Preparation method of chip dam glue and application thereof

Abstract

The application discloses a preparation method of a chip dam glue and application thereof, and the preparation method comprises the following steps: taking raw materials of the chip dam glue and performing centrifugal stirring; the raw materials of the chip dam glue comprise the following components: 70-74 wt.% of inorganic fillers, 13-16 wt.% of epoxy resin, 12-15 wt.% of a curing agent, 0.1-0.4 wt.% of a solid modified imidazole latent accelerator and 0-0.2 wt.% of pigments; wherein the epoxy resin comprises liquid bisphenol A epoxy resin and / or liquid alicyclic epoxy resin; the process parameters of the centrifugal stirring are as follows: 1500 r / min-3000 r / min of rotation speed, 1000 r / min-1800 r / min of revolution speed and 100 s-200 s of stirring time. The chip dam glue prepared by the application has a room temperature viscosity of 270-430 Pa.s, a thixotropy value of 4.8-6.6, suitable viscosity and significantly improved thixotropy performance, and can be applied to a dam filling process of a chip.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor chip packaging, and particularly relates to a preparation method of a chip dam glue and application thereof. BACKGROUND

[0002] The dam glue is also called cofferdam glue and can be applied to a dam filling process. In the process, dam glue (DAM glue) and filling glue (Fill glue) are needed. The dam glue is used to form a cofferdam around the periphery of a chip, and the cofferdam serves as a physical barrier to isolate the chip and gold wires from the external environment, thereby protecting the chip and gold wires. The filling glue is used to encapsulate the area surrounded by the cofferdam, thereby packaging the chip. In the dam filling process, the flow and setting of the dam glue need to be accurately controlled, so a dam glue with large thixotropy is needed. The dam glue can quickly flow to form a cofferdam when dispensing, and can quickly set to form a reliable physical barrier after dispensing. SUMMARY

[0003] One of the purposes of the application is to provide a preparation method of a chip dam glue, comprising: taking each raw material of the chip dam glue and performing centrifugal stirring.

[0004] The raw material of the chip dam glue comprises: inorganic filler 70-74 wt.%, epoxy resin 13-16 wt.%, curing agent 12-15 wt.%, solid modified imidazole latent accelerator 0.1-0.4 wt.%, and pigment 0-0.2 wt.%; wherein the epoxy resin comprises liquid bisphenol A epoxy resin and / or liquid alicyclic epoxy resin.

[0005] The process parameters of the centrifugal stirring are: rotation speed 1500 r / min-3000 r / min, revolution speed 1000 r / min-1800 r / min, and stirring time 100 s-200 s.

[0006] In some embodiments, the preparation method further comprises: dispersing the mixture after centrifugal stirring. The dispersion can select a three-roll mill, and the dispersion process parameters are: the feeding gap and the discharging gap of the three-roll mill are 200 um-250 um and 100 um-150 um, respectively.

[0007] Further, the preparation method further comprises: vacuum degassing the mixture after dispersion. The vacuum degassing can select a centrifugal stirrer, and the process parameters of the vacuum degassing are: rotation speed 2500 r / min, revolution speed 800 r / min, and vacuum degassing time 100 s.

[0008] In some embodiments, the solid modified imidazole latent accelerator can be selected from HMA-2300, JTN-30, or PN-23.

[0009] In some embodiments, the inorganic filler is preferably silica with a particle size of 25-75um.

[0010] In some embodiments, the curing agent is selected from organic anhydride curing agent or amine curing agent. Further, the curing agent can be selected from methyl nadic anhydride, benzoic anhydride or m-phenylenediamine.

[0011] The second object of the present application is to provide the application of the above-mentioned chip dam adhesive in the dam filling process of the chip.

[0012] In the present application, the solid-state modified imidazole latent accelerator can be adsorbed on the surface of the inorganic filler particles, occupy the active sites on the surface of the inorganic filler particles, hinder the inorganic filler particles from approaching each other through steric hindrance effect, prevent the agglomeration of inorganic filler, maintain the stability of inorganic filler dispersion, and thus improve the thixotropy. The combination between the epoxy resin and the inorganic filler particles is through hydrogen bond and / or van der Waals force, the high shear force of centrifugal stirring cuts off the combination between the epoxy resin and the inorganic filler particles, more active sites on the surface of the inorganic filler particles are released to combine with the solid-state modified imidazole latent accelerator, and the steric hindrance effect is further enhanced, so that the thixotropy is further improved.

[0013] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0014] The chip dam adhesive prepared in the present application has a room temperature viscosity of 270-430Pa.s, and a thixotropy value of 4.8-6.6, the viscosity is suitable, and the thixotropy is significantly improved. DETAILED DESCRIPTION

[0015] The technical solutions of the present application will be described clearly and completely in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0016] The preparation method of the chip dam adhesive provided by the embodiments of the present application comprises: taking each raw material of the chip dam adhesive and performing centrifugal stirring; the raw materials of the above-mentioned chip dam adhesive comprise: inorganic filler 70-74wt.%, epoxy resin 13-16wt.%, curing agent 12-15wt.%, solid-state modified imidazole latent accelerator 0.1-0.4wt.%, and pigment 0-0.2wt.%; wherein, the epoxy resin comprises liquid bisphenol A epoxy resin and / or liquid alicyclic epoxy resin; the process parameters of the above-mentioned centrifugal stirring are: rotation speed 1500r / min-3000r / min, revolution speed 1000r / min-1800r / min, and stirring time 100s-200s.

[0017] In some embodiments, the mixture after the centrifugal stirring is further dispersed. The dispersion can be performed by a three-roll mill, and the dispersion process parameters can be: the feeding gap and the discharging gap of the three-roll mill are 200-250um and 100-150um, respectively.

[0018] Further, the mixture after the dispersion is further vacuum defoamed. The vacuum defoaming can be performed by a centrifugal mixer, and the vacuum defoaming process parameters can be: the rotation speed is 2500r / min, the revolution speed is 800r / min, and the vacuum defoaming time is 100s.

[0019] In the present application, the inorganic filler is mainly used to reduce the internal stress and the thermal expansion coefficient of the dam glue, and a conventional inorganic filler such as silicon dioxide can be selected. In some embodiments, the inorganic filler is selected to be silicon dioxide, and the particle size is preferably 25-75um. A larger particle size helps to improve the filling ratio of the inorganic filler, thereby improving the modulus and glass transition temperature Tg of the dam glue.

[0020] In the present application, the epoxy resin is used as the resin matrix, the curing agent is used to react with the epoxy resin at a specific temperature to promote the curing reaction, and the accelerator is used to promote the curing reaction. In some embodiments, the epoxy resin is preferably a liquid bisphenol A epoxy resin or a liquid alicyclic epoxy resin, for example, DER336 type liquid bisphenol A epoxy resin, ERL-4221 type liquid alicyclic epoxy resin, S-06E type liquid alicyclic epoxy resin.

[0021] The curing agent can be selected from the curing agents disclosed in the prior art that match the epoxy resin. In some embodiments, the curing agent can be selected from organic acid anhydride curing agents or amine curing agents, such as methyl nadic anhydride, benzoic anhydride, and m-phenylenediamine. In some embodiments, the solid-state modified imidazole latent accelerator can be selected from HMA-2300, JTN-30, or PN-23.

[0022] The above-prepared chip dam glue can be applied to the dam filling process of the chip to form a dam structure around the chip.

[0023] In the present application, the thixotropy of the dam glue is significantly improved by the combination of the solid-state modified imidazole latent accelerator and the centrifugal stirring. The imidazole ring nitrogen atom in the solid-state modified imidazole latent accelerator has strong polarity and can be adsorbed on the surface of the inorganic filler particles by van der Waals force and / or electrostatic force, forming a "protective film" on the surface of the inorganic filler particles, reducing the direct contact between the inorganic filler particles, and preventing agglomeration. Because the solid-state modified imidazole latent accelerator adsorbed on the surface of the inorganic filler particles occupies the active sites on the surface of the inorganic filler particles, it can hinder other inorganic filler particles from approaching, thereby maintaining the stability of the inorganic filler dispersion, and thus helping to improve the thixotropy of the dam glue.

[0024] The surface of the inorganic filler particles is also combined with the epoxy resin through hydrogen bonds and / or Van der Waals forces. Under the action of high shear of centrifugal stirring, the polymer chain segments of the epoxy resin move violently to generate friction heat, the local temperature rises, the polymer chain segments are disentangled, the combination between the inorganic filler and the epoxy resin is broken, and the solid-state modified imidazole latent accelerator can occupy more active sites on the surface of the inorganic filler particles, the steric hindrance effect is further enhanced, and the thixotropy of the dam glue is further improved. After the centrifugal stirring stops, the thermal motion of the polymer chain segments is weakened, the structure destroyed by shear is gradually reconstructed, and energy is consumed in the reconstruction process, resulting in additional heat effects inside and outside the system, and the local temperature rises; the structure reconstruction reduces the free volume, and the intermolecular forces such as hydrogen bonds and Van der Waals forces reoccupy the dominant position, the viscosity increases, and the thixotropy is enhanced.

[0025] Generally speaking, the greater the shear force or the longer the shear duration, the more active sites occupied by the solid-state modified imidazole latent accelerator, the greater the steric hindrance effect, and the better the thixotropy of the dam glue. When the solid-state modified imidazole latent accelerator is completely and uniformly adsorbed on the surface of the inorganic filler particles, the steric hindrance effect no longer increases, and at this time the thixotropy reaches the best. If the amount of the solid-state modified imidazole latent accelerator is continuously increased, the thixotropy can be further enhanced until the active sites on the surface of the inorganic filler particles are again fully occupied.

[0026] To further illustrate the present application, examples and comparative examples will be provided below, and the raw materials used in the examples and comparative examples are as follows:

[0027] Inorganic filler: commercially available silica, particle size range 25um-75um;

[0028] Epoxy resin: liquid bisphenol A epoxy resin, brand: DER336, 25℃ viscosity: 11000mPa·s-15000mPa·s, epoxy value: 0.51eq / 100g-0.54eq / 100g;

[0029] Curing agent: methyl nadic anhydride;

[0030] Solid-state modified imidazole latent accelerator: HMA-2300;

[0031] Carbon black: commercially available.

[0032] Example 1

[0033] The raw materials of the chip dam glue and the mass percentage of each raw material in this example are as follows:

[0034] Silicon dioxide 73%;

[0035] DER336 14.5%;

[0036] Methyl nadic anhydride 12.05%;

[0037] Carbon black 0.2%;

[0038] HMA-2300 0.25%;

[0039] The centrifugal stirring parameters are: rotation 2200 r / min, revolution 1400 r / min, and centrifugal stirring time 150 s.

[0040] Example 2

[0041] The raw materials and the mass percentage of each raw material of the chip dam glue in this example are as follows:

[0042] Silicon dioxide 73%;

[0043] DER336 14.5%;

[0044] Methyl nadic anhydride 12.05%;

[0045] Carbon black 0.2%;

[0046] HMA-2300 0.25%;

[0047] The centrifugal stirring parameters are: rotation 3000 r / min, revolution 1800 r / min, and centrifugal stirring time 200 s.

[0048] Example 3

[0049] The raw materials and the mass percentage of each raw material of the chip dam glue in this example are as follows:

[0050] Silicon dioxide 73%;

[0051] DER336 14.5%;

[0052] Methyl nadic anhydride 12.05%;

[0053] Carbon black 0.2%;

[0054] HMA-2300 0.25%;

[0055] The centrifugal stirring parameters are: rotation 1500 r / min, revolution 1000 r / min, and centrifugal stirring time 100 s.

[0056] Example 4

[0057] The raw materials and the mass percentage of each raw material of the chip dam glue in this example are as follows:

[0058] Silicon dioxide 72.85%;

[0059] DER 336 14.5%;

[0060] Methyl nadic anhydride 12.05%;

[0061] Carbon black 0.2%;

[0062] HMA-2300 0.4%;

[0063] The centrifugal stirring parameters are: 2200 r / min of rotation, 1400 r / min of revolution, and 150 s of centrifugal stirring time.

[0064] Example 5

[0065] The raw materials of the chip dam adhesive and the mass percentage of each raw material in this example are as follows:

[0066] Silicon dioxide 73%;

[0067] DER 336 14.5%;

[0068] Methyl nadic anhydride 12.2%;

[0069] Carbon black 0.2%;

[0070] HMA-2300 0.1%;

[0071] The centrifugal stirring parameters are: 2200 r / min of rotation, 1400 r / min of revolution, and 150 s of centrifugal stirring time.

[0072] Comparative Example 1

[0073] The raw materials of the chip dam adhesive and the mass percentage of each raw material in this example are as follows:

[0074] Silicon dioxide 73%;

[0075] DER 336 14.5%;

[0076] Methyl nadic anhydride 12.05%;

[0077] Carbon black 0.2%;

[0078] Diethyl tetramethyl imidazole 0.25%;

[0079] The centrifugal stirring parameters are: 2200 r / min of rotation, 1400 r / min of revolution, and 150 s of centrifugal stirring time.

[0080] Comparative Example 2

[0081] The raw materials of the chip dam adhesive and the mass percentage of each raw material in this example are as follows:

[0082] Silicon dioxide 73%;

[0083] DER 336 14.5%;

[0084] Methyl nadic anhydride 12.05%;

[0085] Carbon black 0.2%;

[0086] N,N-dimethyl benzylamine 0.25%;

[0087] The centrifugal stirring parameters are: 2200 r / min of rotation, 1400 r / min of revolution, and 150 s of centrifugal stirring time.

[0088] Comparative Example 3

[0089] The raw materials and the mass percentages of each raw material of the chip dam adhesive in the present comparative example are as follows:

[0090] Silicon dioxide 73%;

[0091] DER 336 14.5%;

[0092] Methyl nadic anhydride 12.05%;

[0093] Carbon black 0.2%;

[0094] HMA-2300 0.25%;

[0095] The centrifugal stirring parameters are: 3500 r / min of rotation, 2300 r / min of revolution, and 250 s of centrifugal stirring time.

[0096] Comparative Example 4

[0097] The raw materials and the mass percentages of each raw material of the chip dam adhesive in the present comparative example are as follows:

[0098] Silicon dioxide 73%;

[0099] DER 336 14.5%;

[0100] Methyl nadic anhydride 12.05%;

[0101] Carbon black 0.2%;

[0102] HMA-2300 0.25%;

[0103] The centrifugal stirring parameters are: 1000 r / min of rotation, 700 r / min of revolution, and 80 s of centrifugal stirring time.

[0104] The chip dam adhesive samples of the above examples and comparative examples are prepared by the following method:

[0105] (1) Take each raw material of the core surrounding dam glue, and centrifugal stir with a centrifugal stirrer:

[0106] (2) Disperse the mixture after centrifugal stirring with a three-roll mill, and the feeding gap and discharging gap of the three-roll mill are 200 um and 100 um, respectively;

[0107] (3) Vacuum defoaming of the dispersed mixture is carried out with a centrifugal stirrer, and the process parameters of vacuum defoaming are: rotation speed 2500 r / min, revolution speed 800 r / min, and vacuum defoaming time 100 s.

[0108] The performance parameters of the core surrounding dam glue samples of the examples and the comparative examples are tested, and the testing method is as follows:

[0109] 1. Viscosity: the viscosity value of the sample at 25°C is measured with a rotary viscometer at a rotation speed of 5 rpm;

[0110] 2. Thixotropy value: the viscosity values P1 and P2 at rotation speeds of 5 rpm and 50 rpm at 25°C are measured with a rotary viscometer, and P1 / P2 is the thixotropy value;

[0111] 3. Premixing temperature: the temperature of the glue after centrifugal stirring is measured with an infrared temperature gun.

[0112] Table 1 Performance parameters of the surrounding dam glue samples of the examples and the comparative examples

[0113]

[0114] The test data are listed in Table 1, and it can be seen from Table 1 that the thixotropy values of the examples 1-5 of the application can reach 4.8-6.6, and the thixotropy performance is significantly improved; in the surrounding dam filling process of the chip, when the viscosity of the surrounding dam glue exceeds 450 Pa.s, the glue will not be smooth during dispensing, so the viscosity of the surrounding dam glue is preferably not more than 450 Pa.s, and the viscosity of the examples 1-5 of the application is appropriate.

[0115] Comparing the example 1 with the comparative examples 1-2, the only difference is the accelerator, the accelerator in the example 1 is a solid modified imidazole latent accelerator HMA-2300, the accelerator in the comparative example 1 is a liquid imidazole accelerator, and the accelerator in the comparative example 2 is a liquid tertiary amine accelerator, compared with the example 1, the thixotropy values of the comparative examples 1-2 are only 1.0-1.2, and the thixotropy performance is far inferior to that of the example 1.

[0116] Comparing Example 1-3 and Comparative Example 3, the only difference is the process parameters of centrifugal stirring, the rotation and revolution speed of centrifugal stirring in Comparative Example 3 is too large and the centrifugal stirring time is too long, although the thixotropic value of Comparative Example 3 is increased, but the viscosity is also significantly increased, which is obviously more than 450 Pa.s. The inventor believes that it may be that when the rotation and revolution speed of centrifugal stirring is too large and the centrifugal stirring time is too long, the colloid is significantly heated, and the premixing temperature of Comparative Example 3 is as high as 80℃, which may cause part of the epoxy resin to start and occur curing reaction, resulting in a significant increase in viscosity.

[0117] Comparing Example 1-3 and Comparative Example 4, the only difference is the process parameters of centrifugal stirring, the rotation and revolution speed of centrifugal stirring in Comparative Example 4 is smaller and the centrifugal stirring time is shorter, compared with Comparative Examples 1-2, the thixotropic value of Comparative Example 4 is improved, but still far lower than the thixotropic value of Examples 1-5. The inventor believes that it may be that when the rotation and revolution speed of centrifugal stirring is smaller and the centrifugal stirring time is shorter, the colloid temperature is lower, the hydrogen bond and / or van der Waals force between the epoxy resin and the inorganic filler particles is not completely destroyed, the solid modified imidazole latent accelerator cannot occupy more active sites on the surface of the inorganic filler particles, the steric hindrance effect is limited, and the thixotropic property cannot be significantly improved.

[0118] The above examples are only for clearly illustrating the examples made, and are not a limitation on the embodiments. Based on the above description, other different forms of changes or variations can also be made by those of ordinary skill in the art, and here it is not necessary and impossible to exhaust all the embodiments, therefore the obvious changes or variations still within the protection scope of the present application.

Claims

1. A method for preparing a die dam adhesive, characterized by, The method comprises the following steps: The raw materials of the core surrounding dam glue are centrifugally stirred; The raw materials of the core surrounding dam glue comprise: inorganic filler 70-74 wt.%, epoxy resin 13-16 wt.%, curing agent 12-15 wt.%, solid modified imidazole latent accelerator 0.1-0.4 wt.%, and pigment 0-0.2 wt.%; wherein the epoxy resin comprises liquid bisphenol A epoxy resin; The process parameters of the centrifugal stirring are: rotation speed 1500 r / min-3000 r / min, revolution speed 1000 r / min-1800 r / min, and stirring time 100 s-200 s; The inorganic filler is selected from silica with a particle size of 25 um-75 um; The curing agent is selected from methyl nadic anhydride; The solid modified imidazole latent accelerator is selected from HMA-2300; The liquid bisphenol A epoxy resin is selected from DER336.

2. The method for preparing the core surrounding dam glue according to claim 1, further comprising: The mixture after the centrifugal stirring is dispersed.

3. The method for preparing the core surrounding dam glue according to claim 2, further comprising: The mixture after the dispersion is vacuum degassed.

4. The application of the core surrounding dam glue prepared by the method according to any one of claims 1-3 in the surrounding dam filling process of a chip. ​ ​

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