JP2010225851A - Substrate for controlling solder deposition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for controlling solder deposition which makes an electrode hardly peeled off from the substrate, can cope with the fine pitch of the electrode, and does not cause a short circuit between the electrodes. <P>SOLUTION: There is provided a substrate 1 for controlling solder deposition which mounts a connecting electrode of an electronic component in a flip-chip manner via solder on the arrangement of a substrate side electrode 2 the portion of which is exposed from a solder resist opening 4 formed at the substrate 1. At least one of both ends forming longitudinal directions of ends of an exposed portion of the substrate side electrode 2 is inclined by a predetermined electrode spread angle. One of both the ends forming the transverse directions of the ends of the exposed portion of the substrate side electrode 2 forms a maximum width in the transverse direction of the exposed portion of the substrate side electrode 2. The other end forms a minimum width in the transverse direction of the exposed portion of the substrate side electrode 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a substrate in which an electronic component such as a semiconductor chip represented by a silicon chip is flip-chip mounted on a substrate on which an electrode pattern is formed using a solder material.

  In recent years, the density of electronic components such as semiconductor chips has been rapidly increased, and accordingly, the pitch of electrodes serving as external connection terminals provided in the electronic components has also been reduced. Therefore, even in a flip chip mounting substrate on which this electronic component is flip-chip mounted, it is necessary to form electrodes with high density and to be flip-chip mounted with high connection reliability. .

  In general, when an electronic component such as a semiconductor chip is flip-chip mounted on a flip-chip mounting substrate, solder as a connection medium is disposed in advance on an electrode formed on the flip-chip mounting substrate. A semiconductor chip is flip-chip mounted on a flip-chip mounting substrate by bonding a connection electrode provided on the semiconductor chip to the electrode.

  As a method for supplying solder to an electrode formed on a flip chip mounting substrate, for example, there is a method in which a solder paste containing solder powder is printed on the electrode, and the solder paste is heated and melted in a reflow furnace. At this time, surface tension is generated in the melted and liquid solder, and the surface tension causes the solder to form a bump, and a solder pool is formed at an unspecified position on the flip chip mounting board side electrode.

  Therefore, when the electronic component is made to face the flip chip mounting substrate, the position of the connection electrode of the electronic component and the solder pool is displaced. When the misalignment occurs, only the solder thin film is formed at the position facing the connection electrode of the electronic component. Therefore, even if the electronic component is mounted on the flip chip mounting board, the electronic component is connected. There is a problem that a sufficient bonding force cannot be obtained between the electrodes for use and the electrodes of the flip chip mounting substrate, and the connection reliability is lowered. Furthermore, there is a problem that sufficient solder supply to the flip chip mounting substrate side electrode is difficult due to the miniaturization of the electrode pitch.

  Therefore, in order to solve these problems, a connection portion conductor pattern constituted by a wiring pattern to be a wiring and a wiring pattern and a connection pad formed continuously at a position where a solder bump of an electronic component is joined. Thus, there is a flip chip mounting substrate in which the width dimension of the connection pad is larger than the width dimension of the wiring pattern (Patent Document 1). Since this board forms solder pools on the connection pads, when mounting electronic components on flip chip mounting boards, there will be solder pools at the solder bump connection positions, and the electronic parts and flip chip mounting boards The connection reliability can be improved. Further, since the width dimension of the connection pad is increased, a sufficient amount of solder can be secured to the flip chip mounting board side electrode.

  However, in Patent Document 1, since the wiring pattern portion is an elongated rectangular shape, the contact area with the substrate is small. Accordingly, the adhesion strength with the substrate becomes weak and the portion is easily peeled off from the substrate, which causes a problem in mechanical reliability. In addition, since the connection pad has a rectangular shape with a large width dimension, a solder pool is still formed at an unspecified portion on the connection pad. Further, the shape is not suitable for fine pitching of the electrode arrangement, but the space between the connection pads becomes small, and there is a problem that a short circuit with an adjacent electrode is caused.

JP 2000-77471 A

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a solder deposition control substrate that does not cause electrodes to be peeled off from the substrate, can cope with fine pitches in the electrode arrangement, and does not cause a short circuit between the electrodes. .

  According to a first aspect of the present invention, a solder for flip-chip mounting a connection electrode of an electronic component via a solder on an array of substrate-side electrodes partially exposed from a solder resist opening formed on a substrate A deposition control substrate, wherein at least one of both end portions forming the longitudinal direction of the exposed portion of the substrate-side electrode is inclined at a predetermined electrode spreading angle, and the substrate-side electrode is exposed. One end of both ends forming the short direction among the ends of the portion forms the maximum width in the short direction of the exposed portion of the substrate side electrode, and the other end is the short direction of the exposed portion of the substrate side electrode The solder deposition control board is characterized in that a minimum width is formed.

  In the first aspect, at least one of both end portions forming the longitudinal direction of the substrate side electrode is inclined at a predetermined electrode spreading angle. By this inclined portion, the electrode has a shape in which the width in the lateral direction continuously increases as it proceeds in the longitudinal direction from the end forming the minimum width in the lateral direction. When the solder is heated and melted and liquefied, the large droplets have a lower internal pressure, so the liquefied solder collects into large droplets, and the surface tension of the molten solder and the molten solder are the electrodes. From the balance with the force to wet and spread the top, the solder pool is formed at a specific position where the width of the electrode in the short direction is widened by a predetermined amount. On the other hand, a solder thin film is formed in a portion other than the position where the solder pool is formed.

  Here, the “electrode spreading angle” refers to an angle formed by an end portion in the longitudinal direction of the electrode exposed portion and a normal direction of the end portion forming the minimum width in the short side direction of the electrode exposed portion.

  According to a second aspect of the present invention, there is provided the solder deposition control substrate, wherein the electrode spreading angle is 0.5 ° to 10 °.

  According to a third aspect of the present invention, both end portions forming the longitudinal direction are inclined at the same electrode spread angle, and the electrode spread angle is 1 ° to 3 °. This is a deposition control substrate.

  According to a fourth aspect of the present invention, the end portion forming the maximum width in the short direction and the end portion forming the minimum width in the short direction are alternately arranged. This is a deposition control substrate. In this aspect, with respect to the arrangement of the substrate-side electrodes, the end portions forming the maximum width in the lateral direction are alternately directed in the substrate outer edge direction and the substrate center direction, that is, in the zigzag pattern in the solder resist opening. Is arranged. Therefore, the solder pools are also arranged in a staggered manner with respect to the substrate surface.

  According to a fifth aspect of the present invention, at least one of both end portions forming the longitudinal direction is inclined at a predetermined electrode spreading angle, and the substrate-side electrode is formed at a portion other than the end portion in the short direction. An electrode for forming a maximum width of the exposed portion in the short side direction is further disposed. In this embodiment, one end of both end portions forming the short direction forms the maximum width in the short direction of the electrode exposed portion, and the other end forms the minimum width in the short direction of the electrode exposed portion. In the arrangement of (A), an electrode (B) in which the maximum width in the short direction of the electrode exposed portion is formed at a portion other than the end portion in the short direction is appropriately disposed. Therefore, the wide part in the short direction of the electrode (B) is formed from the central part in the longitudinal direction as compared with the electrode (A), and therefore the part of the electrode (B) is compared with the electrode (A). Thus, a solder pool is formed from the central portion in the longitudinal direction.

  According to a sixth aspect of the present invention, in the electrode (B), the maximum width in the lateral direction is formed at the center in the longitudinal direction of the exposed portion of the substrate-side electrode. Substrate. Therefore, since the wide part in the short direction of the electrode (B) is formed in the central part in the longitudinal direction, the solder pool is formed in the central part in the longitudinal direction in the part of the electrode (B).

  In a seventh aspect of the present invention, the surface of the substrate side electrode is formed of a metal selected from the group consisting of Cu, Ag, Au, Sn, Ni, Ni / Au, and Ni / Pd / Au. A solder deposition control board characterized by the following.

  According to an eighth aspect of the present invention, there is provided a solder deposition control substrate, wherein the surface of the substrate-side electrode is further subjected to rust prevention treatment with an organic film.

  According to the first aspect of the present invention, the width of the electrode that forms the short direction is a form that continuously spreads from the end that forms the minimum width in the short direction, so the electrode width in the short direction is narrow. Even in the portion, the area between the substrate and the electrode can be secured. Therefore, it can suppress that the adhesive force of the board | substrate side electrode to the board | substrate falls, and the mechanical reliability between a board | substrate side electrode and a board | substrate improves. Furthermore, since the mechanical reliability between the substrate-side electrode and the substrate is improved, the minimum width in the short direction can be further reduced, and a further fine pitch of the electrode arrangement can be achieved.

  In addition, the shape of the substrate-side electrode is such that the width in the short direction continuously narrows from the end that forms the maximum width in the short direction in the longitudinal direction, thus ensuring space with other adjacent electrodes. It is possible to prevent a short circuit even if the pitch is fine. Furthermore, since the substrate-side electrode has a simple shape in which the width in the short-side direction continuously increases, when manufacturing an electrode manufacturing mask, less coordinate data corresponding to the electrode shape is required, and manufacturing of the substrate is easy. is there. Further, since the solder reservoir is formed at a specific position where the electrode width is increased by a predetermined amount, the connection between the electrode for connecting the electronic component and the solder reservoir is facilitated, and the connection reliability between the substrate and the electronic component is improved.

  According to the second aspect of the present invention, an appropriate amount of solder pool can be formed at a certain position by setting the electrode spreading angle to 0.5 ° to 10 °.

  According to the third aspect of the present invention, since the electrode spreading angle is limited to 1 ° to 3 °, it is possible to cope with the fine pitch of the electrode arrangement while improving the accuracy of the position of the solder pool. Further, since both end portions forming the longitudinal direction have the same electrode spreading angle, the space between the electrodes can be made uniform, and short circuit prevention is facilitated.

  According to the fourth aspect of the present invention, since the end portions forming the maximum width in the short direction are alternately arranged, a space between the electrodes, particularly a space between the wide portions in the short direction is ensured. Therefore, it is possible to cope with severe fine pitch while reliably preventing a short circuit. In addition, since there is a sufficient space between the electrodes, it is possible to accurately perform electrode patterning by etching.

  According to the fifth aspect of the present invention, since the electrode (B) in which the wide portion in the short direction is formed from the central portion in the longitudinal direction is further arranged, the connection electrode for the electronic component having a fine pitch is provided. Even if a part thereof deviates from a specific position, the connection facing the solder pool of the substrate side electrode is possible.

  According to the sixth aspect of the present invention, since the electrode (B) has a maximum width in the short direction at the central portion in the longitudinal direction, the control of the space between the electrodes is easy, and the short circuit between the electrodes. Can be prevented.

  According to the seventh aspect of the present invention, it is possible to cope with various electrode surface treatments by making the electrode surface the above metal.

  According to the eighth aspect of the present invention, since the surface of the substrate side electrode is subjected to rust prevention treatment, it is possible to prevent the solder pool from peeling off from the substrate side electrode.

It is a partial top view of the board | substrate for solder deposition control which concerns on the example of 1st Embodiment of this invention. It is a partial top view of the board | substrate for solder deposition control which concerns on the 2nd Example of this invention. (A) A figure is a top view of the board | substrate side electrode exposed from the soldering resist opening part, (b) A figure is a side view of the board | substrate side electrode exposure part at the time of solder precoat. It is a top view of the board | substrate side electrode exposed from the soldering resist opening part which concerns on the other embodiment of this invention.

  Next, a solder deposition control substrate according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partial plan view of a solder deposition control substrate according to the first embodiment, FIG. 2 is a partial plan view of a solder deposition control substrate according to the second embodiment, and FIG. The top view of the board | substrate side electrode exposed from the resist opening part, the same figure (b) is a side view of the board | substrate side electrode at the time of solder precoat, FIG. 4 is from the soldering resist opening part which concerns on the other embodiment of this invention. It is a top view of the exposed substrate side electrode.

  As shown in FIG. 1, a plurality of substrate-side electrodes 2 having the same shape and the same dimensions are arranged on the surface of the solder deposition control substrate 1 according to the first embodiment at the same electrode pitch. A certain solder resist 3 covers the substrate side electrode 2. However, a rectangular solder resist opening 4 is formed at the peripheral edge of the solder deposition control substrate 1, and a part of the substrate-side electrode 2 is exposed therefrom. The opening width W of the solder resist opening 4 is not particularly limited. For example, the lower limit is preferably 150 μm in order to secure the capacity of the solder applied to the substrate side electrode 2 and improve the connection reliability. The upper limit is preferably 500 μm in order to prevent a short circuit due to excessive supply of solder, and particularly preferably 200 μm in order to reduce the size of the solder deposition control substrate 1.

  The substrate side electrode 2 is made of copper, for example, and is patterned into a predetermined pattern by pattern etching. In this embodiment, the substrate side electrodes 2 are arranged at regular intervals on the outer edge of the substrate.

  The substrate-side electrode 2 includes an elongated rectangular portion 6 having an electrode width W2 and a trapezoidal portion 5 having a maximum electrode width W1 that is formed continuously with the rectangular portion 6. In the first embodiment, all the substrate-side electrodes 2 are arranged so that the trapezoidal portion 5 faces the peripheral edge of the substrate. The substrate-side electrode 2 is covered with a solder resist 3 in the vicinity of the end portions on the peripheral edge side of the rectangular portion 6 and the trapezoidal portion 5. On the other hand, a portion from the boundary between the rectangular portion 6 and the trapezoidal portion 5 to the trapezoidal portion 5 is exposed to the outside through the solder resist opening 4 and serves as a connection portion 7 with an electronic component. Accordingly, the connecting portions 7 arranged in the solder resist opening have the same shape and the same dimensions, and the length in the longitudinal direction of the connecting portion 7 is W, which is the solder resist opening width, and the width of the connecting portion 7 is short. Is the electrode width W2 of the rectangular portion 6, and the maximum width in the short direction is W1 ′ slightly narrower than the maximum electrode width W1 of the trapezoidal portion 5.

  As shown in FIGS. 1 and 3 (a), both end portions forming the longitudinal direction of the connecting portion 7 are in the normal direction of the end portion forming the minimum width W2 of the connecting portion 7 in the short direction. A predetermined electrode spread angle 8 is provided. Accordingly, the electrode width in the short direction of the connecting portion 7 is configured to gradually widen from W2 to W1 ′ toward the peripheral edge of the substrate, and the space between the substrate side electrodes 2 is directed toward the center of the substrate. It is structured to gradually spread. The electrode width W2 is not particularly limited, but is, for example, 20 to 50 μm from the viewpoints of etching accuracy and miniaturization of the distance between the substrate-side electrodes 2.

  As shown in FIG. 3A, in the present embodiment example, both end portions forming the longitudinal direction of the connecting portion 7 have the same electrode spreading angle 8. The electrode spreading angle 8 is not particularly limited, but the lower limit is preferably 0.5 ° from the viewpoint of the etching accuracy, and the solder reservoir 9 described later is surely placed at a certain position by accurately inclining the end in the longitudinal direction. The angle of 1.0 ° is particularly preferable from the viewpoint of forming. Further, the upper limit is preferably 10 ° from the viewpoint of the positional accuracy of the solder reservoir 9, and particularly preferably 3.0 ° from the viewpoint of fine pitching of the substrate side electrode 2 array.

  Next, a solder pre-coating method according to this embodiment will be described. On the substrate side electrode 2, for example, a solder paste is supplied to the solder resist opening 4 by a printing method, and then the solder is heated and melted to be liquefied. Then, since the large-sized droplet has a lower internal pressure, the liquefied solder gathers into the large droplet, and as shown in FIG. 3B, on the connection portion 7 of the substrate-side electrode 2. A solder pool 9 is formed. At this time, the solder pool 9 is formed at a specific position where the width of the electrode in the short direction is widened from the balance between the surface tension of the molten solder and the force with which the molten solder wets and spreads on the substrate-side electrode 2. The Therefore, the solder pools 9 are arranged in a substantially straight line at regular intervals on the solder deposition control substrate 1. On the other hand, a solder thin film 10 is formed at a portion where the electrode width in the short direction is narrower than the position where the solder pool 9 is formed.

  The pitch interval of the substrate-side electrode 2 array is not particularly limited, and can be appropriately set according to the solder resist opening width W, the electrode spreading angle 8, the electrode width W2, and the like. However, in order to prevent a short circuit between the substrate-side electrodes 2 due to the solder pool 9 protruding from the connection portion 7 when the electronic components are joined, the electrode width W1 ′ of both ends in the short direction of the connection portion 7 is reduced. The distance between the end portions is preferably 25 μm or more. Therefore, it is preferable to secure an electrode pitch of 50 to 60 μm in order to cope with the miniaturization of the electrode pitch.

  Next, a second embodiment of the present invention will be described. The solder deposition control substrate 31 according to the second embodiment is different from the solder deposition control substrate 1 according to the first embodiment in the arrangement relationship between adjacent substrate-side electrodes 32. Details will be described below.

  As shown in FIG. 2, the solder deposition control substrate 31 according to the second embodiment has a plurality of substrate-side electrodes 32 regularly arranged on the surface thereof. The substrate-side electrode 32 includes an elongated rectangular portion 36 having an electrode width W2 and a trapezoidal portion 35 having a maximum electrode width W1 that is formed continuously with the rectangular portion 36. In the second embodiment, the substrate-side electrode 32 has its trapezoidal portions 35 and rectangular portions 36 arranged alternately. That is, the substrate-side electrode 32 is arranged such that the trapezoidal portions 35 and the rectangular portions 36 are alternately opposed to the peripheral edge of the substrate.

  In the second embodiment as well, the solder resist 33, which is an insulating material, covers the substrate-side electrode 32, but the peripheral portion of the solder deposition control substrate 30 has the same configuration as the first embodiment. Thus, a rectangular solder resist opening 34 is formed, from which a part of the substrate-side electrode 32 is exposed. Accordingly, the connection portions 37 having the same shape and the same dimensions are arranged in the solder resist opening, and the minimum width in the short direction of the connection portion 37 is the electrode width W2 of the rectangular portion 36, and the maximum width is a trapezoid. W1 'is slightly narrower than the maximum electrode width W1 of the portion 35.

  As shown in FIGS. 2 and 3 (a), both ends forming the longitudinal direction of the connecting portion 37 are in the normal direction of the end portion forming the minimum width W2 of the connecting portion 37 in the short direction. A predetermined electrode spread angle 38 is provided. Accordingly, the electrode width in the short direction of the connecting portion 37 is configured to gradually and gradually expand from W2 to W1 ′.

  As shown in FIG. 2, also in this embodiment, both end portions forming the longitudinal direction of the connecting portion 37 have a predetermined electrode spreading angle 38, and the angles are also the same. On the other hand, since the end portion of the connection portion 37 having the electrode width W1 ′ and the end portion of the connection portion 37 having the electrode width W2 are arranged so as to alternately oppose the peripheral edge portion of the substrate, the solder pool 9 Will be formed in a staggered pattern. Further, since the space between the adjacent substrate-side electrodes 32 is uniform along the longitudinal direction, the distance between the substrate-side electrodes 32 is (W1-W2) compared to the first embodiment. / 2 can be packed. Actually, as described above, the arrangement of the solder reservoirs 9 is not a straight line but a staggered pattern, so that it is possible to suppress a short circuit between the electrodes when joining the electronic components. / 2 or more can be packed.

  Also in the second embodiment, the electrode spread angle 38 is not particularly limited, but the lower limit is preferably 0.5 ° from the viewpoint of the etching accuracy, and the end portion in the longitudinal direction is inclined with high accuracy to ensure a specific value. From the point of forming a solder pool at the position, 1.0 ° is particularly preferable. The upper limit is preferably 10 ° from the viewpoint of preventing short circuit due to excessive supply of solder, and particularly preferably 3.0 ° from the viewpoint of fine pitching of the substrate side electrode 32 array.

  Next, another embodiment of the present invention will be described. In the above embodiment example, both end portions forming the longitudinal direction of the connecting portions 7 and 37 have the same electrode spread angles 8 and 38, but the electrode spread angles 8 and 38 may not be the same, Further, only one of the end portions may have electrode spreading angles 8 and 38. Further, the positions of the solder resist openings 4 and 34 in which the connecting portions 7 and 37 are arranged are not limited to the outer edge of the substrate, but may be the central portion of the substrate, and the electrode pitch may not be constant.

  In the above embodiment example, all the connection portions 7 and 37 of the substrate side electrodes 2 and 32 have the same shape and the same size, but the shape and dimensions are the same as the connection portions 7 and 37 of the substrate side electrodes 2 and 32. For example, the substrate-side electrodes 2 and 32 having different electrode spreading angles 8 and 38 may be arranged. Further, in the substrate side electrodes 2 and 32 of the above-described embodiment example, the end portions of the connection portions 7 and 37 have the maximum width in the short direction, but as shown in FIG. In addition, in the arrangement of 7 and 37, the connecting portion 40 in which the maximum width in the short direction of the connecting portion is formed in a portion other than the end portion may be appropriately arranged. Further, the “part other than the end portion” may be a central portion in the longitudinal direction of the connection portion or a peripheral portion in the longitudinal direction.

  In the above embodiment, each of the substrate side electrodes 2 and 32 is made of Cu, but at least the surface thereof is made of Cu, Ag, Au, Sn, Ni, Ni / Au or Ni / Pd / Au. Further, the surface of the substrate side electrodes 2 and 32 may be subjected to an antirust treatment with an organic film.

[Example 1]
Preparation of Solder Precoated Substrate An electrode array was formed on the outer edge of the substrate by pattern etching on a FR4 substrate having a length of 40 mm, a width of 40 mm, and a thickness of 0.6 mm coated with a 9 μm thick copper foil. Each electrode constituting the electrode array was composed of a rectangular part and a trapezoidal part, and had the same shape and the same dimensions. The dimensions of the rectangular part were 40 μm width × 300 μm length, and the longitudinal dimension of the trapezoidal part was 220 μm. The electrode arrangement is 80 μm pitch when the electrode spread angle is 0 ° to 3 °, and 160 μm pitch when the angle is 6 ° to 11 °. The total number of electrodes formed on the substrate is 124 when the pitch is 80 μm and when the pitch is 160 μm. The number was 62. As in the first embodiment, all the electrodes were regularly arranged in a direction in which the trapezoidal portion faces the peripheral edge of the substrate. About each electrode, the electrode spreading angle of the both ends which form the longitudinal direction of a trapezoid part was made the same. The electrode spreading angles of the electrodes of each FR4 substrate were 0 °, 0.5 °, 1 °, 2 °, 3 °, 6 °, 8 °, 10 °, and 11 °, respectively.

  As in Embodiment 1, a part of the trapezoidal part having the same shape and the same size is exposed from the inside of the solder resist opening to each FR4 substrate in which the electrode array having each electrode spreading angle is formed, and the connection part A solder resist was applied so that the array was formed (the thickness of the solder resist was 25 μm), and a test material having a solder resist opening width of 200 μm × 10000 μm was prepared through the steps of exposure, development, and thermosetting. Therefore, the width in the longitudinal direction of the connecting portion is 200 μm, and the minimum width in the short direction of the connecting portion is located at the end of the solder resist opening, and the width is 40 μm, which is the width of the rectangular portion. Each created test material was made into the test materials 1-9 according to the said 9 types of electrode spreading angles. Next, a solder paste having a solder powder content of 40% by mass prepared by mixing a vehicle and solder powder is supplied to the electrode array exposed from the opening of the solder resist by a printing method using a metal mask having a thickness of 30 μm. did. Thereafter, the FR4 substrate was passed through a reflow furnace having a peak temperature of 250 ° C. to form a solder precoat layer on the electrode. The position of the solder pool formed on the electrode was measured by observing the distance from the edge of the maximum width in the short direction of the connecting portion to the center of the solder pool with a microscope.

Evaluation of solder pool As a result of microscopic observation, solder pools were formed on all electrodes. Table 1 shows the relationship between the electrode spreading angle and the position of the solder pool. In Table 1, the solder pool position is the distance from the edge of the maximum width in the short direction of the connecting portion to the center of the solder pool when the solder resist opening width of 200 μm is 1, that is, the short direction of the connecting portion. It means a value obtained by dividing the distance A (μm) from the end of the maximum width to the center of the solder pool by 200. Moreover, the average value of the solder pool position was calculated for all solder pools.

  From Table 1, when the electrode spread angle is 0.5 ° to 10 °, the standard deviation of the solder pool position is suppressed to 1/5 or less compared to the test material having the electrode spread angle of 0 °. The dispersion of the reservoir position was remarkably reduced. In particular, at 1 ° to 3 °, the standard deviation was suppressed to about 1/20, and the solder pool position control ability was particularly excellent. Even when the electrode spreading angle was 11 °, a solder pool could be formed, but the positional accuracy was slightly inferior. In any of the electrode arrays having the electrode spreading angles of 0.5 ° to 10 °, no electrode peeling phenomenon including short-circuiting between electrodes and the vicinity of the minimum width in the short direction was observed.

[Example 2]
For each FR4 substrate having an electrode spreading angle of 1 ° and 2 °, solder the FR4 substrate having the same configuration as that of Example 1 (referred to as test materials 10 and 11 respectively) except that the electrode arrangement pitch is 160 μm. By supplying a solder paste having a powder content of 60 mass% by a printing method using a metal mask having a thickness of 50 μm and an aperture ratio twice that of Example 1, the amount of solder supplied is that of Example 1. About 4 times. Thereafter, the FR4 substrate was passed through a reflow furnace having a peak temperature of 250 ° C. to form a solder precoat layer on the electrode. Table 2 shows the relationship between the electrode spreading angle and the position of the solder pool.

  From Table 2, even if the solder supply amount was increased, solder pools were formed on all the electrodes, and the solder pools could be controlled at a certain position. It was also found that when the amount of solder supplied was increased, the solder pool moved to the side where the electrode width was narrowed. Therefore, it is possible to adjust the solder pool position by adjusting the solder supply amount.

  Since the electrodes are difficult to peel off from the substrate, the electrodes can be made finer, and no short circuit occurs between the electrodes, which is highly useful in the field of flip chip mounting substrates.

DESCRIPTION OF SYMBOLS 1,31 Board | substrate for solder deposition control 2,32 Board | substrate side electrode 3,33 Solder resist 4,34 Solder resist opening part 5,35 Trapezoid part 6,36 Rectangular part 8,38 Electrode spreading angle

Claims (8)

A solder deposition control board that flip-chip-mounts connection electrodes for electronic components via solder on an array of board-side electrodes, part of which is exposed from a solder resist opening formed on the board,
Of the end portions of the exposed portion of the substrate side electrode, at least one of both end portions forming the longitudinal direction is inclined at a predetermined electrode spreading angle, and the end portion of the exposed portion of the substrate side electrode is short. One end of both end portions forming the hand direction forms a maximum width in the short direction of the exposed portion of the substrate side electrode, and the other end forms a minimum width in the short direction of the exposed portion of the substrate side electrode. A board for solder deposition control.   The solder deposition control substrate according to claim 1, wherein the electrode spreading angle is 0.5 ° to 10 °.   2. The solder deposition control according to claim 1, wherein both end portions forming the longitudinal direction are inclined at the same electrode spreading angle, and the electrode spreading angle is 1 ° to 3 °. substrate.   2. The solder deposition control according to claim 1, wherein an end portion that forms a maximum width in the short-side direction and an end portion that forms a minimum width in the short-side direction are alternately arranged. substrate.   At least one of both end portions forming the longitudinal direction is inclined at a predetermined electrode spreading angle, and the exposed portion of the substrate-side electrode is the outermost portion in the short direction at a portion other than the end portion in the short direction. The solder deposition control substrate according to claim 1, wherein an electrode forming a large portion is further arranged.   6. The solder deposition control substrate according to claim 5, wherein the maximum width in the lateral direction is formed at a central portion in the longitudinal direction of the exposed portion of the substrate-side electrode.   The surface of the substrate side electrode is formed of a metal selected from the group consisting of Cu, Ag, Au, Sn, Ni, Ni / Au, and Ni / Pd / Au. PCB for solder deposition control.   The solder deposition control substrate according to claim 7, wherein the surface of the substrate-side electrode is further subjected to rust prevention treatment with an organic film.

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