JP2006114571A - Semiconductor device and electronic apparatus provided therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for mounting a semiconductor device by which, when a Pb-free solder is used for soldering, air bubbles generating from a flux in the solder can be easily discharged, or the shape of a solder fillet near a lead tip end can be stabilized. <P>SOLUTION: A surface-mounting semiconductor device such as TQFP or the like is provided with a lead 1 for external connection, which has a tapered part on its tip. When a Pb-free solder is used for soldering, air bubbles are moved to the lead tip end in the tapered part 1b under the lead 1 while a plurality of micro air bubbles are joined in a solder, and in addition, the solder is made easy to be brought along not only the tapered part 1b on the lower side, but also the tapered part 1c on the side surface of the lead 1 or the surface of the side of the lead 1 and to be easily wetted and spread, and furthermore, the solder is made easy to be wetted and spread on the tapered part 1a on the upper side of the lead 1, too. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mounting technique for a semiconductor device, and in particular, reflow soldering using lead-free solder (herein referred to as Pb-free solder), and the electronic structure of a mounting structure soldered by the reflow soldering method. It relates to technology that is effective when applied to equipment.

  According to a study by the present inventor, the following technologies can be considered as a semiconductor device mounting technology.

  For example, as a conventional method of soldering electrical appliances to circuit boards such as organic substrates, reflow soldering is performed by blowing hot air on the circuit board and melting the solder paste printed on the electrodes to solder the surface mount components. The process is mainstream. As conventional techniques related to a mounting method using Pb-free solder, techniques described in Patent Documents 1 to 6 are known.

  Patent Document 1 describes Sn—Ag—Bi solder or Sn—Ag—Bi—Cu solder alloy as Pb-free solder.

  Patent Document 2 describes that Sn—Ag—Bi based solder that is promising as Pb-free solder is connected to an electrode having a Sn—Bi based layer on the surface.

  In Patent Document 3, the electronic component is composed of Sn as a main component on each of the first and second surfaces of the organic substrate, Bi is 0 to 65% by mass, and Ag is 0.5 to 4.0. It is described that reflow soldering is performed by Pb-free solder containing 0 to 3.0% by mass of Cu, and / or In by mass%.

  Patent Document 4 describes that in a method of connecting an electronic component and a circuit board using Pb-free solder containing Bi, the solder is cooled at a cooling rate of about 10 to 20 ° C./s.

  In Patent Document 5, electronic components are surface-mounted by reflow soldering on the A side of the substrate, and then the solder of the electronic component inserted from the A side is flow soldered to the electrodes by flow soldering on the B side of the substrate. In the connection mounting method, the solder used for reflow soldering on the A side is Sn- (1.5 to 3.5 wt%) Ag- (0.2 to 0.8 wt%) Cu- (0 to 4 wt. %) In- (0 to 2 wt%) Bi, which is a Pb-free solder having a composition of Sn- (0 to 3.5 wt%) Ag- (0. 2 to 0.8 wt%) Pb-free solder composed of Cu.

In Patent Document 6, when performing flow soldering using a Pb-free solder having a higher melting point than that of conventional Sn-37Pb and having a eutectic composition, a solder is provided by providing a heat conductive material between the component main body and the substrate. It is described that the temperature difference between the organic substrate and the electronic component main body is not increased when the substrate is cooled after attachment.
JP-A-10-166178 JP 11-179586 A JP-A-11-221694 Japanese Patent Laid-Open No. 11-354919 JP 2001-168519 A JP 2001-36233 A

  By the way, as a result of examination by the present inventor regarding the mounting technology of the semiconductor device as described above, the following has been clarified.

  For example, in any of the techniques described in Patent Documents 1 to 6 described above, the following points are not considered.

  That is, as a problem, reflow soldering of lead surface mount components using a solder paste such as Sn-3Ag-0.5Cu (unit: mass%), which is a typical Pb-free solder with high connection reliability. In this case, since this solder has poor wetting and spreading to the electrode material as compared with the conventional Sn-37Pb solder, the wettability of the solder to the portion where the lead tip is not plated is deteriorated. A sufficient solder fillet may not be formed at the tip of the lead, and the connection reliability may be reduced as compared with the case where the connection is made by conventional Sn-37Pb.

  Further, Pb-free solder such as Sn-3Ag-0.5Cu has a higher surface tension when the solder is melted than conventional Sn-37Pb solder.

  Furthermore, since Pb-free solder generally has poor wettability to electrode materials than conventional Sn-37Pb solder, the flux used for soldering Pb-free solder is the same as that used for Sn-37Pb solder. Is different.

  As a result, in many cases, those having a high surface tension at the time of soldering are increasing, and the flux covers the solder of the connection portion. Therefore, at the time of connection by Pb-free solder, the gas component generated by the reaction of the flux generated in the solder is not easily discharged out of the connection part, and tends to remain as a void in the connection part. And since this void may accelerate | stimulate the crack progress in a solder connection part, compared with the case where it connects by the conventional Sn-37Pb, the case where a connection reliability falls arises.

  In addition, this reduction in connection reliability tends to become prominent when the soldering connection portion is narrowed to a pitch of approximately 0.5 mm or less and the connection portion is miniaturized due to higher mounting density.

  In addition, this decrease in connection reliability is due to the fact that most of the leads are embedded in the component mold, so the solder connection between the side surface of the lead exposed outside the mold and the electrode on the board or the tip of the lead It has been found that this is likely to occur in a leaded package such as TSOP (Thin Small Outline Package) that needs to be soldered to the electrode on the substrate by a solder fillet.

  Therefore, the object of the present invention is to solve the above-mentioned problems, and to easily discharge bubbles generated from the flux in the solder from the solder when soldering using Pb-free solder, or the solder fillet near the lead tip. It is an object of the present invention to provide a semiconductor device mounting technique capable of stabilizing the shape.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  The semiconductor device according to the present invention is applied to a surface mount type semiconductor device to be soldered by a reflow soldering method using Pb-free solder, has a lead for external connection, and is tapered at the tip of the lead. Is provided with a tapered portion. In this reflow soldering method, a Pb-free solder alloy such as Sn-3Ag-0.5Cu (unit: mass%) can be applied to the connection of electronic components to a circuit board such as an organic board, and solder at around 220 ° C. It is an alternative to Sn-37Pb (unit: mass%) solder used for soldering.

  Further, at this time, the shape of the tapered portion near the tip of the lead is desirably created by rolling after the lead is plated.

  Furthermore, the lead tip has a quadrangular cross-sectional shape, and the taper is provided on the lower surface, upper surface, and side surface of the tip, and the angle formed by the circuit board surface and the taper on the upper surface of the lead is approximately 45 degrees to 60 degrees. It is also desirable that the angle formed by the circuit board surface and the taper portion of the lower surface of the lead is approximately 15 degrees or more and 45 degrees or less, or has a shape approximate to this.

  An electronic apparatus according to the present invention includes a semiconductor device having the above-described external connection lead and a circuit board on which the semiconductor device is mounted.

  At this time, it is desirable that the inclination of the upper surface of the solder fillet near the tip of the lead is approximately 45 degrees by adjusting the electrode size of the circuit board surface.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  According to the present invention, at the time of soldering using Pb-free solder, it is possible to easily discharge bubbles generated from the flux in the solder from the solder, or to stabilize the shape of the solder fillet near the tip of the lead. Become.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  First, an example of the configuration of a semiconductor device according to an embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view showing a semiconductor device according to the present embodiment, FIG. 2 is a perspective view showing a lead tip portion, FIG. 3 is a perspective view showing a state in which solder is likely to wet and spread on the lead tip portion, and FIG. It is a perspective view which shows a mode that a solder is difficult to spread on the front-end | tip part of the conventional lead.

  The semiconductor device according to the present embodiment includes, as an example of a surface mount package, a semiconductor device 10 of TQFP (Thin Quad Flat Package) as shown in FIG. 1, for example, and has a lead 1 for external connection. Yes. As shown in FIG. 2, the lead 1 for external connection is provided with a tapered portion so as to be tapered at the tip. The leading end of the lead 1 has a quadrangular cross-sectional shape, and the tapered portion includes a tapered portion 1a on the upper surface, a tapered portion 1b on the lower surface, and tapered portions 1c on the left and right side surfaces. Show the surface.

  The package is not limited to this. For example (not shown), for example, a semiconductor chip on which a circuit is formed is mounted on a lead frame having leads 1 provided with a tapered portion. The lead frame and the lead frame are manufactured by wire bonding or flip chip bonding and molding with a sealing resin.

  As shown in FIG. 2, by providing a taper portion so that the tip of the lead 1 is tapered, bubbles generated from flux in the solder can be easily discharged from the solder when soldering using Pb-free solder. can do. The reason for this is that the bubbles move toward the tip of the lead while bonding a plurality of fine bubbles in the solder at the tapered portion 1b of the lower surface of the lead 1, and the lead 1 is not only the tapered portion 1b of the lower surface. This is because it is easy to spread and spread through the side taper portion 1c and the side surface of the lead 1, so that the bubbles can be easily moved to the side of the lead where there is little fear of causing a significant decrease in connection reliability.

  Further, the shape of the solder fillet near the tip of the lead 1 can be stabilized. The reason for this is that, as described above, the solder easily propagates through the side surface of the lead 1 as well as the tapered portion 1 b on the lower surface of the lead 1, and further spreads to the tapered portion 1 a on the upper surface of the lead 1. As a result, as shown in FIG. 3, the solder 2 is first wetted to the lower surface, the side surface, and the upper surface of the leading end portion of the lead 1, so that no plating is applied near the leading end of the lead 1. This is because the solder 2 can easily surround the cut surface 1d of the leading end portion of the lead 1 which is in a state of being difficult to wet.

  Once the solder 2 surrounds the cutting surface 1d of the tip of the lead 1, the surface tension of the solder 2 boosts the wetting in addition to the wetting force of the solder 2, so that the solder 2 becomes the tip of the lead 1. It becomes easy to get wet to the cut surface 1d. For example, in the case of a lead having a conventional shape as shown in FIG. 4, it is difficult for the solder to enclose the cutting surface of the tip of the lead, and as a result, the cohesive force of the solder 2 near the tip of the lead becomes small. The wetting of the cut surface 1d tends to be incomplete.

  Next, an example of the configuration of the electronic device according to the present embodiment will be described with reference to FIG. FIG. 5 is a perspective view showing an electronic apparatus according to the present embodiment.

  The electronic apparatus according to the present embodiment includes a lead 1 having a tapered portion at the tip as shown in FIG. 2, and a surface-mounted semiconductor device 10 as shown in FIG. The circuit board 3 is mounted with the semiconductor device 10 mounted thereon. A plurality of types of TQFPs 10a having different numbers of leads, TSOPs 10b having other structures, and the like are mounted on the circuit board 3 as the surface-mount type semiconductor device 10. In addition, chip parts 11 such as resistors and capacitors, connectors 12 for connection, and the like are also mounted.

  Next, an example of a method for forming the tapered portion of the lead tip in the semiconductor device according to the present embodiment will be described with reference to FIGS. FIG. 6 is an explanatory view showing a method of forming a tapered portion at the tip of the lead, FIG. 7 is an explanatory view showing a case where the lead is bent during rolling, and FIG. 8 is an angle of the tapered portion of the lead tip and the upper surface of the fillet. FIG. 9 is an explanatory diagram showing a case where the inclination of the fillet upper surface is decreased from 45 degrees, and FIG. 10 is an explanatory diagram showing a case where the inclination of the fillet upper surface is increased from 45 degrees.

  As shown in FIG. 6, the taper portion of the tip of the lead 1 is formed by cutting the lead frame on which plating has been performed and then providing the tip of the lead 1 on which plating is present by processing such as rolling. It is the simplest and less worried to damage the plating.

  Further, since the side surface of the lead is expanded by this rolling, as shown in FIG. 6, the taper portion 1e is previously provided on the original side surface of the lead so as to taper toward the tip of the lead, and the lead 1 is etched. It is desirable to keep it.

  Other than the above-described method for processing the tapered portion, cutting and polishing can be considered. However, any of these methods is not desirable because the surface plating is scraped off and solder wetting is hindered.

  Further, the angle A formed by the surface of the circuit board 3 and the tapered portion 1a of the upper surface of the lead 1 is preferably set to approximately 45 degrees to 60 degrees as shown in FIG.

  This is because if the angle A formed with the taper portion 1a on the upper surface of the lead 1 is approximately 45 degrees or less, the solder is less likely to wet up to the upper surface of the taper portion along the side surface of the taper portion. Further, when the angle A formed by the taper portion 1a on the upper surface of the lead 1 is approximately 60 degrees or more, it becomes difficult to fix the lead tip portion during rolling for tapering the lead tip portion as shown in FIG. . That is, when rolling for tapering the tip portion of the lead 1 is performed, the tip portion of the lead 1 is not completely fixed, the taper shape of the tip portion becomes uneven, and the lead 1 is also bent. Furthermore, it is because the plating film which was originally applied becomes easy to peel off. This peeling of the plating film is undesirable because it leads to variations in the wettability of the solder.

  Further, the angle B formed by the surface of the circuit board 3 and the tapered portion 1b of the lower surface of the lead 1 is approximately 15 degrees or more and 45 degrees or less, as shown in FIG. It is also desirable to have.

  That is, if the angle B formed by the circuit board surface and the taper portion 1b of the lower surface of the lead 1 is approximately 15 degrees or less, the bubbles generated in the solder during reflow soldering only sink the component due to gravity. This is because it is difficult to be discharged, and a greater force is required for discharging. Also, if the angle B formed by the circuit board surface and the tapered portion 1b of the lower surface of the lead 1 is approximately 45 degrees or more, the bubbles generated in the solder are only subducted due to the gravity acting on the components. This is because it is hard to be discharged just by moving inside the solder.

  Further, by adjusting the size of the electrode 3a (mainly the length in the lead direction) on the surface of the circuit board 3, the inclination C of the upper surface of the solder fillet near the tip of the lead is approximately 45 degrees as shown in FIG. It is also desirable that

  As shown in FIG. 9, when the fillet of the solder 2 is normally formed and becomes a normal fillet shape 2a, the circuit board 3 is arranged so that the inclination of the upper surface of the fillet is significantly lower than 45 degrees. When the size of the electrode 3a is adjusted, the solder 2 has a wide free surface that does not come into contact with either the lead 1 or the electrode 3a of the circuit board 3, and the solder 2 gathers in a portion away from the lead 1, whereby the lead 1 and the circuit board As a result, solder that is not involved in the connection with the three electrodes 3a is generated, so that the probability that the connection strength is lowered is increased.

  Furthermore, as shown in FIG. 10, when the fillet of the solder 2 is formed normally and becomes a normal fillet shape 2b, the inclination of the upper surface of the fillet is remarkably increased from 45 degrees. When the size of the electrode 3a is adjusted, the solder 2 is less likely to collect at the tip end portion of the lead 1, so that the wetting and spreading force 4 acting on the solder 2 is weakly applied to the unplated portion of the cut surface 1d at the tip portion of the lead 1. Become. This also leads to a decrease in connection strength.

  Next, with reference to FIGS. 11 to 15, the result of mounting the semiconductor device according to the present embodiment on a circuit board and performing cross-sectional observation of the connecting portion and board bending test will be described. FIG. 11 is an explanatory view showing a case where a substrate bending test is performed, FIG. 12 is an explanatory view showing a result of a cross-sectional observation of a connecting portion in a TQFP having a copper alloy lead, and FIG. FIG. 14 is an explanatory diagram showing the results of carrying out the cross-sectional observation of the connecting portion in the TQFP having the iron-nickel alloy lead, FIG. 15 is an explanatory diagram showing the results of carrying out the substrate bending test, It is.

[TQFP with copper alloy lead]
TQFP (part size: 14 mm × 14 mm, pitch: 0.5 mm, number of leads: 100, lead thickness: 0.15 mm, lead material: copper alloy, lead plating composition: Sn-2% Bi), solder paste (supply) (Thickness: 0.15 mm) was mounted on a printed circuit board, and reflow soldering was performed under a minimum temperature condition where the supplied solder paste could be reflowed.

  In addition, the apparatus used for reflow soldering uses a combination of infrared and hot air in the heating zone (a pair of heaters located above and below the substrate transport conveyor), the number of heating zones is 5, and nitrogen is used for the soldering atmosphere, oxygen The concentration is 100 ppm.

  In addition to this TQFP, a solder (solid solder) having a composition of Sn-3Ag-0.5Cu-7In is used for mounting an FPGA (Field Programmable Gate Array) having the lowest heat resistant temperature (heat resistant temperature: 225 ° C.) on the circuit board. Phase temperature: 198 ° C., liquidus temperature: 211 ° C.).

  In addition, the solder of this composition tends to increase the degree of oxide formation on the solder surface and the surface tension in the molten state compared to conventional solder, so the bubbles formed in the solder are discharged out of the solder. I know that it may be difficult to do.

  Regarding this TQFP, the lead tip has no taper specification, the lead tip has an upper surface and a lower surface, and the angle formed by the circuit board surface and the lead tip upper surface has a taper of 50 degrees. A total of two types of specifications were prepared in which the angle formed by the circuit board surface and the taper portion of the lower surface of the lead tip was 30 degrees.

  However, the taper is not provided on the side surface of the lead tip part in the lead etching process before the taper is provided on the upper and lower surfaces of the lead tip part by rolling.

  Therefore, a taper is generated so that the influence of the lead shape change is exerted on the side surface of the lead tip portion due to rolling on the upper surface and the lower surface of the lead tip portion, and as a result, the side surface of the lead tip portion becomes wider toward the lead tip. The taper angle of the taper toward the tip of the lead was approximately 10 degrees on both side surfaces.

  The above two types of TQFPs have a solder peak temperature of 223 ° C. and a liquidus temperature of the solder of 211 ° C. or more, and the duration of the solder is 35 seconds. Reflow soldering was performed so that the peak temperature of the body portion was 225 ° C.

  After this soldering, in order to evaluate the connection strength by the solder, a cross-sectional observation of the connection portion and a substrate bending test were performed. In the cross-sectional observation of the connection part, 25 connection parts are arbitrarily selected from 100 connection parts per part, and the average diameter of bubbles existing in the solder of the connection part and the bubbles existing in one connection part are selected. The average number of was measured.

  In the bending test of the board, according to the method of FIG. 11, using the support jig 5, a level difference of 3 mm is provided between the back side of the board at the component connection position and the circuit board 3 on both sides at a distance of 5 cm. After the release, the number of connection portions where damage occurred at the connection portions at the tip portions of the 50 leads affected by the substrate bending was counted.

  FIG. 12 shows the result of cross-sectional observation of the connecting portion. According to this, by providing a taper on the upper surface and the lower surface of the lead tip, the average diameter of the bubbles present in the solder of the connecting portion and the one connecting portion are reduced. It can be seen that there is an improvement in each of the average number of bubbles present. The average diameter of bubbles was improved from 40 μm to 16 μm, and the average number of bubbles was improved from 0.65 to 0.22.

  FIG. 13 shows the result of the bending test of the substrate. According to this, it can be seen that the improvement can be seen similarly. The number of damage at the connection has been improved from 19 to 0.

[TQFP with iron-nickel alloy lead]
TQFP (component size: 14 mm × 14 mm, pitch: 0.5 mm, number of leads: 100, lead thickness: 0.15 mm, lead material: iron-nickel alloy, lead plating composition: Sn-2% Bi) with solder paste ( (Supplied thickness: 0.15 mm) was mounted on a printed circuit board, and reflow soldering was performed under the minimum temperature condition where the supplied solder paste could be reflowed.

  In addition, the apparatus used for reflow soldering uses a combination of infrared and hot air in the heating zone (a pair of heaters located above and below the substrate transport conveyor), the number of heating zones is 5, and nitrogen is used for the soldering atmosphere, oxygen The concentration is 100 ppm.

  In addition to this TQFP, in order to mount an FPGA having the lowest heat resistant temperature (heat resistant temperature: 225 ° C.) on the circuit board, a solder having a composition of Sn-3Ag-0.5Cu-7In (solidus temperature: 198 ° C. , Liquidus temperature: 211 ° C.).

  In addition, the solder of this composition tends to increase the degree of oxide formation on the solder surface and the surface tension in the molten state compared to conventional solder, so the bubbles formed in the solder are discharged out of the solder. I know that it may be difficult to do.

  Regarding this TQFP, the lead tip has no taper specification, the lead tip has an upper surface and a lower surface, and the angle formed by the circuit board surface and the lead tip upper surface has a taper of 50 degrees. A total of two types of specifications were prepared in which the angle formed by the circuit board surface and the taper portion of the lower surface of the lead tip was 30 degrees.

  However, before providing the taper on the upper surface and the lower surface of the lead tip portion by rolling, a taper of 20 degrees is provided on the side surface of the lead tip portion in the lead etching process.

  As a result, although the influence of the lead shape changes on the side of the lead tip due to rolling to the upper and lower surfaces of the lead tip, as a result, a taper occurs on the side of the lead tip so as to taper toward the lead tip. It was. Further, the taper angle of the taper toward the tip of the lead was approximately 10 degrees on both side surfaces.

  The above two types of TQFPs have a solder peak temperature of 223 ° C. and a liquidus temperature of the solder of 211 ° C. or more, and the duration of the solder is 35 seconds. Reflow soldering was performed so that the peak temperature of the body portion was 225 ° C.

  After this soldering, in order to evaluate the connection strength by the solder, a cross-sectional observation of the connection portion and a substrate bending test were performed. In the cross-sectional observation of the connection part, 25 connection parts are arbitrarily selected from 100 connection parts per part, and the average diameter of bubbles existing in the solder of the connection part and the bubbles existing in one connection part are selected. The average number of was measured.

  The substrate bending test was performed in accordance with the same method as in FIG. 11 described above, and the level difference between the back side of the circuit board 3 at the component connection position and the board on the both sides at a distance of 10 cm was provided by the support jig 5. After canceling, the number of connection portions where damage occurred at the connection portions at the 50 lead end portions affected by the bending of the substrate was counted.

  FIG. 14 shows the result of cross-sectional observation of the connecting portion. According to this, by providing taper on the upper and lower surfaces of the lead tip, the average diameter of the bubbles present in the solder of the connecting portion and within one connecting portion are shown. It can be seen that there is an improvement in each of the average number of bubbles present. The average diameter of the bubbles was improved from 36 μm to 12 μm, and the average number of bubbles was improved from 0.59 to 0.18.

  FIG. 15 shows the result of the bending test of the substrate. According to this, it can be seen that the improvement can be seen similarly. The number of damages at the connection has been improved from 22 to 0.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  For example, the surface mount type package is not limited to TQFP, and can be widely applied to all semiconductor devices having external connection leads such as TSOP, QFP, and SOP.

  In addition to a semiconductor device, the present invention can also be applied to a surface mount type electronic component having a lead.

  Furthermore, the tip portion of the lead can be applied to other shapes such as a round shape and an ellipse in addition to the square cross-sectional shape.

It is a perspective view which shows the semiconductor device which is one embodiment of this invention. In the semiconductor device which is one embodiment of this invention, it is a perspective view which shows a lead front-end | tip part. In the semiconductor device which is one embodiment of this invention, it is a perspective view which shows a mode that a solder tends to wet and spread to a lead front-end | tip part. It is a perspective view which shows a mode that a solder is difficult to wet and spread to the conventional lead front-end | tip part with respect to the semiconductor device which is one embodiment of this invention. It is a perspective view which shows the electronic device which mounted the semiconductor device which is one embodiment of this invention. FIG. 11 is an explanatory diagram showing a method of forming a tapered portion at the lead tip in the semiconductor device according to one embodiment of the present invention. In the semiconductor device which is one embodiment of this invention, in the method which forms a taper part in a lead front-end | tip part, it is explanatory drawing which shows the case where a lead bends in the case of rolling. In the semiconductor device which is one embodiment of this invention, it is explanatory drawing which shows the angle of the taper part of a lead front-end | tip part, and the inclination of a fillet upper surface. In the semiconductor device which is one embodiment of this invention, it is explanatory drawing which shows the case where the inclination of a fillet upper surface reduces from 45 degree | times. In the semiconductor device which is one embodiment of this invention, it is explanatory drawing which shows the case where the inclination of a fillet upper surface increases more than 45 degree | times. It is explanatory drawing which shows the case where the semiconductor device which is one embodiment of this invention is mounted in a circuit board, and performs the bending test of a board | substrate. It is explanatory drawing which shows the result of having mounted the semiconductor device (TQFP which has a copper-type alloy lead) which is one embodiment of this invention on the circuit board, and implementing the cross-sectional observation of the connection part. It is explanatory drawing which shows the result of having mounted the semiconductor device (TQFP which has a copper-type alloy lead) which is one embodiment of this invention in a circuit board, and implementing the bending test of the board | substrate. It is explanatory drawing which shows the result of having mounted the semiconductor device (TQFP which has an iron nickel series alloy lead) which is one embodiment of this invention in a circuit board, and implemented cross-sectional observation of the connection part. It is explanatory drawing which shows the result of having mounted the semiconductor device (TQFP which has an iron nickel series alloy lead) which is one embodiment of this invention in a circuit board, and implementing the bending test of the board | substrate.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lead, 1a ... Tapered part of upper surface, 1b ... Tapered part of lower surface, 1c ... Tapered part of side surface, 1d ... Cut surface, 1e ... Tapered part, 2 ... Solder, 2a, 2b ... Fillet shape, 3 ... Circuit board DESCRIPTION OF SYMBOLS 3a ... Electrode, 4 ... Wetting spreading force, 5 ... Support jig, 10 ... Semiconductor device, 10a ... TQFP, 10b ... TSOP, 11 ... Chip component, 12 ... Connector.

Claims (12)

A surface-mount type semiconductor device having leads for external connection,
A semiconductor device, wherein a taper portion is provided so as to be tapered at a tip portion of the lead. The semiconductor device according to claim 1,
The shape of the taper portion is formed by rolling after the lead is plated. The semiconductor device according to claim 2,
A taper portion is formed on the side surface of the tip portion before the rolling. The semiconductor device according to claim 1,
The lead portion has a quadrangular cross-sectional shape, and the taper portion is provided on the lower surface, the upper surface, and the side surface of the tip portion. The semiconductor device according to claim 4.
The taper portion on the upper surface is formed so that an angle formed with a surface of a circuit board on which the semiconductor device is mounted is 45 degrees or more and 60 degrees or less. The semiconductor device according to claim 5.
The tapered portion of the lower surface is formed so that an angle formed with the surface of the circuit board is not less than 15 degrees and not more than 45 degrees. The semiconductor device according to claim 1,
The semiconductor device is made of TQFP or TSOP. The semiconductor device according to claim 1,
The lead is made of a copper-based alloy or an iron-nickel-based alloy. The semiconductor device according to claim 1,
2. A semiconductor device according to claim 1, wherein a cutting surface of the tip of the lead is not plated. An electronic device in which the semiconductor device according to any one of claims 1 to 9 is mounted,
A semiconductor device having a lead for external connection;
An electronic device comprising: a circuit board on which the semiconductor device is mounted. The electronic device according to claim 10, wherein
On the surface of the circuit board, after the semiconductor device is mounted on the circuit board by solder, the dimension of the solder is adjusted so that the inclination of the upper surface of the fillet is 45 degrees with respect to the surface of the circuit board. An electronic device including an electrode. The electronic device according to claim 11, wherein
The electronic device is characterized in that the solder is made of a Sn-Ag-Cu solder alloy.

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