WO2020047714A1 - Method for preparing semiconductor packaging material and semiconductor packaging material prepared thereby - Google Patents

Abstract

Disclosed by the present invention is a method for preparing a semiconductor packaging material, comprising the steps of: providing spherical silicone resin fine powder with T-unit siloxane as a component, wherein a T unit = R-SiO₃-, and R is a hydrocarbon group or hydrogen atom having 1-16 independently selectable carbon atoms; carrying out calcination and surface densification on the spherical silicon resin fine powder at 400-800°C to obtain a spherical carbon-containing silicon oxide filler having an average particle diameter of 0.3-30 microns; and grading the spherical carbon-containing silicon oxide filler in a resin to form a semiconductor packaging material. The semiconductor packaging material has a low induction rate, a low induction loss, no conductive foreign matter, no coarse particles, and a low radioactivity.

Description

Preparation method of semiconductor packaging material and semiconductor packaging material obtained thereby Technical field

The present invention relates to a semiconductor package, and more particularly, to a method for preparing a semiconductor packaging material and a semiconductor packaging material obtained thereby.

Background technique

In the packaging process of the semiconductor back-end process, packaging materials such as plastic encapsulant, patch glue, underfill, and chip carrier board are required. In addition, when assembling passive components, semiconductor components, electro-acoustic devices, display devices, optical devices and radio frequency devices into equipment, high-density interconnect boards (HDI), high-frequency high-speed boards, and motherboards must also be used. Such packaging materials and circuit boards are generally mainly composed of organic polymers such as epoxy resins and fillers, where the fillers are mainly angular or spherical silica, whose main function is to reduce the thermal expansion coefficient of organic polymers. Reducing the viscosity of the filler and increasing the filling rate. Existing fillers use spherical silica for tight filling gradation. The chemical structure of the silica is the Q unit of Si, namely SiO4-.

On the one hand, with the advancement of technology, the signal frequency used by semiconductors is getting higher and higher, and the increase in signal transmission speed and low loss requires fillers with low induction rate and low induction loss. On the other hand, the material's induction rate (also known as relative dielectric constant, which is usually a relative value of 1 when vacuum is used) and induction loss (also known as dielectric loss) basically depend on the chemical composition and structure of the material Silica has its inherent value of electric induction and electric induction loss. Therefore, the existing filler cannot meet the requirements of lower electric induction and electric induction loss.

Similarly, with the advancement of technology, the degree of integration of semiconductors is getting higher and higher, and the size is getting smaller and smaller, which requires fillers to have high purity, in which there are no conductive foreign matter and no coarse particles. However, spherical silica is generally made by high-temperature dry processes such as the flame melting method and the metal silicon powder deflagration method, which are easily mixed with conductive foreign materials such as iron. It is difficult to avoid the inclusion of coarse particles and conductive foreign materials. . Moreover, once coarse particles and conductive foreign matter are mixed in, they cannot be removed dryly. Therefore, the existing fillers cannot meet the requirements of no conductive foreign matter and no coarse particles.

For semiconductor memory, fillers are required to have low radioactivity. However, the current low-radiation fused spherical silica is selected from natural quartz ore. It is made by smashing and melting and spheroidizing after pickling and purifying the sand, so its purity depends to a large extent on the purity of the natural mineral itself. Therefore, the existing fillers cannot meet the requirements of low radioactivity.

Summary of the Invention

The invention aims to provide a method for preparing a semiconductor packaging material and a semiconductor packaging material obtained thereby. The semiconductor packaging material provided thereby has a low electromotive force, a low electromotive loss, no conductive foreign matter, no coarse particles and low radioactivity. .

The invention provides a method for preparing a semiconductor packaging material. The method includes the steps of: S1, providing spherical silicone resin powder containing T units of siloxane as a component, wherein T units = R-SiO _3- , and R is independently selectable Hydrocarbon atom or hydrogen atom of 1 to 16 carbon atoms; S2, calcining and surface densifying the spherical silicone resin powder at 400 degrees to 800 degrees, so that the silicon hydroxyl groups in the spherical silicone resin powder are condensed, and at the same time, Spherical silicon resin fine powder oxidizes a part of R-Si and loses organic groups to obtain spherical carbon-containing silicon oxide filler having an average particle diameter of 0.3 to 30 microns; and S3, the spherical carbon-containing silicon oxide filler is graded in the resin to form Semiconductor packaging materials.

In the invention, the spherical silicon resin fine powder is calcined at 400-800 degrees, and the outer surface of the fine powder Si-OH and the inner Si-OH are condensed, thereby reducing the induction rate and the induction loss; at the same time, the outer surface of the fine powder R- Si loses the organic group first, and a dense silicon oxide layer is formed on the surface with the progress of the reaction. Once the dense silicon oxide layer is formed, the organic group of R-Si inside the fine powder will not be removed by oxidation, so that the spherical filler formed is carbon-containing silicon oxide. A filler, in which a part of organic R is retained in the carbon-containing silicon oxide filler, thereby reducing the electric induction rate and electric induction loss. In order to characterize the carbon-containing silicon oxide filler obtained here, the weight reduction by heating at 120 degrees to 400 degrees will be described. Specifically, the weight reduction from 120 degrees to 400 degrees heating is less than 0.5%. In addition, in order to characterize the carbon-containing silicon oxide filler obtained here, the carbon content is used for explanation. Specifically, the carbon content is 0.2 to 5% by weight. In particular, part of the oxygen atoms of the carbon-containing silicon oxide filler are replaced by carbon atoms, the charge polarization (polarity) of Si-C is smaller than that of Si-O, and the density of the particles also becomes smaller, so the electric induction rate and the induction are greatly reduced Electricity loss.

In the step S1, methyltrimethoxysilane is used as a raw material to prepare the spherical silicone resin fine powder. For the synthesis method, please refer to: "Spherical Silicone Resin Fine Powder", Huang Wenrun, Silicone Materials, 2007, 21 (5) 294-299; Japanese Patent P2001-192452A, P2002-322282A, Japanese Patent Laid-Open No. 6-49209, Japanese Patent Laid-Open No. 6-279589 , P2000-345044A. It should be understood that the spherical silicone resin powder can also be prepared by other methods, for example, methyl trichlorosilane and the like are used as raw materials to prepare the spherical silicone resin powder.

Preferably, in the step S1, the spherical silicone resin fine powder is prepared by a wet method. The spherical carbon-containing silicon oxide filler obtained by the calcination has less mechanical abrasion and less magnetic foreign matter / conductive foreign matter. Since the raw materials are organic, radioactive elements such as uranium or plutonium are also essentially free of them. It should be understood that the "essential" mentioned here refers to the principle. In other words, "essentially less" means less in principle, but it does not exclude unintended introduction during operation; "essentially free" means not in principle, but does not exclude during operation Unexpectedly introduced.

Preferably, in the step S2, the temperature of the calcination and surface densification is 400 degrees to 600 degrees. Preferably, the time for calcination and surface densification is 0.5h-24h. It should be understood that when less than 0.5h, the silicon surface is insufficiently densified, and all carbon elements are oxidized when heated; when it exceeds 24h, the processing cost is increased needlessly. In the same way, too low temperature will cause the formation of dense silicon oxide layer; too high temperature will cause all carbon elements to be oxidized. In a preferred embodiment, the densification temperature is 400 degrees, and the densification holding time is 0.5 h. It should be understood that the accumulated time when the temperature reaches 400 degrees or more is the time for the densification and heat preservation. For example, when the temperature is raised at a rate of 5 ° C / min, and when calcined at 550 ° C, the time for which the temperature is increased after the temperature reaches 400 ° C is also included in the densification holding time. That is, 400 degrees + (5 degrees / minute) * 30 minutes = 550 degrees, just before the calcination temperature has reached the surface densification level.

The true specific gravity of the spherical carbon-containing silicon oxide after the calcination and surface densification of the spherical silicon resin fine powder is between 1.6 and 2.2, and the specific gravity increases when the calcination temperature is high. The true specific gravity of the spherical silica prepared by the flame melting method or the elemental silicon combustion method is 2.2. In addition, the charge fraction of Si-C is smaller than that of Si-O. The specific permittivity (relative permittivity) is lower than that of the spherical silica prepared by the flame melting method or the elemental silicon combustion method.

Preferably, the preparation method includes using dry or wet sieving or inertial classification to remove coarse particles above 75 microns in the spherical carbon-containing silicon oxide filler. Preferably, coarse particles larger than 55 microns are removed from the spherical carbon-containing silicon oxide filler. Preferably, coarse particles larger than 45 microns are removed from the spherical carbon-containing silicon oxide filler. Preferably, coarse particles above 20 microns are removed from the spherical carbon-containing silicon oxide filler. Preferably, coarse particles of 10 micrometers or more in the spherical carbon-containing silicon oxide filler are removed. Preferably, coarse particles larger than 5 microns are removed from the spherical carbon-containing silicon oxide filler. Preferably, coarse particles larger than 3 microns are removed from the spherical carbon-containing silicon oxide filler. Preferably, coarse particles larger than 1 micron in the spherical carbon-containing silicon oxide filler are removed.

The measurement results show that the electromotive force of the spherical carbon-containing silicon oxide filler at 500 MHz is only 2.6-3.0, which is less than 3.5, and that of the existing silica filler is about 3.8-4.5. Therefore, the spherical carbon-containing silicon oxide filler of the present invention has a greatly reduced electric induction rate, and can meet the material requirements for high-frequency signals in the 5G era.

The measurement results show that the induction loss of the spherical carbon-containing silicon oxide filler of the present invention at 500 MHz is only 0.001 to 0.003, which is less than 0.005, while the existing silica filler has an induction loss of about 0.006-0.01. Therefore, the spherical carbon-containing silicon oxide filler of the present invention has a greatly reduced induction loss and can meet the material requirements for high-frequency signals in the 5G era.

The measurement results show that the thermal expansion coefficient of the spherical carbon-containing silicon oxide filler of the present invention is 1-10 ppm, less than 15 ppm, while the thermal expansion coefficient of the existing fused silica is about 0.5 ppm, and the crystalline silica (quartz) is 8 to 13ppm. Therefore, the thermal expansion coefficient of the spherical carbon-containing silicon oxide filler of the present invention is equivalent to that of general inorganic fillers, and can meet the requirements for high-frequency signal materials in the 5G era.

In step S3, the spherical carbon-containing silicon oxide filler is used as a main powder, a medium powder, and / or a fine powder to tightly fill a gradation in a resin to form a semiconductor packaging material. The "main powder" mentioned here refers to the powder of the large particle segment of the total filler filled in the resin, and the "medium powder" refers to the powder of the middle particle segment of the total filler filled in the resin. "Powder" refers to the powder of small particle segments of the total filler filled in the resin. The “large particle segment”, “medium particle segment”, and “small particle segment” mentioned here are relative concepts. Those skilled in the art are familiar with how to select the particle size range of each segment, and will not repeat them here. The respective volume percentages of the "main powder", "medium powder" and "fine powder" included in the total filler mentioned here are also well known to those skilled in the art. In a preferred embodiment, the main powder accounts for 70% of the total filler volume percentage, the medium powder accounts for 20% of the total filler volume percentage, and the fine powder accounts for 10% of the total filler volume percentage. In the preferred grading process, the resin is first filled with "main powder", then "medium powder", and finally "fine powder". However, it is also possible to complete the grading process by filling only the "medium powder" after filling the "main powder". Of course, it is also possible to complete the grading process by filling only the "fine powder" after filling the "main powder".

Preferably, in the step S3, a flame melting method spherical silica or elemental silicon combustion method spherical silica is used as a medium powder and / or a fine powder to closely fill the gradation to form a semiconductor packaging material in the resin.

In step S3, the spherical carbon-containing silicon oxide filler is tightly packed and graded in a resin to form a semiconductor packaging material after being treated with a surface treatment agent. The reason for adding the surface treatment agent is to improve the affinity between the spherical carbon-containing silicon oxide filler and the organic polymer resin. Among them, the surface treatment agent can be treated by a dry method or a wet method. Obviously, the surface treatment agent can be a silane coupling agent, disilazane, a higher fatty acid, or a surfactant. Preferably, the silane coupling agent is a silane coupling agent having a radical polymerization reaction, such as a vinyl silane coupling agent, and the like; and a silane coupling agent that reacts with an epoxy resin, such as an epoxy silane coupling agent, and aminosilane. Coupling agents, etc .; Hydrocarbyl silane coupling agents with high affinity for hydrophobic resins, such as dimethyldimethoxysilane, diphenyldimethoxysilane, phenylsilane coupling agents, long-chain alkyl groups Silane coupling agents and the like.

The present invention also provides a semiconductor packaging material obtained according to the above manufacturing method. Preferably, the semiconductor packaging material can be used for a plastic packaging material, a patch glue, an underfill, a chip carrier board, a circuit board, or an intermediate semi-finished product thereof. The molding compound is a molding compound in the form of DIP, a molding compound in the form of SMT, a molding compound in MUF, FO-WLP, and FCBGA. Preferably, the circuit board is an HDI, a high-frequency high-speed board, or a motherboard.

It is known that the thermal expansion coefficient of a semiconductor packaging material can be approximately calculated by the following formula 1:

Formula 1: α = V ₁ × α ₁ + V ₂ × α ₂

α: coefficient of thermal expansion of the semiconductor packaging material; V ₁ : volume fraction of the resin; α ₁ : coefficient of thermal expansion of the resin; V ₂ : volume fraction of the filler; α ₂ : coefficient of thermal expansion of the filler.

The thermal expansion coefficient α ₁ of the resin is 60 to 120 ppm. The thermal expansion coefficient α ₂ of the spherical carbon-containing silicon oxide filler of the present invention is 1 to 10 ppm, which is much lower than the thermal expansion coefficient of the resin. It can reduce the curing after curing like the existing inorganic filler. The thermal expansion coefficient of the resin composition matches the thermal expansion of the lead metal or wafer. Therefore, by adjusting the volume fractions of the resin and the spherical carbon-containing silicon oxide filler, the thermal expansion coefficient required by the semiconductor packaging material can be designed as needed to form the packaging material, the circuit board and its intermediate semi-finished products.

It is known that the inductance of a semiconductor packaging material can be approximated by the following Equation 2:

Equation 2: logε = V ₁ × logε ₁ + V ₂ × logε ₂

ε: the induction rate of the semiconductor packaging material; V ₁ : the volume fraction of the resin; ε ₁ : the volume fraction of the resin; V ₂ : the volume fraction of the filler; ε ₂ : the volume fraction of the filler.

Therefore, by adjusting the volume fractions of the resin and the spherical carbon-containing silicon oxide filler, the inductance required for the semiconductor packaging material can be designed as needed to form the packaging material, the circuit board and its intermediate semi-finished products.

In addition, the induced loss of the semiconductor packaging material is determined by the induced loss of the resin and the filler, and the number of polar groups on the surface of the filler. The spherical carbon-containing silicon oxide filler according to the present invention has a low electromotive force, and the fewer polar groups it has on the surface of the filler, therefore, the semiconductor packaging material has a low electromotive loss.

In short, the spherical carbon-containing silicon oxide filler obtained according to the preparation method of the present invention has a low electric induction rate and a low electric induction loss. The spherical carbon-containing silicon oxide filler is used for high filling, and the formed semiconductor packaging material has a low viscosity while ensuring no coarse particles, which meets the new requirements imposed by technological progress. In addition, the raw materials of the preparation method according to the present invention are organic materials, and do not involve angular crushed quartz and the like that are conventionally used, and can be refined by industrial methods such as distillation. The spherical carbon-containing silicon oxide filler formed thereby does not contain uranium and thorium. Radioactive element. In addition, the spherical silicon-containing silica powder calcined spherical carbon-containing silicon oxide filler according to the present invention has a lower electromotive force than that of a conventional spherical silica, so as to satisfy the low-inductance proposed for high-speed signal transmission and low loss. Power requirements.

detailed description

The preferred embodiments of the present invention are given below and described in detail.

The detection methods involved in the following embodiments include:

The average particle diameter was measured with a laser particle size analyzer LA-700 from HORIBA. The solvent is isopropanol;

The specific surface area was measured by FlowSorbIII2305 of SHIMADZU;

True specific gravity was determined using BELPycno of MicrotracBEL;

Coefficient of Thermal Expansion A resin with a known coefficient of thermal expansion and specific gravity is added to a 50% (volume) filler sample to make a cured sheet. The thermal expansion coefficient of the cured sheet was measured to calculate the thermal expansion coefficient of the filler sample.

Uranium and plutonium content were determined by Agilent 7700X ICP-MS. The sample preparation method is to prepare the sample completely with hydrofluoric acid after burning at 800 degrees;

Carbon content was measured with Sichuan Cynes CS-8810C carbon and sulfur analyzer;

Weight reduction from 120 to 400 degrees heating was measured with Shimadzu's DTG-60 / 60, and the heating rate was 5 degrees / minute in air atmosphere.

The induction rate and the induction loss were measured by KEYCOM's perturbation method, sample cavity closed cavity resonance method, induction rate, induction loss measurement device Model No. DPS18.

example 1

Using methyltrimethoxysilane as a raw material, refer to the methods of Japanese Patent P2001-192452A, P2002-322282A, JP-A-6-49209, JP-A6-279589, P2000-345044A to make spherical silicone resin powders with different average particle diameter body. The powder was placed in an electric furnace, and the temperature was raised to a predetermined temperature at a temperature increase rate of 5 degrees / minute, and the samples of various examples and comparative examples were held for different times. The results are listed in Table 1. All samples contained uranium and plutonium below 0.5 ppb.

Table 1

Obviously, the samples obtained according to Examples 1 to 13 are less than 3.5 and the loss of induction is less than 0.005, so that the 5G era filler has low induction (small signal delay) and low induction loss. (Less signal loss).

The above description is only the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. The above embodiments of the present invention can also make various changes. That is, any simple and equivalent changes and modifications made according to the claims of the present application and the contents of the description fall within the protection scope of the claims of the present invention. What is not described in detail in the present invention is conventional technical content.

Claims (8)

1. A method for preparing a semiconductor packaging material is characterized in that it includes steps:

   S1, providing spherical silicone fine powder with siloxane as a unit of T units, wherein T unit = R-SiO _3- , and R is a hydrocarbon group or hydrogen atom of independently selectable carbon atoms 1 to 16;

   S2, calcining and surface densifying the spherical silicone resin powder at 400 ° -800 ° C, so that the silicon hydroxyl groups in the spherical silicone resin powder are condensed, and at the same time, a part of the spherical silicone resin powder is oxidized and lost. An organic group to obtain a spherical carbon-containing silicon oxide filler having an average particle diameter of 0.3 to 30 microns; and

   S3, grading the spherical carbon-containing silicon oxide filler in a resin to form a semiconductor packaging material.
2. The preparation method according to claim 1, wherein the spherical carbon-containing silicon oxide filler obtained in step S2 has a weight reduction of less than 0.5% when heated from 120 degrees to 400 degrees.
3. The method according to claim 1, wherein the carbon content of the spherical carbon-containing silicon oxide filler obtained in step S2 is 0.2 to 5% by weight.
4. The method according to claim 1, wherein in the step S2, the temperature of calcination and surface densification is 400 degrees to 600 degrees.
5. The preparation method according to claim 1, characterized in that the preparation method comprises using dry or wet sieving or inertial classification to remove 1, 3, 5, 10, 20, 45, Coarse particles larger than 55 or 75 microns.
6. The method according to claim 1, wherein in the step S3, the spherical carbon-containing silicon oxide filler is tightly filled and graded in a resin to form a semiconductor packaging material after being treated with a surface treatment agent.
7. The method according to claim 1, wherein in step S3, spherical carbon-containing silicon oxide fillers of different particle sizes are graded in a resin to form a semiconductor packaging material.
8. The semiconductor packaging material obtained by the manufacturing method according to any one of claims 1-7.