JP3819220B2 - Resin composition for sealing and semiconductor sealing device - Google Patents

Description

（但し、式中、Ｒ¹ は水素原子、ハロゲン原子又はアルキル基を、Ｒ² は水素原子又はアルキル基を、ｎは０又は１以上の整数をそれぞれ表す）
これらのエポキシ樹脂は、単独もしくは２種以上混合して用いることができる。
【００１０】
本発明に用いる（Ｂ）ノボラック型フェノール樹脂としては、フェノール、アルキルフェノール等のフェノール類とホルムアルデヒド、パラホルムアルデヒド等のアルデヒド類とを反応させて得られるノボラック型フェノール樹脂およびこれらの変性樹脂、例えばエポキシ化もしくはブチル化ノボラック型フェノール樹脂等が挙げられ、これらの樹脂は、単独もしくは２種以上混合して用いる。ノボラック型フェノール樹脂の配合割合は、前述したエポキシ樹脂のエポキシ基（ａ）とノボラック型フェノール樹脂のフェノール性水酸基（ｂ）との当量比［（ａ）／（ｂ）］が０．１〜１０の範囲内であることが望ましい。当量比が０．１未満もしくは１０を超えると、耐熱性、耐湿性、成形作業性および硬化物の電気特性が悪くなり、いずれの場合も好ましくない。従って上記の範囲内に限定するのが良い。
【００１１】
本発明に用いる（Ｃ）のｏ，ｏ′−ジベンズアミドジフェニルジスルフィドは、次の構造式に示されるものである。
【００１２】
【化２】

ｏ，ｏ′−ジベンズアミドジフェニルジスルフィドの配合割合は、全体の樹脂組成物に対して０．００８〜０．４重量％含有することが望ましい。この割合が０．００８重量％未満では、Ｐｄ、Ｐｄ−Ａｕ、Ａｇ等のプレプレーティングフレームとの接着力の向上に効果なく、また、０．４重量％を超えると、封止樹脂の硬化等に悪影響を与え、実用に適さず好ましくない。
【００１３】
本発明に用いる（Ｄ）無機質充填剤としては、シリカ粉末、アルミナ粉末、三酸化アンチモン、タルク、炭酸カルシウム、チタンホワイト、クレー、マイカ、ベンガラ、ガラス繊維等が挙げられ、これらは単独又は２種以上混合して使用することができる。これらの中でも特にシリカ粉末やアルミナ粉末が好ましく、よく使用される。無機質充填剤の配合割合は、全体の樹脂組成物に対して２５〜９５重量％の割合で含有することが望ましい。その割合が２５重量％未満では、耐熱性、耐湿性、半田耐熱性、機械的特性および成形性が悪くなり、また、９５重量％を超えるとカサバリが大きくなり、成形性に劣り実用に適さない。
【００１４】
本発明の封止用樹脂組成物は、エポキシ樹脂、ノボラック型フェノール樹脂、ｏ，ｏ′−ジベンズアミドジフェニルジスルフィドおよび無機質充填剤を必須成分とするが、本発明の目的に反しない限度において、また必要に応じて、例えば天然ワックス類、合成ワックス類、直鎖脂肪酸の金属塩、酸アミド類、エステル類、パラフィン類等の離型剤、塩素化パラフィン、ブロム化トルエン、ヘキサブロムベンゼン、三酸化アンチモン等の難燃剤、カーボンブラック、ベンガラ等の着色剤、種々の硬化促進剤等を適宜、添加配合することができる。
【００１５】
本発明の封止用樹脂組成物を成形材料として調製する場合の一般的な方法としては、エポキシ樹脂、ノボラック型フェノール樹脂、ｏ，ｏ′−ジベンズアミドジフェニルジスルフィド、無機質充填剤およびその他の成分を配合し、ミキサー等によって十分均一に混合した後、さらに熱ロールによる溶融混合処理又はニーダ等による混合処理を行い、次いで冷却固化させ、適当な大きさに粉砕して成形材料とすることができる。こうして得られた成形材料は、半導体装置をはじめとする電子部品あるいは電気部品の封止、被覆、絶縁等に適用すれば、優れた特性と信頼性を付与させることができる。
【００１６】
本発明の半導体封止装置は、上記のようにして得られた封止用樹脂を用いて、半導体チップを封止することにより容易に製造することができる。封止の最も一般的な方法としては、低圧トランスファー成形法があるが、射出成形、圧縮成形、注型等による封止も可能である。封止用樹脂組成物を封止の際に加熱して硬化させ、最終的にはこの組成物の硬化物によって封止された半導体封止装置が得られる。加熱による硬化は、１５０℃以上に加熱して硬化させることが望ましい。封止を行う半導体装置としては、例えば集積回路、大規模集積回路、トランジスタ、サイリスタ、ダイオード等で特に限定されるものではない。
【００１７】
【作用】
本発明の封止用樹脂組成物および半導体封止装置は、樹脂成分としてｏ，ｏ′−ジベンズアミドジフェニルジスルフィドを用いたことによって、目的とする特性が得られるものである。即ち、ｏ，ｏ′−ジベンズアミドジフェニルジスルフィドは樹脂組成物のＰｄ、Ｐｄ−Ａｕ、Ａｇ等のプレプレーティングフレームとの接着力を向上させ、半導体パッケージにおいて耐リフロークラック性等の信頼性を向上させることができる。
【００１８】
【発明の実施の形態】
次に本発明を実施例によって説明するが、本発明はこれらの実施例によって限定されるものではない。以下の実施例及び比較例において「％」とは「重量％」を意味する。
【００１９】
実施例１
クレゾールノボラックエポキシ樹脂（エポキシ当量２１５）１９％に、ノボラック型フェノール樹脂（フェノール当量１０７）９％、次の化３に示したｏ，ｏ′−ジベンズアミドジフェニルジスルフィド０．２％、
【化３】

溶融シリカ粉末７１％、硬化促進剤０．３％およびエステル系ワックス類０．３％を配合し、常温で混合し、さらに９０〜９５℃で混練してこれを冷却粉砕して成形材料を製造した。この成形材料を１７０℃に加熱した金型内にトランスファー注入し、硬化させて成形品（封止品）をつくった。この成形品についてＰｄとＰｄ−Ａｕのプレプレーティングフレームに対する接着力、耐湿性を試験したので、その結果を表１に示した。特に接着力において本発明の顕著な効果が認められた。
【００２０】
実施例２
クレゾールノボラックエポキシ樹脂（エポキシ当量２１５）１９％に、ノボラック型フェノール樹脂（フェノール当量１０７）９％、ｏ，ｏ′−ジベンズアミドジフェニルジスルフィド０．２％を予め溶融シリカ粉末と混合しシリカ粉末の表面を処理したもの７１％、硬化促進剤０．３％およびエステル系ワックス類０．３％を実施例１と同様に混合、混練、粉砕して成形材料を製造した。また、実施例１と同様にして成形品をつくり、ＰｄとＰｄ−Ａｕのプレプレーティングフレームに対する接着力、耐湿性の特性試験を行ったのでその結果を表１に示した。特に接着力において本発明の顕著な効果が認められた。
【００２１】
比較例
クレゾールノボラック型エポキシ樹脂（エポキシ当量２１５）１９％に、ノボラック型フェノール樹脂（フェノール当量１０７）９％、シリカ粉末７１％、硬化促進剤０．３％およびエステル系ワックス類０．３％を混合し、実施例１と同様にして成形材料を製造した。この成形材料を用いて成形品とし、成形品の諸特性について実施例１と同様にして試験を行い、その結果を表１に示した。
【００２２】
【表１】

＊１：トランスファー成形によって接着面積４ｍｍ² の成形品を、ＰｄまたはＰｄ−Ａｕプレプレーティングされた上に成形し、１７５℃，８時間放置した後、剪断接着力を求めた。
【００２３】
＊２：成形材料を用いて、２本以上のアルミニウム配線を有するシリコン製チップ（テスト用素子）をＰｄプレプレーティングフレームに接着し、１７５℃で２分間トランスファー成形して、ＱＦＰ−２０８Ｐ，２．８ｍｍ^t の成形品をつくり、これを１７５℃，８時間の後硬化を行った。こうして得た成形品を予め、４０℃，９０％ＲＨ，１００時間の吸湿処理した後、Ｍａｘ２４０℃のＩＲリフロー炉を４回通した。その後、１２７℃，２．５気圧の飽和水蒸気中でＰＣＴを行い、アルミニウムの腐食による断線を不良として評価した。
【００２４】
【発明の効果】
以上の説明および表１から明らかなように、本発明の封止用樹脂組成物および半導体封止装置は、Ｐｄ、Ｐｄ−Ａｕ、Ａｇメッキのインサートとの接着性に優れ、ＩＲリフロー後においても剥離することなく、耐湿性に優れ、その結果、電極の腐食による断線や水分によるリーク電流の発生等を著しく低減することができ、しかも長期間にわたって信頼性を保証することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an epoxy resin composition excellent in reliability such as reflow crack resistance and a semiconductor sealing device in a semiconductor package using a frame plated with Pd, Au, and Ag.
[0002]
[Prior art]
In recent semiconductor devices, an increasing number of semiconductor packages adopt a frame pre-plated with Pd, Pd—Au or the like instead of solder plating.
[0003]
A semiconductor device employing a pre-plating frame such as Pd or Pd-Au encapsulated with a resin composition comprising a conventional epoxy resin, novolak-type phenol resin and an inorganic filler includes the pre-plating frame and a sealing resin. There was a drawback that the adhesion of the resin was extremely poor. In particular, when a semiconductor device that has absorbed moisture is surface-mounted by an infrared (IR) reflow method, peeling occurs between the sealing resin and the lead frame, or between the sealing resin and the semiconductor chip, resulting in significant moisture resistance degradation, which is caused by electrode corrosion. As a result, the semiconductor device has a drawback that long-term reliability cannot be guaranteed. For this reason, there has been a strong demand for the development of a material having a low moldability and having a low moisture resistance deterioration even when the entire semiconductor device is subjected to surface mounting by IR reflow.
[0004]
[Problems to be solved by the invention]
The present invention has been made to solve the above-mentioned drawbacks and meet the above-mentioned demands, and has high adhesiveness with a pre-plating frame such as Pd, Pd-Au, Ag, etc., and particularly after reflow resistance and after reflow. An object of the present invention is to provide a sealing resin composition and a semiconductor sealing device that are excellent in reliability and have good moldability.
[0005]
[Means for Solving the Problems]
As a result of intensive research aimed at achieving the above object, the present inventor has preplated Pd, Pd-Au, Ag, etc. by blending o, o'-dibenzamide diphenyl disulfide into the resin composition. The present invention has been completed by finding that the adhesiveness with the frame is greatly improved and the above object is achieved.
[0006]
That is, the present invention
(A) epoxy resin,
(B) a novolac type phenolic resin,
(C) o, o'-dibenzamide diphenyl disulfide and (D) an inorganic filler as essential components, and (C) o, o'-dibenzamide diphenyl disulfide is added to the resin composition in an amount of 0.008-0. 4% by weight, and (D) an inorganic filler in a proportion of 25 to 95% by weight. Moreover, it is a semiconductor sealing device characterized by sealing a semiconductor chip with the hardened | cured material of this resin composition for sealing.
[0007]
Hereinafter, the present invention will be described in detail.
[0008]
The (A) epoxy resin used in the present invention is not particularly limited in molecular structure and molecular weight as long as it is a compound having at least two epoxy groups in the molecule, and is generally used as a sealing material. Can be widely included. Examples thereof include aromatic resins such as biphenyl type and bisphenol type, aliphatic types such as cyclohexane derivatives, and epoxy novolac type epoxy resins represented by the following general formula.
[0009]
[Chemical 1]

(Wherein, R ¹ represents a hydrogen atom, a halogen atom or an alkyl group, R ² represents a hydrogen atom or an alkyl group, and n represents 0 or an integer of 1 or more.)
These epoxy resins can be used alone or in combination of two or more.
[0010]
As the (B) novolac type phenol resin used in the present invention, novolac type phenol resins obtained by reacting phenols such as phenol and alkylphenol with aldehydes such as formaldehyde and paraformaldehyde, and modified resins thereof, for example, epoxidation Alternatively, butylated novolac type phenol resins and the like can be mentioned, and these resins are used alone or in combination of two or more. The mixing ratio of the novolac type phenol resin is such that the equivalent ratio [(a) / (b)] of the epoxy group (a) of the epoxy resin and the phenolic hydroxyl group (b) of the novolac type phenol resin is 0.1 to 10%. It is desirable to be within the range. When the equivalent ratio is less than 0.1 or exceeds 10, the heat resistance, moisture resistance, molding workability, and electrical properties of the cured product are deteriorated, which is not preferable in any case. Therefore, it should be limited to the above range.
[0011]
The o, o'-dibenzamide diphenyl disulfide (C) used in the present invention is represented by the following structural formula.
[0012]
[Chemical 2]

The blending ratio of o, o′-dibenzamide diphenyl disulfide is preferably 0.008 to 0.4% by weight based on the entire resin composition. If this ratio is less than 0.008% by weight, there is no effect in improving the adhesive strength with preplating frames such as Pd, Pd—Au, Ag, etc., and if it exceeds 0.4% by weight, the sealing resin is cured. This is not preferable because it is not suitable for practical use.
[0013]
Examples of the inorganic filler (D) used in the present invention include silica powder, alumina powder, antimony trioxide, talc, calcium carbonate, titanium white, clay, mica, bengara, glass fiber, and the like. These can be used in combination. Among these, silica powder and alumina powder are particularly preferable and often used. The blending ratio of the inorganic filler is desirably 25 to 95% by weight with respect to the entire resin composition. If the ratio is less than 25% by weight, the heat resistance, moisture resistance, solder heat resistance, mechanical properties and moldability deteriorate, and if it exceeds 95% by weight, the crevice becomes large and the moldability is inferior, making it unsuitable for practical use. .
[0014]
The encapsulating resin composition of the present invention contains an epoxy resin, a novolac type phenol resin, o, o′-dibenzamide diphenyl disulfide and an inorganic filler as essential components. If necessary, for example, natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, paraffins and other mold release agents, chlorinated paraffin, brominated toluene, hexabromobenzene, trioxide A flame retardant such as antimony, a colorant such as carbon black and bengara, various curing accelerators, and the like can be appropriately added and blended.
[0015]
As a general method for preparing the sealing resin composition of the present invention as a molding material, epoxy resin, novolac type phenol resin, o, o'-dibenzamide diphenyl disulfide, inorganic filler and other components are used. After blending and mixing sufficiently uniformly with a mixer or the like, the mixture can be further melt-mixed with a hot roll or mixed with a kneader, then cooled and solidified, and pulverized to an appropriate size to obtain a molding material. If the molding material obtained in this way is applied to the sealing, coating, insulation, etc. of electronic parts and electric parts including a semiconductor device, excellent characteristics and reliability can be imparted.
[0016]
The semiconductor sealing device of the present invention can be easily manufactured by sealing a semiconductor chip using the sealing resin obtained as described above. The most common method of sealing is a low-pressure transfer molding method, but sealing by injection molding, compression molding, casting or the like is also possible. The sealing resin composition is heated and cured at the time of sealing, and finally a semiconductor sealing device sealed with a cured product of this composition is obtained. The curing by heating is preferably performed by heating to 150 ° C. or higher. The semiconductor device for sealing is not particularly limited, for example, with an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, or the like.
[0017]
[Action]
The encapsulating resin composition and the semiconductor encapsulating device of the present invention can achieve the desired characteristics by using o, o'-dibenzamidodiphenyl disulfide as a resin component. That is, o, o'-dibenzamide diphenyl disulfide improves the adhesive strength with Pd, Pd-Au, Ag, etc. of the resin composition and improves the reliability such as reflow crack resistance in the semiconductor package. Can be made.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLES Next, although an Example demonstrates this invention, this invention is not limited by these Examples. In the following examples and comparative examples, “%” means “% by weight”.
[0019]
Example 1
Cresol novolac epoxy resin (epoxy equivalent 215) 19%, novolac type phenol resin (phenol equivalent 107) 9%, o, o'-dibenzamide diphenyl disulfide 0.2% shown in the following chemical formula 3,
[Chemical 3]

Blended with 71% fused silica powder, 0.3% curing accelerator and 0.3% ester wax, mixed at room temperature, kneaded at 90-95 ° C, cooled and crushed to produce a molding material did. This molding material was transferred and injected into a mold heated to 170 ° C. and cured to produce a molded product (sealed product). The molded product was tested for Pd and Pd—Au adhesion to the pre-plating frame and moisture resistance, and the results are shown in Table 1. In particular, the remarkable effect of the present invention was recognized in the adhesive strength.
[0020]
Example 2
Cresol novolak epoxy resin (epoxy equivalent 215) 19%, novolac type phenol resin (phenol equivalent 107) 9%, o, o'-dibenzamide diphenyl disulfide 0.2% is mixed with fused silica powder in advance and the surface of the silica powder A molding material was produced by mixing, kneading, and pulverizing 71% of the above, 71% of the curing accelerator, 0.3% of the curing accelerator and 0.3% of the ester wax in the same manner as in Example 1. In addition, a molded product was produced in the same manner as in Example 1, and Pd and Pd—Au adhesive strength to the pre-plating frame and a moisture resistance characteristic test were conducted. The results are shown in Table 1. In particular, the remarkable effect of the present invention was recognized in the adhesive strength.
[0021]
Comparative Example Cresol novolak type epoxy resin (epoxy equivalent 215) 19%, novolac type phenol resin (phenol equivalent 107) 9%, silica powder 71%, curing accelerator 0.3% and ester wax 0.3% After mixing, a molding material was produced in the same manner as in Example 1. The molding material was used to form a molded product, and various properties of the molded product were tested in the same manner as in Example 1. The results are shown in Table 1.
[0022]
[Table 1]

* 1: A molded article having an adhesion area of 4 mm ² was molded by transfer molding on Pd or Pd-Au preplated, and allowed to stand at 175 ° C. for 8 hours, and then the shear adhesive strength was determined.
[0023]
* 2: Using a molding material, a silicon chip (test element) having two or more aluminum wirings is adhered to a Pd pre-plating frame, transfer molded at 175 ° C. for 2 minutes, and QFP-208P, 2 A molded product of .8 mm ^t was produced and post-cured at 175 ° C. for 8 hours. The molded product thus obtained was preliminarily treated with moisture absorption at 40 ° C. and 90% RH for 100 hours, and then passed through an IR reflow furnace at Max 240 ° C. four times. Thereafter, PCT was performed in saturated steam at 127 ° C. and 2.5 atm, and disconnection due to corrosion of aluminum was evaluated as defective.
[0024]
【The invention's effect】
As is clear from the above description and Table 1, the sealing resin composition and the semiconductor sealing device of the present invention are excellent in adhesion to Pd, Pd—Au, and Ag plating inserts, and even after IR reflow. It does not peel off and has excellent moisture resistance. As a result, disconnection due to electrode corrosion, generation of leakage current due to moisture, etc. can be remarkably reduced, and reliability can be ensured over a long period of time.

Claims (2)

(A) epoxy resin,
(B) a novolac type phenolic resin,
(C) o, o'-dibenzamide diphenyl disulfide and (D) an inorganic filler as essential components, and (C) o, o'-dibenzamide diphenyl disulfide is added to the resin composition in an amount of 0.008-0. 4% by weight, and (D) the inorganic filler is contained in a proportion of 25 to 95% by weight. (A) epoxy resin,
(B) a novolac type phenolic resin,
(C) o, o'-dibenzamide diphenyl disulfide and (D) an inorganic filler as essential components, and (C) o, o'-dibenzamide diphenyl disulfide is added to the resin composition in an amount of 0.008-0. A semiconductor sealing device, wherein a semiconductor chip is sealed with a sealing resin composition containing 4 wt% and (D) the inorganic filler in a proportion of 25 to 95 wt%.