Prepreg, substrate material for semiconductor packaging, and method for manufacturing substrate material for semiconductor packaging.
The prepreg with a woven fibrous base and controlled modulus ratio addresses warping in semiconductor packages by forming a composite substrate that mitigates thermal stress, enhancing package stability.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- RESONAC CORP
- Filing Date
- 2021-01-15
- Publication Date
- 2026-06-02
AI Technical Summary
Existing semiconductor packages experience significant warping due to thermal stress, which current simulation methods struggle to predict and mitigate effectively.
A prepreg comprising a woven fibrous base material with a curable resin composition, where the tensile modulus ratio in the warp and 45° directions is controlled to 0.60 or less, forming a composite substrate with suppressed warping properties.
The prepreg and composite substrate significantly reduce warping in semiconductor packages by managing thermal stress through controlled modulus ratios and thermal expansion coefficients.
Smart Images
Figure 0007868311000002 
Figure 0007868311000003 
Figure 0007868311000001
Abstract
Description
[Technical Field]
[0001] The present invention relates to prepregs, substrate materials for semiconductor packages, and methods for manufacturing substrate materials for semiconductor packages. [Background technology]
[0002] In semiconductor packages having semiconductor chips mounted on a substrate material, it is desirable to suppress the occurrence of warping as much as possible. For this reason, a method is sometimes employed to predict the degree of warping by simulation using the properties of the materials constituting the semiconductor package as input parameters (for example, Non-Patent Documents 1 and 2). [Prior art documents] [Non-patent literature]
[0003] [Non-Patent Document 1] Proceedings of the 28th Symposium on Microelectronics, 2018, pp. 49-52 [Non-Patent Document 2] 2019 International 3D Systems Integration Conference, 3DIC2019.4056 [Overview of the project] [Problems that the invention aims to solve]
[0004] One aspect of the present invention is to provide a prepreg that can suppress warping of semiconductor packages, and a substrate material for semiconductor packages formed therefrom. [Means for solving the problem]
[0005] One aspect of the present invention provides a prepreg comprising a fibrous base material which is a woven fabric having warp and weft threads, and a curable resin composition impregnated into the fibrous base material. When the curable resin composition hardens, a composite base material comprising the cured product of the curable resin composition and the fibrous base material is formed, and the tensile modulus of the composite base material is E0 in the direction of the warp threads and E in the direction at a 45° angle to the direction of the warp threads. 45 Therefore, the modulus ratio E 45 / E0 is 0.60 or less.
[0006] Another aspect of the present invention provides a substrate material for semiconductor packaging. The substrate material has a composite substrate comprising a fibrous substrate which is a woven fabric having warp and weft threads, and a cured product of a curable resin composition impregnated into the fibrous substrate. The tensile modulus of the composite substrate is E0 in the direction of the warp threads and E in the direction at a 45° angle to the direction of the warp threads. 45 Therefore, the modulus ratio E 45 / E0 is 0.60 or less.
[0007] A further aspect of the present invention provides a method for manufacturing a substrate material for semiconductor packaging. The substrate material comprises a composite substrate comprising a fibrous substrate which is a woven fabric having warp and weft threads, and a cured product of a curable resin composition impregnated into the fibrous substrate. The method provides that the tensile modulus of the composite substrate is E0 in the direction of the warp threads and E in the direction at a 45° angle to the direction of the warp threads. 45 Therefore, the modulus ratio E 45 This includes selecting a prepreg containing the fiber substrate and the curable resin composition such that / E0 is 0.60 or less. [Effects of the Invention]
[0008] According to one aspect of the present invention, a prepreg capable of suppressing warping of semiconductor packages, and a substrate material formed therefrom are provided. [Brief explanation of the drawing]
[0009] [Figure 1] This is a plan view showing one embodiment of a prepreg. [Figure 2] It is a cross-sectional view showing a model of a semiconductor package.
Embodiments for Carrying out the Invention
[0010] Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.
[0011] FIG. 1 is a plan view showing an embodiment of a prepreg. The prepreg 1 shown in FIG. 1 includes a fiber base material 10 which is a fabric having warp yarns 11 and weft yarns 12, and a curable resin composition 20 impregnated in the fiber base material 10. When the curable resin composition 20 in the prepreg 1 cures, a composite base material including a cured product of the curable resin composition 20 and the fiber base material 10 is formed.
[0012] The fiber base material 10 is a fabric composed of a plurality of warp yarns 11 aligned along a certain direction (warp direction D11) and a plurality of weft yarns 12 aligned along a weft direction D12 orthogonal to the warp direction D11. The angle formed by the warp direction D11 and the weft direction D12 does not necessarily have to be exactly 90°, and can vary within a range of, for example, 90±2°. Usually, the warp yarns 11 and the weft yarns 12 are fiber bundles including a plurality of single yarns.
[0013] The fiber base material 10 may be a glass cloth, and in that case, the warp yarns 11 and the weft yarns 12 include glass fibers.
[0014] The curable resin composition 20 may be a thermosetting resin composition containing a thermosetting resin and, if necessary, a curing agent. The thermosetting resin is a compound that forms a crosslinked polymer by reaction with a curing agent and / or self-polymerization. The thermosetting resin may be, for example, an epoxy resin. The curable resin composition 20 may further contain one or more other components selected from a thermoplastic resin, an elastomer, a compound having a polysiloxane chain, and a filler. The thermoplastic resin may be, for example, an acrylic polymer containing (meth)acrylate as a monomer unit. The filler may be, for example, an inorganic filler such as silica particles. The blending of components selected from an acrylic polymer, an elastomer, and a compound having a polysiloxane chain tends to lower the elastic modulus of the cured product formed from the curable resin composition. A low content of the inorganic filler also tends to lower the elastic modulus of the cured product formed from the curable resin composition.
[0015] When the tensile elastic modulus of the composite substrate is E0 in the warp direction D11 of the fiber substrate 10 and E in the direction D45 at 45° with respect to the warp D11 direction of the fiber substrate 10 45 then the elastic modulus ratio E 45 / E0 is 0.60 or less. When the elastic modulus ratio E 45 / E0 is 0.60 or less, the warp of the semiconductor package including the substrate material having the composite substrate is significantly suppressed. From the same viewpoint, E 45 / E0 may be 0.55 or less, 0.50 or less, 0.45 or less, 0.35 or less, or 0.30 or less, and may be 0.10 or more, 0.15 or more, or 0.20 or more.
[0016] The elastic modulus ratio E 45 / E0 of the composite substrate can be adjusted to 0.60 or less, for example, by controlling one or more material properties selected from the elastic modulus of the fibers constituting the fiber substrate 10, the elastic modulus of the cured product of the curable resin composition 20, and the volume ratio of the fiber substrate in the prepreg 1.
[0017] When the elastic modulus of the fibers constituting the fiber substrate 10 is small, the elastic modulus ratio E 45The ratio of elastic modulus E tends to decrease. 45 From the viewpoint of appropriate control of / E0, the tensile modulus of the fibers constituting the fibrous base material 10 may be 60 to 90 GPa, or 70 to 80 GPa.
[0018] If the elastic modulus of the cured product of the curable resin composition 20 is small, the elastic modulus ratio E 45 The ratio of elastic modulus E tends to decrease. 45 From the viewpoint of appropriate control of / E0, the tensile modulus of the cured product of the curable resin composition 20 may be 0.5 GPa or more or 1.0 GPa or more, or it may be 5.0 GPa or less, 4.0 GPa or less, or 3.0 GPa or less.
[0019] If the volume ratio of the fiber base material in prepreg 1 is small, the elastic modulus ratio E 45 The ratio of elastic modulus E tends to decrease. 45 From the viewpoint of appropriate control of / E0, the ratio of the fiber base material 10 may be 35% or more by volume, or 40% or more by volume, based on the volume of the prepreg 1, or 70% or less by volume, or 65% or less by volume.
[0020] The low thermal expansion coefficient of the cured product of the curable resin composition 20 can also contribute to reducing warping. The thermal expansion coefficient of the cured product of the curable resin composition 20 may be, for example, 40 ppm / °C or less, or 30 ppm / °C or less, or 10 ppm / °C or more, or 20 ppm / °C or more. The thermal expansion coefficient here may be the average value of the thermal expansion coefficient in the range of 20 to 100°C.
[0021] The composite substrate formed from prepreg 1 may be used as a substrate material for semiconductor packaging. Conductor wiring may be further provided on the surface of the composite substrate or laminate and / or inside the laminate. The composite substrate may be a laminate formed from two or more prepregs. In this case, the two or more prepregs are usually laminated in such a way that the warp directions of the fibrous substrates are substantially the same. However, the warp directions of the fibrous substrates may vary between the two or more prepregs, for example, within a range of ±2°.
[0022] One embodiment of a method for manufacturing substrate material for semiconductor packaging is a composite substrate in which the tensile modulus of elasticity is E0 in the warp direction D11 and E in the direction D45, which is 45° to the warp direction D11. 45 Therefore, the modulus ratio E 45 This includes selecting prepreg 1 such that / E0 is 0.60 or less. (Equivalent modulus ratio E) 45 By selecting a prepreg based on the / E0 value, a substrate material can be obtained that provides a semiconductor package with suppressed warping. The method for manufacturing the substrate material may further include curing a curable resin composition by heating a single layer of prepreg or a laminate containing two or more layers of prepreg, thereby forming a composite substrate.
[0023] Below is the elastic modulus ratio E of the composite substrate. 45 This section describes the results of a simulation that examined the relationship between / E0 and the amount of warpage in semiconductor packages.
[0024] 1. Analysis of composite substrates (1) Prepreg For analysis using a material property prediction tool, the properties of the composite substrate formed from the prepreg were set as follows as input parameters: The ratio of the fibrous substrate relative to the volume of the prepreg was set to 45% or 60% by volume. Fibers (warp and weft) that make up the fibrous base material • Tensile modulus: 75 GPa Poisson's ratio: 0.25 ·Density: 1.3g / cm 3 • Thermal expansion coefficient: 5.6 ppm / ℃ • Angle between warp and weft threads: 90° Curable resin composition (cured product) • Tensile modulus: 1.0 GPa, 2.5 GPa, or 10 GPa Poisson's ratio: 0.3 ·Density: 2.6g / cm 3 • Coefficient of thermal expansion: 25 ppm / ℃
[0025] (2) Analysis using material property prediction tools For the prepregs of Examples 1-3 and Comparative Example 1, in which the combinations of the tensile modulus of the cured cured product of the curable resin composition and the volume ratio of the fibrous substrate were set as shown in Table 1, analysis using a material property prediction tool (Digimat2019, manufactured by MSC Software, Inc.) revealed that the tensile modulus E0,E of the composite substrate formed from each prepreg was 45 , and the modulus ratio E 45 We calculated / E0. At a temperature of 20°C, the stress in the warp direction was determined by analysis when a 1% strain was applied to the composite substrate in the warp direction at a strain rate of 0.1 / sec. The tensile modulus E0 was calculated by dividing the determined stress by the strain. The tensile modulus E0 was calculated using the same method as for E0, except that the direction in which the strain was applied to the composite substrate was changed to a 45° direction relative to the warp direction. 45 The elastic modulus ratio E was calculated from the obtained value. 45 We calculated / E0.
[0026] 2. Warpage of semiconductor packages Regarding the semiconductor package (FC-BGA) model shown in Figure 2, the amount of warping that occurs due to chip mounting and underfill hardening was determined by analysis using structural analysis software (MSC Software, Inc., Marc2017). The semiconductor device 30 shown in Figure 2 has a substrate material 3 made of a composite substrate 1A formed from the prepregs of each example or comparative example, a semiconductor chip 5 mounted on the substrate material 3, and an underfill 7 interposed between the substrate material 3 and the semiconductor chip 5. The substrate material 3 has a square main surface, and the semiconductor chip 5 is placed at the corners of the main surface. The following values were set as input parameters for the substrate material 3, semiconductor chip 5, and underfill 7. Substrate material (composite base material) • Size: 60mm x 60mm (thickness 0.8mm) semiconductor chips • Size: 25mm x 25mm (thickness 0.725mm) • Tensile modulus: 167 GPa Poisson's ratio: 0.27 • Thermal expansion coefficient: 3.2 ppm / ℃ Underfill • Size: 25mm x 25mm (thickness 0.09mm) • Tensile modulus: 11 GPa Poisson's ratio: 0.3 • Coefficient of thermal expansion: 20 ppm / ℃
[0027] Considering the structural symmetry, the analysis was performed using a 1 / 4 model. The element class was a 20-node hexahedron. The fabricated model had 11,631 nodes and 2,350 elements. The stress at 140°C was set as the zero point, and the amount of warpage of the semiconductor package was determined as the temperature decreased from there to 20°C. The warpage occurred in a direction that was convex towards the semiconductor chip. The calculated amount of warpage is the maximum height of the bottom surface of substrate material 3, relative to its initial position.
[0028] As shown in the analysis results in Table 1, the elastic modulus ratio E 45 It was confirmed that when / E0 is 0.60 or less, the occurrence of warping is significantly suppressed. Elastic modulus ratio E 45 A small / E0 indicates that the tensile modulus of the composite material is relatively high in the warp or weft direction, which is thought to contribute to suppressing warping caused by thermal stress. 45 When the coefficient of thermal expansion is relatively low, the stress caused by the difference in thermal expansion coefficients between the components is relieved, and this is also thought to contribute to suppressing warping.
[0029] [Table 1] [Explanation of Symbols]
[0030] 1...Prepreg, 1A...Composite substrate, 3...Substrate material, 5...Semiconductor chip, 7...Underfill, 10...Fiber substrate, 11...Warp, 12...Weft, 20...Curable resin composition, 30...Semiconductor package, D11...Warp direction, D12...Weft direction, D45...Direction at 45° to the warp direction.
Claims
1. A textile base material which is a woven fabric having warp threads and weft threads, A curable resin composition impregnated into the aforementioned fibrous substrate, Includes, When the curable resin composition hardens, a composite substrate is formed that includes the cured product of the curable resin composition and the fibrous substrate, and the tensile modulus of the composite substrate is E in the warp direction. ０ Then, in a direction 45° with respect to the direction of the warp threads, E ４５ Therefore, the modulus ratio E ４５ / E ０ A prepreg in which the ratio is 0.15 or more and 0.35 or less, E ０ However, at a temperature of 20°C, the tensile modulus of elasticity is calculated by dividing the stress in the warp direction by the strain when a 1% strain is applied to the composite substrate in the warp direction at a strain rate of 0.1 / second. E ４５ However, at a temperature of 20°C, the tensile modulus of elasticity is calculated by dividing the stress in the direction 45° to the warp direction by the strain when a 1% strain is applied to the composite substrate at a strain rate of 0.1 / second in the direction 45° to the warp direction. The aforementioned fiber base material is glass cloth, The ratio of the aforementioned fiber base material is 35 to 70% by volume, based on the volume of the prepreg. A prepreg comprising the curable resin composition, wherein the curable resin composition contains an inorganic filler.
2. A textile base material which is a woven fabric having warp threads and weft threads, A cured product of a curable resin composition impregnated into the aforementioned fibrous substrate, Having a composite substrate including, The aforementioned fiber base material is glass cloth, The ratio of the fiber base material is 35 to 70% by volume, based on the volume of the composite base material. The curable resin composition comprises an inorganic filler, The tensile elastic modulus of the composite base material is E in the warp direction. ０ where it is E in the direction 45° with respect to the warp direction. ４５ The elastic modulus ratio E ４５ / E ０ is 0.15 or more and 0.35 or less. A substrate material for semiconductor packaging, E ０ However, at a temperature of 20°C, the tensile modulus of elasticity is calculated by dividing the stress in the warp direction by the strain when a 1% strain is applied to the composite substrate in the warp direction at a strain rate of 0.1 / second. E ４５ However, at a temperature of 20°C, the tensile modulus of elasticity is calculated by dividing the stress in the direction 45° to the warp direction by the strain when a 1% strain is applied to the composite substrate at a strain rate of 0.1 / second in the direction 45° to the warp direction. Substrate material for semiconductor packaging.
3. A method for manufacturing substrate materials for semiconductor packages, The substrate material comprises a composite substrate which includes a fibrous substrate which is a woven fabric having warp and weft threads, and a cured product of a curable resin composition impregnated into the fibrous substrate. In this method, the tensile modulus of the composite substrate is E in the direction of the warp threads. ０ Then, in a direction 45° with respect to the direction of the warp threads, E ４５ Therefore, the modulus ratio E ４５ / E ０ This includes selecting a prepreg containing the fiber substrate and the curable resin composition such that the ratio is 0.15 or more and 0.35 or less. E ０ However, at a temperature of 20°C, the tensile modulus of elasticity is calculated by dividing the stress in the warp direction by the strain when a 1% strain is applied to the composite substrate in the warp direction at a strain rate of 0.1 / second. E ４５ However, at a temperature of 20°C, the tensile modulus of elasticity is calculated by dividing the stress in the direction 45° to the warp direction by the strain when a 1% strain is applied to the composite substrate at a strain rate of 0.1 / second in the direction 45° to the warp direction. The aforementioned fiber base material is glass cloth, The ratio of the aforementioned fiber base material is 35 to 70% by volume, based on the volume of the prepreg. A method comprising the curable resin composition containing an inorganic filler.