Die attach adhesive for LED and preparation method therefor

Abstract

The present application provides a die attach adhesive for an LED and a preparation method therefor, aiming to solve problems existing in the conventional preparation of die attach adhesives using a vinyl MQ resin as a matrix resin, such as the generation of volatile substances during curing when the resin is dissolved in a solvent, and the undesirable phenomenon of a reduced die shear force or stringing when the resin is dissolved in a low-viscosity small-molecule vinyl silicone oil. The die attach adhesive comprises siloxane resins, a catalyst and a functional additive, wherein the siloxane resins comprise a first siloxane resin, a second siloxane resin and a third siloxane resin, the first siloxane resin comprises a vinyl MQ resin, the second siloxane resin comprises an organohydrogenpolysiloxane resin, and the third siloxane resin comprises a compound represented by formula 1: (A3SiO1 / 2)x(A2ESiO1 / 2)4-xSi, Formula 1 where x is a natural number from 0 to 3, A is selected from C1-C10 alkyl, and E is selected from C1-C10 alkenyl. The die attach adhesive for an LED provided by the present application has good hardness and adhesion, a relatively high die shear force, a moderate viscosity, good operability in a die bonding process, and a low volatility during curing.

Description

A die-attach adhesive for LEDs and its preparation method

[0001] This application claims priority to Chinese Patent Application No. 202510195549.9, filed on February 21, 2025, entitled "A die bond adhesive for LEDs and its preparation method", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of die bond technology, and more particularly to a die bond for LEDs and its preparation method. Background Technology

[0003] In recent years, light-emitting diode (LED) devices have been trending towards miniaturization, placing increasingly stringent demands on the adhesion of die-bonding materials. LED devices utilize silicone-based die-bonding materials; poor adhesion can lead to serious defects such as chip peeling and bonding failures during subsequent wire bonding processes. To improve the adhesion of silicone-based die-bonding materials and ensure high chip push force in the final die-bonding adhesive, current technologies typically use vinyl MQ resin with a three-dimensional network structure as the base resin. However, vinyl MQ resin is usually solid at room temperature and cannot be used directly. If solvents are used to dissolve the vinyl MQ resin, significant amounts of volatiles are generated during curing. If these volatiles deposit on the chip electrode pads, they can affect subsequent wire bonding steps. If linear, low-viscosity, small-molecule vinyl silicone oil is used for dissolution, adding too much low-viscosity, small-molecule vinyl silicone oil will cause a decrease in the hardness and die-bonding force of the resulting die-bonding material; adding too little low-viscosity, small-molecule vinyl silicone oil will cause the viscosity of the resulting die-bonding material to be too high, resulting in undesirable phenomena such as stringing, glue splattering, and tailing during die bonding. Summary of the Invention

[0004] To address the problems of existing die-attach adhesives prepared using vinyl MQ resin as the main resin, such as the generation of volatiles during solvent dissolution and curing, or the decrease in die-attach force or stringing when dissolved with low-viscosity small-molecule vinyl silicone oil, this application provides an LED die-attach adhesive and its preparation method.

[0005] To address the aforementioned problems, this invention provides a die-attach adhesive for LEDs, comprising a siloxane resin, a catalyst, and functional additives. The siloxane resin includes a first siloxane resin, a second siloxane resin, and a third siloxane resin. The first siloxane resin comprises vinyl MQ resin, the second siloxane resin comprises an organohydrogen polysiloxane resin, and the third siloxane resin comprises a compound shown in Formula 1.

[0006] (A3SiO 1 / 2 )x (A2ESiO 1 / 2 ) 4-x Si Formula 1

[0007] Where x is a natural number from 0 to 3;

[0008] A is selected from C1 to C10 alkyl groups, and E is selected from C2 to C10 alkenyl groups.

[0009] Preferably, A is selected from C1 to C5 alkyl groups, and E is selected from C2 to C5 alkenyl groups.

[0010] Preferably, the vinyl MQ resin comprises the unit shown in Formula 2, the unit shown in Formula 3, and SiO2. 4 / 2 One or more of the units;

[0011] F3SiO 1 / 2 Equation 2,

[0012] F2RSiO 1 / 2 Formula 3;

[0013] Wherein, F is selected from alkyl groups of C1 to C10, and R is selected from alkenyl groups of C2 to C10.

[0014] Preferably, the vinyl content in the vinyl MQ resin is 0.06-0.15 mol / 100g.

[0015] Preferably, the organohydrogen polysiloxane comprises at least two hydrogen atoms bonded to silicon atoms;

[0016] The organohydrogen polysiloxane resin includes one or both of HMQ and HMD compounds.

[0017] The HMQ compound includes the unit shown in Formula 4, the unit shown in Formula 5, and SiO. 4 / 2 One or more of the units;

[0018] L3SiO 1 / 2 Equation 4,

[0019] L2HSiO 1 / 2 Formula 5;

[0020] The HMD compound includes one or more of the units shown in Formula 4, Formula 6, and Formula 7;

[0021] LHSiO 2 / 2 Formula 6,

[0022] H2SiO 2 / 2 Formula 7;

[0023] Wherein, L is selected from C1 to C10 alkyl groups.

[0024] Preferably, the number of hydrogen atoms bonded to silicon atoms in the organohydrogen polysiloxane resin is B1, and the total number of vinyl atoms bonded to silicon atoms in the vinyl MQ resin and the third siloxane resin is B2, with B1:B2 being (1-3):1.

[0025] Preferably, the die-bonding adhesive comprises the following parts by weight: 30-100 parts of a first siloxane resin, 20-90 parts of a second siloxane resin, 10-100 parts of a third siloxane resin, and 1-50 parts of functional additives.

[0026] The catalyst is present in parts by weight of 1 to 100 ppm of the total weight of the first siloxane resin, the second siloxane resin, and the third siloxane resin.

[0027] Preferably, based on the weight parts of the die bond adhesive, the functional additives include 1 to 15 parts of tackifier, 0.01 to 5 parts of hydrosilylation inhibitor, and 1 to 20 parts of thixotropic agent.

[0028] Preferably, the tackifier is an organosilicon polymer containing epoxy and vinyl groups; in the organosilicon polymer, the vinyl content is 0.05-1 mol / 100g, and the epoxy equivalent is 200-600 g / eq;

[0029] The catalyst includes platinum metal catalysts;

[0030] The hydrosilylation reaction inhibitors include alkynyl alcohols;

[0031] The thixotropic agent comprises substances with a specific surface area of ​​150–300 m². 2 / g of hydrophobic fumed silica.

[0032] Secondly, this application provides a method for preparing the above-mentioned LED die bond adhesive, comprising the following steps: uniformly mixing a first siloxane resin, a second siloxane resin, a third siloxane resin, a catalyst, and a functional additive to obtain the die bond adhesive.

[0033] The LED die bond adhesive provided in this application utilizes Si-H bonds in organohydrogen polysiloxane resins to react with vinyl groups (MQ resins) and trisiloxane resins bonded to silicon atoms to form a stable three-dimensional network structure. This structure offers the following advantages: 1) It exhibits good hardness and excellent adhesion, achieving high chip push force with short curing times, providing high die bond push force for both large and small chips; 2) It has moderate viscosity, ensuring good operability during the die bond process and preventing issues such as stringing, glue splattering, and tailing; 3) Furthermore, it has low volatile content during curing, avoiding adverse effects on subsequent wire bonding steps. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] To illustrate the technical solution of the present invention, specific embodiments are described below.

[0036] On one hand, this application provides a die-attach adhesive for LEDs, comprising a siloxane resin, a catalyst, and functional additives. The siloxane resin includes a first siloxane resin, a second siloxane resin, and a third siloxane resin. The first siloxane resin includes a vinyl MQ resin, the second siloxane resin includes an organohydrogen polysiloxane resin, and the third siloxane resin includes a compound shown in Formula 1.

[0037] (A3SiO 1 / 2 ) x (A2ESiO 1 / 2 ) 4-x Si Formula 1

[0038] Where x is a natural number from 0 to 3;

[0039] A is selected from C1 to C10 alkyl groups, and E is selected from C2 to C10 alkenyl groups.

[0040] Specifically, x is a natural number from 0 to 3, such as x can be 0, 1, 2 or 3.

[0041] C1 to C10 alkyl groups include straight-chain alkyl groups with 1 to 10 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl, etc. C1 to C10 alkyl groups can also be branched alkyl groups with 1 to 10 carbon atoms, such as isobutyl, isopropyl, etc.

[0042] Alkenes with C2 to C10 carbon atoms include straight-chain alkenes with 2 to 10 carbon atoms, such as vinyl, propenyl, CH=CHCH2CH3, 1-pentene, cis-2-pentene, trans-2-pentene, etc. Alkenes with C2 to C10 carbon atoms can also be branched alkenes with 2 to 10 carbon atoms, such as CH3CH2CH=C(CH3)CH2CH3, etc.

[0043] The LED die-bonding adhesive provided in this application does not use solvents to dissolve vinyl MQ resin, resulting in low volatile emissions during curing and no adverse effects on subsequent wire bonding steps. The alkenyl groups in the first and third siloxane resins undergo hydrosilylation with the hydrogen in the second siloxane, forming a stable three-dimensional network structure. This reaction produces no byproducts or releases small molecules, while maintaining a dense cross-linked network, resulting in high hardness, low volatility, excellent adhesion, and high die-bonding thrust. Furthermore, the second and third siloxanes have low viscosity and strong thinning ability, eliminating the need for additional small-molecule thinning agents to achieve extremely low viscosity. This results in a moderate overall viscosity formulation, further reducing volatile emissions during curing, and ensuring good operability during die bonding, preventing stringing, glue splattering, and tailing. Using the composition provided in this application in the die-bonding process will not adversely affect subsequent wire bonding.

[0044] In some preferred embodiments, A is selected from C1 to C5 alkyl groups, and E is selected from C2 to C5 alkenyl groups.

[0045] Specifically, A is preferably one or a combination of methyl, ethyl, propyl, and isopropyl, with methyl being more preferred.

[0046] E is preferably one or a combination of vinyl, propylene, and butenyl, and more preferably vinyl.

[0047] A is selected from alkyl groups of C1 to C5 and E is selected from alkenyl groups of C2 to C5. The resulting LED die bond adhesive has higher adhesion and higher die bond push, which is beneficial to the normal progress of subsequent wire bonding processes for light-emitting diode devices and avoids defects such as failure to bond.

[0048] In some preferred embodiments, x is 0.

[0049] When x is 0, the structural formula of the third siloxane resin is (A2ESiO). 1 / 2 )4Si produces LED die bond adhesive with higher adhesion, less curing volatiles, moderate viscosity, and better operability in the die bond process.

[0050] In some embodiments, the vinyl MQ resin includes the unit shown in Formula 2, the unit shown in Formula 3, and SiO2. 4 / 2 One or more of the units;

[0051] R'3SiO 1 / 2 Equation 2,

[0052] R'2RSiO 1 / 2 Formula 3;

[0053] Wherein, R' is selected from alkyl groups of C1 to C10, and R is selected from alkenyl groups of C2 to C10.

[0054] Specifically, the vinyl MQ resin can be composed of siloxane units as shown in Formula 2, or of units as shown in Formula 3, SiO2, etc. 4 / 2 The siloxane units shown are composed of, or are composed of, the units shown in Formula 2, the units shown in Formula 3, and SiO2. 4 / 2 The diagram shows various compositional methods, including the siloxane unit composition.

[0055] Vinyl MQ resin can improve the adhesion strength between LED die bonders and chips and substrates, and has good high temperature resistance, which can help die bonders maintain their performance in high temperature environments; it can also increase the elastic modulus and mechanical strength of die bonders, and improve their ability to resist physical stress.

[0056] In some preferred embodiments, R' is selected from C1-C5 alkyl groups, and R is selected from C2-C5 alkenyl groups. The preferred ranges of R' and R in the vinyl MQ resin enable stronger adhesion between the die bond adhesive and the chip and substrate.

[0057] More preferably, R' is selected from methyl and R is selected from vinyl.

[0058] In some embodiments, the vinyl content in the vinyl MQ resin is 0.06-0.15 mol / 100g.

[0059] The vinyl content in vinyl MQ resin is 0.06-0.15 mol / 100g. Specifically, it means that the molar content of vinyl in 100g of vinyl MQ resin is 0.06-0.15 mol. This can provide better flexibility and elasticity, and improve the mechanical properties of the die bond adhesive, such as hardness.

[0060] Vinyl MQ resin is a white solid at 25°C.

[0061] In some embodiments, the organohydrogen polysiloxane comprises at least two hydrogen atoms bonded to silicon atoms;

[0062] The organohydrogen polysiloxane resin includes one or both of HMQ and HMD compounds.

[0063] The HMQ compound includes the unit shown in Formula 4, the unit shown in Formula 5, and SiO. 4 / 2 One or more of the units;

[0064] L3SiO 1 / 2 Equation 4,

[0065] L2HSiO 1 / 2 Formula 5;

[0066] The HMD compound includes one or more of the units shown in Formula 4, Formula 6, and Formula 7.

[0067] LHSiO 2 / 2 Formula 6,

[0068] H2SiO 2 / 2 Formula 7;

[0069] Wherein, L is selected from C1 to C10 alkyl groups.

[0070] Specifically, the organohydrogen polysiloxane includes at least two hydrogen atoms bonded to silicon atoms, selected from one or both of HMQ and HMD compounds, and can undergo an addition curing reaction under the action of platinum metal catalysts to react with vinyl MQ resin and the compound shown in Formula 1 to form a three-dimensional network structure, thereby improving the mechanical properties, thermal stability and adhesion properties of the die bond adhesive.

[0071] L is selected from C1 to C10 alkyl groups, including straight-chain alkyl groups with 1 to 10 carbon atoms, or alkyl groups with 1 to 10 carbon atoms containing branches; C1 to C10 alkyl groups may be methyl, ethyl, propyl, or isopropyl, etc.

[0072] In some embodiments, the viscosity of the organohydrogen polysiloxane resin is 1-500 cp, and the hydrogen content is 0.6-2 mol / 100g.

[0073] Specifically, the viscosity of the organohydrogen polysiloxane resin is in the range of 1-500 cp, ensuring that the die-attach adhesive has suitable flowability and wetting ability during preparation. Resin with moderate viscosity can better fill the tiny gaps between microelectronic components, ensuring good adhesion. The hydrogen content of the organohydrogen polysiloxane resin is 0.6-2 mol / 100g, controlling the rate and extent of the curing reaction and optimizing the crosslinking density of the cured product, thereby obtaining ideal mechanical properties and thermal stability.

[0074] In some embodiments, the number of hydrogen atoms bonded to silicon atoms in the organohydrogen polysiloxane resin is B1, and the total number of vinyl atoms bonded to silicon atoms in the vinyl MQ resin and the third siloxane resin is B2, with B1:B2 being (1-3):1.

[0075] Specifically, the ratio of B1 to B2 is limited to (1 to 3): 1. The Si-H bonds in the organohydrogen polysiloxane resin can undergo a curing reaction with the vinyl groups bonded to silicon atoms in the vinyl MQ resin and the trisiloxane resin to form a stable three-dimensional network structure, which improves the adhesion of the die bond adhesive, has a higher die bond thrust, improves the viscosity of the die bond adhesive, and reduces volatiles during curing.

[0076] The value of B1:B2 can be 1:1, 1.2:1, 1.4:1, 1.8:1, 2.0:1, 2.3:1, 2.5:1, 2.8:1, or 3.0:1, as long as B1:B2 is within the range of (1 to 3):1.

[0077] In some embodiments, the die bond comprises the following parts by weight: 30-100 parts of a first siloxane resin, 20-90 parts of a second siloxane resin, 10-100 parts of a third siloxane resin, and 1-50 parts of a functional additive; the catalyst comprises 1-100 ppm by weight of the total parts by weight of the first siloxane resin, the second siloxane resin, and the third siloxane resin.

[0078] Specifically, the content of each component added to the die bond adhesive is as shown above. This facilitates the Si-H bond in the organohydrogen polysiloxane resin to undergo a curing reaction with the vinyl groups bonded to silicon atoms in the vinyl MQ resin and trisiloxane resin under the action of catalysts and functional additives. This crosslinks to form a stable three-dimensional network structure, improving the hardness and adhesion performance of the die bond adhesive. It also produces less volatile matter during the curing process and has a higher die bond thrust.

[0079] In some embodiments, based on the weight parts of the die bond adhesive, the functional additives include 1 to 15 parts of tackifier, 0.01 to 5 parts of hydrosilylation inhibitor, and 1 to 20 parts of thixotropic agent.

[0080] Specifically, 1-15 parts of tackifier are added to increase the adhesion between the die-attach adhesive and the chip. 0.01-5 parts of hydrosilylation inhibitor are added to inhibit the formation of silane bonds during the silanization reaction; this inhibitor reduces or prevents the formation of silane bonds by competing with hydrogen silane bonds or silane bonds for the reaction.

[0081] Adding 1 to 20 parts of thixotropic agent can improve the viscosity of the die bond adhesive, making it easier to handle and process.

[0082] In some embodiments, the thickener is an organosilicon polymer containing epoxy and vinyl groups; the catalyst includes a platinum metal catalyst.

[0083] The hydrosilylation reaction inhibitors include alkynyl alcohols;

[0084] The thixotropic agent comprises substances with a specific surface area of ​​150–300 m². 2 / g of hydrophobic fumed silica.

[0085] In some preferred embodiments, the vinyl content in the organosilicon polymer is 0.05–1 mol / 100 g, and the epoxy equivalent is 200–600 g / eq;

[0086] Specifically, the tackifier contains 0.05–1 mol / 100g of vinyl groups and 200–600 g / eq of epoxy equivalent, which helps to improve the adhesion and cohesion of the die bond adhesive, thereby enhancing its bonding effect on the chip substrate.

[0087] In every 100g of the organosilicon polymer, the vinyl content can be 0.05mol, 0.1mol, 0.15mol, 0.2mol, 0.3mol, 0.4mol, 0.5mol, 0.6mol, 0.8mol, 1.0mol, etc., as long as it is within the range of 0.05 to 1mol / 100g. In every 100g of the organosilicon polymer, the epoxy equivalent can be in the following ranges: 200 to 300g / eq, 300 to 400g / eq, 400 to 500g / eq, 500 to 600g / eq, as long as the epoxy group content is within the range of 200 to 600g / eq.

[0088] Secondly, this application provides a method for preparing the above-mentioned LED die bond adhesive, comprising the following steps: uniformly mixing a first siloxane resin, a second siloxane resin, a third siloxane resin, a catalyst, and a functional additive to obtain the die bond adhesive.

[0089] The method for preparing LED die bond adhesive provided in this application is simple and low in cost.

[0090] In some embodiments, the method for preparing LED die bond adhesive includes the following steps: first, mixing a first siloxane resin and a third siloxane resin evenly, then adding a thixotropic agent and mixing evenly to obtain a first mixture; then adding a second siloxane resin, a tackifier, and a hydrosilylation inhibitor to the first mixture and mixing evenly to obtain a second mixture; and finally adding a catalyst to the second mixture and mixing evenly to obtain die bond adhesive.

[0091] The present invention will be further illustrated by the following examples.

[0092] Example 1

[0093] S1: Preparation of die-bonding adhesive:

[0094] First, 100 parts of the first siloxane resin and 10 parts of the third siloxane resin are mixed evenly, and then 6 parts of thixotropic agent are added and mixed evenly to obtain the first mixture. Then, 20 parts of the second siloxane resin, 4 parts of tackifier, and 0.5 parts of hydrosilylation reaction inhibitor are added to the first mixture and mixed evenly to obtain the second mixture. Finally, 0.01 parts of catalyst are added to the second mixture and mixed evenly to obtain the die bond.

[0095] The first siloxane resin is (Me3SiO) 1 / 2 ) 0.3 (Me2ViSiO1 / 2 ) 0.1 (SiO 4 / 2 ) 0.6 The vinyl content is 0.14 mol / 100g;

[0096] The second siloxane resin is (Me2HSiO) 1 / 2 ) 0.75 (SiO 4 / 2 ) 0.25 Viscosity 37cp, hydrogen content 1.2mol / 100g;

[0097] The third siloxane resin is (A3SiO) 1 / 2 ) x (A2ESiO 1 / 2 ) 4-x Si, where A is selected from methyl, x is 0, and E is selected from vinyl;

[0098] The tackifier is (Me2ViSiO) 1 / 2 ) 0.1 (MeEpSiO 2 / 2 ) 0.4 (MeSiO 3 / 2 ) 0.4 The vinyl content is 0.12 mol / 100g, and the epoxy equivalent is 215 g / eq; Ep represents epoxy group, Me represents methyl group, and Vi represents vinyl group.

[0099] The inhibitor of hydrosilylation reaction is 1-acetylenecyclohexanol;

[0100] Thixotropic agents with a specific surface area of ​​200m² 2 / g of hydrophobic fumed silica;

[0101] The catalyst is platinum metal.

[0102] Examples 2-9 and Comparative Examples 1-3

[0103] Examples 2-9 and Comparative Examples 1-3 are largely the same as Example 1, except that the components of the first siloxane resin, second siloxane resin, third siloxane resin, tackifier, hydrosilylation inhibitor, and thixotropic agent added are different, as detailed in Table 1.

[0104] Comparative Examples 1, 2, and 3 did not contain a third siloxane resin. Comparative Example 2 contained vinyl silicone oil, which was used to dissolve the first siloxane resin. Comparative Example 3 contained toluene, which was used as a solvent to dissolve the first siloxane resin.

[0105] Table 1

[0106] Example 10

[0107] Most of the steps in this embodiment are the same as those in Embodiment 1, the difference being that the third siloxane resin is (A3SiO2). 1 / 2 ) x (A2ESiO 1 / 2 ) 4-x Si, wherein A is selected from methyl, x is 1, and the rest is the same as in Example 1.

[0108] Example 11

[0109] Most of the steps in this embodiment are the same as those in Embodiment 1, the difference being that the third siloxane resin is (A3SiO2). 1 / 2 ) x (A2ESiO 1 / 2 ) 4-x Si, wherein A is selected from methyl, x is 3, and the rest is the same as in Example 1.

[0110] Performance testing

[0111] The LED die-attach adhesives prepared in the above embodiments and comparative examples were subjected to the following tests:

[0112] 1) Viscosity test: At 25℃, the viscosity of the prepared LED die bond adhesive was tested using a Brookfield cap2000+ cone-plate viscometer according to the instructions.

[0113] 2) Volatilization: Weigh 1g±0.1g of glue and test the weight loss before and after curing at 170℃ for 1 hour;

[0114] 3) Wire pulling and glue spinning during die bonding: The equipment used was the Xinyichang dual-head high-speed die bonder GTS100 BH-PA, with a die bonding rate of 50k / h. 10×30mil and 8×15mil LED chips were bonded to 2835 brackets. Each type of die bonder was paired with one bracket for each type of chip (the 2835 bracket specifications were 16×36, totaling 576 chips). After the chips were bonded, the proportion of residual glue left on the brackets and chips due to glue spinning was counted under a microscope.

[0115] 4) Thrust test: The support for the solidified chip was cured at 170°C for 1 hour, and the thrust value when the chip was pushed away was tested using a force gauge LB-8100A.

[0116] The test results are shown in Table 2.

[0117] Table 2

[0118] As can be seen from Tables 1 and 2, compared with Comparative Examples 1-3, Examples 1-2 and Comparative Examples 1-3 do not contain the third siloxane resin of the compound shown in Structural Formula 1. Comparative Example 1 did not use solvent and vinyl silicone oil to dissolve the vinyl MQ resin, and therefore could not be cured and crystallized. Comparative Example 2 used vinyl silicone oil as a solvent to dissolve the vinyl MQ resin, resulting in a slightly lower volatility, but also a low die-bonding force. Comparative Example 3 used toluene as a solvent to dissolve the vinyl MQ resin, resulting in a higher volatility and a low die-bonding force. This indicates that the LED die-bonding adhesive provided in this application does not use solvent to dissolve the vinyl MQ resin, resulting in a low volatility during curing, which will not adversely affect the subsequent wire bonding steps. At the same time, the first siloxane resin, the second siloxane resin, and the third siloxane resin contained in the adhesive form a stable three-dimensional network structure. The reaction does not produce byproducts or release small molecules, while maintaining a dense cross-linked network, resulting in high hardness, low volatility, excellent adhesion, and high die-bonding force of the reaction product.

[0119] Comparing Examples 1 and 4, the content of the first siloxane resin was less than 30-100 parts, resulting in low viscosity of the die bond adhesive and low die bond push force. This is presumably because the low content of the first siloxane resin reduced the amount of hydrogen in the second siloxane resin that could undergo hydrosilylation, leading to decreased stability of the resulting three-dimensional network structure, lower hardness of the die bond adhesive, and reduced adhesion between the die bond adhesive and the scaffold. Comparing Examples 1 and Examples 5 and 7, the content of the third siloxane resin was less than 10-100 parts, resulting in excessively high viscosity of the die bond adhesive, causing stringing or glue splattering; when the content of the third siloxane resin was greater than 10-100 parts, the viscosity of the die bond adhesive was lower, also causing stringing or glue splattering, and low die bond push force. Comparing Examples 1 and Examples 6 and 8, the content of the second siloxane resin in Example 6 was greater than 20-90 parts, resulting in low viscosity of the die bond adhesive, increased volatility, and low die bond push force; the content of the second siloxane resin in Example 8 was less than 20-90 parts, resulting in high viscosity of the die bond adhesive and low die bond push force. Based on the above comparisons and data from Examples 1-3 and Example 9, it can be concluded that in the LED die bond adhesive, 30-100 parts of the first siloxane resin, 20-90 parts of the second siloxane resin, and 10-100 parts of the third siloxane resin undergo a hydrosilylation reaction with the hydrogen in the second siloxane resin to form a stable three-dimensional network structure. The resulting die bond adhesive has high hardness, low volatility, excellent adhesion, and high die bond push force.

[0120] In Examples 10-11, the thrust also changed significantly when the functional group of the third siloxane changed. This was mainly due to changes in the ratio or functional groups of the first, second, and third siloxanes. Changes in the content of vinyl groups and hydrogen groups in the composition led to changes in the density of the crosslinked network, thus affecting the thrust. Furthermore, the second and third siloxanes have low viscosity, and changes in their content caused changes in the viscosity of the composition, affecting the workability.

[0121] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A die bond for LEDs, characterized in that, The product includes siloxane resins, catalysts, and functional additives. The siloxane resins include a first siloxane resin, a second siloxane resin, and a third siloxane resin. The first siloxane resin includes a vinyl MQ resin, the second siloxane resin includes an organohydrogen polysiloxane resin, and the third siloxane resin includes a compound shown in Formula 1. (A3SiO 1 / 2 ) x (A2ESiO 1 / 2 ) 4-x Si Formula 1 Where x is a natural number from 0 to 3; A is selected from C1 to C10 alkyl groups, and E is selected from C2 to C10 alkenyl groups.

2. The die bond adhesive for LEDs according to claim 1, characterized in that, A is selected from C1 to C5 alkyl groups, and E is selected from C2 to C5 alkenyl groups.

3. The die bond adhesive for LEDs according to claim 1, characterized in that, The vinyl MQ resin includes the unit shown in Formula 2, the unit shown in Formula 3, and SiO. 4 / 2 One or more of the units; R'3SiO 1 / 2 Equation 2, R'2RSiO 1 / 2 Formula 3; Wherein, R' is selected from alkyl groups of C1 to C10, and R is selected from alkenyl groups of C2 to C10.

4. The die bond adhesive for LEDs according to claim 1, characterized in that, The vinyl content in the vinyl MQ resin is 0.06-0.15 mol / 100g.

5. The die bond adhesive for LEDs according to claim 1, characterized in that, The organohydrogen polysiloxane comprises at least two hydrogen atoms bonded to silicon atoms; The organohydrogen polysiloxane resin includes one or both of HMQ and HMD compounds. The HMQ compound includes the unit shown in Formula 4, the unit shown in Formula 5, and SiO. 4 / 2 One or more of the units; L3SiO 1 / 2 Formula 4, L2HSiO 1 / 2 Formula 5; The HMD compound includes one or more units shown in Formula 4, Formula 6, and Formula 7; LHSiO 2 / 2 Formula 6, H2SiO 2 / 2 Formula 7; Wherein, L is selected from C1 to C10 alkyl groups.

6. The die bond adhesive for LEDs according to claim 1, characterized in that, The number of hydrogen atoms bonded to silicon atoms in the organohydrogen polysiloxane resin is B1, and the total number of vinyl atoms bonded to silicon atoms in the vinyl MQ resin and the third siloxane resin is B2, with B1:B2 being (1~3):

1.

7. The die bond adhesive for LEDs according to claim 1, characterized in that, The die-bonding adhesive comprises the following parts by weight: 30-100 parts of a first siloxane resin, 20-90 parts of a second siloxane resin, 10-100 parts of a third siloxane resin, and 1-50 parts of functional additives. The catalyst is present in parts by weight of 1 to 100 ppm of the total weight of the first siloxane resin, the second siloxane resin, and the third siloxane resin.

8. The die bond adhesive for LEDs according to claim 7, characterized in that, Based on the weight parts of the die bond adhesive, the functional additives include 1 to 15 parts of tackifier, 0.01 to 5 parts of hydrosilylation inhibitor, and 1 to 20 parts of thixotropic agent.

9. The die bond adhesive for LEDs according to claim 8, characterized in that, The tackifier is an organosilicon polymer containing epoxy and vinyl groups; in the organosilicon polymer, the vinyl content is 0.05-1 mol / 100g, and the epoxy equivalent is 200-600g / eq.

10. The die bond adhesive for LEDs according to claim 9, characterized in that, The catalyst includes platinum metal catalysts; The inhibitors of the hydrosilylation reaction include alkynyl alcohols; The thixotropic agent comprises substances with a specific surface area of ​​150–300 m². 2 / g of hydrophobic fumed silica.

11. A method for preparing the die-attach adhesive for LEDs according to any one of claims 1 to 10, characterized in that, The process includes the following steps: mixing a first siloxane resin, a second siloxane resin, a third siloxane resin, a catalyst, and functional additives evenly to obtain the solidification adhesive.

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