Wafer detection probe card electronic glue and probe repair method

Abstract

The application discloses wafer detection probe card electronic glue and a probe repairing method. The wafer detection probe card electronic glue comprises a heat-curing resin and a heat-degradation polymer, the heat-curing resin has a curing trigger temperature less than the heat-degradation temperature of the heat-degradation polymer; the heat-curing resin is softened at the heat-degradation temperature, and the heat-degradation polymer is compatible with the softened heat-curing resin after degradation. The glue can make the bonding strength between the probe and the Pad stronger, and can also make the glue easy to fall off during maintenance.

Description

Technical Field

[0001] This application belongs to the field of probe card technology, and specifically relates to an electronic adhesive for wafer inspection probe cards and a probe repair method. Background Technology

[0002] Wafer-level IC testing, by discarding defective components, avoids unnecessary packaging costs and is an indispensable part of the chip fabrication process. Probe cards provide the electrical contact interface connecting the I / O pins of the wafer under test to the testing equipment, making them a key tool in wafer-level IC testing.

[0003] For probe cards designed for high-end chips such as HBM, solder paste is typically used to achieve the mechanical and electrical bonding between the MEMS probe and the pad. During the soldering process, Sn forms an intermetallic compound (IMC) with the surface metal of the pad. However, under continuous high and low temperature cycling tests, the IMC thickness increases, and the bonding strength gradually decreases. In high-intensity testing environments, it may fail, leading to the probe peeling off from the pad.

[0004] Therefore, to improve the bonding strength between the probe and the pad and avoid probe card failure under harsh environments, probe card manufacturers consider applying thermosetting adhesive to the probe tail. However, due to the special manufacturing and usage environment of probes, general thermosetting adhesives cannot meet the requirements. The reasons are as follows:

[0005] First, since the probe spacing is less than 100μm, after the electronic adhesive is applied between the probes, the capillary force and the shrinkage stress during the curing process may cause the probes to deform, thus affecting the tip position accuracy.

[0006] Secondly, during the testing process, some probes may be damaged. In this case, the probes need to be repaired without damaging the pad or PI, and thermosetting adhesives are usually difficult to remove. Summary of the Invention

[0007] The purpose of this application is to overcome the shortcomings of the prior art and provide an electronic adhesive for wafer inspection probe cards and a probe repair method. The adhesive provides strong bonding strength between the probe and the pad, but also allows for easy detachment due to reduced strength, thus facilitating probe repair.

[0008] To achieve the above objectives, the technical solution adopted in this application is as follows: an electronic adhesive for wafer inspection probe cards includes a thermosetting resin and a thermally degradable polymer, wherein the curing trigger temperature of the thermosetting resin is lower than the thermal degradation temperature of the thermally degradable polymer. At the thermal degradation temperature, the thermosetting resin softens, and the thermally degradable polymer dissolves in the softened thermosetting resin after degradation.

[0009] In some embodiments, the electronic adhesive for the wafer inspection probe card includes a latent curing agent, the activation temperature of which is lower than the thermal degradation temperature.

[0010] In some embodiments, the latent curing agent includes at least one of boron trifluoride-monoethylamine complex, modified imidazole, dicyandiamide and modified dicyandiamide, ketimine, aldolimine, iodonium salt, and thiodonium salt.

[0011] In some embodiments, the electronic adhesive for the wafer inspection probe card includes a curing accelerator, wherein the curing accelerator is 0.2-2 wt%.

[0012] In some embodiments, the curing accelerator includes at least one of 2-methylimidazole, 2-ethyl-4-methylimidazole, 3-(3,4-dichlorophenyl)-1, 1-dimethylurea, 4-chlorophenyl-N, N-dimethylurea, benzyldimethylamine, triethanolamine, tris(dimethylaminomethyl)phenol, benzyltriethylammonium chloride, and tetrabutylammonium bromide.

[0013] In some embodiments, the thermosetting resin includes at least one of epoxy resin, cyanate ester resin, and bismaleimide resin; the thermally degradable polymer includes polyacrylate, polycarbonate, polyurethane with chemical bonds broken upon heat treatment, polymers with chemical bonds broken upon heat treatment, and copolymers or blends thereof.

[0014] In some embodiments, when the electronic adhesive for the wafer inspection probe card includes the latent curing agent, the epoxy resin, and the polyacrylate:

[0015] Epoxy resin: 20-60 wt%; Polyacrylate: 2-30 wt%

[0016] Latent curing agent: 2-18 wt%.

[0017] In some embodiments, the electronic adhesive for the wafer inspection probe card includes at least one of the following features:

[0018] a) The epoxy resin is at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic epoxy resin, alicyclic epoxy resin, and hydrogenated bisphenol A type epoxy resin;

[0019] (b) The polyacrylate is prepared by solution polymerization of acrylate monomers. The acrylate monomers are at least one selected from methyl methacrylate, methyl acrylate, butyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate, methacrylic acid, and acrylic acid.

[0020] c) The curing trigger temperature is 60-100℃, and the thermal degradation temperature is not less than 150℃.

[0021] In some embodiments, the electronic adhesive for the wafer inspection probe card includes a toughening agent, wherein the toughening agent is 1-18 wt%.

[0022] In some embodiments, the toughening agent includes at least one of carboxyl-terminated butadiene-acrylonitrile rubber, amino-terminated butadiene-acrylonitrile rubber, hydroxyl-terminated butadiene-acrylonitrile rubber, polyethylene glycol, hydroxyl-terminated polyester, and hydroxyl-containing polyacrylate.

[0023] In some embodiments, the electronic adhesive for the wafer inspection probe card includes an adhesion promoter, wherein the adhesion promoter is 0.2-3 wt%;

[0024] In some embodiments, the adhesive aid includes at least one of aminosilane coupling agents, epoxysilane coupling agents, methacryloxysilane coupling agents, and titanate coupling agents.

[0025] In some embodiments, the electronic adhesive for the wafer inspection probe card includes a filler, wherein the filler comprises 20-70 wt%;

[0026] In some embodiments, the filler includes at least one of nano-calcium carbonate, fumed silica, carbon black, and titanium dioxide.

[0027] On the other hand, this application discloses a probe repair method for a wafer inspection probe card. The probes of the probe card include any of the aforementioned electronic adhesives for wafer inspection probe cards; the repair method includes the following steps: heating the tail of the probe to a temperature greater than the thermal degradation temperature, so that the electronic adhesive for the wafer inspection probe card detaches.

[0028] This application has the following advantages compared with the prior art:

[0029] 1) The thermosetting resin begins to cure after the curing trigger temperature. During the curing process, it will not cause the tip to deviate because the curing trigger temperature is lower than the thermal degradation temperature, so the thermal degradation polymer will not destroy the adhesiveness of the thermosetting resin. Therefore, the electronic adhesive used for the wafer inspection probe makes the bonding strength between the probe and the pad stronger, which helps to avoid the problem of probe card failure under harsh environments.

[0030] 2) The probe is connected to the pad via micron-level solder paste joints and then encapsulated and fixed with the adhesive. If the adhesive has a high curing shrinkage rate during curing, it will generate internal shrinkage stress. However, the thermosetting resin has a low curing shrinkage rate, which reduces this internal stress. Therefore, the adhesive of this application is beneficial for preventing the probe tip from shifting during curing, and also for preventing the probe from deforming easily, reducing signal interference, and facilitating high-precision and high-density packaging. In addition, the low curing shrinkage rate has the following advantages: 2.1) A low curing shrinkage rate means that the adhesive exerts less pulling force on the interface during curing, forming a tighter and less stressful bonding interface, thereby significantly improving the bonding strength between the adhesive and the probe and the PI (polyimide) substrate; 2.2) Adhesives with low curing shrinkage rates generally have a better matching coefficient of thermal expansion, generating less thermal stress during temperature changes, thus being more fatigue-resistant and having a longer lifespan.

[0031] 3) Thermosetting resins soften (modulus decreases) after thermal degradation, but their chemical structure remains largely intact. (For epoxy resins, the curing trigger temperature can be considered the glass transition temperature Tg. When the temperature exceeds Tg, the epoxy resin transitions from a glassy state to a highly elastic state (rubber state), and the modulus decreases significantly, resulting in softening and viscoelasticity.) The degradation of the thermodegradable polymer completely destroys the continuity of the thermosetting resin. After dissolving with the softened thermosetting resin, numerous microcracks, voids, and interfacial debonding are generated in the softened thermosetting resin. Simultaneously, the thermosetting resin itself softens due to high temperature, reducing its load-bearing capacity and making it unable to resist the structural damage caused by the degradation of the thermodegradable resin. Ultimately, under the synergistic effect of both, the electronic adhesive macroscopically exhibits a loss of strength (or a reduction in strength). In other words, it is no longer a solid whole but becomes a loose, brittle, or peelable residue. This loss of strength is primarily attributed to the structural collapse caused by the chemical degradation of the biodegradable polymer, while the thermosetting resin itself undergoes chemical failure, ultimately leading to a reduction in bond strength (including complete loss of strength, i.e., reduction to zero). Consequently, the adhesive is easily detached, facilitating probe repair without damaging the Pad or PI.

[0032] When the thermosetting resin is epoxy resin and the thermodegradable polymer is polyacrylate, epoxy adhesive can achieve strong bonding strength between the probe and the pad due to its high adhesion, low curing shrinkage, and excellent insulation properties. However, conventional epoxy adhesives have excellent temperature resistance and can even work for extended periods at temperatures above 150°C, but they are difficult to soften or even degrade at 150°C. Polyacrylate has the characteristic of rapid degradation at around 220°C. At the same time, polyacrylate itself has excellent adhesion and compatibility with epoxy resin. Introducing polyacrylate into epoxy resin causes the colloidal structure to be damaged when the ambient temperature is above 220°C, leading to reduced strength or even detachment of the adhesive, facilitating adhesive removal and probe repair. Detailed Implementation

[0033] To illustrate the technical content, structural features, achieved objectives, and effects of the invention in detail, the technical solutions in the embodiments of this application are described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. In the following description, for illustrative purposes, numerous specific details are set forth to provide a detailed description of various exemplary embodiments or implementations of the invention. However, various exemplary embodiments can also be implemented independently without these specific details or in one or more equivalent arrangements. Furthermore, the various exemplary embodiments may differ, but are not necessarily exclusive. For example, without departing from the inventive concept, the specific shape, structure, and characteristics of the exemplary embodiments may be used or implemented in another exemplary embodiment.

[0034] This application discloses an electronic adhesive for wafer inspection probe cards. The electronic adhesive for wafer inspection probe cards comprises a thermosetting resin and a thermally degradable polymer. In embodiments of this application, the thermosetting resin includes at least one of epoxy resin, cyanate ester resin, and bismaleimide resin, but is not limited thereto.

[0035] The advantages of the aforementioned thermosetting resins are described below:

[0036] Epoxy resin: It has excellent mechanical strength and good resistance to acids and alkalis, and can withstand complex use environments such as subsequent cleaning; however, its curing speed is usually slow.

[0037] Cyanate ester resins: They have excellent dielectric properties and pose a low risk of affecting probe electrical performance testing when used as adhesives. However, they are brittle and relatively expensive.

[0038] Bismaleimide resin: It has better heat resistance than epoxy resin, but lower fracture toughness.

[0039] They can be used individually, or combined to achieve a balance of strength, toughness, and corrosion resistance.

[0040] In some embodiments, the epoxy resin is at least one selected from bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic epoxy resin, alicyclic epoxy resin, and hydrogenated bisphenol A type epoxy resin, thereby having the following advantages:

[0041] Bisphenol A type epoxy resin: It is beneficial for strong bonding strength between the probe and the pad for the following reasons: 1) The epoxy groups at the ends of its molecules and the hydroxyl groups in its molecular backbone can form strong van der Waals forces and hydrogen bonds with the surfaces of substrates such as metals (probes, pads) and PI (polyimide), and form chemical bonds through coupling agents, thus resulting in strong intrinsic adhesive strength; 2) After curing, it can form a three-dimensional network with high cross-linking density, giving the adhesive layer high tensile strength, compressive modulus, and hardness, thus providing good cohesive strength and mechanical properties; 3) It has a wide viscosity range (from low-viscosity liquids to semi-solids), which can be adjusted according to the formulation to ensure that the adhesive can fully wet and coat the probe tail and the pad surface, excluding air and forming a tight contact. Good wettability is a prerequisite for obtaining high interfacial strength. In summary, at least based on the above 1 to 3, it is beneficial for strong bonding strength between the probe and the pad. 2) Bisphenol A type epoxy resin is also beneficial for adhesive detachment for the following reasons: 1) Definite glass transition behavior and thermal softening characteristics: Bisphenol A epoxy cured products have a defined glass transition temperature. When the maintenance temperature (>150℃) is much higher than its Tg (usually around 120-150℃), the epoxy network softens (enters a highly elastic state), the modulus decreases, but it still maintains the integrity of the chemical structure (does not decompose). This "softened but not disintegrated" state provides a "deformable" matrix for the gases and stresses generated by the degradation of thermally degradable polymers (such as polyacrylates). If the epoxy remains rigid at 150℃, the destructive force generated by the degradation phase may have nowhere to be released; if the epoxy has already decomposed at this temperature, the degradation process will be chaotic and uncontrollable. The just-right thermal softening of bisphenol A epoxy allows the destructive force to be effectively converted into the mechanical force that leads to the collapse of the overall structure; 2) forming a rigid continuous phase to achieve "brittle" collapse: its highly cross-linked network is still "harder" than many thermoplastics after softening at high temperatures. When the dispersed polyacrylate "sacrificial phase" degrades and disappears, the softened rigid skeleton, riddled with holes, will undergo brittle fracture or pulverization due to loss of internal support and thermal stress, rather than flowing like a viscous liquid. This directly leads to the "structural overall failure" of the adhesive layer, manifested as pulverization, crumbling, or peeling off in sheets, making it easy to remove mechanically (such as by blowing or brushing), thus achieving "easy removal"; 3) Chemical stability ensures the "purity" of the removed material: at the degradation temperature (~150℃) of thermally degradable polymers (such as polyacrylate), the chemical crosslinking network of bisphenol A epoxy itself will not undergo thermal decomposition (its thermal decomposition initiation temperature is usually >300℃). This means that during the repair process, there are no or very few degradation byproducts (such as tar and small molecules) from the epoxy resin itself. This ensures a relatively clean interface after removal, with few residues, facilitating subsequent repair operations.

[0042] Bisphenol F type epoxy resin: Bisphenol F has a more compact molecular structure, containing more epoxy groups per unit mass or volume. This means that under the same curing conditions, it can form a three-dimensional network with a higher crosslinking density. Higher crosslinking density directly leads to a higher glass transition temperature, higher modulus, and better heat resistance and solvent resistance. Under high-temperature testing conditions, the adhesive layer can better maintain rigidity and resist creep, thus resulting in a stronger bond between the probe and the pad. Although its cured network is more heat-resistant, at repair temperatures far above its Tg (>150℃), this highly crosslinked and rigid network becomes more brittle after softening. When the thermally degradable polymer (polyacrylate phase) degrades, the surrounding more brittle continuous phase is less able to resist crack propagation, and is more likely to cause large-scale, pulverizing structural collapse due to internal damage, rather than localized, ductile tearing. This is more conducive to the overall powdering of the adhesive layer, making it easier for the adhesive to fall off.

[0043] Phenolic epoxy resin: This results in a strong bond between the probe and the pad for the following reasons: 1) Phenolic epoxy is a multifunctional epoxy (each molecule contains an average of more than two epoxy groups). After curing, it forms a three-dimensional network with extremely high cross-linking density. This gives it an extremely high glass transition temperature, typically easily exceeding 180℃, and even reaching over 200℃. At this temperature, phenolic epoxy maintains a rigid glassy state, providing absolutely stable and non-loosening support for the probe, ensuring long-term stability of the test contact resistance; 2) The highly cross-linked network results in extremely high hardness, compressive strength, and tensile modulus. The adhesive layer itself is extremely difficult to undergo plastic deformation or creep. It can withstand extremely high contact pressure during probe testing (each probe may require several grams to tens of grams of force) and frequent impacts, exhibiting extremely strong resistance to fretting wear. The bond strength decays very slowly under long-term mechanical fatigue. This also facilitates adhesive removal for the following reasons: The highly cross-linked network of phenolic epoxy resin does not soften significantly before reaching its thermal degradation temperature (>150°C) (because its Tg may already be close to or exceed the maintenance temperature). This means that when the thermally degradable polymer (such as polyacrylate) phase degrades at 150°C, it is rigidly constrained by the surrounding continuous epoxy phase. This rigid constraint leaves the gases and stresses generated by the degradation of polyacrylate with nowhere to buffer. Once the internal pressure exceeds the critical point, it will cause the adhesive layer to undergo brittle fracture, disintegrating into fine particles. This failure is more thorough, resulting in clean detachment, and ultimately, the adhesive is easier to remove.

[0044] Alicyclic epoxy resins are advantageous for strong bonding strength between the probe and the pad for the following reasons: The saturated alicyclic structure is extremely stable, not easily damaged by ultraviolet light, and its resistance to yellowing and aging far exceeds that of benzene-ring-containing epoxy resins. During long-term use or storage, the adhesive layer performance will not degrade due to light exposure, avoiding interfacial embrittlement or strength reduction caused by material aging, ensuring the stability of long-term bonding strength, which is beneficial to strong bonding strength between the probe and the pad. The symmetrical and non-polar molecular structure, with extremely low dielectric constant and dielectric loss, also indirectly contributes to strong bonding strength between the probe and the pad. Alicyclic epoxy resins also facilitate adhesive removal for the following reasons: The thermal stability of certain alicyclic epoxy resins and their cured products at high temperatures is not infinitely high. Unlike the robust benzene ring structure of aromatic epoxy resins, their alicyclic and ether bonds may undergo chain segmentation and depolymerization at relatively low temperatures (e.g., in the 250-300℃ range). This means that at maintenance temperatures (>150℃), not only does the polyacrylate degrade, but the continuous epoxy resin phase itself may also begin to chemically decompose. This creates a synergistic effect between "sacrificial phase degradation" and "matrix phase decomposition," potentially leading to the adhesive layer escalating from "physical collapse" to "chemical disintegration." The peeling will be more thorough, leaving less residue, and may require less heat or a shorter time.

[0045] Hydrogenated bisphenol A epoxy resin is advantageous for strong bonding strength between the probe and the pad for the following reasons: After the benzene ring is hydrogenated, the molecular polarity decreases, and the hygroscopicity decreases (typically more than 50% lower than that of bisphenol A). Simultaneously, the saturated cyclohexane structure is more stable than the benzene ring and less prone to oxidation. Moisture is the "number one killer" of electronic adhesive failure. The extremely low hygroscopicity of hydrogenated bisphenol A epoxy means: 1) After high-temperature and high-humidity testing or storage, the volume expansion of the adhesive layer is small, and the moisture-induced stress acting on the bonding interface is small, which helps avoid interfacial delamination caused by moisture absorption and expansion; 2) The electrical insulation properties (volume resistivity, dielectric strength) decrease very little in humid and hot environments, which is beneficial to strong bonding strength between the probe and the pad. The hydrogenated bisphenol A epoxy resin also facilitates adhesive removal for the following reasons: When the saturated hydrocarbon structure undergoes thermal decomposition at high temperatures (>150℃), its products are mainly small molecule gases and volatile liquids such as alkanes and alkenes, which are relatively simple and inert in chemical properties. Hydrogenated bisphenol A epoxy resin leaves fewer decomposition residues, is less sticky, and is easier to volatilize or remove. This helps avoid the risk of the adhesive layer carbonizing and becoming sticky during maintenance, contaminating the pad and probe, and facilitates adhesive removal.

[0046] When the thermosetting resin comprises at least two of the above-mentioned substances, better results can be obtained, some examples of which are described below:

[0047] Regarding the bonding strength between the probe card and the pad: 1) Bisphenol A / F type + hydrogenated bisphenol A type / flexible polyether epoxy: Bisphenol A provides high strength and rigidity, while the hydrogenated or flexible components act like "molecular springs" interwoven in the network, absorbing impact energy and preventing crack propagation. The final adhesive layer is both hard and not easily brittle, able to withstand repeated impacts and testing stresses from the probe, and the bonding interface is not easily peeled off due to brittleness, which is beneficial to the strong bonding strength between the probe and the pad. 2) Phenolic epoxy + bisphenol A / F type: Pure phenolic epoxy has high viscosity, high brittleness, and poor processability. The addition of bisphenol A / F type significantly improves the fluidity, wettability, and curing toughness of the resin system, making the formulation feasible. At the same time, the introduction of phenolic epoxy significantly increases the glass transition temperature and high temperature modulus of the entire system, ensuring that the adhesive layer does not soften during high-temperature testing and maintains stable bonding pressure, thus contributing to the strong bonding strength between the probe card and the pad. 3) Alicyclic epoxy (weather resistant / low dielectric) + bisphenol A type (high adhesion): While maintaining excellent adhesive strength, it gives the adhesive layer special UV aging resistance or extremely low dielectric loss, meeting the needs of special probe cards (such as outdoor use, high frequency testing), and also helps to strengthen the bonding strength between the probe card and the Pad.

[0048] Regarding adhesive detachment, when at least two of the above-mentioned components are used, the Tg and thermal softening behavior of different resins vary. By compounding, the temperature range for the adhesive layer to transition from a glassy state to a highly elastic state can be broadened or precisely set. During the degradation of the thermally degradable polymer, the adhesive layer can effectively release stress through the softening phase and efficiently transfer destructive force through the rigid phase, thereby inducing a uniform and complete overall collapse rather than localized failure, which is beneficial for adhesive detachment.

[0049] In a further embodiment, the epoxy resin includes at least one selected from bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic epoxy resin, alicyclic epoxy resin, and hydrogenated bisphenol A type epoxy resin. Preferably, the epoxy resin is bisphenol A type, and more preferably, it includes two bisphenol A epoxy resins, E-51 and E-44. This provides the following advantages:

[0050] Type A epoxy resin provides a strong bond between the probe and the pad for the following reasons: 1) Excellent intrinsic adhesive strength: Its molecular structure (terminal epoxy groups and hydroxyl groups in the backbone) allows it to form strong physical adsorption and hydrogen bonds with various substrates such as metals, ceramics, and PI, and chemical bonds through coupling agents, resulting in strong bonding strength; 2) Good cohesive strength and mechanical properties: After curing, it forms a cross-linked three-dimensional network, giving the adhesive layer high hardness, high modulus, and high compressive strength. This means the adhesive layer itself is very strong, firmly "locking" the probe in place, and does not undergo cohesive failure under test stress. The force can be effectively transferred to the interface, resulting in strong bonding strength; 3) Wide viscosity range: It can be applied from low-viscosity liquid (e.g., E-51) to semi-solid (e.g., E-44), facilitating perfect wetting of the probe and pad surfaces through formulation adjustments, eliminating air, and forming a dense, defect-free interface layer, thus resulting in strong bonding strength.

[0051] Type A epoxy resin also facilitates the removal of the adhesive and the repair of the probe for the following reasons: 1) Bisphenol A epoxy has a defined glass transition temperature (Tg) after curing (typically between 120-150°C, depending on the curing system). When repair heating reaches 150°C, this temperature is much higher than its Tg, and the epoxy network softens significantly (entering a highly elastic state), with a sharp drop in modulus, but still maintaining the integrity of the chemical structure. This "softened but not disintegrated" state provides a "deformable and collapsible" matrix for the gases and stresses generated by the degradation of the thermally degradable polymer (polyacrylate). If the epoxy remains rigid at 150°C (e.g., insufficiently cured or with an excessively high Tg), the degradative forces have nowhere to be released; if the epoxy has already decomposed at this temperature, the process becomes chaotic. The moderate softening of bisphenol A epoxy allows the degradative forces to be efficiently converted into mechanical forces that lead to the collapse of the overall structure, thus facilitating adhesive removal. 2) Even after softening, its modulus is still significantly higher than that of many thermoplastics. When the internal thermally degradable polymer (polyacrylate) "sacrificial phase" degrades and disappears, the hollowed-out, softened rigid skeleton will undergo brittle fracture or pulverization due to loss of internal support and thermal stress. This directly leads to the collapse of the overall structure of the adhesive layer, manifesting as pulverization or crumbling, which is easily removed mechanically (by blowing air or light brushing). 3) At the thermal degradation temperature (~150℃) of the thermally degradable polymer (such as polyacrylate), the chemical crosslinking network of bisphenol A epoxy itself does not undergo large-scale thermal decomposition (its initial decomposition temperature is usually >300℃). This means that there are no or very few viscous, coking byproducts from the epoxy resin itself during maintenance. The detachment is mainly a collapse of the physical structure, rather than a chaotic decomposition of chemical substances, ensuring a relatively clean interface after removal, with little residue and solid powder, making it easy to clean.

[0052] Bisphenol F epoxy resin provides stronger bonding strength between the probe and the pad for the following reasons: 1) Bisphenol F has a more compact molecular structure, containing more epoxy groups (functionality) per unit mass or volume than bisphenol A. Under the same curing conditions, it can form a three-dimensional network with a higher crosslinking density, which means a higher glass transition temperature, higher modulus, and better heat and solvent resistance after curing. In the high-temperature testing environment of the chip, the adhesive layer can better maintain rigidity and resist creep, thus providing a more durable and stable bonding force. 2) Its low viscosity allows the adhesive to more easily and thoroughly wet the complex microstructure of the probe tail and the pad surface, expelling microbubbles and forming better interfacial contact. 3) Due to its low viscosity, a higher proportion of inorganic fillers can be added to the formulation to reduce curing shrinkage and coefficient of thermal expansion without making the adhesive too viscous. Lower curing shrinkage means less internal curing stress, and lower CTE means less thermal cycling stress. These two stresses are the main culprits leading to interfacial microcracks and ultimately a decrease in bonding strength. Therefore, bisphenol F improves the long-term reliability of the bond from the root by allowing for high filling.

[0053] Bisphenol F type epoxy resin also facilitates adhesive removal for the following reasons: 1) Its higher crosslinking density network, after softening at maintenance temperatures far above Tg (>150℃), exhibits more pronounced brittleness than the bisphenol A network. When the thermally degradable polymer (polyacrylate) phase degrades, the surrounding, more brittle continuous phase is less resistant to crack propagation, making it easier to induce widespread, pulverizing structural collapse rather than ductile, localized damage. This is more conducive to the overall pulverization of the adhesive layer, achieving clean and efficient removal. 2) The low viscosity allows for more uniform and fine dispersion of the thermally degradable polymer (such as polyacrylate) and fillers in the epoxy matrix, forming a composite material with better isotropy. During thermal degradation, the distribution of failure trigger points is extremely uniform, and the stress concentration effect is weakened, allowing failure to be initiated and propagated almost synchronously throughout the entire adhesive layer. This avoids incomplete removal or large clumps of adhesive residue caused by local structural inhomogeneity, making the removal process more thorough and predictable.

[0054] Phenolic epoxy resin provides a strong bond between the probe and the pad for the following reasons: 1) High functionality (each molecule contains more than two epoxy groups), resulting in a highly cross-linked three-dimensional network after curing. Its glass transition temperature is extremely high, easily exceeding 180℃, reaching 200-250℃ or even higher. In high-temperature chip testing (e.g., 150-175℃), conventional epoxy resins may approach or exceed their Tg, beginning to soften and causing a loosening of the clamping force on the probe and unstable contact resistance. Phenolic epoxy, however, maintains a rigid glassy state at this temperature, providing absolutely stable and non-loosening support, ensuring long-term test stability. 2) The highly cross-linked network endows it with extremely high hardness, modulus, and creep resistance. The adhesive layer itself is extremely difficult to plastically deform. It can withstand extremely high contact pressure and frequent impacts during probe testing, exhibiting strong resistance to fretting wear. Its low coefficient of thermal expansion also means that the size changes very little when the temperature changes, and there will be no periodic shear stress on the interface due to thermal expansion and contraction. The bonding strength decays very slowly under thermal cycling.

[0055] Phenolic epoxy resin adhesives are easy to remove for the following reasons: Their highly cross-linked network shows minimal softening before reaching the thermal degradation temperature (>150℃) (because their Tg may already be close to the maintenance temperature). When the polyacrylate phase degrades, the surrounding continuous epoxy phase remains an extremely rigid "constraint." This rigid constraint causes a rapid accumulation of gases and stress generated during degradation, with no buffer. Once the internal pressure exceeds a critical point, it triggers an "explosive" brittle fracture, instantly disintegrating the adhesive layer into fine particles. This failure is very thorough, with almost no stickiness or stringing, and the removed material is clean and easy to remove.

[0056] Alicyclic epoxy resins provide strong bonding between the probe and the pad for the following reasons: The saturated alicyclic structure is extremely stable, exhibiting strong resistance to ultraviolet light and ozone, and showing almost no yellowing or powdering. During long-term use or storage, the adhesive layer of the probe card will not degrade or become brittle due to photoaging. This means that its mechanical properties and interfacial bonding strength are exceptionally stable over time, avoiding premature failure caused by material aging itself, making it particularly suitable for probe cards used in high-reliability, long-life testing equipment or outdoor testing devices. 2) The molecular structure is symmetrical and nonpolar, resulting in extremely low dielectric constant and dielectric loss factor.

[0057] Alicyclic epoxy resins are easier to remove from adhesives for the following reasons: 1) Certain alicyclic epoxy resins and their cured products may have relatively low thermal decomposition initiation temperatures (e.g., in the 250-350℃ range), and the decomposition process may be cleaner. In addition to the degradation of the thermally degradable polymer, the continuous phase of the thermosetting resin itself may also begin to undergo chain segmentation. This creates a double whammy of sacrificial phase degradation and matrix phase weakening. As a result, the adhesive layer may disintegrate more rapidly and thoroughly with lower energy input, and may even escalate from physical collapse to chemical-physical synergistic disintegration, leaving less residue. 2) Their cured network is usually brittle (high internal stress, low toughness), and the brittle network is prone to initiation and crack propagation when heated and internally damaged.

[0058] Hydrogenated bisphenol A epoxy resin enhances the bonding strength between the probe and the pad for the following reasons: The substitution of the benzene ring with saturated cyclohexane reduces molecular polarity, leading to a decrease in hygroscopicity. Simultaneously, the saturated structure is more stable and exhibits stronger antioxidant properties. Moisture is the primary factor causing interface degradation in electronic adhesives. Lower hygroscopicity means less volume expansion of the adhesive layer after high-temperature, high-humidity testing or storage, resulting in less moisture-induced stress at the bonding interface and mitigating interfacial delamination caused by hygroscopic expansion. 2) The cyclohexane structure is more flexible, resulting in lower internal stress in the cured network. This allows for better absorption and release of internal stress generated by curing shrinkage and thermal cycling, reducing the destructive effect of stress on the bonding interface and making the bond more durable and fatigue-resistant.

[0059] Hydrogenated bisphenol A epoxy resin adhesive is easy to remove for the following reasons: 1) When the saturated hydrocarbon structure thermally decomposes at high temperatures (>150℃), it mainly produces small molecule gases such as alkanes and alkenes, and volatile liquids. The products are relatively simple and inert. Hydrogenated bisphenol A epoxy leaves fewer decomposition residues, is less sticky, and is easier to volatilize and remove, which helps avoid the risk of the adhesive layer carbonizing and becoming sticky during maintenance, contaminating the surface of precision pads and probes. 2) When the adhesive layer loses strength due to degradation, its interface with the substrate may separate more easily and cleanly, reducing adhesive residue.

[0060] When the epoxy resin comprises at least two components, it can leverage the strengths of both to overcome the limitations of a single component. Furthermore, by adjusting the proportions of different resins, the viscosity, reactivity, gel time, curing temperature, and other properties of the adhesive can be precisely controlled. Some examples are illustrated below:

[0061] Phenolic epoxy + bisphenol A / F type or hydrogenated bisphenol A: Phenolic epoxy provides extremely high high-temperature modulus and heat resistance, preventing probe pressure relaxation under high-temperature testing. The addition of toughening resin significantly reduces brittleness and curing stress, avoiding cohesive cracking or interfacial delamination. The final result is a high-temperature resistant and tough adhesive layer with extremely stable bond strength over a wide temperature range and under mechanical fatigue.

[0062] Hydrogenated bisphenol A + alicyclic epoxy + bisphenol F: In this combination, hydrogenated bisphenol A ensures stability under humid and thermal conditions, the alicyclic epoxy resists ultraviolet light and ensures electrical properties, and bisphenol F provides a solid adhesive foundation. The resulting adhesive layer can maintain extremely high bonding strength and functional integrity for a long time in harsh composite environments such as outdoor use, high frequency, and high humidity.

[0063] Bisphenol F + Hydrogenated Bisphenol A: The extreme wettability of bisphenol F ensures the formation of a perfect interface, while the low polarity and toughness of hydrogenated bisphenol A further reduce interfacial stress. This combination maximizes the actual contact area at the interface and minimizes destructive stress from both physical and chemical perspectives, thereby achieving the highest measurable actual bond strength.

[0064] In some embodiments, the thermally degradable polymer includes, but is not limited to, polyacrylates, polycarbonates, polyurethanes whose chemical bonds break upon heat treatment, polymers whose chemical bonds break upon heat treatment, and copolymers or blends thereof.

[0065] In a further embodiment, the polyacrylate is prepared by solution polymerization of acrylate monomers. The acrylate monomer is at least one selected from methyl methacrylate (MMA), methyl acrylate (MA), butyl methacrylate (BMA), butyl acrylate (BA), 2-ethylhexyl acrylate (EHA), hydroxyethyl methacrylate (HEMA), hydroxyethyl acrylate (HEA), methacrylic acid (MAA), and acrylic acid (AA). Preferably, when the acrylate monomer is selected from at least one of MMA, BA, HEMA, and HEA, the suitable solvent for the acrylate monomer is at least one selected from ethyl acetate, propyl acetate, butyl acetate, toluene, xylene, acetone, and butanone. Preferably, the organic solvent is selected from ethyl acetate, toluene, or butanone. Preferably, the mass ratio of the organic solvent to the acrylate monomer is (1-5):1. The initiator is at least one of azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), and tert-butyl perethylhexanoate (TBPO). Preferably, the initiator is selected from AIBN or BPO. Preferably, the mass ratio of the initiator to the acrylate monomer is (0.01-0.5):1.

[0066] The curing trigger temperature of the thermosetting resin is lower than the thermal degradation temperature of the thermally degradable polymer. In some embodiments, the curing trigger temperature is 60-100°C, and the thermal degradation temperature is not less than 150°C. However, the curing trigger temperature and the initial thermal degradation temperature are not limited to the above temperatures. At the thermal degradation temperature, the thermosetting resin softens, and the thermally degradable polymer is miscible with the softened thermosetting resin after degradation. Of course, those skilled in the art will understand that the electronic adhesive for wafer inspection probes includes other components besides the thermosetting resin and the biodegradable polymer, which are not listed here.

[0067] As described above, the adhesive has at least the following advantages:

[0068] 1) The thermosetting resin begins to cure after the curing trigger temperature. During the curing process, it will not cause the tip to deviate because the curing trigger temperature is lower than the thermal degradation temperature, so the thermal degradation polymer will not destroy the adhesiveness of the thermosetting resin. Therefore, the electronic adhesive used for the wafer inspection probe makes the bonding strength between the probe and the pad stronger, which helps to avoid the problem of probe card failure under harsh environments.

[0069] 2) The probe is connected to the pad via micron-level solder paste joints and then encapsulated and fixed with the adhesive. If the adhesive has a high shrinkage rate during curing, it will generate internal shrinkage stress. However, the thermosetting resin has a low curing shrinkage rate, which reduces this internal stress. Therefore, the adhesive of this application is beneficial for preventing the probe tip from shifting during curing, and also for preventing the probe from deforming easily, reducing signal interference, and facilitating high-precision and high-density packaging. In addition, the low curing shrinkage rate has the following advantages: 2.1) A low curing shrinkage rate means that the adhesive exerts less pulling force on the interface during curing, forming a tighter and less stressful bonding interface, thereby significantly improving the bonding strength between the adhesive and the probe and the PI (polyimide) substrate; 2.2) Adhesives with low shrinkage rates generally have a better matching coefficient of thermal expansion, generating less thermal stress during temperature changes, thus being more fatigue-resistant and having a longer lifespan.

[0070] 3) Thermosetting resins soften (modulus decreases) after thermal degradation, but their chemical structure remains largely intact. (For epoxy resins, the curing trigger temperature can be considered the glass transition temperature Tg. When the temperature exceeds Tg, the epoxy resin transitions from a glassy state to a highly elastic state (rubber state), and the modulus decreases significantly, resulting in softening and viscoelasticity.) The degradation of the thermodegradable polymer completely destroys the continuity of the thermosetting resin. After dissolving with the softened thermosetting resin, numerous microcracks, voids, and interfacial debonding are generated in the softened thermosetting resin. Simultaneously, the thermosetting resin itself softens due to high temperature, reducing its load-bearing capacity and making it unable to resist the structural damage caused by the degradation of the thermodegradable resin. Ultimately, under the synergistic effect of both, the electronic adhesive macroscopically exhibits a loss of strength (or a reduction in strength). In other words, it is no longer a solid whole but becomes a loose, brittle, or peelable residue. This loss of strength is primarily attributed to the structural collapse caused by the chemical degradation of the biodegradable polymer, coupled with the chemical failure of the thermosetting resin itself. Ultimately, this leads to a reduction in bond strength (including complete loss of strength, i.e., a reduction to zero). Consequently, the adhesive easily detaches, facilitating probe repair without damaging the pad or PI. This detachment can be complete or partial, ensuring easy probe repair.

[0071] When the thermosetting resin is epoxy resin and the thermodegradable polymer is polyacrylate, epoxy adhesive can achieve strong bonding strength between the probe and the pad due to its high adhesion, low curing shrinkage, and excellent insulation properties. However, conventional epoxy adhesives have excellent temperature resistance and can even work for extended periods at temperatures above 150°C, but they are difficult to soften or even degrade at 150°C. Polyacrylate has the characteristic of rapid degradation at around 220°C. At the same time, polyacrylate itself has excellent adhesion and compatibility with epoxy resin. Introducing polyacrylate into epoxy resin causes the colloidal structure to be damaged when the ambient temperature is above 220°C, leading to reduced strength or even detachment of the adhesive, facilitating adhesive removal and probe repair.

[0072] In some embodiments, the electronic adhesive for the wafer inspection probe card includes a latent curing agent, the activation temperature of which is lower than the thermal degradation temperature.

[0073] As described above, the latent curing agent, after being mixed with the thermosetting resin at room temperature, has a long shelf life (i.e., latent nature). It only rapidly initiates a curing reaction under specific external conditions (such as heating, ultraviolet light, and humidity), ensuring the operability and storage stability of the adhesive, and facilitating mixing and dispensing during production. Furthermore, latent curing agents typically require a longer curing time or a higher post-curing temperature to achieve full performance. This allows for the addition of large amounts of toughening agents and fillers to reduce shrinkage without worrying about stress concentration due to excessively rapid curing. It provides a controllable process window for achieving high-strength, low-shrinkage composite materials, which is beneficial for achieving low curing shrinkage and, consequently, helps prevent needle tip deviation during curing.

[0074] The latent curing agent is beneficial to the strong bonding strength between the probe and the Pad for the following reasons: 1) The thermosetting resin and the latent curing agent can fully crosslink in a pure environment without competing reactions, forming a network with high conversion rate and high crosslinking density, which is beneficial to the strong bonding strength; 2) The relatively low temperature curing reaction results in milder exothermic reaction and more controllable reaction rate, reducing curing shrinkage stress and thermal stress. This ensures that the probe does not shift and that the bonding interface between the thermosetting resin and the probe / Pad is not prematurely damaged or develops microcracks due to internal stress. The latent curing agent is also beneficial to adhesive detachment for the following reasons: 1) Since the thermally degradable polymer is not damaged during the curing stage, its chemical structure remains intact. When the temperature rises to the degradation temperature, it is the only component in the adhesive layer that undergoes a drastic chemical change. This makes the degradation process energy-concentrated and fast, generating more gas and chain breakage in a short time, causing better damage to the surrounding epoxy continuous phase, thus triggering the brittle collapse (pulverization) of the overall structure; 2) It provides a huge thermodynamic driving force for the degradation reaction of the thermodegradable polymer, which means that once the degradation reaction is triggered, it will proceed with high efficiency, which helps to ensure the complete loss of adhesive layer strength, provides a clear physical window for probe removal, and facilitates adhesive detachment; 3) At the degradation temperature, the rigid thermosetting resin network softens and has a certain deformation capacity. When the brittle thermodegradable polymer degrades, the stress generated by the volume change cannot be effectively buffered in the softened thermosetting resin matrix, thus rapidly converting into mechanical energy that leads to matrix rupture, thereby facilitating adhesive detachment.

[0075] In some embodiments, the latent curing agent includes at least one of boron trifluoride-monoethylamine complex, modified imidazole, dicyandiamide and modified dicyandiamide, ketimine, aldolimine, iodonium salt, and thiodonium salt.

[0076] When the latent curing agent includes boron trifluoride-monoethylamine complex, it has the following advantages: 1) It has extremely high reactivity and can cure quickly; 2) It has excellent latency and is very stable when mixed with epoxy resin at room temperature, ensuring the operability and storage stability of the adhesive, facilitating mixing and dispensing during production, and also contributing to the low curing shrinkage rate, preventing needle tip deviation during the curing process.

[0077] When the latent curing agent includes modified imidazole, the modified imidazole achieves a balance between latency and low-temperature activity in the adhesive, and can also achieve a highly efficient catalytic curing reaction. This is beneficial for a strong bond between the probe and the pad, for the following reasons: 1) The network formed by imidazole catalysis has a high degree of cross-linking, giving the adhesive layer high hardness, high modulus, and excellent heat resistance (high glass transition temperature Tg), making the adhesive layer itself very robust. The epoxy network cured by imidazole generally has better toughness than many amine curing agents. This means that the adhesive layer is less prone to brittle cracking when subjected to the impact and cyclic stress of the probe, resulting in a more durable bond. 2) It can quickly gel and fully cure at low temperatures of 60-100℃. This shortens the production cycle, and more importantly, reduces the thermal relaxation or displacement that may occur when the probe is subjected to prolonged high temperatures, which is beneficial for maintaining accuracy and achieving rapid and sufficient low-temperature curing. 3) Imidazole and its modifiers have good compatibility with thermosetting resins, fillers, etc., which helps to form a homogeneous system, reduce defects, and thus improve the integrity of the adhesive layer and its ability to protect the interface. This ensures a controllable and clean detachment process, indirectly facilitating adhesive removal for the following reasons: 1) High catalytic activity ensures extremely high conversion rates of thermosetting resins (such as epoxy resins), resulting in fewer unreacted substances remaining in the system. These residual active small molecules are the main culprits behind charring and sticky byproducts. Modified imidazole fundamentally eliminates this problem, ensuring that the adhesive layer does not flow viscously during thermal degradation, but rather undergoes a dry physical structural collapse; 2) The moderate toughness of the imidazole-cured network allows it to more effectively disperse stress and induce numerous microcracks when the internal polyacrylate degrades after softening at high temperatures. This causes the adhesive layer to uniformly pulverize into fine particles (pulverization) rather than disintegrate into large, hard lumps with sharp edges. Pulverization is the easiest form of detachment to clean up; 3) Modified imidazole is consumed during the curing reaction, becoming part of the network. During subsequent maintenance heating, it has no residual catalytic activity to interfere with or catalyze the thermal decomposition of the epoxy network itself, which makes the thermal degradation of polyacrylate the only dominant chemical event, and the shedding behavior is pure and predictable.

[0078] When the latent curing agent includes dicyandiamide and modified dicyandiamide, dicyandiamide / modified dicyandiamide is beneficial to the strong bonding strength between the probe and the pad for the following reasons: 1) The epoxy network cured by dicyandiamide has a high glass transition temperature and excellent high-temperature modulus retention. This means that in the high-temperature testing environment of the chip (such as 125-150℃), the adhesive layer does not soften or creep, the clamping force on the probe is stable for a long time, and the contact resistance is reliable, thus contributing to the strong bonding strength; 2) The cured product has a dense structure, low moisture absorption, and excellent resistance to hydrolysis and media. In the harsh environment of high temperature and high humidity, its mechanical and electrical properties decay very little, which helps to ensure that the bonding interface between the probe and the pad is not weakened by moisture erosion, thus contributing to the strong bonding strength. Dicyandiamide / modified dicyandiamide is beneficial for adhesive removal for the following reasons: 1) The network of dicyandiamide curing has a high degree of cross-linking and limited chain segment mobility, resulting in high modulus and high brittleness. Even after softening at repair temperatures (>150℃), its brittle nature remains. When the internal thermally degradable polymer degrades and causes damage, this hard and brittle continuous phase has very weak resistance to crack propagation, easily triggering microcrack propagation and leading to overall pulverization of the adhesive layer (powdering), thus facilitating adhesive removal; 2) With the action of a suitable accelerator, dicyandiamide can react completely, avoiding complex side reactions (such as stickiness and carbonization) of unreacted curing agents or accelerators at high temperatures, ensuring that the removal process is not affected by other substances.

[0079] When the latent curing agent includes ketimine or aldehyde imine, it has the following advantages: 1) It can react with water to achieve deep curing, thereby improving strength; 2) It has low viscosity, which can reduce the overall viscosity of the adhesive and improve the wettability of the bonding material, thereby improving the bonding strength.

[0080] When the latent curing agent includes iodonium salt or thiodonium salt, iodonium salt or thiodonium salt is beneficial to the strong bonding strength between the probe and the Pad for the following reasons: 1) As a cationic thermal latent initiator, the polyether bond formed by cationic polymerization has a chemical stability far exceeding that of the hydroxyl and tertiary amine structures formed by amine curing. The ether bond is not easily hydrolyzed and has low network polarity, which makes the cured product have extremely low moisture absorption and excellent resistance to humid heat and hydrolysis. Under high temperature and high humidity environments, the mechanical properties (modulus, strength) and electrical insulation properties of the adhesive layer decay by a very small margin, providing protection for the bonding interface between the probe and the Pad and ensuring stable bonding strength; 2) Cationic polymerization sometimes has the characteristics of "living polymerization" and is not sensitive to oxygen (no oxygen inhibition layer). The curing process is uniform and the volume shrinkage is relatively slow. Therefore, it has low curing shrinkage stress and internal stress, which means: avoiding micro-displacement of the probe due to internal stress; and having less destructive energy stored at the interface, with the initial bonding strength closer to the theoretical value of the material.

[0081] Iodonium or thionium salts are beneficial for adhesive removal for the following reasons: 1) The thermal decomposition products of polyether networks at high temperatures may be simpler than those of amine-cured systems (which may produce complex products such as nitrogen-containing heterocycles). At a repair temperature of 150°C, the cured resin network itself may produce fewer sticky and charring byproducts, which helps to achieve cleaner, less residue-free removal and reduces the risk of contamination to the pad; 2) It can easily form a network with a high glass transition temperature. At the repair temperature, although it softens, its highly cross-linked nature makes it still relatively brittle. When polyacrylate degrades, this brittle phase is prone to "pulverization" and facilitates pulverization removal; 3) The uniform curing process forms a uniform network structure, which makes it easier for thermal degradation-triggered failure to occur synchronously throughout the adhesive layer, resulting in more consistent and predictable removal behavior.

[0082] When the adhesive includes at least two of the above-mentioned components, different latent curing agents play different roles in the curing reaction (such as initiators, accelerators, and primary curing agents) and are activated at different temperature stages. By combining these components, the kinetics of the curing reaction can be precisely controlled, achieving further optimization of performance and process.

[0083] In some embodiments, the electronic adhesive for the wafer inspection probe card includes a curing accelerator, which is 0.2-2 wt%. For example, the curing accelerator can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2. The content of the curing accelerator is within the above range, and the curing accelerator is not limited to the components described below.

[0084] As described above, the content of the curing accelerator within the aforementioned range is beneficial for a strong bond between the probe and the Pad, for the following reasons: 1) It helps ensure sufficient and complete curing: providing optimal catalytic efficiency, ensuring that the thermosetting resin (such as epoxy resin) and the latent curing agent achieve high conversion rate and high crosslinking density within the low-temperature window, resulting in high bulk strength, high modulus, and high heat resistance (high Tg); 2) By precisely controlling the content, the curing reaction can be started quickly but proceeded smoothly, avoiding violent exothermic reactions, which helps reduce curing thermal stress and curing shrinkage, thereby preventing tip deviation, and ensuring a good bonding interface between the thermosetting resin and the probe / Pad, without microcracks or weakening caused by internal stress; 3) A suitable accelerator helps to form a more uniform and denser crosslinking network. The content of curing accelerator within the above range is also beneficial for adhesive removal for the following reasons: 1) It helps ensure complete reaction and prevents stickiness: Highly efficient accelerators ensure complete curing, reduce unreacted residues, and chemically guarantee that the adhesive layer undergoes a "dry" physical structural collapse during degradation; 2) The curing accelerator produces a highly cross-linked, high-modulus epoxy network, which, although softening at high temperatures (>Tg), still maintains a certain degree of brittleness. When the thermally degradable polymer degrades and causes internal damage, this hard and brittle continuous phase is more likely to undergo an overall, pulverized structural collapse, rather than a slow, sticky peeling, which is beneficial for rapid and thorough removal; 3) The curing accelerator within the above content range is completely consumed or chemically bonded during the curing reaction, leaving no residual activity in the system. This makes the thermal degradation of the thermally degradable polymer the sole dominant and undisturbed chemical event during probe repair, which is beneficial for adhesive removal.

[0085] In some embodiments, the curing accelerator includes at least one of 2-methylimidazole, 2-ethyl-4-methylimidazole, 3-(3,4-dichlorophenyl)-1, 1-dimethylurea, 4-chlorophenyl-N,N-dimethylurea, benzyldimethylamine, triethanolamine, tris(dimethylaminomethyl)phenol, benzyltriethylammonium chloride, and tetrabutylammonium bromide.

[0086] As described above, the highly reactive tertiary amines of 2-methylimidazole and 2-ethyl-4-methylimidazole act as both accelerators and medium-temperature curing agents, which is beneficial for strong bonding strength between the probe and the pad. The reasons are as follows: their extremely high activity allows for rapid initiation and curing at 60-100℃, quickly establishing a highly cross-linked network, providing excellent initial strength and high Tg, thus contributing to high strength. Furthermore, imidazole-cured epoxy networks generally have better toughness and resistance to microcracks than ordinary amine-cured products, contributing to good network toughness. They also facilitate adhesive removal because their high activity ensures full participation in the reaction, resulting in less residue and preventing residual alkaline centers from catalyzing the thermal decomposition of the epoxy itself at 150℃, which could lead to stickiness.

[0087] 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (diuron) and 4-chlorophenyl-N,N-dimethylurea (meturon): These compounds contribute to strong bonding strength between the probe and the pad for the following reasons: 1) They lower the curing temperature of dicyandiamide from ~180℃ to 120-140℃, thus enabling the construction of the bonding interface by utilizing the unparalleled heat resistance, chemical resistance, and long-term reliability of the dicyandiamide system. Together with dicyandiamide, they form a high Tg, high rigidity, and extremely stable network, providing durable and reliable bonding strength. They also facilitate adhesive removal for the following reasons: The network formed by the dicyandiamide / substituted urea system is hard and brittle. At high temperatures, this brittle network is more prone to internal degradation and overall pulverization, resulting in clean removal.

[0088] Benzyl dimethylamine, triethanolamine, and tris(dimethylaminomethyl)phenol: provide strong catalytic power, ensuring curing depth and speed, which is beneficial for strong bonding strength between the probe and the pad. Furthermore, for benzyl dimethylamine, a suitable amount of benzyl dimethylamine avoids stickiness through complete curing, which is beneficial for the removal of the adhesive. For tris(dimethylaminomethyl), an appropriate amount of tris(dimethylaminomethyl) can strongly catalyze and ensure complete curing, and its toughening and chain transfer effects on the phenol structure, as well as its ability to reduce internal stress, are all beneficial for the removal of the adhesive. For triethanolamine, the plasticizing and stress-buffering effects of the hydroxyl groups in triethanolamine cause the triethanolamine-containing network to soften earlier and more uniformly (Tg decreases) during maintenance heating. When polyacrylate degrades, this softened continuous phase is more easily "torn" into small fragments under the action of internal gas and stress, which may also facilitate removal.

[0089] In some embodiments, where the electronic adhesive for the wafer inspection probe card includes the latent curing agent, the epoxy resin, and the polyacrylate: Epoxy resin: 20-60 wt%, for example, values ​​can be 20, 22, 25, 28, 30, 32, 35, 37, 40, 42, 45, 47, 50, 52, 55, 58, or 60; Polyacrylate: 2-30 wt%, for example, values ​​can be 2, 5, 8, 10, 12, 15, 17, 18, 20, 22, 25, 27, 28, or 30; Latent curing agent: 2-18 wt%, for example, values ​​can be 2, 3, 5, 8, 10, 12, 14, 16, or 18.

[0090] As described above, epoxy resin at 20-60 wt% has the following advantages: As a continuous phase matrix, epoxy resin provides the basis for mechanical strength, adhesion, insulation, and heat resistance. The above content is sufficient to form a strong and tough continuous phase, which can fully encapsulate and support other functional components (fillers, toughening agents, polyacrylates). This ensures that the adhesive layer has sufficient cohesive strength and modulus to resist test stress and effectively transfer the load to the interface, which is beneficial to the strong bonding strength between the probe and the pad. As a carrier matrix for the "degradable phase", its distinct thermal softening characteristics (modulus decreases above Tg but chemical structure remains intact) are the mechanical basis for the overall structural collapse caused by the degradation of polyacrylates, which is beneficial to the removal of the adhesive.

[0091] Polyacrylate at 2-30 wt% offers the following advantages: As a dispersible "sacrificial phase," its sole function is rapid thermal degradation at specific high temperatures (>150°C), disrupting the adhesive layer structure from within. The content is sufficient to form a uniform and effective network of disrupting points within the epoxy matrix. Below 2% is insufficient to trigger overall failure; above 30% will over-dilute and weaken the epoxy network. It remains chemically inert at curing and service temperatures, does not interfere with the construction of the epoxy network, and does not affect initial strength, thus contributing to strong probe-pad bonding. At this content, its degradation effectively triggers a chain reaction of brittle fracture (pulverization) in the continuous epoxy phase, thereby achieving non-destructive and clean probe removal.

[0092] The advantages of latent curing agents at 2-18 wt% are as follows: They achieve single-component storage stability and controllable initiation of curing at 60-100℃, serving as a bridge between process and performance. Content within this range ensures a balance between sufficient curing and adequate latency. They ensure the formation of a high-crosslink density, high-performance epoxy network at low temperatures, which is the chemical basis for high strength. Simultaneously, their controllable curing kinetics help reduce curing stress, contributing to strong bonding strength between the probe and the pad. Their activation temperature (~80-100℃) is much lower than their degradation temperature (150℃), ensuring a pure curing process without triggering early degradation. Furthermore, the high-quality network they construct provides an ideal brittle matrix for subsequent thermally induced powdering, facilitating adhesive detachment.

[0093] In summary, by ensuring that the content of each component is within the aforementioned range, it is beneficial to ensure that, in terms of microstructure, an ideal composite material structure can be formed in which a "rigid continuous phase" encapsulates a "uniformly dispersed functional phase." In terms of chemical timing, it is possible to strictly distinguish between the two key stages of "strong bonding strength between the probe and the Pad" and "degradation of the adhesive, leading to a decrease in strength." Ultimately, this facilitates achieving the aforementioned strong bonding strength between the probe and the Pad, as well as reducing the strength of the adhesive.

[0094] In some embodiments, the electronic adhesive for the wafer inspection probe card includes a toughening agent, wherein the toughening agent is 1-18 wt%, for example, the resin of the toughening agent can be 1, 3, 5, 7, 9, 10, 11, 13, 15, 17 or 18. In this case, when the toughening agent is within the above range, it is not limited to the toughening agents included below.

[0095] As described above, a toughening agent within the specified range is beneficial for strong bonding strength between the probe and the pad, for the following reasons: 1) Achieving lower curing stress helps prevent tip deviation: Toughening particles efficiently absorb and dissipate strain energy generated by curing shrinkage through mechanisms such as self-deformation and induced shear bands, resulting in low curing shrinkage and preventing tip deviation. 2) Obtaining a high-toughness and high-strength composite material: Forming an ideal structure of rigid epoxy network + uniformly dispersed flexible particles. Under stress, the rigid network provides strength, while the flexible particles prevent crack propagation through mechanisms such as crack pinning, particle bridging, and voiding, significantly improving fracture toughness and impact resistance. The material is both strong and resistant to cracking. It also facilitates adhesive detachment for the following reasons: 1) Optimizing the network guides "pulverization" rather than "disintegration": An appropriate amount of toughening agent avoids extreme brittleness of the network. During high-temperature degradation, this moderately toughened network can more uniformly transmit destructive stress, causing the adhesive layer to pulverize into fine particles (pulverization) rather than disintegrate into a few large pieces. Pulverization is the easiest form of detachment to clean up. 2) Absorbing residual stress and promoting uniform failure: The toughening agent can absorb some of the thermal residual stress, making the adhesive layer more stable during heat repair. This helps the degradation and destruction of polyacrylate to be triggered more synchronously and uniformly throughout the adhesive layer, avoiding localized failure that leads to incomplete detachment.

[0096] In some embodiments, the toughening agent includes at least one selected from carboxyl-terminated butadiene-acrylonitrile rubber, amino-terminated butadiene-acrylonitrile rubber, hydroxyl-terminated butadiene-acrylonitrile rubber, polyethylene glycol, hydroxyl-terminated polyester, and hydroxyl-containing polyacrylate. In this case, the content of the toughening agent may be 1-18 wt%, or it may not be specified.

[0097] As described above, carboxyl-terminated nitrile butadiene rubber (NBR) reacts with the carboxyl group and epoxy / curing agent to chemically bond into the network, forming an elastic microparticle phase with an "island structure." This is beneficial for strong bonding strength between the probe and the pad, for the following reasons: 1) Strong toughening effect: The NBR phase acts as a stress concentration point, efficiently initiating crazes and shear bands, absorbing huge impact energy, and significantly improving fracture toughness. Excellent interfacial bonding: Chemical bonding ensures a super-strong interface between the elastomer phase and the epoxy matrix, resulting in high load transfer efficiency and preventing phase peeling. It is also beneficial for adhesive detachment, for the following reasons: 1) Providing uniform microscopic defect points: The rubber microparticles formed soften at high temperatures (>Tg), becoming readily available stress concentration points, which is beneficial for the uniform initiation and propagation of cracks during polyacrylate degradation, promoting overall pulverization; 2) Stable chemical bonds: The reaction is complete, with no residual small molecules interfering with thermal degradation.

[0098] Amino-terminated nitrile butadiene rubber (NTBN): The amino groups exhibit higher reactivity, resulting in faster and more complete reactions with thermosetting resins (such as epoxy resins). This is beneficial for strong bonding strength between the probe and the pad, for the following reasons: the toughening mechanism is the same as CTBN. Due to its high reactivity, it may form smaller, more uniformly distributed rubber microparticles, potentially leading to higher toughening efficiency, but with a more significant impact on the curing process (gel time). It is also beneficial for adhesive detachment, for the following reasons: similar to CTBN, high reactivity ensures complete reaction, and the resulting finer microstructure may lead to more uniform thermal failure.

[0099] Hydroxyl-terminated nitrile butadiene rubber (CTBN): The hydroxyl groups exhibit mild reactivity, requiring a catalyst (such as a tertiary amine) for optimal reaction, thus providing a wider processing window. This is beneficial for strong probe-pad bonding strength because, in acid-sensitive curing systems (such as certain metal complexes), the hydroxyl-based type is a safer choice than the carboxyl-based type. It provides good physical toughening, but its network strength enhancement effect is weaker than CTBN. It is also more prone to adhesive debonding because its mild reactivity may result in slightly weaker interfacial bonding with epoxy compared to CTBN. At high temperatures, this relatively weaker interface may preferentially debond.

[0100] Polyethylene glycol / hydroxyl-terminated polyester: Long, flexible chains act as "molecular springs" interwoven within the epoxy network, providing physical plasticization and stress buffering. This contributes to strong bonding strength between the probe and the pad for the following reasons: 1) Excellent stress relaxation capability: It effectively absorbs and relaxes curing shrinkage stress and thermal stress, which helps reduce internal stress and prevent probe tip deviation; 2) Improved toughness: It significantly increases elongation at break and reduces brittleness. It also facilitates adhesive removal for the following reasons: It makes the continuous epoxy phase at high temperatures more prone to plastic deformation and tearing, rather than brittle fracture. This helps the adhesive layer to be "torn apart" into fine fragments during degradation.

[0101] Hydroxyl-containing polyacrylates: These act as both toughening agents and potentially biodegradable polymers. Their acrylate segments provide flexibility, while the hydroxyl groups provide reaction sites with epoxy. This contributes to strong bonding strength between the probe and the pad for the following reasons: as a toughening agent, its mechanism of action is similar to CTBN, but due to its chemical similarity to the main degrading phase (polyacrylate), its compatibility is likely excellent, allowing for more uniform dispersion and enhanced interfacial bonding. It also facilitates adhesive removal for the following reasons: through molecular design, it can provide toughening while its main chain undergoes thermal degradation simultaneously with the main degrading phase at repair temperatures. This means the toughening agent itself becomes a sacrificial phase, potentially achieving a unified function of toughening and removal promotion, resulting in more synchronous and thorough removal.

[0102] In some embodiments, the electronic adhesive for wafer inspection probe cards includes an adhesion promoter, said adhesion promoter being 0.2-3 wt%. The adhesion promoter value can be 0.2, 0.5, 0.7, 0.9, 1, 1.2, 1.5, 1.7, 1.8, 2, 2.1, 2.2, 2.5, 2.7, 2.9, or 3. In this embodiment, the adhesion promoter is not limited to the components listed below.

[0103] As described above, with the adhesive content within the specified range, the molecular bridging function can be perfectly utilized, achieving a strong and durable interface. This is beneficial for the strong bonding strength between the probe and the pad, for the following reasons: 1) Maximizing interfacial bonding strength and durability: Forming a dense, ordered monolayer achieves maximum chemical bonding coverage. This elevates the interfacial strength from physical adsorption to chemical bonding, improving peel strength; 2) Strong resistance to damp heat and thermal cycling: The silane layer forms a hydrophobic barrier, effectively preventing water molecules from penetrating to the interface, resulting in strong resistance to damp heat; the chemical bonds resist oxidative aging at high temperatures and can withstand the shear stress generated by high and low temperature cycling, resulting in strong thermal cycling resistance. It is also beneficial for adhesive detachment, for the following reasons: 1) Providing a strong interface to ensure a "cohesive failure" mode: Ideal detachment is internal (cohesive) failure of the adhesive layer, rather than peeling from the interface. Strong interfacial bonding (chemical bonds) ensures that during maintenance heating, the weak points of the adhesive layer are locked within the adhesive layer itself (polyacrylate phase and epoxy group), rather than at the interface. This confines the destructive force within the adhesive layer when the thermally degradable polymer degrades, thus more effectively triggering overall, fragmented cohesive failure (pulverization) and achieving clean detachment. 2) Maintaining interfacial stability and avoiding abnormal failure at high temperatures: The stable chemically bonded interface will not undergo premature, unpredictable degradation or slippage at the maintenance temperature of 150°C. This ensures that the thermal failure behavior of the entire system is entirely dominated by the designed polyacrylate degradation, making the detachment process predictable and repeatable. There will be no accidental probe detachment or irregular adhesive residue due to premature interface failure.

[0104] In some embodiments, the adhesive aid includes at least one selected from aminosilane coupling agents, epoxysilane coupling agents, methacryloxysilane coupling agents, and titanate coupling agents. In such embodiments, the content of the adhesive aid may be within the aforementioned range or may be absent. With the above-described configuration, each component has the following advantages:

[0105] Aminosilane coupling agents: For the siloxane end, after hydrolysis, they form Si-OM covalent bonds with inorganic surfaces (metal oxides, glass, ceramics, silicon wafers); for the amino end, the primary amino group (-NH2) has high reactivity and can undergo ring-opening addition reactions with the epoxy groups of epoxy resins to form strong chemical bonds. Simultaneously, the amino group can also catalyze epoxy curing. Therefore, this is beneficial for strong bonding strength between the probe card and the pad, for the following reasons: 1) Providing the strongest interfacial chemical bonding: Its direct chemical reactivity is the strongest among all coupling agents, significantly improving initial adhesive strength; 2) Excellent resistance to damp heat aging: The formed chemical bonds are very stable, effectively resisting moisture erosion and providing excellent long-term reliability. The above-mentioned content of adhesive aids is beneficial for adhesive detachment, for the following reasons: 1) Achieving ultimate interfacial chemical homogeneity, which eliminates weak connections or gaps at the interface. When heated during maintenance, the heat and stress are evenly distributed at the interface. This allows subsequent damage caused by the degradation of the thermally degradable polymer to be transmitted synchronously and evenly from the entire interface to the interior of the adhesive layer, avoiding localized peeling, residual adhesive, or viscous flow caused by uneven interface. 2) Formation of a high-strength, high-modulus rigid interface layer: The chemical bond (CN) formed between amino and epoxy is extremely strong, and the aminosilane itself can also form a dense siloxane network. This forms an extremely thin but extremely rigid transition layer on the surface of the inorganic substrate. Thus, it has the following effect on adhesive peeling: At 150℃, the thermosetting resin matrix has softened (above Tg), but this rigid interface layer still maintains a high modulus. At this time, the adhesive layer becomes a soft matrix-hard interface structure. When the internal thermally degradable polymer degrades, generating microcracks and gas pressure, the rigid interface layer acts like an "anvil," restricting the deformation direction of the softened matrix below. This forces the released energy to be converted more into tensile stress perpendicular to the interface, which propagates and extends upwards along the brittle, softened epoxy matrix. This effect is highly conducive to inducing overall lamellar cracking and pulverization of the adhesive layer, parallel to the interface. 3) Significantly reduced residual stress at the interface: Strong chemical bonding and uniform coverage minimize and evenly distribute the shrinkage stress generated at the interface during epoxy resin curing. Thus, a low-stress interface means that the adhesive layer does not suddenly release a huge amount of internally stored energy when heated. The failure process is more gentle and controllable, with energy mainly used to create new pulverized surfaces rather than driving violent, unpredictable cracking.

[0106] Epoxy-based silane coupling agents: For the siloxane end, the effect is the same as described above. For the epoxy end, the epoxy groups at the molecular end can directly participate in the curing network of the epoxy resin matrix, becoming part of the cross-linking network. This is beneficial for strong bonding strength between the probe and the pad, for the following reasons: 1) Good interface integration: It has the best chemical compatibility with the thermosetting resin matrix, and is completely integrated into the main network through covalent bonds, forming a gradient interface layer from the inorganic surface to the organic resin without stress concentration. 2) Excellent long-term durability: The integrated structure has extremely strong resistance to environmental stress (humid heat, thermal cycling), and the bonding strength decays the slowest. It is beneficial for adhesive removal, for the following reasons: 1) Providing a stable and strong interface: As mentioned above, the strong interface forces failure to occur inside the adhesive layer, which is conducive to achieving cohesive powdering and removal; 2) Chemical inertness: After its epoxy groups react, they become part of the network, with no residual active functional groups, and will not catalyze side reactions at high temperatures, ensuring the chemical purity of the removal process.

[0107] Methacryloxysilane coupling agent: Same as above for the siloxane end; for the methacryloxy end, it contains an unsaturated double bond (C=C) and mainly participates in free radical polymerization. It is beneficial for strong bonding strength between the probe and the pad, for the following reasons: Directional reinforcement of the interface with the degradable phase: In this formulation, its main role may not be to reinforce the epoxy group, but rather to specifically strengthen the bonding between the polyacrylate phase and the inorganic interface. Its double bond can copolymerize with the polyacrylate monomer or interact with the polymer chain through a free radical mechanism. Ultimately, this ensures that the polyacrylate "sacrificial phase" firmly adheres to the interface during curing and use, preventing premature peeling from the interface and ensuring effective degradation starting from the interface. The following reasons facilitate adhesive removal: 1) Changing the center of gravity of interfacial bonding: The terminal methacryloyloxy group (C=C double bond) is a free radical reactive group, which preferentially chemically bonds with the thermodegradable polymer in the formulation (through copolymerization or free radical reaction), or at least has a very strong physical affinity for this phase. As a result, it forms a polyacrylate-loving interfacial layer on the substrate surface, thus firmly anchoring the sacrificial phase of the thermodegradable polymer to the substrate interface. 2) Guiding the initiation of destruction in the core functional area: When heated to 150°C during repair, the thermodegradable polymer undergoes rapid thermal degradation. If its bonding with the thermosetting resin is weak (physical adsorption), it may first shrink and detach from the thermosetting resin before degrading, thus dispersing the destructive force on the thermosetting resin. When methacryloyloxysilane is used, the thermodegradable polymer is chemically anchored to the thermosetting resin. When degradation occurs, severe chain breakage and gas generation occur directly at the point of closest contact with the thermosetting resin, i.e., the place with the greatest stress.

[0108] Titanate coupling agents: The core is titanium atoms, which can react with protons on inorganic surfaces, while their long-chain organic parts can also entangle and be compatible with resins. Their main functions are to treat fillers and improve rheology. They are beneficial for strong bonding strength between probes and pads for the following reasons: 1) Improved performance of highly filled systems: Their coupling effect on low surface energy fillers (such as calcium carbonate and some thermally conductive fillers) is superior to silanes. 2) Reduced system viscosity and improved processing: They can significantly reduce the viscosity of highly filled adhesives, improving dispensing performance. They are also beneficial for adhesive removal because they improve filler dispersion, potentially resulting in a more uniform adhesive layer that is easier to remove.

[0109] In some embodiments, the electronic adhesive for the wafer inspection probe card includes a filler, the filler being 20-70 wt%. For example, the filler content can be 20, 23, 25, 28, 30, 32, 35, 38, 40, 42, 45, 48, 50, 52, 55, 58, 60, 62, 65, 67, 69, or 70. When the filler content is within this range, the filler is not limited to the components described below.

[0110] As described above, a filler content within the specified range is beneficial for strong bonding strength between the probe and the pad, for the following reasons: 1) Achieving ultra-low curing shrinkage and stress: As a non-shrinkable rigid skeleton, the filler physically offsets the curing shrinkage of the resin to the greatest extent, which is beneficial for achieving low curing shrinkage rate and preventing tip deviation. 2) Obtaining matched and excellent mechanical properties: 2.1) High modulus and high hardness: Rigid fillers give the adhesive layer sufficient rigidity to stably support the probe and resist test pressure; 2.2) Controllable toughness: By working in conjunction with toughening agents, a composite material with a balance of strength and toughness can be obtained. 3) Optimizing thermal compatibility and improving long-term reliability: By adjusting the filler content and type (such as silica powder), the coefficient of thermal expansion of the adhesive layer can be matched to that of the probe (metal) and the substrate (ceramic), minimizing thermal cycling stress and greatly improving the durability of the bonding interface under temperature changes. It is also beneficial for adhesive detachment, for the following reasons: 1) Providing uniform "internal defect points" to guide controllable failure: The interface between countless filler particles and the thermosetting resin is a weak point within the material. When the thermally degradable polymer degrades and softens the overall structure, these uniformly distributed weaknesses become ready-made channels for crack initiation and propagation. This efficiently connects and permeates localized damage, leading to a uniform, overall pulverization and collapse (powdering) of the adhesive layer, rather than localized, incomplete destruction. 2) Adjusting thermal conductivity to influence localized heating behavior: During laser or hot air repair, appropriate thermal conductivity helps to distribute heat more evenly, avoiding localized overheating that leads to excessive decomposition of the thermally degradable polymer and the generation of fumes, or insufficient heat that results in incomplete degradation. This optimizes the controllability and cleanliness of the detachment process.

[0111] In some embodiments, the filler includes at least one of nano-calcium carbonate, fumed silica, carbon black, and titanium dioxide. In this case, the content of the filler can be 20-70 wt%, or may not fall within the aforementioned range.

[0112] As described above, the role of nano-calcium carbonate in the adhesive is as follows: 1) Excellent reinforcement and toughening: Nanoparticles can effectively prevent crack propagation, significantly increasing the toughness of the composite material while improving hardness and modulus; 2) Reduced shrinkage and cost: As the main filler, it effectively reduces curing shrinkage and cost; 3) Good flowability: Regular morphology, easy to disperse, and relatively mild impact on viscosity. Based on the above effects, the nano-calcium carbonate is beneficial to the strong bonding strength between the probe and the pad for the following reasons: 1) Strengthening the matrix: It makes the adhesive layer both hard and not brittle, better able to withstand the impact and cyclic stress during testing, and protects the interface from failure due to matrix cracking. 2) Reducing internal stress: It absorbs some curing stress through the toughening mechanism, indirectly benefiting the integrity of the interface. It is beneficial to adhesive detachment for the following reasons: It provides uniform nanoscale weaknesses: Its huge interface area means countless weak bonding points with epoxy resin. After the thermally degradable polymer degrades and the thermosetting resin softens, these interfaces easily become uniform starting points for microcracks, promoting the overall uniform pulverization of the adhesive layer and the fineness of the detached material.

[0113] Fumed silica: Its role in adhesives: 1) Providing strong thixotropy (core value): making the adhesive non-flowing like a paste when still, and thinning when subjected to shear (dispensing). This is beneficial for precise dispensing and maintaining the adhesive shape on vertical planes or between dense probes; 2) Anti-settling: the network structure prevents other heavy fillers from settling; 3) Reinforcing and thickening: improving strength, hardness, and viscosity. It is beneficial for strong bonding strength between probes and pads for the following reasons: 1) preventing adhesive flow after dispensing, which could lead to probe short circuits or contamination, thus ensuring reliable bonding strength; 2) providing some reinforcement. It is also beneficial for adhesive detachment for the following reasons: forming a uniform, fragile network: its three-dimensional network collapses at high temperatures (>silanol hydrogen bond dissociation temperature). When thermally degradable polymers degrade, this pre-existing nanonetwork becomes the first scaffold to collapse, guiding the rapid release of stress and greatly promoting the disintegration and pulverization of the overall structure.

[0114] Carbon black's role in adhesives: 1) Functional filler: Primarily provides electrical / thermal conductivity or coloring / UV shielding. 2) Reinforcement: Offers excellent reinforcement to polymers. It promotes strong bonding between probes and pads for the following reasons: 1) It protects the chip and test circuitry by preventing static buildup, providing an "electrically reliable" bonding strength; 2) Weather resistance: Protects the adhesive layer from UV degradation, maintaining long-term mechanical properties. It also facilitates adhesive removal for the following reasons: Carbon black has a strong absorption capacity for near-infrared lasers, efficiently converting light energy into heat energy. During repairs, irradiating the failed probe area with a laser causes the carbon black to instantly generate temperatures exceeding 150°C, triggering ultra-fast and precise degradation of the thermally degradable polymer while having minimal thermal impact on surrounding probes. This makes removal extremely efficient, precise, and controllable.

[0115] Titanium dioxide: Its role in adhesives: 1) Coloring and masking: Provides a permanent white color, ensuring a uniform appearance of the adhesive layer and facilitating visual inspection and positioning. 2) Weather resistance and stability: Extremely stable chemical properties, resistant to light and heat, improving the durability of the adhesive layer. 3) Slight reinforcement: Improves hardness and abrasion resistance. It is beneficial for strong bonding between probes and pads for the following reasons: 1) White color facilitates automated optical detection of adhesive dot position and shape, indirectly ensuring process quality and bonding reliability; 2) Its inertness helps the adhesive layer maintain stable performance over long-term use. It is beneficial for adhesive removal for the following reasons: Titanium dioxide is extremely stable at high temperatures and hardly participates in any chemical reactions. During removal, it does not interfere with the dominant degradation mechanism of thermally degradable polymers, nor does it produce harmful byproducts. Its role is to provide a predictable, neutral physical presence, allowing the removal behavior to be completely controlled by a designed chemical mechanism (thermally degradable polymer degradation). If using a laser, the white color may reflect some energy, requiring parameter adjustment.

[0116] On the other hand, this application also discloses a probe repair method for a wafer inspection probe card. The probes of the probe card include any of the aforementioned electronic adhesives for wafer inspection probe cards. The repair method includes the following steps: heating the tail of the probe to a temperature greater than the thermal degradation temperature, so that the electronic adhesive for the wafer inspection probe card detaches. For example, heating the tail of the probe to above 150°C causes the cured electronic adhesive to lose strength due to structural damage, allowing the probe to be removed from the pad without damage. The method of heating is not limited; for example, laser heating. The device used for heating is also not limited; for example, a needle implantation device can be used for heating.

[0117] The following are some implementation methods and comparative examples of the adhesive described in more detail.

[0118] Comparative Example 1

[0119] (1) Weigh 100 g of E-44 epoxy resin, 20 g of polyethylene glycol (number average molecular weight of 2000 g / mol), 2 g of methacryloyloxysilane coupling agent, and 100 g of hydrophilic nano CaCO3, and ball mill them at 150 rpm for 8 h to obtain epoxy mixed resin A.

[0120] (2) Weigh 20 g of boron trifluoride-monoethylamine complex and 2 g of 2-methylimidazole and add them to epoxy mixed resin A. After ball milling at 150 rpm for 2 h, use a three-roll mill to grind until the grinding fineness is less than 5 μm to obtain epoxy glue.

[0121] (3) The above-mentioned epoxy electronic adhesive was applied to the tail of the probe and cured at a temperature gradient of 80 ℃ for 1 h and 100 ℃ for 3 h. After curing, the curing shrinkage rate of the electronic adhesive was 2%, the offset of the probe tip position in the X direction was 20 μm, and the offset in the Y direction was 15 μm. The lateral tilting force of the probe increased from 5 N when the adhesive was not applied to 12 N. After heat treatment at 250 ℃ for 30 min, the lateral tilting force of the probe was still 12 N. The structure of the electronic adhesive was not destroyed and could not be removed.

[0122] Comparative Example 2

[0123] (1) Weigh 20 g of ethyl acetate and add it to the reactor. Stir at 150 rpm and 70 °C. At the same time, weigh 10 g of MMA, 6 g of BA, 4 g of HEA, 1 g of AIBN, and 40 g of ethyl acetate and dissolve and mix them to obtain mixed solution A. After the temperature in the reactor is constant at 70 °C, add solution A dropwise to the reactor over 2 h. After the addition is complete, keep it at 70 °C for 3 h, and then cool it to room temperature to obtain solution B.

[0124] (2) Weigh 100 g of E-51 and add it to solution B. At the same time, heat the reactor to 60 °C and stir at 200 rpm for 2 h to form solution C.

[0125] (3) Weigh 20 g of polyethylene glycol (number average molecular weight of 2000 g / mol) and 2 g of methacryloyloxysilane coupling agent, and add them to solution C. Stir at 60 °C and 200 rpm for 2 h, and then cool to obtain solution D.

[0126] (4) The solvent was removed by placing solution D in a rotary evaporator at 90 °C and a vacuum of -0.08 MPa. The rotation speed was 100 rpm. The rotary evaporation ended after no liquid was distilled out, and mixed resin E was obtained.

[0127] (5) Weigh 50 g of hydrophilic nano CaCO3 and add it to the mixed resin E. After ball milling at 150 rpm for 8 h, the mixed resin F is obtained.

[0128] (6) Weigh 20 g of modified dicyandiamide and 2 g of 3-(3,4-dichlorophenyl)-1,1-dimethylurea and add them to mixed resin F. After ball milling at 150 rpm for 2 h, grind them with a three-roll mill until the grinding fineness is less than 5 μm. The electronic adhesive for wafer detection probe cards is then prepared.

[0129] (7) The above-mentioned epoxy electronic adhesive was applied to the probe tail and cured at a temperature gradient of 80 ℃ for 1 h and 100 ℃ for 2 h. After curing, the curing shrinkage rate of the electronic adhesive was 1.5%, the offset of the probe tip position in the X direction was 13 μm, and the offset in the Y direction was 15 μm. The lateral tilting force of the probe increased from 5 N when the adhesive was not applied to 11 N. After heat treatment at 240 ℃ for 30 min, the lateral tilting force of the probe decreased to 7 N. The residual part of the electronic adhesive was strong and difficult to remove.

[0130] Implementation Method 1

[0131] An electronic adhesive for wafer inspection probe cards and a probe repair method are as follows:

[0132] (1) Weigh 20 g of ethyl acetate and add it to the reactor. Stir at 150 rpm and 70 °C. At the same time, weigh 10 g of MMA, 6 g of BA, 4 g of HEA, 1 g of AIBN, and 40 g of ethyl acetate and dissolve and mix them to obtain mixed solution A. After the temperature in the reactor is constant at 70 °C, add solution A dropwise to the reactor over 2 h. After the addition is complete, keep it at 70 °C for 3 h, and then cool it to room temperature to obtain solution B.

[0133] (2) Weigh 100 g of E-51 and add it to solution B. At the same time, heat the reactor to 60 °C and stir at 200 rpm for 2 h to form solution C.

[0134] (3) Weigh 20 g of HTBN (number average molecular weight of 2000 g / mol) and 3 g of KH550 and add them to solution C. Stir at 60℃ and 200 rpm for 2 h and then cool to obtain solution D.

[0135] (4) The solvent was removed by placing solution D in a rotary evaporator at 90 °C and a vacuum of -0.08 MPa. The rotation speed was 100 rpm. The rotary evaporation ended after no liquid was distilled out, and mixed resin E was obtained.

[0136] (5) Weigh 50 g of hydrophobic gaseous SiO2 and add it to the mixed resin E. After ball milling at 150 rpm for 8 h, the mixed resin F is obtained.

[0137] (6) Weigh 20 g of modified dicyandiamide and 2 g of 3-(3,4-dichlorophenyl)-1,1-dimethylurea and add them to mixed resin F. After ball milling at 150 rpm for 2 h, grind them with a three-roll mill until the grinding fineness is less than 5 μm. The electronic adhesive for wafer detection probe cards is then prepared.

[0138] (7) The above epoxy electronic adhesive was applied to the probe tail and cured at a temperature gradient of 80 ℃ for 1 h and 100 ℃ for 2 h. After curing, the curing shrinkage rate of the electronic adhesive was 0.4%, the offset of the probe tip position in the X direction was 2 μm, and the offset in the Y direction was 1 μm. The lateral tilting force of the probe increased from 5 N when the adhesive was not applied to 10 N. After heat treatment at 240 ℃ for 30 min, the lateral tilting force of the probe decreased to 5 N, the electronic adhesive lost its strength, and it could be removed normally.

[0139] Implementation Method 2

[0140] An electronic adhesive for a wafer inspection probe card and a probe repair method are provided, comprising the following:

[0141] (1) Weigh 10 g of ethyl acetate and 10 g of toluene and add them to the reactor. Stir at 150 rpm and 80 °C. At the same time, weigh 4 g of MMA, 10 g of BA, 6 g of HEMA, 2 g of BPO, 30 g of ethyl acetate, and 30 g of toluene and dissolve and mix them to obtain mixed solution A. After the temperature in the reactor is constant at 80 °C, add solution A dropwise to the reactor over 3 h. After the addition is complete, keep the temperature at 80 °C for 3 h, and then cool to room temperature to obtain solution B.

[0142] (2) Weigh 80 g of E-44 and add it to solution B. At the same time, heat the reactor to 70 °C and stir at 150 rpm for 2 h to form solution C.

[0143] (3) Weigh 10 g of HTBN (number average molecular weight of 4000 g / mol) and 1 g of KH560 and add them to solution C. Stir at 70℃ and 150 rpm for 2 h and then cool to obtain solution D.

[0144] (4) The solvent was removed by placing solution D in a rotary evaporator at 110 °C and a vacuum of -0.08 MPa. The rotation speed was 100 rpm. The rotary evaporation ended after no liquid was distilled out, and mixed resin E was obtained.

[0145] (5) Weigh 30 g of hydrophobic nano CaCO3 and add it to the mixed resin E. After ball milling at 150 rpm for 6 h, the mixed resin F is obtained.

[0146] (6) Weigh 15 g of modified imidazole and 2 g of 2-ethyl-4-methylimidazolium and add them to mixed resin F. After ball milling at 150 rpm for 2 h, grind them with a three-roll mill until the grinding fineness is less than 5 μm. The electronic adhesive for wafer detection probe card is then prepared.

[0147] (7) The above epoxy electronic adhesive was applied to the probe tail and cured at a temperature gradient of 60 ℃ for 1 h and 80 ℃ for 3 h. After curing, the curing shrinkage rate of the electronic adhesive was 0.5%, the offset of the probe tip position in the X direction was 2 μm, and the offset in the Y direction was 3 μm. The lateral tilting force of the probe increased from 5 N when the adhesive was not applied to 9 N. After heat treatment at 250 ℃ for 30 min, the lateral tilting force of the probe decreased to 5 N, the electronic adhesive lost its strength, and it could be removed normally.

[0148] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope. The scope of protection of the present invention is defined by the appended claims, specification, and their equivalents.

Claims

1. An electronic adhesive for wafer inspection probe cards, characterized in that, The electronic adhesive for the wafer inspection probe card includes a thermosetting resin and a thermally degradable polymer, wherein the curing trigger temperature of the thermosetting resin is lower than the thermal degradation temperature of the thermally degradable polymer. The thermosetting resin softens at the thermal degradation temperature; the thermally degradable polymer is miscible with the softened thermosetting resin after degradation.

2. The electronic adhesive for wafer inspection probe cards according to claim 1, characterized in that, It includes a latent curing agent, wherein the activation temperature of the latent curing agent is lower than the thermal degradation temperature.

3. The electronic adhesive for wafer inspection probe cards according to claim 2, characterized in that, The latent curing agent includes at least one of boron trifluoride-monoethylamine complex, modified imidazole, dicyandiamide and modified dicyandiamide, ketimine, aldolimine, iodonium salt, and thiodonium salt.

4. The electronic adhesive for wafer inspection probe cards according to claim 2, characterized in that, Includes curing accelerator, curing accelerator: 0.2-2 wt%; And / or, the curing accelerator includes at least one of 2-methylimidazole, 2-ethyl-4-methylimidazole, 3-(3,4-dichlorophenyl)-1, 1-dimethylurea, 4-chlorophenyl-N, N-dimethylurea, benzyldimethylamine, triethanolamine, tris(dimethylaminomethyl)phenol, benzyltriethylammonium chloride, and tetrabutylammonium bromide.

5. The electronic adhesive for wafer inspection probe cards according to claim 1, characterized in that, The thermosetting resin includes at least one of epoxy resin, cyanate ester resin and bismaleimide resin; The thermally degradable polymers include polyacrylates, polycarbonates, polyurethanes whose chemical bonds break during heat treatment, polymers whose chemical bonds break during heat treatment, and copolymers or blends thereof.

6. The electronic adhesive for wafer inspection probe cards according to claim 5, characterized in that, In the case where the electronic adhesive for the wafer inspection probe card includes the latent curing agent, the epoxy resin, and the polyacrylate: Epoxy resin: 20-60 wt%; Polyacrylate: 2-30 wt% Latent curing agent: 2-18 wt%.

7. The electronic adhesive for wafer inspection probe cards according to claim 5, characterized in that, The electronic adhesive for the wafer inspection probe card includes at least one of the following features: a) The epoxy resin is at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic epoxy resin, alicyclic epoxy resin, and hydrogenated bisphenol A type epoxy resin; b) The polyacrylate is prepared by solution polymerization of acrylate monomers; the acrylate monomers are at least one selected from methyl methacrylate, methyl acrylate, butyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate, methacrylic acid, and acrylic acid. c) The curing trigger temperature is 60-100℃, and the thermal degradation temperature is not less than 150℃.

8. The electronic adhesive for wafer inspection probe cards according to claim 1, characterized in that, Includes a toughening agent, wherein the toughening agent is 1-18 wt%; And / or, the toughening agent includes at least one of carboxyl-terminated butadiene-acrylonitrile rubber, amino-terminated butadiene-acrylonitrile rubber, hydroxyl-terminated butadiene-acrylonitrile rubber, polyethylene glycol, hydroxyl-terminated polyester, and hydroxyl-containing polyacrylate.

9. The electronic adhesive for wafer inspection probe cards according to claim 1, characterized in that, Includes an adhesive aid, wherein the adhesive aid is 0.2-3 wt%; And / or, the adhesive aid includes at least one of aminosilane coupling agents, epoxysilane coupling agents, methacryloxysilane coupling agents, and titanate coupling agents.

10. The electronic adhesive for wafer inspection probe cards according to claim 1, characterized in that, Includes packing material, wherein the packing material is 20-70 wt%; And / or, the filler includes at least one of nano-calcium carbonate, fumed silica, carbon black, and titanium dioxide.

11. A probe repair method for a wafer inspection probe card, characterized in that, The probe of the probe card includes the electronic adhesive for wafer inspection probe cards as described in any one of claims 1 to 10; the repair method includes the following steps: heating the tail of the probe to a temperature greater than the thermal degradation temperature, so that the electronic adhesive for wafer inspection probe cards detaches.