A high-performance bottom filling glue, preparation method thereof and chip packaging structure

Abstract

The present invention provides a high-performance bottom filling glue, a preparation method thereof and a chip packaging structure. The high-performance bottom filling glue comprises the following components by mass percentage: 56% to 71% of silicon dioxide, 22% to 27% of epoxy resin, 7% to 16% of curing agent, 0.1% to 0.2% of carbon black, and 0.3% to 0.5% of toughening agent; the epoxy resin is composed of bisphenol F type epoxy resin, biphenyl type epoxy resin and organosilicon modified epoxy resin; by adjusting the ratio of biphenyl type epoxy resin, bisphenol F type epoxy resin and organosilicon modified epoxy resin, a bottom filling glue with good fluidity, high heat resistance, high moisture and heat resistance and high toughness can be obtained. The high-performance bottom filling glue provided by the present application can not only improve the reliability and life of chip packaging, but also has a higher glass transition temperature, and can be applied to more fields.

Description

Technical Field

[0001] The invention belongs to the technical field of bottom filling glue packaging, and in particular relates to a high-performance bottom filling glue, a preparation method thereof and a chip packaging structure. Background Art

[0002] Bottom filler is a key material in electronic device packaging technology. It is mainly used to fill the narrow gap between the chip and the substrate, disperse the stress on the chip surface, and relieve the internal stress caused by the mismatch of thermal expansion coefficients between the chip, solder and substrate. It protects the chip from damage caused by physical, chemical and other environmental factors, and increases the processability, reliability and service life of the chip and packaged devices.

[0003] When chips or electronic devices are working, they usually release a lot of heat and generate high temperatures. At the same time, chips or electronic devices also work in various humidity and temperature environments, which will cause the bottom filler package to fail. Therefore, the bottom filler needs to have not only high heat resistance, but also high moisture and heat resistance.

[0004] It can be seen that how to provide a high-performance bottom filling glue to improve the packaging reliability of the chip is a technical problem that technical personnel in this field need to solve urgently. Summary of the invention

[0005] The object of the present invention is to provide a high-performance bottom filling glue, a preparation method thereof and a chip packaging structure, so as to solve at least one of the above-mentioned technical problems.

[0006] To achieve the above-mentioned purpose, the first aspect of the present invention provides a high-performance bottom filling glue, which includes the following components by mass percentage: 56% to 71% silicon dioxide, 22% to 27% epoxy resin, 7% to 16% curing agent, 0.1% to 0.2% carbon black, and 0.3% to 0.5% toughening agent; the epoxy resin is composed of bisphenol F type epoxy resin, biphenyl type epoxy resin and silicone modified epoxy resin.

[0007] In the first aspect, the mass percentage of the bisphenol F epoxy resin is 10%, the mass percentage of the biphenyl epoxy resin is 4% to 10%, and the mass percentage of the organosilicon-modified epoxy resin is 4% to 10%.

[0008] In the first aspect, the mass percentage of the silicon dioxide is 58% to 62%, the mass percentage of the curing agent is 15%, and the mass percentage of the toughening agent is 0.4%.

[0009] In the first aspect, the biphenyl type epoxy resin is a tetramethylbiphenyl diphenol type epoxy resin.

[0010] In the first aspect, the structural formula of the silicone-modified epoxy resin is:

[0011]

[0012] In the first aspect, the curing agent includes at least one of SH-3823-36 and SH-300.

[0013] In the first aspect, the toughening agent is CMP-410.

[0014] A second aspect of the present invention provides a method for preparing the high-performance bottom filling adhesive as described in the first aspect, the preparation method comprising:

[0015] S1. Add each component into a stirring cup according to their respective mass percentages, stir and mix, and obtain a first slurry, wherein the mass percentages of the components specifically include: 56% to 71% silicon dioxide, 22% to 27% epoxy resin, 7% to 16% curing agent, 0.1% to 0.2% carbon black, and 0.3% to 0.5% toughening agent; the epoxy resin is composed of bisphenol F epoxy resin, biphenyl epoxy resin, and silicone-modified epoxy resin;

[0016] S2, transferring the first slurry into a centrifugal mixer, stirring and mixing, to obtain a second slurry;

[0017] S3, transferring the second slurry to a three-roll mill for dispersion treatment to obtain a uniformly dispersed third slurry;

[0018] S4, transferring the third slurry into a centrifugal mixer for vacuum degassing to obtain bottom filling glue.

[0019] In the second aspect, the mass percentage of the bisphenol F type epoxy resin is 10%, the mass percentage of the biphenyl type epoxy resin is 4% to 10%, and the mass percentage of the organosilicon modified epoxy resin is 4% to 10%.

[0020] The third aspect of the present invention provides a chip packaging structure, comprising a substrate, a chip arranged on the substrate, and a plurality of spaced solder bumps arranged between the substrate and the chip and electrically connected to the substrate and the chip, a gap is formed between the substrate and the chip, the high-performance bottom filling glue liquid described in the first aspect is arranged at the edge of the substrate, so that the bottom filling glue liquid flows from one end of the gap to the other end of the gap by capillary action to fill the gap; the bottom filling glue liquid is cured; after the curing is completed, a chip packaging structure is obtained.

[0021] Beneficial effects:

[0022] The invention provides a high-performance bottom filling glue, which comprises the following components by mass percentage: 56% to 71% silicon dioxide, 22% to 27% epoxy resin, 7% to 16% curing agent, 0.1% to 0.2% carbon black, and 0.3% to 0.5% toughening agent; the epoxy resin is composed of bisphenol F epoxy resin, biphenyl epoxy resin and organosilicon-modified epoxy resin; the epoxy resin formed by compounding bisphenol F epoxy resin, biphenyl epoxy resin and organosilicon-modified epoxy resin is used as a matrix material, and an organosilicon segment is introduced into the matrix material, which can not only improve the heat resistance of the matrix material, but also enhance the toughness of the matrix material after curing, and the silicon-containing polymer has good flame retardant properties, and the low surface energy of the silicon-containing group causes it to migrate to the surface of the matrix to form a heat-resistant protective layer, thereby avoiding further thermal degradation of the matrix material; The biphenyl structure is introduced into the material, and the nearly planar structure of the biphenyl group increases the regularity of the chain and the intermolecular force, and the crosslinking density of the matrix material is increased in the isotropic crosslinking network, thereby improving the heat resistance of the matrix material and reducing the hygroscopicity of the matrix material. At the same time, in the bisphenol F type epoxy resin, the biphenyl type epoxy resin can also be used as a filler to make up for the interface separation caused by thermal expansion, and enhance the adhesion and mechanical properties of the matrix material. On this basis, silicon dioxide and a toughening agent are added to further enhance the hygroscopicity and toughness of the bottom filling glue. The present invention adjusts the ratio among the bisphenol F type epoxy resin, the biphenyl type epoxy resin and the organosilicon modified epoxy resin, and under the action of silicon dioxide, a curing agent and a toughening agent, the heat resistance, moisture and heat resistance and toughness of the bottom filling glue are improved, thereby improving the packaging efficiency of the bottom filling glue. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 The present invention is a flow chart of a method for preparing a high-performance bottom filling adhesive. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below in conjunction with specific implementations and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific implementations and examples are used to illustrate the present invention, rather than to limit the present invention.

[0026] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. In the event of a conflict, the present specification takes precedence.

[0027] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or obtained by existing methods.

[0028] The general idea of ​​the present invention is as follows:

[0029] Temperature is one of the main factors affecting package failure. High-power electronic devices (such as power amplifiers, high-brightness LEDs, etc.) release a lot of heat when working, generating high temperatures. For every 10°C increase in temperature, their lifespan will decrease by 50%. The heat resistance of packaging materials is directly related to the service life and reliability of the equipment. Materials with good heat resistance can maintain stability and safety when the temperature rises, ensuring that electronic equipment can work stably for a long time. In addition, during the packaging test process, electronic devices absorb moisture molecules, causing the metal materials and insulating materials inside the electronic components to be corroded and oxidized, thereby affecting their electrical performance. Based on this, the bottom filling glue packaging material should have good heat resistance and moisture and heat resistance.

[0030] The present application provides a high-performance bottom filling glue, which includes the following components in mass percentage: 56% to 71% silicon dioxide, 22% to 27% epoxy resin, 7% to 16% curing agent, 0.1% to 0.2% carbon black, and 0.3% to 0.5% toughening agent; the epoxy resin is composed of bisphenol F type epoxy resin, biphenyl type epoxy resin and silicone modified epoxy resin.

[0031] Specifically, the present invention provides a high-performance bottom filling glue, which includes the following components in mass percentage: 56% to 71% silicon dioxide, 22% to 27% epoxy resin, 7% to 16% curing agent, 0.1% to 0.2% carbon black, and 0.3% to 0.5% toughening agent; the epoxy resin is composed of bisphenol F epoxy resin, biphenyl epoxy resin and silicone modified epoxy resin; the epoxy resin formed by compounding bisphenol F epoxy resin, biphenyl epoxy resin and silicone modified epoxy resin is used as the matrix material, and the silicone chain segment is introduced into the matrix material, which can not only improve the heat resistance of the matrix material, but also enhance the toughness of the matrix material after curing, and the silicon-containing polymer has good flame retardant properties, and the low surface energy of the silicon-containing group causes it to migrate to the surface of the matrix to form a heat-resistant protective layer, thereby avoiding further thermal degradation of the matrix material; The biphenyl structure is introduced into the bulk material, and the nearly planar structure of the biphenyl group increases the regularity of the chain and the intermolecular force, and the crosslinking density of the matrix material is increased in the isotropic crosslinking network, thereby improving the heat resistance of the matrix material and reducing the hygroscopicity of the matrix material. At the same time, in the bisphenol F epoxy resin, the biphenyl epoxy resin can also be used as a filler to make up for the interface separation caused by thermal expansion, and enhance the adhesion and mechanical properties of the matrix material. On this basis, silicon dioxide and a toughening agent are added to further enhance the hygroscopicity and toughness of the bottom filling glue. The present invention adjusts the ratio among the bisphenol F epoxy resin, the biphenyl epoxy resin and the silicone-modified epoxy resin, and under the action of silicon dioxide, a curing agent and a toughening agent, the heat resistance, moisture-heat resistance and toughness of the bottom filling glue are improved, thereby improving the packaging efficiency of the bottom filling glue.

[0032] In some possible embodiments, the mass percentage of the bisphenol F epoxy resin is 10%, the mass percentage of the biphenyl epoxy resin is 4% to 10%, and the mass percentage of the organosilicon-modified epoxy resin is 4% to 10%.

[0033] In some possible embodiments, the mass percentage of the silicon dioxide is 58% to 62%, the mass percentage of the curing agent is 15%, and the mass percentage of the toughening agent is 0.4%.

[0034] Those skilled in the art will appreciate that by adjusting the ratio between the various components of the raw materials, the fluidity, glass transition temperature, elongation and tensile strength of the bottom filling glue can be controlled, so that the prepared bottom filling glue has better performance, thereby improving packaging efficiency and packaging reliability.

[0035] In some possible embodiments, the biphenyl epoxy resin is a tetramethylbiphenyl diphenol epoxy resin.

[0036] This is because the biphenyl group in the tetramethylbiphenyl epoxy resin is a highly rigid heat-resistant group, and the nearly planar structure of the biphenyl group increases the regularity of the chain segment and the intermolecular force, thereby increasing the cross-linking density of the bottom filler in the isotropic cross-linked network. At the same time, the four methyl groups in the biphenyl structure give it greater steric hindrance, which not only gives the bottom filler excellent toughness, heat resistance and dynamic mechanical properties, but also reduces the hygroscopicity of the bottom filler. That is, adding tetramethylbiphenyl epoxy resin to the bottom filler can improve heat resistance and moisture-heat resistance.

[0037] In some possible embodiments, the structural formula of the organosilicon-modified epoxy resin is:

[0038]

[0039] In some possible embodiments, the curing agent includes at least one of SH-3823-36 and SH-300.

[0040] Those skilled in the art will appreciate that the curing agent reacts with the epoxy resin to generate a thermosetting compound with a three-dimensional network structure, which can improve the mechanical properties of the bottom filling adhesive.

[0041] In some possible embodiments, the toughening agent is CMP-410.

[0042] This is because CMP-410 epoxy resin active toughening agent is a long-chain aliphatic compound containing polypropylene glycol diglycidyl ester, which has good compatibility with epoxy resin and does not produce stratification after mixing, which is beneficial to increasing the reaction speed. At the same time, it can also undergo cross-linking reaction with epoxy resin and curing agent, so that the bottom filling glue has excellent toughness and crack resistance. In addition, CMP-410 has low viscosity and has the dual functions of toughening and diluting epoxy resin. It has low volatility, high purity, small shrinkage after curing, and good electrical properties.

[0043] Based on a general inventive concept, see Figure 1 The present application also provides a method for preparing the high-performance bottom filling glue as described in the first aspect, the preparation method comprising:

[0044] S1. Add each component into a stirring cup according to their respective mass percentages, stir and mix, and obtain a first slurry, wherein the mass percentages of the components specifically include: 56% to 71% silicon dioxide, 22% to 27% epoxy resin, 7% to 16% curing agent, 0.1% to 0.2% carbon black, and 0.3% to 0.5% toughening agent; the epoxy resin is composed of bisphenol F epoxy resin, biphenyl epoxy resin, and silicone-modified epoxy resin; wherein the stirring time of the stirring cup is set to 60 to 90 seconds, the rotation is 750 r / min, and the revolution is 1050 r / min;

[0045] S2, transferring the first slurry into a centrifugal mixer, stirring and mixing, to obtain a second slurry; wherein the stirring time of the centrifugal mixer is set to 125-140s, the rotation speed is 1120r / min, and the revolution speed is 1350r / min;

[0046] S3, transferring the second slurry to a three-roll mill for dispersion treatment to obtain a uniformly dispersed third slurry; wherein the feed gap of the three-roll mill is set to 15-35 μm, and the discharge gap is set to 10-15 μm

[0047] S4. Transfer the third slurry into a centrifugal mixer for vacuum degassing to obtain bottom filling glue; wherein, the vacuum degassing time in the centrifugal mixer is set to 75-85s, the rotation is 1120r / min, and the revolution is 1350r / min.

[0048] As another optional embodiment, the mass percentage of the bisphenol F epoxy resin is 10%, the mass percentage of the biphenyl epoxy resin is 4% to 10%, and the mass percentage of the organosilicon-modified epoxy resin is 4% to 10%.

[0049] Based on a general inventive concept, the present invention also provides a chip packaging structure, comprising a substrate, a chip disposed on the substrate, and a plurality of solder bumps disposed between the substrate and the chip and electrically connected to the substrate and the chip, wherein a gap is formed between the substrate and the chip.

[0050] (1) placing the high-performance bottom filling glue liquid described in the first aspect at the edge of the substrate, so that the bottom filling glue liquid flows from one end of the gap to the other end of the gap by capillary action to fill the gap;

[0051] (2) curing the glue liquid of the bottom filling glue;

[0052] (3) After curing, a chip packaging structure is obtained.

[0053] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0054] The components of the bottom filling glue in Examples 1-3 and Comparative Examples 1-4 are shown in Table 1 according to mass percentage:

[0055] Table 1 Raw material components mass percentage

[0056]

[0057] The bottom filling glue provided in Examples 1-3 and Comparative Examples 1-4 was tested for fluidity, glass transition temperature, elongation / tensile strength, thermal stability and moisture and heat resistance. The specific testing process is as follows:

[0058] 1. Test method for fluidity: Stick a square Si wafer with a width of 20 mm, a length of 20 mm, and a thickness of 0.5 mm on the substrate with 50 μm thick double-sided tape at the four corners. Use a dispensing machine to dispense (35-40) mg of the bottom filling glue to be tested along one side of the square Si wafer. Place it on a 110°C hot plate and start timing at the same time. Under the action of capillary force, the bottom filling glue will flow to the bottom of the Si wafer. Record the time when it flows to half of the Si wafer and when it is full.

[0059] 2. DMA test (Tg): Reference standard: ASTM E2254-2018, take a sample that is fully cured at 165°C for 2h, the size of the test sample is 55mm×10mm×3mm, measurement mode: dual cantilever mode, vibration frequency: 1Hz, amplitude: 10μm, heating rate: 5°C / min.

[0060] 3. Elongation / tensile strength test: Use DMA test, take a sample that is fully cured at 165°C for 2h, and prepare a test sample with a size of 12mm×3mm×(0.1-0.3)mm. Measuring mode: DMA Controlled Force, force 5N / min increased to 18N.

[0061] 4. Thermal stability test: Use thermogravimetric analyzer TGA test, take 165℃, take 5-10mg of the sample that is completely cured for 2h, experimental conditions: nitrogen protection, flow rate is 20mL / min; temperature range is 100-800℃, heating rate: 10℃ / min.

[0062] 5. Moisture and heat resistance test: The sample is cast in a pudding mold with a diameter of 3mm and a height of 2mm. One end of the cast sample is in contact with the silicon wafer. The silicon wafer and the pudding mold are fixed. After curing at 165℃ / 2h, the pudding mold is removed, the sample is taken out, and tested with a thrust machine; the sample is cooked in a high temperature and high pressure cooking apparatus (PCT) at a temperature of 120℃ and a humidity of 100% for 48h, and then taken out and tested with a thrust machine; the thrust machine test speed is 50um / s, and the contact height is 20μm.

[0063] The test results are shown in Table 2 below:

[0064] Table 2 Test results

[0065]

[0066] From the above table, we can see that:

[0067] (1) In Comparative Example 1, no biphenyl epoxy resin was added, only bisphenol F epoxy resin and silicone modified epoxy resin were added, and the bottom filling glue after curing had poor moisture and heat resistance and heat resistance;

[0068] (2) In Comparative Example 2, no silicone-modified epoxy resin was added, and only bisphenol F epoxy resin and biphenyl epoxy resin were added. The toughness, moisture and heat resistance, and heat resistance of the bottom filling adhesive after curing were poor;

[0069] (3) In comparative examples 3-4, three resins (biphenyl epoxy resin, bisphenol F epoxy resin and silicone modified epoxy resin) were all added, but the added amounts were not within the specified percentage range, and the bottom filling adhesive obtained had average performance; in embodiments 1-3, the amount of each component was within the optimal range, and a bottom filling adhesive with high heat resistance, high moisture and heat resistance and high toughness could be obtained.

[0070] To summarize, the bottom filling glue prepared with each raw material component within the specified range of this application, and adjusting the ratio of biphenyl epoxy resin, bisphenol F epoxy resin and silicone modified epoxy resin within a fixed range can obtain a bottom filling glue with good fluidity, high heat resistance, high moisture and heat resistance and high toughness. That is, the present application provides a high-performance bottom filling glue with high moisture and heat resistance, heat resistance and good silicon adhesion, which can improve the reliability and life of chip packaging; in addition, the bottom filling glue of the present application also has a high glass transition temperature and can be applied to more fields.

[0071] Finally, it should be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article, or apparatus.

[0072] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0073] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A high performance bottom filler, characterized in that: The high-performance bottom filling glue is composed of the following components by mass percentage: 58% to 62% silicon dioxide, epoxy resin, 7% to 16% curing agent, 0.1% to 0.2% carbon black, and 0.3% to 0.5% toughening agent; the epoxy resin is composed of bisphenol F type epoxy resin, biphenyl type epoxy resin and silicone modified epoxy resin; The mass percentage of the bisphenol F type epoxy resin is 10%, the mass percentage of the biphenyl type epoxy resin is 4% to 10%, and the mass percentage of the organosilicon modified epoxy resin is 4% to 10%; The biphenyl type epoxy resin is a tetramethyl biphenyl diphenol type epoxy resin; The structural formula of the organosilicon-modified epoxy resin is: 。 2. The high performance bottom filler according to claim 1, characterized in that: The mass percentage of the silicon dioxide is 58% to 62%, the mass percentage of the curing agent is 15%, and the mass percentage of the toughening agent is 0.4%.

3. The high performance bottom filling glue according to claim 2, characterized in that: The curing agent includes at least one of SH-3823-36 and SH-300.

4. The high performance bottom filling adhesive according to claim 3, characterized in that: The toughening agent is CMP-410.

5. A method for preparing a high-performance bottom filling adhesive as claimed in any one of claims 1 to 4, characterized in that: The preparation method comprises: S1. Add each component into a stirring cup according to their respective mass percentages, stir and mix, and obtain a first slurry, wherein the mass percentages of the components specifically include: 58% to 62% silicon dioxide, epoxy resin, 7% to 16% curing agent, 0.1% to 0.2% carbon black, and 0.3% to 0.5% toughening agent; the epoxy resin is composed of bisphenol F epoxy resin, biphenyl epoxy resin, and organosilicon-modified epoxy resin; the mass percentage of the bisphenol F epoxy resin is 10%, the mass percentage of the biphenyl epoxy resin is 4% to 10%, and the mass percentage of the organosilicon-modified epoxy resin is 4% to 10%; S2, transferring the first slurry into a centrifugal mixer, stirring and mixing, to obtain a second slurry; S3, transferring the second slurry to a three-roll mill for dispersion treatment to obtain a uniformly dispersed third slurry; S4, transferring the third slurry into a centrifugal mixer for vacuum degassing to obtain bottom filling glue.

6. A chip packaging structure, comprising a substrate, a chip disposed on the substrate, and a plurality of solder bumps disposed between the substrate and the chip and electrically connected to the substrate and the chip, wherein a gap is formed between the substrate and the chip, characterized in that: Disposing the high-performance bottom filling glue liquid of any one of claims 1 to 4 at the edge of the substrate, so that the bottom filling glue liquid flows from one end of the gap to the other end of the gap by capillary action to fill the gap; Curing the glue liquid of the bottom filling glue; After curing, a chip packaging structure is obtained.

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