JP2004067930A - Liquid encapsulation resin composition, semiconductor device using same and manufacturing process of the semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid resin composition that has an excellent electrical insulation and a short encapsulation time equal to the products of the prior arts, improves the affinity of a material to a semiconductor device, reduces air entrapment and realizes an air-free condition hitherto difficult to achieve in an area array packaging in which a semiconductor device, particularly the one having bump terminals on the circuit surface is encapsulated with the liquid resin composition. <P>SOLUTION: The liquid encapsulation resin composition comprises (A) an epoxy resin having more than one epoxy group per molecule, (B) a compound having flux action and at least two phenolic hydroxy groups per molecule and at least one carboxylic group per molecule, (C) a curing promotor and (D) a leveling agent. Preferably the maximum particle diameter or length of the component (B) is ≤ 30 μm. <P>COPYRIGHT: (C)2004,JPO

Description

【００２７】
表１に示したように、実施例１−４及び６では適当量のレベリング剤の添加により濡れ性が向上（接触角が低下）することで部材とのなじみ性が向上し、巻き込みエアなどのボイドを発生させることなくＰＫＧ化することが可能であった。また、これによりフェノール系硬化物に稀に見られるひけなどの現象が、部材とのなじみ性が向上することで発生しにくくなったことも原因の一つであると考えられる。
また，実施例５ではフィラー系であるため、接続性に若干の懸念点を残すものの、微小巻き込みエアと思われるボイドを含むサンプルもあったが、概ね良好な結果を示した。
一方、比較例１―３ではレベリング剤が含まれていない為に接触角が高く，部材とのなじみ性が劣り、巻き込みエアと思われるボイドを多く含んでしまったと考えられる。
以上の結果から、本樹脂系において、高熱プロセスを踏まえる本半導体装置の組立方においても、巻き込みエア、材料ひけなどのボイドを含むことなく良好な半導体装置の組立を達成できることが見いだされた。
【００２８】
【発明の効果】
本発明に従うとエリア実装素子を回路基板に直接実装することができ、封止プロセスの短縮化とともに、ボイドフリー化の達成かつ良好な接続信頼性を与える封止樹脂を提供でき、パッケージとしての信頼性も向上する。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a liquid resin composition for semiconductor encapsulation which has excellent reliability, has good wettability to each member of a semiconductor device, and can simplify an assembling process, and a semiconductor encapsulated with the liquid resin composition. The present invention relates to a device and a method for manufacturing a semiconductor device.
[0002]
[Prior art]
2. Description of the Related Art In recent years, there has been a remarkable technological innovation to reduce the size and weight of semiconductor packages, and various package structures have been proposed and commercialized. It is particularly important to use an area mounting method of bonding to a circuit board by using a projecting electrode such as solder instead of the conventional lead frame bonding.
[0003]
Among them, a flip chip in which a protruding electrode is directly provided on a circuit surface of a semiconductor chip is one of methods for minimizing a package. In the flip chip mounting, in the case of a solder electrode, the solder electrode is treated with a flux to remove an oxide film on the surface of the solder electrode, and then joined by a method such as reflow. Therefore, the flux remains around the solder electrodes, the circuit board, and the like, and becomes a problem as an impurity. Therefore, the liquid is sealed after performing cleaning for removing the flux. The reason for this is that when a reliability test, such as a temperature cycle test, is performed to directly bond to a circuit board (motherboard) with a protruding electrode, an electrical defect at the electrode bonding portion occurs due to the difference in the linear expansion coefficient between the chip and the circuit board. Is caused.
[0004]
In sealing with a liquid resin, a liquid sealing resin is applied to one side or a plurality of surfaces of a chip, and the resin is caused to flow into a gap between the circuit board and the chip by using a capillary phenomenon. However, this method requires a long process due to the flux treatment and cleaning, and requires strict environmental management such as a problem of treating a cleaning waste liquid. Furthermore, since the liquid sealing is performed by the capillary phenomenon, the sealing time becomes longer, and there is a problem in productivity.
[0005]
Therefore, a method has been devised in which resin is directly applied to a circuit board, a chip having solder electrodes is mounted thereon, and solder bonding and resin sealing are performed simultaneously (US Pat. No. 5,128,746). In this case, in order to bond the solder to the circuit board, a characteristic feature is that a component having a flux action is added to a resin composition comprising a thermosetting resin and a curing agent. However, as a substance having a flux action, a carboxylic acid having a strong acidity is exemplified, and when added to a sealing resin, ionic impurities or electric conductivity may increase. There was a possibility of causing a problem in the insulating properties of the stop material.
[0006]
In order to solve the above problems, a method for obtaining a highly reliable semiconductor device by finally incorporating a flux active substance into a thermosetting matrix by using a compound having a curing agent and a flux activity at the same time has been studied. I have. Among them, compounds having at least two or more phenolic hydroxyl groups per molecule and at least one or more carboxylic acid groups per molecule have been found to have flux activity and to exhibit a role as a curing agent. (JP-A-2001-106770).
[0007]
In this method, the resin is directly applied to the circuit board, a chip with solder electrodes is mounted from above, and solder bonding and resin sealing are performed at the same time. Due to exposure, volatile voids derived from the sealing resin material or voids due to volatile gas from the organic substrate remain in the semiconductor device, or the liquid sealing resin composition is directly applied to the circuit board receiving the sealing resin material. The characteristic assembling method of applying and positioning the circuit board and the semiconductor chip so that the electrodes are electrically joined causes entrapment air to be included, which remains as a void and reduces reliability. There were concerns.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide an area mounting method for sealing a semiconductor chip, particularly a semiconductor chip having a protruding electrode on a circuit surface, using a liquid resin composition. In addition, in the present liquid resin material composition, a resin composition capable of improving conformability between a material and a semiconductor device, making it difficult to generate entrained air, and achieving a void-free process, which has been difficult so far, and a method for producing the same. To provide.
[0009]
[Means for Solving the Problems]
The present invention
(1) (A) an epoxy resin having two or more epoxy groups per molecule, (B) having a flux action, having at least two or more phenolic hydroxyl groups per molecule, and having at least one carboxylic acid per molecule. A liquid sealing resin composition comprising a compound having an acid group, (C) a curing accelerator, and (D) a leveling agent;
(2) The compound having a flux action and having at least two or more phenolic hydroxyl groups per molecule and at least one or more carboxylic acid groups per molecule has a maximum particle size or a maximum length of 30 μm or less. The liquid resin composition according to the above item,
(3) The liquid sealing resin composition according to (1), wherein the liquid sealing resin composition comprises 0.01 to 1 part of a leveling agent with respect to all epoxy resins.
(4) The liquid sealing resin composition according to (1), wherein the liquid sealing resin composition is used in an area mounting method.
(5) A semiconductor device manufactured using the liquid sealing resin composition according to (1),
(6) In an area mounting method in which a semiconductor chip having a protruding electrode provided on a circuit surface is bonded to a circuit board, the circuit board or the circuit surface of the semiconductor chip (protrusion electrode forming surface) and / or the circuit board receiving the same are provided with ( A) an epoxy resin having two or more epoxy groups per molecule, (B) having a flux action and having at least two or more phenolic hydroxyl groups and one or more carboxylic acid groups per molecule. A liquid sealing resin composition having a compound, a (C) curing accelerator and a (D) leveling agent is applied, and the circuit board and the semiconductor chip are aligned so that the electrodes are electrically joined, and then heated. A method for manufacturing a semiconductor device, comprising: electrically bonding the projecting electrode to a circuit board; and curing and manufacturing the resin.
(7) A semiconductor device manufactured using the method for manufacturing a semiconductor device according to (6).
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described in detail. The epoxy resin used in the present invention can be used without any particular limitation as long as it has two or more epoxy groups per molecule. For example, existing bisphenol-based diglycidyl ethers, those obtained by converting an aromatic ring into a saturated hydrocarbon by a hydrogenation reaction thereof, glycidyl ether obtained by a reaction between phenol novolak and epichlorohydrin, and liquid at room temperature, etc. Or a mixture thereof. Further, a liquid epoxy resin such as a diglycidyl ether of dihydroxynaphthalene or a diglycidyl ether of tetramethylbiphenol may be mixed with these liquid resins to make them liquid.
[0011]
Next, examples of the compound having at least two or more phenolic hydroxyl groups per molecule and at least one or more aromatic carboxylic acid per molecule used in the present invention include 2,3-dihydroxybenzoic acid, 2,4 -Dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, gallic acid, 1,4-dihydroxy-2-naphthoic acid, 3,5-dihydroxy-2 -Naphthoic acid, phenolphthalin, diphenolic acid and the like. The compound having at least 2 or more phenolic hydroxyl groups per molecule and at least 1 or more aromatic carboxylic acid per molecule as a curing agent has a flux action, and is an epoxy resin for area-sealing type resin sealing. Preferred as a curing agent.
Here, the flux property refers to a property capable of reducing a metal oxide film and removing the oxide film, similarly to a flux agent usually used.
[0012]
All of these compounds having at least two or more phenolic hydroxyl groups per molecule and at least one or more aromatic carboxylic acid per molecule are crystalline, and the maximum particle size or the maximum length is not particularly limited. Is preferably 30 μm or less. If the value is larger than the upper limit, the amount of volatiles incorporated in the crystal or in the crystal aggregate increases, and the volatiles become voids due to a rapid rise in temperature during curing, and the degree of dispersion decreases. This is because there is a possibility that unevenness of the cured product is generated, and sink marks are generated therefrom.
[0013]
The amount of the compound having at least two or more phenolic hydroxyl groups per molecule and at least one or more aromatic carboxylic acid per molecule used in the present invention is 5 to 60% by weight based on the epoxy resin. , Preferably 5 to 50% by weight. Outside this range, there is a problem that the crosslink density decreases, and in particular, the adhesive strength decreases. If the amount is too large, the carboxylic acid may be released, which is not preferable. The compounds can be added alone or in combination.
[0014]
It is also possible to add a curing agent other than a compound having at least two or more phenolic hydroxyl groups per molecule and at least one or more aromatic carboxylic acid per molecule according to the present invention as long as the effects of the present invention are not impaired. is there. Examples thereof include phenol resins such as phenol novolak resins and orthocresol novolak resins, various bifunctional or higher phenol compounds, and amine compounds such as imidazole, diaza compounds, hydrazide compounds, and dicyandiamide. It is preferable that the addition amount is 50% by weight or less based on the whole curing agent. Above this, the effect as flux decreases.
[0015]
The curing accelerator used in the present invention is generally used as a curing accelerator for an epoxy resin, and examples thereof include imidazoles, phosphorus compounds, diaza compounds, and tertiary amines.
[0016]
As the leveling agent used in the present invention, an alkyl siloxane such as diethyl ether siloxane or dipropyl ether siloxane, an acrylic siloxane, or the like is used. The leveling material used in the present invention preferably contains 0.01 to 1 part of the total epoxy resin. If the amount is less than 0.01 part, the effect of improving the conformability is not exhibited, and if it exceeds 1 part, there are many concerns such as an increase in volatile components and an adverse effect on the conformability.
[0017]
In the present invention, an inorganic filler can be used to the extent that the properties of the resin composition are not impaired. Examples of the inorganic filler include, for example, calcium carbonate, silica, alumina, aluminum nitride and the like. A plurality of these may be mixed depending on the application, but silica is preferred in terms of reliability and cost. The amount of addition is not particularly limited, but is not more than 60% by weight of the liquid sealing resin composition in order to maintain characteristics (moisture resistance, workability, etc.) as the sealing resin. If the content exceeds 60% by weight, the possibility that the insulating filler will hinder the bonding between the protruding electrode of the semiconductor element and the circuit board electrode during bonding extremely increases.
[0018]
The shape of the inorganic filler is preferably spherical. This is because, in the case of a so-called crushable filler, the sharp surface may destroy the circuit on the surface of the semiconductor element.
The average particle size of the inorganic filler is not particularly limited, but is preferably from 0.1 to 5 μm. If it is smaller than the lower limit, the surface area of the inorganic filler may increase, and the viscosity may increase. If it is larger than the upper limit, bonding of the semiconductor element may be hindered.
[0019]
The liquid sealing resin composition of the present invention includes, in addition to the liquid epoxy resin, a curing agent, a curing accelerator, and an inorganic filler, a reactive diluent, a pigment, a dye, a defoaming agent, a coupling material, and the like, if necessary. It can be produced by mixing additives and degassing in vacuum.
[0020]
Using the liquid sealing resin composition of the present invention, semiconductor elements such as flip chips and CSPs (chip size packages) can be sealed. In the liquid sealing resin composition of the present invention, without adding a flux, for example, the resin of the present invention is directly applied to a circuit board, and a chip having solder electrodes is mounted from above and heat-cured to perform solder bonding. And resin sealing can be performed simultaneously. It is also possible to apply the resin according to the present invention on a chip, mount it on a circuit board, and simultaneously perform solder joining and resin sealing.
[0021]
The method of manufacturing a semiconductor device according to the present invention is directed to an area mounting method for bonding a semiconductor chip having a protruding electrode on a circuit surface to a circuit board, wherein (1) a circuit surface of the circuit substrate or the semiconductor chip (protrusion electrode forming surface). And / or a step of applying the liquid sealing resin composition described above to a circuit board receiving the same, (2) a step of aligning the circuit board and the semiconductor chip such that the electrodes are electrically joined, and (3). In this step, the projecting electrodes and the circuit board are electrically joined by heating to cure the resin.
[0022]
The method for applying the above liquid sealing resin composition includes a dispensing method and a printing method, and is not particularly limited. The conditions for preheating the resin are 40 to 100 ° C., and the mounting time is about 1 to 5 minutes per package. Heating for electrical bonding of the electrodes includes, but is not particularly limited to, a method such as reflow, pulse heating, and direct heating using a hot plate.
A conventionally known method can be used for the manufacture of the semiconductor element and other manufacturing steps of the semiconductor device.
[0023]
【Example】
<Example 1-6, Comparative Example 1-3>
It was weighed according to the prescription in Table 1, kneaded with a mixer, vacuum degassed, and then a liquid resin composition was prepared.
[0024]
Next, the following substitute characteristics were evaluated in order to grasp the characteristics.
(1) Normal viscosity: The thixotropic ratio was defined as the initial viscosity (cone rotation speed: 2.5 rpm) at 25 ° C. with an E-type viscometer manufactured by Toki Sangyo Co., Ltd. and the ratio of 0.5 rpm / 2.5 rpm at 25 ° C.
(2) Void evaluation: dispensing an appropriate amount (20 to 23 mg for a filler system, 15 to 17 mg for a fillerless system) of a liquid resin composition on a glass slide to simulate a commonly used process. Then, a 10 × 10 mm square chip with bumps (900 bumps) was mounted using a flip chip bonder manufactured by Shibuya Kogyo. Then, after applying a heat history in the same manner as in the joined state using reflow (peak at 215 ° C.), after curing at 150 ° C. for 2 hours, the occurrence of voids was observed with a microscope (10 tests), and voids were observed. Samples in which occurred were counted.
(3) Contact angle: Droplets of the material composition were dropped on a lead frame (80-pin copper), and the contact angle with the lead frame was measured to determine the wettability with the member.
(4) Solder bump bonding ratio: A liquid sealing resin composition is applied on a substrate using a bumped chip manufactured by Sumisho Kagaku Kogyo Co., Ltd. and a paired substrate having a thickness of 0.75 mm, and a flip manufactured by Shibuya Kogyo Co., Ltd. Temporary pressure bonding was performed using a chip bonder. The sample was passed through a reflow having a profile of a peak temperature of 230 ° C. and a time of 183 ° C. or more for 60 seconds and a total time of 300 seconds, and the bonding property of the bumps was observed with a tester (10 tests), and the number of connection failures was counted.
[0025]
The contents of the raw materials used in the examples are as follows.
-Bisphenol F type epoxy resin: viscosity: 2,000 cps (room temperature)
-Allylated bisphenol A: viscosity: 1,000 to 10,000 cps (room temperature)
・ Naphthalene skeleton epoxy resin: Softening point 60 ℃
A compound having at least two or more phenolic hydroxyl groups per molecule and at least one or more aromatic carboxylic acid per molecule:
2,5-hydroxybenzoic acid, phenolphthaline, curing accelerator: diazabicycloundecene (DBU)
-Leveling agent: manufactured by Elementes, trade name: DABLO S65, manufactured by Nippon Yunika, trade name: SILWET806
・ Spherical silica: average particle size: 2 μm, maximum particle size: 10 μm
[0026]
[Table 1]

[0027]
As shown in Table 1, in Examples 1-4 and 6, the wettability is improved (the contact angle is reduced) by adding an appropriate amount of the leveling agent, so that the familiarity with the member is improved, and the entrainment air and the like are improved. It was possible to make PKG without generating voids. It is also considered that one of the causes is that phenomena such as sink marks, which are rarely seen in the phenol-based cured product, are less likely to occur due to the improvement of the compatibility with the member.
Further, in Example 5, although there were some concerns about the connectivity due to the filler system, there were some samples containing voids considered to be minute entangled air, but generally good results were shown.
On the other hand, in Comparative Examples 1-3, it is considered that the contact angle was high because the leveling agent was not included, the conformability with the member was poor, and many voids considered to be entrained air were included.
From the above results, it has been found that in the present resin system, even in the method of assembling the present semiconductor device based on the high heat process, it is possible to achieve good assembly of the semiconductor device without including voids such as entrapped air and material sink.
[0028]
【The invention's effect】
According to the present invention, an area mounting element can be directly mounted on a circuit board, shortening the sealing process, and providing a sealing resin that achieves void-free and provides good connection reliability. The performance is also improved.

Claims (7)

(A) an epoxy resin having two or more epoxy groups per molecule, (B) having a flux action, comprising at least two or more phenolic hydroxyl groups and one or more carboxylic acid groups per molecule. A liquid encapsulating resin composition comprising a compound having the compound (A), a curing accelerator (C) and a leveling agent (D). The compound having a flux action and having at least two or more phenolic hydroxyl groups per molecule and at least one or more carboxylic acid groups per molecule has a maximum particle size or maximum length of 30 µm or less. Liquid resin composition. 2. The liquid sealing resin composition according to claim 1, comprising 0.01 to 1 part of a leveling agent with respect to all epoxy resins. The liquid sealing resin composition according to claim 1, wherein the liquid sealing resin composition is used in an area mounting method. A semiconductor device manufactured using the liquid sealing resin composition according to claim 1. In an area mounting method for bonding a semiconductor chip having a protruding electrode on a circuit surface to a circuit board, the circuit board or the circuit surface of the semiconductor chip (protruding electrode forming surface) and / or a circuit board receiving the same are provided with (A) 1 An epoxy resin having two or more epoxy groups per molecule, (B) a compound having a flux action and having at least two or more phenolic hydroxyl groups per molecule and at least one or more carboxylic acid groups per molecule, A liquid sealing resin composition having a curing accelerator (C) and a leveling agent (D) is applied, and the circuit board and the semiconductor chip are aligned so that the electrodes are electrically joined. And a circuit board are electrically connected to each other, and the resin is cured to manufacture the semiconductor device. A semiconductor device manufactured by using the method for manufacturing a semiconductor device according to claim 6.