力学性能参数。描述了纳米压痕测量技术的原理以及对铜线材料样品进行纳米压痕测量的参数选择,进行了测量试验。结果表明,原始铜线、FAB(金属熔球)、焊点的平均硬度分别为1.46,1.51和1.65GPa,为键合铜线材料的选择和键合工艺参数的优化提供了依据。