Bonding method for electronic components with ultra-narrow pitch micro-bumps

Abstract

The embodiment of the application provides a bonding method applied to electronic elements with ultra-narrow pitch micro-bumps, and the method comprises the following steps: obtaining an electronic element to be bonded; pre-bonding micro-bumps of the electronic element to be bonded through solid-state diffusion bonding to obtain a pre-bonding sample; and heating and reflowing the pre-bonding sample to generate a bonding sample. The micro-bumps are pre-bonded through low-temperature solid-state diffusion bonding, and the extrusion degree of Sn is accurately controlled by adjusting the bonding pressure during the pre-bonding process. Then, high-temperature rapid reflow is used to realize high-reliability and high-efficiency bonding of the electronic element applied to ultra-narrow pitch micro-bump interconnection.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more particularly to a bonding method for electronic components with ultra-narrow pitch microbumps. Background Technology

[0002] With the rapid development of microelectronics integration technology, processor performance is increasing and the interconnect size between chips is shrinking, creating an urgent need to develop higher-density inter-chip interconnect methods. Among related technologies, high-bandwidth memory (HBM) products utilize ultra-narrow pitch microbump interconnects, primarily achieved through thermal compression with non-conductive film (TC-NCF) processes or mass reflow with molded underfill (MR-MUF) processes. The TC-NCF process encapsulates microbumps within a non-conductive thin film. By applying high temperature and pressure, it can simultaneously interconnect the microbumps and the non-conductive film between chips. However, the non-conductive film has poor thermal conductivity, resulting in high time costs for stacking multiple chips. Under pressure, tin (Sn) is significantly extruded, which can contact surrounding microbumps, causing short circuits at solder joints and potentially eroding the sidewalls of copper (Cu) pillars, leading to a series of reliability issues. The MR-MUF process uses flux to assist in the process. Multiple chips are first attached to the circuit, and then batch reflow is performed at around 260°C, allowing for the interconnection of multiple chips in one step. However, the need for flux requires an additional flux cleaning step. As the microbump interconnect pitch reaches 20 micrometers (μm) and below, flux cleaning becomes extremely difficult. Flux residue can create porous microbumps, severely impacting interconnect reliability. Summary of the Invention

[0003] One object of this invention is to provide a bonding method for electronic components with ultra-narrow pitch microbumps. First, pre-bonding of the microbumps is achieved through low-temperature solid-state diffusion bonding. During the pre-bonding process, the degree of Sn extrusion is precisely controlled by adjusting the bonding pressure. Then, high-temperature rapid reflow enables the electronic components to achieve highly reliable and efficient bonding for ultra-narrow pitch microbump interconnection. Another object of this invention is to provide a bonding apparatus for electronic components with ultra-narrow pitch microbumps. A further object of this invention is to provide a computer-readable medium. A final object of this invention is to provide a computer device.

[0004] To achieve the above objectives, this invention discloses a bonding method for electronic components with ultra-narrow pitch microbumps, comprising:

[0005] Obtain the electronic components to be bonded;

[0006] By using solid-state diffusion bonding, the microbumps of the electronic components to be bonded are pre-bonded to obtain pre-bonded samples.

[0007] The pre-bonded sample is heated and refluxed to generate a bonded sample.

[0008] Preferably, before pre-bonding the microbumps of the electronic components to be bonded by solid-state diffusion bonding to obtain a pre-bonded sample, the method further includes:

[0009] The surface of the electronic components to be bonded is ultrasonically cleaned using a cleaning material to produce cleaned electronic components to be bonded.

[0010] Preferably, the microbumps of the electronic components to be bonded are pre-bonded using solid-state diffusion bonding to obtain a pre-bonded sample, including:

[0011] During the pre-bonding process, protective gas is continuously injected, and the micro-bumps of the electronic components to be bonded are thermo-bonded according to the preset pre-bonding temperature, pre-bonding time, and pre-bonding pressure to generate a pre-bonded sample. The pre-bonding temperature is lower than the melting point of the solder.

[0012] Preferably, the pre-bonding temperature is 200 degrees Celsius, the pre-bonding time is 3 minutes, and the pre-bonding pressure is 0.8 MPa.

[0013] Preferably, a protective gas is continuously injected during the pre-bonding process, including

[0014] Inert gas is injected during the initial bonding process, and the current temperature is checked at preset time intervals to determine whether the preset temperature threshold has been reached.

[0015] If so, begin injecting formic acid gas;

[0016] If not, continue executing the step of determining whether the current temperature has reached the preset temperature threshold at preset time intervals until the current temperature reaches the preset temperature threshold.

[0017] Preferably, the pre-bonded sample is heated and refluxed to generate a bonded sample, including:

[0018] The pre-bonded sample is heated by the hot plate of the bonding equipment according to the preset reflow temperature and reflow time, so that the solder of the upper and lower micro-bumps melts and connects, thus generating a bonded sample.

[0019] Preferably, the reflux temperature is 260 degrees Celsius and the reflux time is 1 minute.

[0020] Preferably, after heating and refluxing the pre-bonded sample to generate a bonded sample, the method further includes:

[0021] The micro-bumps of the bonded sample are filled with a pre-set filling material to complete the filling and protection of the bonded sample.

[0022] Preferably, the electronic components to be bonded include chips and / or wafers, and the bonding samples include chip-to-chip bonding samples, chip-to-wafer bonding samples, or wafer-to-wafer bonding samples.

[0023] Preferably, the diameter of the microbump is less than or equal to 30 micrometers, the microbump pitch is less than or equal to 40 micrometers, the microbump height is less than or equal to 20 micrometers, and the solder thickness is less than or equal to 8 micrometers.

[0024] Preferably, the method further includes:

[0025] The bonded sample is subjected to shear strength test according to the preset shear pressure, and the shear strength is generated based on the shear pressure and the diameter of the micro-bumps.

[0026] The present invention also discloses a computer-readable medium having a computer program stored thereon, which, when executed by a processor, implements the method described above.

[0027] The present invention also discloses a computer device, including a memory and a processor, wherein the memory is used to store information including program instructions, and the processor is used to control the execution of the program instructions, wherein the processor executes the program to implement the method described above.

[0028] The present invention also discloses a computer program product, including a computer program / instruction, which, when executed by a processor, implements the method described above.

[0029] This invention obtains an electronic component to be bonded; pre-bonds the microbumps of the electronic component to be bonded through solid-state diffusion bonding to obtain a pre-bonded sample; heats and reflows the pre-bonded sample to generate a bonded sample, first achieving pre-bonding of the microbumps through low-temperature solid-state diffusion bonding, and precisely controlling the extrusion degree of Sn by adjusting the bonding pressure during the pre-bonding process; then, high-temperature rapid reflow enables the electronic component to achieve highly reliable and efficient bonding for ultra-narrow pitch microbump interconnection. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1A flowchart illustrating a bonding method for electronic components with ultra-narrow pitch microbumps, provided in an embodiment of the present invention;

[0032] Figure 2 A flowchart illustrating another bonding method for electronic components with ultra-narrow pitch micro-bumps, provided as an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of a bonding point under pre-bonding temperature and pre-bonding pressure conditions provided in an embodiment of the present invention;

[0034] Figure 4 A schematic diagram of a bonding point under another pre-bonding temperature and pre-bonding pressure condition provided in an embodiment of the present invention;

[0035] Figure 5 A schematic diagram of a bonding point under another pre-bonding temperature and pre-bonding pressure condition provided in an embodiment of the present invention;

[0036] Figure 6 A schematic diagram of a bonding point under another pre-bonding temperature and pre-bonding pressure condition provided in an embodiment of the present invention;

[0037] Figure 7 A schematic diagram of a bonded sample magnified 500 times after reflux, provided as an embodiment of the present invention;

[0038] Figure 8 A schematic diagram of a bonded sample magnified 1500 times after reflux, provided as an embodiment of the present invention;

[0039] Figure 9 This is a comparative schematic diagram of shear strength testing under different bonding methods provided in an embodiment of the present invention;

[0040] Figure 10 This is a schematic diagram of a bonded sample after SSD-R bonding of electronic component A, provided in an embodiment of the present invention.

[0041] Figure 11 This is a schematic diagram of a bonding sample after SSD-R bonding of electronic component B, provided in an embodiment of the present invention.

[0042] Figure 12 This is a schematic diagram of a bonding sample after SSD-R bonding of electronic component C, provided in an embodiment of the present invention;

[0043] Figure 13 This is a schematic diagram of a bonded sample after SSD-R bonding of electronic component D, provided in an embodiment of the present invention.

[0044] Figure 14 This is a schematic diagram of the structure of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] To facilitate understanding of the technical solutions provided in this application, the relevant content of the technical solutions will be explained below. This application pertains to high-density microbump bonding, and the technologies involved include, but are not limited to, advanced semiconductor packaging, low-temperature solid-state metal bonding, and high-temperature rapid reflow bonding. Currently, the two mainstream high-density interconnection methods in the industry include: copper-copper / silicon dioxide-silicon dioxide (Cu-Cu / SiO2-SiO2) hybrid bonding and fine-pitch microbump bonding. Cu-Cu / SiO2-SiO2 hybrid bonding utilizes hydrogen bonds between SiO2 particles to achieve pre-bonding at room temperature, and then utilizes the difference in thermal expansion coefficients between copper and silicon dioxide to achieve copper-to-copper bonding interconnection through high-temperature annealing at 250℃~300℃. Fine-pitch microbump technology is a mature inter-chip interconnection technology. The microbump structure is generally a copper pillar + solder cap, implemented using a wafer-level electroplating process. Microbumps achieve interconnection by melting and then solidifying solder through thermal compression bonding (TCB) at around 260°C or flux reflow processes. Currently, the industry standard for mass-produced microbumps is approximately 20μm in diameter and 40μm in pitch. The next generation of mass-produced microbumps is expected to achieve a diameter of 10μm and a pitch of 20μm. Compared to hybrid bonding, narrow-pitch microbumps offer advantages such as mature technology, higher interconnect density, controllable process costs, and compatibility with equipment and manufacturers. However, in microbump applications with pitches below 40μm, the melt extrusion of Sn at high temperatures becomes a significant issue affecting process yield. This is because Sn's yield strength decreases under high temperatures, allowing even small pressures to induce significant deformation and extrusion. The extruded Sn can contact surrounding microbumps, causing short circuits and potentially eroding the Cu pillar sidewalls, leading to a series of reliability problems.

[0047] This application utilizes low-temperature solid-state diffusion bonding (SSD) to pre-bond microbumps. During the bonding process, inert gas (N2) protection and formic acid reduction are used to remove the oxide layer on the microbump surface. The degree of Sn extrusion is precisely controlled by adjusting the SSD bonding pressure during pre-bonding. High-temperature rapid reflow enables highly reliable and efficient bonding of the chip. A molding underfill material provides complete protection for the microbumps. For ease of description, this invention is referred to as the SSD-R bonding method.

[0048] Figure 1 A flowchart illustrating a bonding method for electronic components with ultra-narrow pitch microbumps, provided by an embodiment of the present invention, is shown below. Figure 1 As shown, the method includes:

[0049] Step 101: Obtain the electronic components to be bonded.

[0050] Step 102: Pre-bond the microbumps of the electronic components to be bonded by solid-state diffusion bonding to obtain a pre-bonded sample.

[0051] Step 103: Heat and reflux the pre-bonded sample to generate a bonded sample.

[0052] In the technical solution provided by the embodiments of the present invention, an electronic component to be bonded is obtained; the microbumps of the electronic component to be bonded are pre-bonded by solid-state diffusion bonding to obtain a pre-bonded sample; the pre-bonded sample is heated and reflowed to generate a bonded sample. The microbumps are first pre-bonded by low-temperature solid-state diffusion bonding, and the degree of Sn extrusion is precisely controlled by adjusting the bonding pressure during the pre-bonding process; then, the electronic component is bonded to a high reliability and high efficiency for ultra-narrow pitch microbump interconnection by high-temperature rapid reflow.

[0053] Figure 2 A flowchart illustrating another bonding method for electronic components with ultra-narrow pitch microbumps provided in this embodiment of the invention is shown below. Figure 2 As shown, the method includes:

[0054] Step 201: Obtain the electronic components to be bonded.

[0055] In this embodiment of the invention, the electronic components to be bonded include chips and / or wafers. Specifically, if applied to chip-to-chip (D2D) bonding, the chip to be bonded is selected as the electronic component to be bonded; if applied to chip-to-wafer (D2W) bonding, the chip and wafer to be bonded are selected as the electronic components to be bonded; if applied to wafer-to-wafer (W2W) bonding, the wafer to be bonded is selected as the electronic component to be bonded.

[0056] Step 202: Use a cleaning material to ultrasonically clean the surface of the electronic components to be bonded, resulting in cleaned electronic components to be bonded.

[0057] In this embodiment of the invention, the cleaning materials include, but are not limited to, acetone, alcohol, and deionized water. Specifically, a single chip on a wafer is selected, and the chip / wafer surface is ultrasonically cleaned sequentially with acetone, alcohol, and deionized water to remove any residual organic matter or residue, achieving a high degree of cleanliness and generating cleaned electronic components ready for bonding.

[0058] It is worth noting that if applied to W2W bonding, the step of selecting the chip is omitted.

[0059] It is worth noting that the cleaning methods include, but are not limited to, the ultrasonic cleaning method mentioned above. Plasma cleaning, acid washing, and isopropanol cleaning can also be used.

[0060] It is worth noting that the microbump Cu pillars on the chip (in a broad sense) have a copper / nickel / copper (Cu / Ni / Cu) structure, with a microbump diameter of 30μm. The solder cap material is a tin-silver alloy (Sn1.8Ag), and the solder cap thickness is 8μm. Other broadly defined Cu pillar structures (such as Cu, Cu / Ni, Cu / Ni / Cu / Ni, Ni, etc.), solder materials (such as Sn, SnPb, SnAgCu, SnBi, etc.), microbump diameter designs, and microbump layer height designs should all be considered as similar embodiments. This application will not elaborate on them further.

[0061] In this embodiment of the invention, the microbumps are applied to ultra-narrow pitch microbumps, the diameter of the microbumps is less than or equal to 30 μm, the pitch of the microbumps is less than or equal to 40 μm, the height of the microbumps is less than or equal to 20 μm, and the solder thickness is less than or equal to 8 μm.

[0062] Step 203: During the pre-bonding process, protective gas is continuously injected. According to the preset pre-bonding temperature, pre-bonding time, and pre-bonding pressure, the micro-bumps of the electronic components to be bonded are thermo-bonded to generate a pre-bonded sample. The pre-bonding temperature is lower than the melting point of the solder.

[0063] In this embodiment of the invention, the SSD pre-bonding process can be carried out using a thermocompression bonding device. The thermocompression bonding device supports flip-chip, reflow, and thermocompression bonding processes, supports protective atmospheres, has an alignment accuracy of ±3μm, a pre-bonding process temperature range of room temperature to 450 degrees Celsius, and a maximum bonding pressure of 2000N.

[0064] It is worth noting that different hot-press bonding equipment supports different process parameters. Equipment that supports the above process parameters and functions can be used in this application and can be regarded as similar embodiments of this application.

[0065] It is worth noting that the pre-bonding temperature, pre-bonding time, and pre-bonding pressure all have specified selection ranges, and the selection criteria are as follows: the pre-bonding temperature should be lower than the melting point of the selected solder; the pre-bonding time is based on successful pre-bonding; and the pre-bonding pressure is based on successful pre-bonding without Sn extrusion.

[0066] Heating at a temperature higher than the solder's melting point and using a hot-pressing bonding method that achieves bonding through a temperature higher than the solder's melting point is called solid-liquid inter-diffusion (SLID). Figure 3 This is a schematic diagram of a bonding point under pre-bonding temperature and pre-bonding pressure conditions provided in an embodiment of the present invention, as shown below. Figure 3 As shown, under the conditions of a pre-bonding temperature of 260℃ and a pre-bonding pressure of 0.8MPa, Sn extrusion is obvious at the bonding point. Figure 4 This is a schematic diagram of a bonding point under another pre-bonding temperature and pre-bonding pressure condition provided in an embodiment of the present invention, as shown below. Figure 4 As shown, under the conditions of a pre-bonding temperature of 200℃ and a pre-bonding pressure of 2.4MPa, Sn extrusion is obvious at the bonding point. Figure 5 This is a schematic diagram of a bonding point under another pre-bonding temperature and pre-bonding pressure condition provided in an embodiment of the present invention, as shown below. Figure 5 As shown, under the conditions of a pre-bonding temperature of 200℃ and a pre-bonding pressure of 1.6MPa, Sn was slightly extruded at the bonding point. Figure 6 This is a schematic diagram of a bonding point under another pre-bonding temperature and pre-bonding pressure condition provided in an embodiment of the present invention, as shown below. Figure 6 As shown, under the conditions of a pre-bonding temperature of 200℃ and a pre-bonding pressure of 0.8MPa, Sn did not undergo extrusion at the bonding point. Figure 3 As shown, once the temperature is increased above the solder melting point, Sn extrusion is very likely to occur at the solder joint. Different bonding pressures in SSD bonding also affect the degree of Sn extrusion, such as... Figures 4 to 6As shown, a pressure of 0.8 MPa provides the best Sn extrusion control. As a preferred option, a pre-bonding temperature of 200℃, a pre-bonding time of 3 minutes, and a pre-bonding pressure of 0.8 MPa enable solid-state diffusion between solders, and the pre-bonding pressure adjustment prevents Sn extrusion.

[0067] It's worth noting that regardless of the pressure applied during SSD bonding, incomplete contact exists at the bonding interface because the temperature hasn't reached the solder's melting point. This is consistent with the characteristics of cold-pressed metal bonding. To achieve good mechanical strength, these incomplete contact areas need to be eliminated, requiring the introduction of a subsequent rapid reflow process.

[0068] Furthermore, during the initial bonding process, an inert gas is injected, and the current temperature is checked at preset time intervals to determine whether it has reached a preset temperature threshold. If so, formic acid gas is injected. If not, the process of checking whether the current temperature has reached the preset temperature threshold at preset time intervals continues until the current temperature reaches the preset temperature threshold.

[0069] It is worth noting that the preset temperature threshold can be set according to the temperature at which formic acid gas has the optimal reducing power, and this embodiment of the invention does not limit this setting. As an optional solution, the temperature threshold is 150°C.

[0070] In this embodiment of the invention, the inert gas is nitrogen (N2). During the early stage of bonding, an N2 atmosphere is introduced for protection. After heating, formic acid gas is continuously introduced to carry out pre-bonding under the protective atmosphere of formic acid gas to prevent oxidation and thus ensure the reliability of bonding.

[0071] Step 204: Using the hot plate of the bonding equipment, the pre-bonded sample is heated according to the preset reflow temperature and reflow time so that the solder of the upper and lower micro-bumps melts and completes the connection, thus generating a bonded sample.

[0072] In this embodiment of the invention, the bonding equipment can be replaced by any equipment capable of providing high-temperature heating, and the reflow time should be adjusted according to the actual temperature control capability of the equipment and process requirements. This embodiment of the invention does not impose any limitations on this. As an optional solution, to adapt to large-scale production, the reflow time is 1 minute.

[0073] In this embodiment of the invention, the reflux temperature can be adjusted according to the actual equipment temperature control capability and process requirements, and the range of the reflux temperature is greater than or equal to 250°C.

[0074] In this embodiment of the invention, the pre-bonded chip / wafer undergoes high-temperature rapid reflow, causing the solder on the upper and lower microbumps to melt and complete the connection under its own gravity. At this point, the bonding interface is in complete contact, and the mechanical strength is significantly improved.

[0075] As a preferred option, the reflux temperature is 260°C and the reflux time is 1 minute. Figure 7 This is a schematic diagram of a bonded sample magnified 500 times after reflux, provided as an embodiment of the present invention. Figure 7 As shown, the bonding interfaces at the connection points of each upper and lower micro-protrusion are in complete contact.

[0076] Figure 8 This is a schematic diagram of a bonded sample magnified 1500 times after reflux, provided as an embodiment of the present invention. Figure 8 As shown, the bonding interfaces at the connection points of the upper and lower micro-bumps are in complete contact, with virtually no Sn extrusion. The total height after bonding was measured to be 39.78 μm, which meets the design value.

[0077] In this embodiment of the invention, the bonding samples include chip-to-chip bonding samples, chip-to-wafer bonding samples, or wafer-to-wafer bonding samples.

[0078] Step 205: Fill the bottom of the micro-bumps of the bonded sample with the preset filling material to complete the filling protection of the bonded sample.

[0079] In this embodiment of the invention, the filler material can be selected according to actual needs, and this embodiment of the invention does not limit it. As an optional solution, the filler material is liquid epoxy molding compound (LMC).

[0080] It is worth noting that the filler material should have good flowability, curing properties and mechanical properties.

[0081] Specifically, through a filling process, filler material is injected into the bottom gap of the bonded sample to form a stable protective layer, thus completing the filling and protection of the bonded sample.

[0082] It is worth noting that the SSD-R bonding method proposed in this application is not only applicable to the bonding of two-layer chips / wafers, but also to the vertical stacking bonding of multiple chips. Utilizing solid-state bonding completely replaces the deoxidation and adhesion effects of flux, ensuring that the bumps (Sn) are not extruded and avoiding flux residue issues. It shows promise in micro-bump bonding scenarios with narrower pitches (≤20μm).

[0083] Furthermore, the SSD-R bonding method of this application was compared with the traditional TC-NCF and MR-MUF processes using the SLID method. The test results are shown in Table 1.

[0084] Table 1

[0085] Production efficiency × √ √ thermal conductivity × √ √ Sn extrusion control × √ √ Flux Cleaning unnecessary need unnecessary

[0086] Therefore, the SSD-R bonding method of this application has superior performance in terms of production efficiency, thermal conductivity, Sn extrusion control, and flux cleaning.

[0087] Step 206: Perform a shear strength test on the bonded sample according to the preset shear pressure, and generate the shear strength based on the shear pressure and the diameter of the micro-bumps.

[0088] In this embodiment of the invention, the shear strength of the bonding point under different bonding methods is tested. Figure 9 This is a comparative schematic diagram of shear strength testing under different bonding methods provided in an embodiment of the present invention, as shown below. Figure 9 As shown, the bonding methods include SSD, SSD-R, and SLID. SSD is represented by a triangle, SSD-R by a pentagram, and SLID by a pentagon. The horizontal axis of this comparison diagram represents shear strength in MPa, and the vertical axis represents shear strength in MPa.

[0089] In this embodiment of the invention, the shear strength is a nominal value, calculated based on the shear pressure and the diameter of the micro-bump. Specifically, the circular cross-sectional area of ​​the micro-bump is calculated based on its diameter; the shear strength is obtained by dividing the shear pressure by the circular cross-sectional area. As an optional embodiment, the diameter of the micro-bump is 30 μm.

[0090] In this embodiment of the invention, the nominal shear strength of the SLID bonded sample and the 2.4MPa SSD-R bonded sample is actually higher than the actual value because the stress-bearing area increases due to Sn extrusion. Figure 9 As can be seen, the SSD-prebonded samples possess a certain shear strength, which can support the transfer of pre-bonded chips / wafers between different equipment. The shear strength of the SSD-R bonded samples is significantly improved; for example, the shear strength of the 0.8MPa SSD-R bonded sample can reach 22.21MPa, which meets the shear strength standard for microbumps. Therefore, in summary, the SSD-R bonding method can achieve good bonding strength while controlling Sn extrusion.

[0091] The above embodiments primarily used samples with a microbump diameter of 30 μm because the Sn thickness can be made very thick (8 μm in this embodiment), making Sn extrusion control more difficult. Solving the Sn extrusion problem for this sample theoretically allows for the bonding of other microbumps with narrower pitches. Furthermore, the SSD-R bonding method was used to bond electronic components of different sizes to further verify the reliability of the SSD-R bonding method. The electronic components of various sizes are shown in Table 2.

[0092] Table 2

[0093] A 30μm 60μm 20μm 8μm B 30μm 60μm 17μm 6μm C 20μm 40μm 16μm 4μm D 10μm 20μm 10μm 4μm

[0094] Among them, electronic component A has a microbump diameter of 30μm, a microbump pitch of 60μm, a microbump height of 20μm, and a solder thickness of 8μm; electronic component B has a microbump diameter of 30μm, a microbump pitch of 60μm, a microbump height of 17μm, and a solder thickness of 6μm; electronic component C has a microbump diameter of 20μm, a microbump pitch of 40μm, a microbump height of 16μm, and a solder thickness of 4μm; and electronic component D has a microbump diameter of 10μm, a microbump pitch of 20μm, a microbump height of 10μm, and a solder thickness of 4μm.

[0095] Figure 10 This is a schematic diagram of a bonding sample after SSD-R bonding of electronic component A, provided in an embodiment of the present invention. Figure 10 As shown, the left image is a bonded sample magnified 500 times after reflow, and the bonding interfaces at the connection points of each upper and lower micro-bumps are in complete contact; the right image is a bonded sample magnified 1500 times after reflow, and the bonding interfaces at the connection points of the upper and lower micro-bumps are in complete contact, with good bonding effect and no Sn extrusion.

[0096] Figure 11 This is a schematic diagram of a bonding sample after SSD-R bonding of electronic component B, provided in an embodiment of the present invention. Figure 11 As shown, the left image is a bonded sample magnified 500 times after reflow, and the bonding interfaces at the connection points of each upper and lower micro-bumps are in complete contact; the right image is a bonded sample magnified 1500 times after reflow, and the bonding interfaces at the connection points of the upper and lower micro-bumps are in complete contact, with good bonding effect and no Sn extrusion.

[0097] Figure 12 This is a schematic diagram of a bonding sample after SSD-R bonding of electronic component C according to an embodiment of the present invention, as shown below. Figure 12 As shown, the left image is a bonded sample magnified 500 times after reflow, and the bonding interfaces at the connection points of each upper and lower micro-bumps are in complete contact; the right image is a bonded sample magnified 1500 times after reflow, and the bonding interfaces at the connection points of the upper and lower micro-bumps are in complete contact, with good bonding effect and no Sn extrusion.

[0098] Figure 13 This is a schematic diagram of a bonding sample after SSD-R bonding of electronic component D, provided in an embodiment of the present invention. Figure 13As shown, the left image is a bonded sample magnified 500 times after reflow, and the bonding interfaces at the connection points of each upper and lower micro-bumps are in complete contact; the right image is a bonded sample magnified 1500 times after reflow, and the bonding interfaces at the connection points of the upper and lower micro-bumps are in complete contact, with good bonding effect and almost no Sn extrusion.

[0099] The SSD-R bonding method of this application can achieve ultra-narrow pitch microbump interconnects with a pitch of less than 40 μm; it can control the Sn extrusion problem during the bonding process; and it avoids flux-assisted processes in the bonding process. It has good application prospects in next-generation ultra-narrow pitch microbump bonding applications in the industry.

[0100] It is worth noting that the acquisition, storage, use, and processing of data in the technical solution of this application all comply with relevant laws and regulations. The user information in the embodiments of this application was obtained through legal and compliant means, and the acquisition, storage, use, and processing of user information have been authorized and agreed upon by the client.

[0101] The technical solution of the bonding method for electronic components with ultra-narrow pitch micro-bumps provided in this invention involves obtaining an electronic component to be bonded; pre-bonding the micro-bumps of the electronic component to be bonded through solid-state diffusion bonding to obtain a pre-bonded sample; heating and reflowing the pre-bonded sample to generate a bonded sample; firstly, pre-bonding the micro-bumps is achieved through low-temperature solid-state diffusion bonding, and the degree of Sn extrusion is precisely controlled by adjusting the bonding pressure during the pre-bonding process; then, high-temperature rapid reflow enables the electronic component to achieve highly reliable and efficient bonding for ultra-narrow pitch micro-bump interconnection.

[0102] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer device, specifically, a computer device can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0103] This invention provides a computer device, including a memory and a processor. The memory is used to store information including program instructions, and the processor is used to control the execution of the program instructions. When the program instructions are loaded and executed by the processor, they implement the steps of the above-described bonding method for electronic components with ultra-narrow pitch micro-bumps. For a detailed description, please refer to the above-described embodiment of the bonding method for electronic components with ultra-narrow pitch micro-bumps.

[0104] The following is for reference. Figure 14It shows a schematic diagram of the structure of a computer device 600 suitable for implementing the embodiments of this application.

[0105] like Figure 14 As shown, the computer device 600 includes a central processing unit (CPU) 601, which can perform various appropriate tasks and processes based on programs stored in read-only memory (ROM) 602 or programs loaded from storage section 608 into random access memory (RAM) 603. The RAM 603 also stores various programs and data required for the operation of the computer device 600. The CPU 601, ROM 602, and RAM 603 are interconnected via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0106] The following components are connected to I / O interface 605: an input section 606 including a keyboard, mouse, etc.; an output section 607 including a cathode ray tube (CRT), liquid crystal feedback (LCD), etc., and speakers, etc.; a storage section 608 including a hard disk, etc.; and a communication section 609 including a network interface card such as a LAN card, modem, etc. The communication section 609 performs communication processing via a network such as the Internet. A drive 610 is also connected to I / O interface 605 as needed. A removable medium 611, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 610 as needed so that computer programs read from it can be installed in storage section 608 as needed.

[0107] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program tangibly embodied on a machine-readable medium, the computer program including program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 609, and / or installed from removable medium 611.

[0108] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0109] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0110] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0111] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0112] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0113] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0114] The acquisition, storage, use, and processing of data in this application all comply with the relevant provisions of national laws and regulations.

[0115] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0116] This application can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0117] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0118] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A bonding method for electronic components with ultra-narrow pitch microbumps, characterized in that, The method includes: Obtain the electronic components to be bonded; The microbumps of the electronic component to be bonded are pre-bonded by low-temperature solid-state diffusion bonding to obtain a pre-bonded sample. The process includes: continuously injecting protective gas during the pre-bonding process, and performing thermo-press bonding on the microbumps of the electronic component to be bonded according to a preset pre-bonding temperature, pre-bonding time, and pre-bonding pressure to generate the pre-bonded sample. The pre-bonding temperature is lower than the melting point of solder, the pre-bonding time is based on the success of pre-bonding, the pre-bonding pressure is based on the success of pre-bonding and the extrusion of solder, and the microbump pitch is less than or equal to 40 micrometers. The pre-bonded sample is heated and reflowed to generate a bonded sample, which includes: heating the pre-bonded sample through the hot plate of the bonding equipment according to the preset reflow temperature and reflow time so that the solder of the upper and lower micro-bumps melts and connects, thereby generating the bonded sample.

2. The bonding method for electronic components with ultra-narrow pitch microbumps according to claim 1, characterized in that, Before pre-bonding the microbumps of the electronic component to be bonded by solid-state diffusion bonding to obtain a pre-bonded sample, the method further includes: The surface of the electronic component to be bonded is ultrasonically cleaned using a cleaning material to generate a cleaned electronic component to be bonded.

3. The bonding method for electronic components with ultra-narrow pitch microbumps according to claim 1, characterized in that, The pre-bonding temperature is 200 degrees Celsius, the pre-bonding time is 3 minutes, and the pre-bonding pressure is 0.8 MPa.

4. The bonding method for electronic components with ultra-narrow pitch microbumps according to claim 1, characterized in that, The continuous injection of protective gas during the pre-bonding process includes: Inert gas is injected during the initial bonding process, and the current temperature is checked at preset time intervals to determine whether the preset temperature threshold has been reached. If so, begin injecting formic acid gas; If not, continue with the step of determining whether the current temperature has reached the preset temperature threshold at preset time intervals until the current temperature reaches the preset temperature threshold.

5. The bonding method for electronic components with ultra-narrow pitch microbumps according to claim 1, characterized in that, The reflux temperature is 260 degrees Celsius, and the reflux time is 1 minute.

6. The bonding method for electronic components with ultra-narrow pitch microbumps according to claim 1, characterized in that, After heating and refluxing the pre-bonded sample to generate a bonded sample, the process further includes: The bonding sample is filled with a pre-set filling material to fill the micro-bumps at the bottom, thus completing the filling and protection of the bonding sample.

7. The bonding method for electronic components with ultra-narrow pitch microbumps according to claim 1, characterized in that, The electronic components to be bonded include chips and / or wafers, and the bonding samples include chip-to-chip bonding samples, chip-to-wafer bonding samples, or wafer-to-wafer bonding samples.

8. The bonding method for electronic components with ultra-narrow pitch microbumps according to claim 1, characterized in that, The diameter of the microbump is less than or equal to 30 micrometers, the height of the microbump is less than or equal to 20 micrometers, and the solder thickness is less than or equal to 8 micrometers.

9. The bonding method for electronic components with ultra-narrow pitch microbumps according to claim 1, characterized in that, The method further includes: The bonded sample is subjected to shear strength test according to the preset shear pressure, and the shear strength is generated based on the shear pressure and the diameter of the micro-bumps.

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