JPH01129448A - Lead frame - Google Patents
Lead frameInfo
- Publication number
- JPH01129448A JPH01129448A JP62287313A JP28731387A JPH01129448A JP H01129448 A JPH01129448 A JP H01129448A JP 62287313 A JP62287313 A JP 62287313A JP 28731387 A JP28731387 A JP 28731387A JP H01129448 A JPH01129448 A JP H01129448A
- Authority
- JP
- Japan
- Prior art keywords
- tab
- hole
- resin
- angle
- loading surface
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000004065 semiconductor Substances 0.000 claims description 5
- 239000011347 resin Substances 0.000 abstract description 27
- 229920005989 resin Polymers 0.000 abstract description 27
- 238000010438 heat treatment Methods 0.000 abstract description 4
- 229910000679 solder Inorganic materials 0.000 abstract description 3
- 239000000758 substrate Substances 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 6
- 238000005530 etching Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 238000005290 field theory Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000000452 restraining effect Effects 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
- H01L2924/181—Encapsulation
Landscapes
- Structures Or Materials For Encapsulating Or Coating Semiconductor Devices Or Solid State Devices (AREA)
- Lead Frames For Integrated Circuits (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、樹脂封止ＩＣの構造に係り、特に加熱により
発生する樹脂のクラックを防止するのに好適なリードフ
レーム構造に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a resin-sealed IC, and particularly to a lead frame structure suitable for preventing cracks in the resin caused by heating.
樹脂封止■Ｃでは、従来のビン挿入形に代わり、基板に
直接リードをはんだ付する面付実装形が主流になりつつ
ある。面付実装形パッケージでは、高温高湿環境で保存
すると、樹脂が水分を吸収し、はんだリフロー加熱時に
水分がタブと樹脂の間で蒸気になり、この蒸気圧により
第５図に示すように、タブ下面コーナ部にクラックが生
じる場合がある。このクラックは、リフロークラックと
呼ばれている。In resin sealing ■C, instead of the conventional bottle insertion type, the surface mounting type, in which the leads are soldered directly to the board, is becoming mainstream. When a surface-mount package is stored in a high-temperature, high-humidity environment, the resin absorbs moisture, and during solder reflow heating, the moisture turns into steam between the tab and the resin, and due to this vapor pressure, as shown in Figure 5, Cracks may occur at the bottom corner of the tab. This crack is called a reflow crack.
リフロークラックを防止する従来技術としては、特開昭
６０−２０８８４７号公報に記載のように、パッケージ
の裏面に穴をあけ９発生する蒸気を逃がす方法がある。As a conventional technique for preventing reflow cracks, there is a method of making a hole in the back surface of the package 9 to allow the generated steam to escape, as described in Japanese Patent Application Laid-Open No. 60-208847.
また、樹脂とタブの界面の接着強度を向上させ、すきま
を防止する技術として、タブの反素子搭載面に凹凸を設
ける方法が特開昭５８−１９９５４８号公報。Further, as a technique for improving the adhesive strength at the interface between the resin and the tab and preventing gaps, Japanese Patent Application Laid-Open No. 199548 discloses a method of providing unevenness on the surface of the tab opposite to the element mounting surface.
特開昭６０−１８６０４４号公報等に示されている。
。This is disclosed in Japanese Patent Application Laid-open No. 186044/1983.
.
上記従来技術のうち、パッケージ下面に穴をあける方法
は、リフロークラックは防げるものの、パッケージ外部
から内部への水分の通路を作ることになり、チップ電極
の腐食が生じる可能性がある。Among the conventional techniques described above, the method of making holes in the bottom surface of the package can prevent reflow cracks, but it creates a passage for moisture from the outside of the package to the inside, which may cause corrosion of the chip electrodes.
また、タブの反素子搭載面に単純な凹凸を設ける方法は
、タブと樹脂の接着面内の変位を拘束する効果はあるも
のの１両者を引き離す方向の変位については、凹部に入
り込んだ樹脂が簡単に抜けるため、効果が期待できない
。In addition, the method of providing simple unevenness on the surface opposite to the element mounting surface of the tab has the effect of restraining the displacement within the bonding surface between the tab and the resin; The effect cannot be expected because of the leakage.
本発明者は先に特殊な形状の貫通穴を設ける方法が最も
効果があるが１貫通穴に入り込んだ樹脂の応力集中につ
いて配慮がされておらず、第６図に示すように蒸気圧に
より貫通穴内部の樹脂が破壊する恐れがあった。The inventor of the present invention found that the most effective method was to first provide a through hole of a special shape, but no consideration was given to the stress concentration of the resin that entered the through hole, and as shown in There was a risk that the resin inside the hole would be destroyed.
本発明の目的は、上記の従来技術の欠点を克服し、蒸気
圧により生じるリフロークラックを防止することにある
。The object of the present invention is to overcome the above-mentioned drawbacks of the prior art and to prevent reflow cracks caused by vapor pressure.
上記目的は、従来技術のうちリフロークラックに対して
最も効果がある特殊な貫通穴を有するタブにおいて、貫
通穴内部の樹脂の応力集中を低減することにより達成さ
れる。The above object is achieved by reducing stress concentration in the resin inside the through hole in a tab having a special through hole that is most effective against reflow cracks among the conventional techniques.
本願第１番目の発明に係るリードフレームは、素子搭載
面における貫通穴の面積を反素子搭載面における貫通穴
の面積よりも大きくし、貫通穴の内面とタブの反素子搭
載面のなす角度を６０度以上とすることを特徴とする。In the lead frame according to the first invention of the present application, the area of the through hole on the element mounting surface is made larger than the area of the through hole on the anti-element mounting surface, and the angle between the inner surface of the through hole and the anti-element mounting surface of the tab is adjusted. It is characterized by being 60 degrees or more.
本願第２番目の発明に係るリードフレームは。The lead frame according to the second invention of the present application is as follows.
穴がタブの反素子搭載面に対して傾めに開けられており
、この貫通穴の内面とタブの反素子搭載面とのなす角度
が６０度以上であることを特徴とする。The hole is formed at an angle with respect to the anti-element mounting surface of the tab, and the angle between the inner surface of the through hole and the anti-element mounting surface of the tab is 60 degrees or more.
いずれの発明にせよタブ側面とタブの反素子搭載面のな
す角度は６０度以上が好ましい。In either invention, the angle between the side surface of the tab and the surface opposite to the element mounting surface of the tab is preferably 60 degrees or more.
貫通穴の部分の樹脂に発生する応力は、第７図に示すよ
うに１貫通穴内面とタブ反素子搭載面が交差する部分（
Ａ点）で最大となり、Ａ点付近の応力分布は特異場の理
論より次式で表わされる。The stress generated in the resin in the through-hole area is the area where the inner surface of the first through-hole intersects with the element mounting surface of the tab (as shown in Figure 7).
The stress distribution near point A is expressed by the following equation based on singular field theory.
σ＝Ｋｒ−１・・・（１）
ここで、ｒはＡ点からの距離、には特異場の強さで、パ
ッケージの全体構造と発生蒸低圧で決まる定数である。σ=Kr-1 (1) Here, r is the distance from point A, and r is the strength of the singular field, which is a constant determined by the overall structure of the package and the generated vapor pressure.
またλは、特異場の指数で、樹脂とタブ材料の物性値お
よび貫通穴内面とタブ反素子搭載面のなす角度θにより
決まる定数であり、０．５≧λ≧０である。（１）式か
ら、Ａ点の応力集中の強さは、λにより決まり、λが大
きいほど応力集中が大きいことがわかる。Further, λ is an index of a singular field, and is a constant determined by the physical property values of the resin and the tab material and the angle θ formed between the inner surface of the through hole and the anti-element mounting surface of the tab, and satisfies 0.5≧λ≧0. From equation (1), it can be seen that the strength of stress concentration at point A is determined by λ, and the larger λ is, the greater the stress concentration is.
本発明の原理は、角度θを適当な値に制御し。The principle of the present invention is to control the angle θ to an appropriate value.
（１）式のλの値を許容値以下に押さえ、応力集中を防
ぐことにより、第７図Ａ点付近の樹脂の破壊を防止する
ことにある。The purpose is to prevent the resin from breaking near point A in FIG. 7 by keeping the value of λ in equation (1) below the allowable value and preventing stress concentration.
θとλの関係を特異場理論により解析した。結果を第８
図に示す。角度Ｏを小さくすることにより、λの値が小
さくなり、従って応力集中が低下することがわかる。The relationship between θ and λ was analyzed using singular field theory. 8th result
As shown in the figure. It can be seen that by decreasing the angle O, the value of λ decreases and therefore the stress concentration decreases.
次に、角度Ｏが４５度から５５度に分布する貫通穴を有
するタブを用いた多数のパッケージａと、６０度から７
５度に分布するパッケージｂを製作し、リフロークラッ
クの発生状況を調べた。その結果、角度θが５５度以下
であるパッケージでは、貫通穴内部の樹脂が破壊し、リ
フロークラックが発生したが、６０度以上のパッケージ
は発生しなかった。従って、λが０．２３以下、すなわ
ち、角度θが６０度以上のパッケージでは、応力集中が
許容値以下になっている。Next, a large number of packages a using tabs with through holes whose angle O is distributed from 45 degrees to 55 degrees, and from 60 degrees to 7
A package b with a 5 degree distribution was manufactured and the occurrence of reflow cracks was investigated. As a result, in packages where the angle θ was 55 degrees or less, the resin inside the through hole was destroyed and reflow cracks occurred, but in packages where the angle θ was 60 degrees or more, no reflow cracks occurred. Therefore, in a package where λ is 0.23 or less, that is, the angle θ is 60 degrees or more, the stress concentration is below the allowable value.
以上述べたように、特殊な形状の貫通穴を有するタブを
用いたパッケージにおいて、貫通穴内面とタブ反素子搭
載面のなす角度が６０度以上であれば、リフロークラッ
クを防止することができる。As described above, in a package using a tab having a specially shaped through hole, reflow cracks can be prevented if the angle between the inner surface of the through hole and the tab anti-element mounting surface is 60 degrees or more.
本発明の第１実施例を第１図を用いて説明する。 A first embodiment of the present invention will be described with reference to FIG.
第１図は、タブ１に素子４を搭載し、これらとリード７
を樹脂５により封止したパッケージを居抜９にはんだ８
で実装するため、リフロー加熱を行つている状況を示し
た図である。このとき、タブと樹脂の界面に水蒸気６が
発生するが、タブ】−には、素子搭載面で広く、反素子
搭載面で狭い貫通穴２ａがあけられているので、樹脂５
はタブ１に拘束され、しかも貫通穴２ａの内面とタブ１
の反素子搭載面とのなす角度３ａが６０度以上であるた
め、貫通穴２ａの部分の樹脂に発生する応力は小さく、
リフロークラックは発生しない。In Figure 1, an element 4 is mounted on a tab 1, and these and a lead 7 are mounted.
The package sealed with resin 5 is soldered 8 to the opening 9.
FIG. 3 is a diagram showing a situation in which reflow heating is performed for mounting. At this time, water vapor 6 is generated at the interface between the tab and the resin, but since the tab has a through hole 2a that is wide on the element mounting surface and narrow on the opposite side,
is restrained by tab 1, and the inner surface of through hole 2a and tab 1
Since the angle 3a formed with the surface opposite to the element mounting surface is 60 degrees or more, the stress generated in the resin at the through hole 2a is small.
No reflow cracks occur.
本発明の第２実施例を第２図を用いて説明する。A second embodiment of the present invention will be described with reference to FIG.
第２図は、第２実施例によるタブ１の断面を示した図で
１本実施例では、水蒸気が発生した場合の樹脂に対する
タブ１の拘束力を増すため、貫通穴２ｂの素子搭載面に
おける面積と反素子搭載面における面積の比を大きくシ
、シかも貫通穴２ｂの内面とタブ１の反素子搭載面の交
差する部分に面取を施し、角度３ｂを６０度以上にする
ことにより、水蒸気が発生した場合の樹脂の応力集中を
防止した。FIG. 2 is a cross-sectional view of the tab 1 according to the second embodiment. In this embodiment, in order to increase the restraining force of the tab 1 on the resin when water vapor is generated, The ratio of the area to the area opposite to the element mounting surface may be increased by chamfering the intersection of the inner surface of the through hole 2b and the opposite element mounting surface of the tab 1, and making the angle 3b 60 degrees or more. This prevents stress concentration in the resin when water vapor is generated.
本発明の第３実施例を第３図を用いて説明する。A third embodiment of the present invention will be described with reference to FIG.
本実施例では１貫通穴２ｃをタブ１に対して斜めにあけ
ることにより、タブ１に樹脂に対する拘束力をもたせた
。この場合１貫通穴の傾き角度を６０度以上９０度未満
とすることにより、角度３ｃを６０度以上にすることが
できる。In this embodiment, one through hole 2c is formed diagonally with respect to the tab 1, so that the tab 1 has a binding force against the resin. In this case, by setting the inclination angle of one through hole to 60 degrees or more and less than 90 degrees, the angle 3c can be 60 degrees or more.
本発明の第４実施例を第４図を用いて説明する。A fourth embodiment of the present invention will be described using FIG. 4.
第５図は、エツチングにより製作したタブの断面を示し
た図である。タブ１は、両面からエツチングされて形成
されるので、貫通穴２ｄとタブ１の側面は平面にはなら
ず、図に示したような曲面となる。この場合、貫通穴の
内面とタブ１の反素子搭載面の接触角３ｄが６０度より
小さいと、樹脂の応力集中により、リフロークラックが
発生する。FIG. 5 is a cross-sectional view of a tab manufactured by etching. Since the tab 1 is formed by etching from both sides, the through hole 2d and the side surfaces of the tab 1 are not flat, but curved as shown in the figure. In this case, if the contact angle 3d between the inner surface of the through hole and the surface opposite to the element mounting surface of the tab 1 is smaller than 60 degrees, reflow cracks will occur due to stress concentration in the resin.
そこで、エツチングパターンとエツチング時間をＷ１４
ａし、角度３ｄを６０度以上にすることにより。Therefore, the etching pattern and etching time were changed to W14.
a, and by setting the angle 3d to 60 degrees or more.
リフロークラックを防止できる。また、タブ１の側面に
おいても、角度３ｄ’ を６０度以上にすることにより
、同様の効果が期待できる。Prevents reflow cracks. Furthermore, a similar effect can be expected on the side surface of the tab 1 by setting the angle 3d' to 60 degrees or more.
［発明の効果〕
本発明によれば、タブにあけた特殊な形状の貫通穴の内
部の樹脂の応力集中を低減できるので、リフロークラッ
クを防止する効果がある。[Effects of the Invention] According to the present invention, it is possible to reduce the stress concentration in the resin inside the specially shaped through hole drilled in the tab, so there is an effect of preventing reflow cracks.
第１図は、本発明の第１実施例に係るリードフレームを
用いた半導体装置の断面図、第２図は本発明の第２実施
例に係る貫通穴近傍の断面図、第３図は同じく第３実施
例の部分断面図、第４図は同じく第４実施例の部分断面
図、第５図は従来のパッケージを加熱したときの断面図
、第６図は、貫通穴内面とタブ反素子搭載面の交差する
部分の樹脂に発生する応力の分布特性図、第７図は貫通
穴内面とタブ素子搭載面のなす角度と特異場の指数の関
係を示す特性図である。
１・・・タブ、２・・・貫通穴、３・・・角度θ、４・
・・素子、５・・・樹脂、６・・・水蒸気、７・・・リ
ード５８・・・はんだ。
９・・・基板、１０・・・クラック。
代理人 弁理士 小川＃男 ゝ
第 １ 口
児 ２ 目
２、）Ｉ
′ｆＩ４− 図
茅 Ｓ 図
、０−一一フラ、フ
Ｘ ｇ 図
の
預 ７ 図
角度 θ 度FIG. 1 is a cross-sectional view of a semiconductor device using a lead frame according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of the vicinity of a through hole according to a second embodiment of the present invention, and FIG. FIG. 4 is a partial cross-sectional view of the fourth embodiment. FIG. 5 is a cross-sectional view of the conventional package when heated. FIG. 6 shows the inner surface of the through hole and the tab anti-element. FIG. 7 is a characteristic diagram showing the distribution of stress generated in the resin at the intersection of the mounting surfaces. FIG. 7 is a characteristic diagram showing the relationship between the angle formed by the inner surface of the through hole and the tab element mounting surface and the index of the singular field. 1...Tab, 2...Through hole, 3...Angle θ, 4...
...Element, 5...Resin, 6...Water vapor, 7...Lead 58...Solder. 9... Board, 10... Crack. Agent Patent Attorney Ogawa #Ogawa ゝ1st 口子 2 目2,）I ′fI4− fig.S fig., 0-11 hula, fu
Claims (1)
の集合体を備える半導体装置用リードフレームのタブに
少なくとも一つの貫通穴を設け、素子搭載面における穴
の面積が、反素子搭載面における穴の面積よりも大きい
リードフレームにおいて、貫通穴の内面とタブの反素子
搭載面のなす角度が６０度以上であることを特徴とする
リードフレーム。 ２、半導体装置を搭載するためのタブとリードフレーム
の集合体を備える半導体装置用リードフレームのタブに
、少なくとも一つの貫通穴を設け、この穴がタブの反素
子搭載面に対して傾めにあけられているリードフレーム
において、貫通穴の内面とタブの反素子搭載面のなす角
度が６０度以上であることを特徴とするリードフレーム
。[Claims] 1. At least one through hole is provided in the tab of a lead frame for a semiconductor device, which includes an assembly of a tab and a lead frame for mounting a semiconductor element, and the area of the hole on the element mounting surface is A lead frame having a larger area than the hole on the element mounting surface, wherein the angle between the inner surface of the through hole and the surface of the tab opposite to the element mounting surface is 60 degrees or more. 2. At least one through hole is provided in the tab of a lead frame for a semiconductor device, which includes an assembly of a tab and a lead frame for mounting a semiconductor device, and this hole is inclined with respect to the surface of the tab opposite to the element mounting surface. 1. A lead frame in which the angle between the inner surface of the through hole and the surface opposite to the element mounting surface of the tab is 60 degrees or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62287313A JPH01129448A (en) | 1987-11-16 | 1987-11-16 | Lead frame |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62287313A JPH01129448A (en) | 1987-11-16 | 1987-11-16 | Lead frame |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01129448A true JPH01129448A (en) | 1989-05-22 |
Family
ID=17715749
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62287313A Pending JPH01129448A (en) | 1987-11-16 | 1987-11-16 | Lead frame |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01129448A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5753535A (en) * | 1991-09-18 | 1998-05-19 | Fujitsu Limited | Leadframe and resin-sealed semiconductor device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63213362A (en) * | 1987-02-27 | 1988-09-06 | Mitsubishi Electric Corp | Resin sealed semiconductor device |
-
1987
- 1987-11-16 JP JP62287313A patent/JPH01129448A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63213362A (en) * | 1987-02-27 | 1988-09-06 | Mitsubishi Electric Corp | Resin sealed semiconductor device |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5753535A (en) * | 1991-09-18 | 1998-05-19 | Fujitsu Limited | Leadframe and resin-sealed semiconductor device |
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