A 0-3 type polymer ferroelectric composite material for an interlayer of an integrated circuit
By combining KBiFe2O5 ferroelectric powder with an epoxy resin matrix, a 0-3 type polymer ferroelectric composite material was prepared. This solved the problem of controlling the dielectric constant and thermal expansion coefficient, achieving low dielectric loss and matching thermal expansion coefficient, and improving the reliability and process compatibility of the material.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI INST OF TECH
- Filing Date
- 2026-04-09
- Publication Date
- 2026-07-07
AI Technical Summary
Existing polymer encapsulation materials cannot simultaneously achieve low dielectric constant, low dielectric loss, and adjustable coefficient of thermal expansion. The introduction of traditional ferroelectric materials often leads to an increase in dielectric constant, which cannot meet the stringent requirements of three-dimensional encapsulation.
A type 0-3 polymer ferroelectric composite material was prepared by combining KBiFe2O5 ferroelectric powder with an epoxy resin matrix and enhancing interfacial bonding through surface modification treatment, thereby controlling the dielectric properties and coefficient of thermal expansion.
It achieves a dielectric constant between 3.0 and 3.5, a dielectric loss of less than 0.005, and a coefficient of thermal expansion between 4.8 and 3.2 ppm/K, meeting the requirements of high-frequency packaging and improving the reliability and process compatibility of the material.
Smart Images
Figure FT_1 
Figure FT_2 
Figure FT_3
Abstract
Description
Technical Field
[0001] This invention belongs to the field of integrated circuit packaging materials technology, specifically relating to a type 0-3 polymer ferroelectric composite material with low dielectric constant and adjustable coefficient of thermal expansion for three-dimensional integrated circuit packaging, and its preparation method. Background Technology
[0002] With the integrated circuit industry entering the post-Moore's Law era, 3D packaging has become a key technological path for improving chip performance. Interposer materials, as the core component of 3D packaging, must simultaneously meet stringent requirements such as low dielectric constant (α < 3.5), low dielectric loss (tan δ < 0.005), a coefficient of thermal expansion (CTE) matching the silicon chip (approximately 3-5 ppm / K), and good process compatibility. Traditional polymer-based packaging materials (such as epoxy resin) possess excellent processing performance and electrical insulation, but their intrinsic dielectric constant is relatively high (α approximately 3.5-4.0) and their coefficient of thermal expansion is too large (CTE approximately 50-70 ppm / K at 20-160℃), making it difficult to directly meet the demands of advanced packaging. Existing solutions often employ the addition of low-dielectric fillers (such as hollow glass microspheres, silica, etc.) to reduce the dielectric constant; however, such methods often lead to further deterioration of the material's coefficient of thermal expansion, and the weak interfacial bonding between the filler and the substrate affects material reliability. Ferroelectric materials possess immense potential for dielectric property control due to their unique polarization characteristics and piezoelectric effect. However, traditional ferroelectric materials (such as barium titanate) exhibit high dielectric constants, and their introduction into polymer matrices typically leads to an increase in the dielectric constant of the composite material, contradicting the goal of low dielectric constant. Therefore, how to utilize the special properties of ferroelectric materials to actively control the coefficient of thermal expansion while maintaining the low dielectric properties of polymers has become a pressing technical challenge in this field. However, the operating temperature of integrated circuit packaging materials is generally below 150 °C. Therefore, combining ferroelectric materials with low dielectric constants, low dielectric losses, and matching coefficients of thermal expansion below 150 °C with traditional polymer-based packaging materials holds promise for further improvements in material performance. Summary of the Invention
[0003] The present invention aims to solve the bottleneck problem in the prior art that polymer encapsulation materials are difficult to achieve simultaneously with low dielectric constant, low loss and adjustable coefficient of thermal expansion, and provides a 0-3 type polymer ferroelectric composite material and its preparation method.
[0004] To achieve the above objectives, the present invention provides the following technical solution:
[0005] A type 0-3 polymer ferroelectric composite material, characterized in that the composite material is composed of the following components in parts by mass: epoxy resin matrix: 100 parts; KBiFe2O5 ferroelectric powder: 5-50 parts; coupling agent: 0.5-5 parts; curing agent: 10-30 parts. The KBiFe2O5 ferroelectric powder is a dispersed phase, uniformly distributed in particulate form within the epoxy resin matrix, constituting a type 0-3 composite material structure.
[0006] Furthermore, the average particle size of the KBiFe2O5 ferroelectric powder is 0.1 ~ 5 μm, preferably 0.5 ~ 2 μm. Its crystal structure is a layered perovskite structure, with a Curie temperature above 300 ℃, exhibiting stable ferroelectricity and piezoelectric response at room temperature.
[0007] Furthermore, the KBiFe2O5 ferroelectric powder undergoes surface modification treatment, and the coupling agent is a silane coupling agent, preferably γ-glycidoxypropyltrimethoxysilane.
[0008] Furthermore, the epoxy resin matrix is one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, or multifunctional epoxy resin.
[0009] This invention also provides a method for preparing the above-mentioned 0-3 type polymer ferroelectric composite material, comprising the following steps:
[0010] (1) KBiFe2O5 ferroelectric powder and coupling agent were ultrasonically dispersed in anhydrous ethanol and surface modified.
[0011] (2) The modified KBiFe2O5 ferroelectric powder was mixed with the epoxy resin matrix and a uniform slurry was obtained by mechanical stirring and ultrasonic dispersion.
[0012] (3) Add curing agent to slurry, stir evenly, and then degas under vacuum;
[0013] (4) Inject the degassed slurry into the mold and cure it at a temperature of 80 ~ 150℃.
[0014] Beneficial effects:
[0015] Compared with the prior art, the present invention has the following beneficial effects:
[0016] 1. Low dielectric constant and low loss: This invention uses KBiFe2O5 ferroelectric powder as a filler. Although this material is ferroelectric, its intrinsic dielectric constant is extremely low (<3.5 @ 1 MHz) at temperatures below 150 ℃, far lower than that of traditional ferroelectric material barium titanate (approximately 1500-2000). By adjusting the filling amount (5 ~ 50 parts), the dielectric constant of the composite material can be controlled between 3.0 and 3.5, and the dielectric loss is less than 0.005 (1 MHz), meeting the requirements of high-frequency packaging applications.
[0017] 2. Adjustable coefficient of thermal expansion: KBiFe2O5 ferroelectric material has a low coefficient of thermal expansion (1.6 ~ 10 ppm / K). Introducing it into an epoxy resin matrix can effectively reduce the thermal expansion of the polymer matrix. Experiments show that when the KBiFe2O5 filler content is 30 parts, the coefficient of thermal expansion of the composite material can be reduced to 4.8 ppm / K, achieving a good match with silicon wafers (3 ~ 4 ppm / K) and significantly reducing thermal cycling stress.
[0018] 3. High interfacial bonding strength: This invention uses a silane coupling agent to modify the surface of KBiFe2O5 powder, forming an organic functional layer on the surface of the ferroelectric particles, which enhances the chemical bonding with epoxy resin. Compared with unmodified fillers, the flexural strength of the composite material is increased by more than 20%, and the reliability is significantly improved.
[0019] 4. Simple preparation process: This invention adopts a conventional polymer composite process, which does not require special equipment, is compatible with existing packaging material production lines, and is easy to scale up. Attached Figure Description
[0020] Figure 1 The cross-sectional scanning electron microscope image of the 0-3 type polymer ferroelectric composite material prepared in Example 1 of the present invention shows that KBiFe2O5 particles are uniformly dispersed in epoxy resin.
[0021] Figure 2 This is a graph showing the dielectric constant at 1 MHz versus temperature in Embodiment 1 of the present invention.
[0022] Figure 3 This is a graph showing the dielectric loss at 1 MHz versus temperature in Embodiment 1 of the present invention.
[0023] Figure 4 This is a graph showing the change of the coefficient of thermal expansion with temperature in Embodiment 2 of the present invention. Detailed Implementation
[0024] The present invention will be described in detail below through specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.
[0025] Example 1
[0026] Prepare the composite material according to the following steps:
[0027] (1) Take 10 parts of KBiFe2O5 powder with an average particle size of 1 μm, add it to anhydrous ethanol containing 2 parts of γ-glycidoxypropyltrimethoxysilane, sonicate for 30 minutes, and then dry for later use.
[0028] (2) Mix the modified KBiFe2O5 powder with 100 parts of bisphenol A epoxy resin, stir mechanically for 1 hour, and then ultrasonically disperse for 30 minutes.
[0029] (3) Add 20 parts of curing agent, stir evenly, and then vacuum degas for 30 minutes;
[0030] (4) Inject the slurry into the mold and cure it at 120°C for 4 hours to obtain the composite material.
[0031] The composite material obtained in this embodiment has a dielectric constant of 3.35, a dielectric loss of 0.0042, and a coefficient of thermal expansion of 18.5 ppm / K at 150 °C and 1 MHz, as tested.
[0032] Example 2
[0033] The difference from Example 1 is that the amount of KBiFe2O5 powder added is 30 parts, while the other steps are the same. The composite material obtained in this example was tested and found to have a dielectric constant of 3.52, a dielectric loss of 0.0048, and a coefficient of thermal expansion of 4.8 ppm / K at 1 MHz.
[0034] Example 3
[0035] The difference from Example 1 is that the amount of KBiFe2O5 powder added is 50 parts, while the other steps are the same. The composite material obtained in this example was tested and found to have a dielectric constant of 3.68, a dielectric loss of 0.0051, and a coefficient of thermal expansion of 3.2 ppm / K at 1 MHz.
[0036] Comparative Example 1
[0037] The difference from Example 1 is that KBiFe2O5 powder was not added; only an epoxy resin matrix was used. Tests showed that the material obtained in this comparative example had a dielectric constant of 3.92, a dielectric loss of 0.0055, and a coefficient of thermal expansion of 62 ppm / K at 1 MHz.
[0038] Comparative Example 2
[0039] The difference from Example 1 is that barium titanate powder was used instead of KBiFe2O5 powder, and the amount added was 30 parts; the other steps were the same. Testing showed that the composite material obtained in this comparative example had a dielectric constant of 7.85 and a dielectric loss of 0.012 at 1 MHz, which does not meet the requirements for low dielectric constant packaging.
[0040] Performance Summary:
[0041] The results of the examples show that, by introducing an appropriate amount of KBiFe2O5 ferroelectric powder, the present invention successfully reduced the coefficient of thermal expansion of the composite material from 62 ppm / K to the range of 3.2-18.5 ppm / K while maintaining a low dielectric constant (≤3.68) and low loss (≤0.0051), thus achieving thermal matching with the silicon wafer. Comparative Example 2 shows that traditional high-dielectric ferroelectric fillers cannot simultaneously meet the requirement of a low dielectric constant.
Claims
1. A type 0-3 polymer ferroelectric composite material, characterized in that, The composite material comprises an epoxy resin matrix and KBiFe2O5 ferroelectric powder dispersed therein.
2. The O-3 type polymer ferroelectric composite material according to claim 1, characterized in that, The KBiFe2O5 ferroelectric powder is in the form of 5 to 50 parts by mass, and the epoxy resin matrix is in the form of 100 parts by mass.
3. The O-3 type polymer ferroelectric composite material according to claim 1, characterized in that, The average particle size of the KBiFe2O5 ferroelectric powder is 1 ~ 5 μm.
4. The O-3 type polymer ferroelectric composite material according to claim 1, characterized in that, The KBiFe2O5 ferroelectric powder was surface modified with a silane coupling agent.
5. The O-3 type polymer ferroelectric composite material according to claim 1, characterized in that, The composite material has a dielectric constant of 3.0 to 3.8 at a frequency of 1 MHz and a dielectric loss of less than 0.
005.
6. The O-3 type polymer ferroelectric composite material according to claim 1, characterized in that, The coefficient of thermal expansion of the composite material is 3 ~ 20 ppm / K.
7. A method for preparing a type 0-3 polymer ferroelectric composite material as described in any one of claims 1-6, characterized in that, Includes the following steps: (a) Surface modification of KBiFe2O5 ferroelectric powder; (b) The modified KBiFe2O5 ferroelectric powder was mixed and dispersed with the epoxy resin matrix; (c) Add curing agent, degas and then cure to form.
8. The preparation method according to claim 7, characterized in that, The coupling agent used for the surface modification is γ-glycidoxypropyltrimethoxysilane.
9. The preparation method according to claim 7, characterized in that, The curing temperature is 80 ~ 150℃.
10. The application of the O-3 type polymer ferroelectric composite material according to any one of claims 1-6 in the intermediate layer material of integrated circuit packaging.