JP4646296B2 - Electronic components - Google Patents

Description

  The present invention has a circuit element such as a plurality of resistance elements and capacitors and an external terminal of the circuit element element made of conductive protrusions on one surface of a substrate made of ceramic or the like, or both surfaces through a substrate through hole. It relates to electronic components.

Regarding a network resistor having a plurality of resistance elements and external terminals of the resistance elements made of conductive protrusions on one surface of the ceramic substrate, US Pat. No. 6,326,677 and International Publication No. WO 97/30461 The gazette has that disclosure.
US Pat. No. 6,326,677 International Publication No. WO 97/30461

  Since an electronic component having such a protruding member acts to peel off the protruding member and the substrate when an external force is applied, it is desirable to have a structure that can suppress such peeling.

  However, especially in an electronic component that occupies the area of one surface of the substrate with a plurality of resistive elements and conductive protrusions, it is not appropriate to enlarge the land in order to have a structure that can withstand external forces. There is a case. The reason for this is that compared to surface-mount electronic components that do not have conductive protrusions, a resistor with predetermined characteristics is placed while the substrate surface is occupied by the presence of conductive protrusions. This is because it is necessary to secure an area to be processed. This should be taken into account as electronic components become smaller.

  Therefore, in an electronic component that occupies the area of one surface of the board with a plurality of circuit elements and conductive protrusions, the circuit element and the land on which the conductive protrusions are mounted are considered in consideration of the particularity of the structure. It is necessary to have a structure that can withstand external force in consideration of the arrangement, the board area occupation ratio, and the like. Such external force includes mechanical stress (impact), thermal stress (impact), and the like.

  The problem to be solved by the present invention is to obtain an electronic component using as a terminal a conductive protrusion having a structure capable of withstanding external force after mounting.

  In order to solve the above problems, a first electronic component of the present invention is an electronic component having a plurality of circuit elements formed on the surface of a rectangular substrate 1 and having external terminals of the circuit elements composed of conductive protrusions 9. The circuit element is covered with an overcoat film 7 while leaving a part of the electrode 2 constituting the circuit element as a land 4, and the substrate 1 long side dimension of the land 4 is the substrate 1 short side dimension. The conductive protrusion 9 is fixed to the land 4 by an amount of fixing member substantially proportional to the land 4 area value.

  The “substrate 1” may be made of ceramic such as alumina, glass fiber mixed epoxy resin molded body, or the like. Among these, ceramic is preferable in terms of increasing the degree of freedom in selecting circuit element materials because it is difficult to change quality even after a process such as firing at the time of circuit element formation. Further, in an electronic component having a structure in which a circuit element is directly formed on the substrate 1, deformation of the substrate 1 due to external force leads to deformation of the circuit element, and the characteristic value of the circuit element tends to deviate from the rated value. From the viewpoint of preventing it as much as possible, it is preferable to use a ceramic having high rigidity.

  The above-mentioned “conductive protrusions 9” are formed by mounting and fixing conductive balls such as so-called solder balls on the lands 4, bumps formed by the so-called subtract method and additive method, and conductive paste by a technique such as printing. Including protrusions formed and solidified.

  The “overcoat film 7” may be a film made of resin, a glass film, or a film made of two or more layers thereof. The overcoat film 7 forms the land 4 and covers the resistance element. In consideration of easiness of patterning when forming a thick film, the entire region other than the land 4 portion may be covered.

  For the “fixing member”, cream solder, conductive adhesive, and the like are suitable. The means for supplying the fixed member in an amount proportional to the land 4 area value to the land 4 surface includes, for example, means for screen printing using a metal mask having an opening having a substantially land size. The above “substantially proportional” means that, for example, when a fixing member such as cream solder is arranged on each land 4 by a normal screen printing technique, the opening area of the screen matches the area of each land 4. It means the relationship between the amount of the fixing member and the area of the land 4. That is, the word “abbreviated” is used to mean that it includes an error of the degree of variation in the amount of discharged matter from the screen opening of normal screen printing.

  One of the purposes of making the “land 4” substrate 1 long side dimension larger than the substrate 1 short side dimension is to increase the land 4 area. When the land 4 area is increased, a sufficient amount of fixing members such as cream solder 8 and epoxy conductive adhesive, which are proportional to the land 4 area value, are secured to fix the conductive protrusions 9. can do. If such fixation is sufficient, a structure that can withstand external force after mounting can be obtained.

  Further, in the conventional circular land 4, for example, as shown in FIG. 1, the long side direction dimension of the substrate 1 is made larger than the short side direction dimension so that the fixing member extends along the long side direction of the substrate 1. It will be reinforced. The substrate 1 is deformed along the long side direction by an external force. The reinforcement acts to suppress deformation of the substrate 1.

  Here, the reason why the first electronic component land 4 of the present invention can be enlarged is that the land 4 region is provided outside the contour of the conventional circular land so that the land 4 has a shorter dimension in the long side direction. This is because it can be larger than the dimension in the side direction. In other words, a square having the same dimension as the diameter of the conventional circular land 4 has a larger area of the land 4 in the same manner as a square having an area 4 / π times larger than the circular shape.

  From the viewpoint of obtaining an effect of ensuring a large area of the land 4, the second electronic component of the present invention has a plurality of circuit elements formed on the surface of the rectangular substrate 1 and the circuit elements including the conductive protrusions 9. In an electronic component having an external terminal, the circuit element is covered with an overcoat film 7 while leaving a part of the electrode 2 constituting the circuit element as a land 4, and the land 4 is rectangular, elliptical, or cornered. The shape is any one of rounded squares (hereinafter referred to as squares or the like).

  “Rectangle” among the rectangles includes a rectangle, a square, a rhombus, a trapezoid, and a shape obtained by slightly deforming these. The land 4 shape according to the first electronic component of the present invention is usually the above-mentioned quadrangle or the like. For example, an electronic component having a rectangular land 4 with rounded four corners shown in FIG. 1 corresponds to both the first and second electronic components of the present invention.

  Therefore, the first and second electronic components of the present invention have a structure that can withstand the external force after mounting because the land 4 area can be increased. For example, the area of one surface can be divided into a plurality of resistance elements and conductive protrusions 9. Even if it is an electronic component occupied by the above, it is not necessary to change the size of the resistor, and the characteristics of the resistance element are not impaired. Therefore, the problem to be solved by the present invention can be solved.

  In the “electronic component”, a plurality of resistance elements are connected by a common electrode film 2b (for example, the one shown in FIG. 1), and a plurality of independent individual resistance elements are arranged on the surface of a single insulating substrate. Network resistors including so-called multiple resistors, so-called network capacitors, multiple capacitors, composite elements of resistor elements and capacitors (so-called CR elements), and the like. In addition, these circuit elements include those obtained by multilayering with a resin layer, a ceramic layer, or the like.

  In the electronic component of the present invention, it is preferable that all circuit elements, lands 4 and conductive protrusions 9 are arranged on one surface of the substrate 1. The reason is that manufacturing can be facilitated. That is, in order to form a member such as a circuit element on both surfaces of the substrate 1, fine adjustment of the alignment between the arrangement of the member on one substrate 1 surface and the arrangement of the member on the other substrate 1 surface may be required. . Such adjustment is difficult because both sides of the substrate 1 cannot be seen simultaneously. Also, when placing a member on one substrate 1 surface, it is necessary to maintain the cleanness of the other substrate 1 surface, or to take care not to damage a member already disposed on the other substrate 1 surface, Impose great restrictions on manufacturing process design. In the configuration in which all the circuit elements, lands 4 and conductive protrusions 9 are arranged on one surface of the point substrate 1, there are no or few such difficulties and limitations. Of course, it goes without saying that a structure in which the circuit elements and the conductive protrusions 9 are respectively arranged on the front and back surfaces of the substrate 1 can be adopted in the present invention. This is because even with such a structure, it is still required to have a structure that can withstand external force after mounting. In the case of this structure, in order to conduct the front and back surfaces of the substrate 1, a conductor is disposed in the through hole of the substrate 1, or an electrode is formed on the end surface of the substrate 1.

  Normally, some kind of display is made on the electronic component. However, such display is generally performed on the surface of the other substrate 1 (there may be a colored intervening film that makes the display stand out). Conceivable. In that case, since no circuit element is formed like the other substrate 1 surface, it is not necessary to consider the adverse effect on the circuit element through the display process, which is advantageous.

  In the electronic component of the present invention, the unit circuit element has two external terminals, and the lands 4 constituting the external terminals are arranged along the short side direction of the substrate 1 as shown in FIG. Is preferred. Specifically, in the case of a resistance element, for example, the current path between the two lands 4 is substantially parallel to the short side direction of the substrate 1. The reason why the configuration is preferable is that, for example, when a plurality of circuit elements are arranged adjacent to the surface of the substrate 1 as shown in FIG. 1, the surface of the substrate 1 between the adjacent circuit elements can be used effectively. It is. For example, when the circuit element is a resistance element, a groove 6 may be formed in the resistor 3 by laser irradiation or the like to adjust the resistance value of the resistance element, thereby narrowing the current flow path. In order to prevent the resistor 3 powder scattered during the formation of the groove 6 from causing a short circuit between the adjacent resistor elements, it is usual to increase the interval between the resistor elements 3 of the adjacent resistor elements. However, there is a certain distance from the region where the groove 6 of the resistor 3 is present, and it is possible to reduce the distance between the resistance element electrodes 2, which is less necessary to provide an interval between the resistors 3. Therefore, the resistance element electrode 2 can be elongated in a direction substantially perpendicular to the current path of the resistance element, and the land 4 that is a part of the electrode 2 can be expanded in the elongated direction.

  In the electronic component of the present invention and a preferred electronic component based on the electronic component, as shown in FIG. 1, at least three lands 4b out of the lands 4 adjacent to the outer end of the substrate 1 have an area larger than that of the lands 4a. When the conductive protrusion 9 is fixed only on the land 4b having a large area, it is more preferable that the electronic component can stand up in a state where the conductive protrusion 9 and the flat ground are in contact with each other. This is because the conductive protrusions 9 that are particularly firmly fixed to the land 4b having a large area are arranged in a well-balanced state in the mounted state. Here, “self-supporting” means that the substrate 1 can be supported by only the conductive protrusion 9 without contacting the flat ground. Due to this good balance, a structure that can withstand external forces from various directions after mounting can be obtained. For example, the area of the land 4b located at the four corners of the rectangular substrate 1 in the “outer end of the substrate 1” is increased. Whether or not it is “self-supporting” is an indicator of whether or not the arrangement is well balanced.

  In the present specification, the land having the large area is collectively referred to as “land 4b”, the other land (ordinary land or land having a small area) is referred to as “land 4a”, and the land 4a and land 4b are collectively referred to. When doing so, it is described as “Land 4”.

  In the electronic component of the present invention and a preferred electronic component based on the electronic component, as shown in FIG. 1, the circuit element is a resistive element having an electrode film 2 and a resistor film 3 extending from a pair of lands. In addition, it is more preferable that the region where the electrode film 2 extending from the land 4 and the resistor film 3 are overlapped and connected is present on the straight line connecting the centers of the lands 4 forming a pair. . This is because the distance in the current direction can be secured in the region where the electrode film 2 and the resistor film 3 overlap. As a rule of thumb, it has been recognized that if this distance is not greater than a certain value, there will be problems in maintaining the resistance element characteristics, such as a change in resistance value when an excessive voltage is applied between the resistance element terminals. However, when the area of a part of the land 4 is increased, the overlapping area of the electrode film 2 and the resistor film 3 extending from the land 4b and the distance must be reduced only for a specific resistance element. Can occur. By avoiding such a straight line and forming a region where the electrode film 2 and the resistor film 3 overlap each other, the distance can be sufficiently secured.

  However, in the present invention, increasing the area of the land 4 does not necessarily reduce the distance between the electrodes 2 of the resistance element. This is because the area of the land 4 can be increased by increasing only the dimension of the land 4 in the long side direction of the substrate 1. This is also a great advantage of the present invention. Here, the “land 4b” in the preferable electronic component means that, as a result of increasing the land 4 area as shown in FIG. 1, the distance between the electrodes 2 extending from the land 4 extends from the land 4 that does not increase the area. It means the land 4 when the distance between the electrodes 2 is smaller than the distance.

  In the electronic component of the present invention and a preferable electronic component based on the electronic component, it is more preferable that the conductive protrusion 9 does not substantially contain lead. In general, the conductive protrusion 9 containing lead (mainly a low-melting point alloy such as solder) has lower rigidity than the conductive protrusion 9 that does not substantially contain lead, and has a poor function as a buffer against external force. There is an advantage that the deterioration of the fixing state between the conductive protrusion 9 and the land 4 due to the influence of external force is small. On the other hand, the conductive protrusions 9 that do not substantially contain lead are inferior in function as such a buffer material, and the influence of external force is relatively large.

  Furthermore, since it is not preferable to contain lead in an electronic component from the viewpoint of environmental harmony, the conductive protrusion 9 is a low melting point metal not containing lead, for example, Sn alone, Sn-Bi alloy, Sn-In-Ag series. Alloy, Sn—Bi—Zn alloy, Sn—Zn alloy, Sn—Ag—Bi alloy, Sn—Bi—Ag—Cu alloy, Sn—Ag—Cu alloy, Sn—Ag—In alloy, It is desirable to use mainly one or more selected from Sn—Ag—Cu—Sb alloys, Sn—Ag alloys, Sn—Cu alloys, and Sn—Sb alloys. The same applies to the cream solder 8 described above.

  Further, in the electronic component of the present invention and a preferable electronic component based on the electronic component, all the elements 3 constituting the electronic component, for example, each resistor 3 in the case where the circuit element is a resistive element have substantially the same shape, and More preferably, the distance between the adjacent resistors 3 is substantially the same. When the resistance element is energized, Joule heat is always generated in the film of the resistor 3. There is no problem if the Joule heat is small and hardly affects the characteristics of the resistance element (for example, resistance temperature characteristics (TCR)). However, when Joule heat that affects the TCR is generated and heat concentration occurs locally due to the arrangement of the resistor 3 of the electronic component, the difference in the characteristics of the respective resistance elements may become significant. is there. This is because it is effective in preventing such local heat concentration. For example, the heat concentration can be prevented by arranging the distances between the adjacent resistors 3 to be substantially equal as in the electrode film 2 and the resistor film 3 shown in FIG.

  From such a viewpoint, it is more preferable that the conductive protrusion 9 is mainly made of copper. Copper has a very high thermal conductivity compared to solder or the like, and Joule heat generated by the resistance element can be quickly released to the mounting circuit board 12. Therefore, even if the resistor 3 is arranged such that Joule heat can be locally concentrated, the resistance element characteristics can be stabilized.

  Further, copper has a coefficient of thermal expansion as small as about 2/3 as compared with conventionally used solder (for example, 37Pb-63Sn alloy). Therefore, even if the substrate 1 is fixed to the land 4 and then exposed to an environment in which heating and cooling are repeated, there is little risk of peeling from the land 4. Also, since copper is very hard compared to solder, the conductive protrusion 9 is hardly deformed by handling in the case of a so-called bump shape, and the height of many conductive protrusions 9 from the substrate 1 surface is constant. Is advantageous.

  Further, it is more preferable that Sn plating is applied to the surface of the copper. This is for improving the solder wettability of the conductive protrusions 9 and for preventing oxidation of the copper surface. When the copper surface is oxidized, it is difficult to alloy with solder at the time of mounting on the mounting board, and it is difficult to obtain an appropriate mounting state with the mounting board or land 4.

  Here, those mainly composed of copper include pure copper, a surface of pure copper plated with Sn, an alloy mainly composed of copper, and a surface of the alloy plated with Sn.

  In addition, it can replace with the said copper and can also use gold | metal | money. The advantage of using gold is that it does not necessarily require an anti-oxidation layer on the surface, and has the same or more flexibility as solder, so it has low rigidity and functions as a buffer against external forces. Therefore, the deterioration of the fixing state between the conductive protrusion 9 and the land 4 due to the influence of external force is small.

  Moreover, in the preferable electronic component of the present invention, it is preferable that the land 4b having a particularly large area is made of a metal glaze material and the entire surface of the land 4b is covered with a fixing member. The metal glaze material is firmly fixed to the surface of the ceramic substrate 1 made of alumina or the like. This fixing force is usually larger than the fixing force of the copper foil formed (fixed) on the surface of the so-called glass fiber mixed epoxy resin substrate 1. In particular, the difference in fixing force increases as the ambient environment becomes higher. Further, since the fixing member is provided on the entire surface of the land 4b, the fixing force between the conductive protrusion 9 and the surface of the land 4 is also ensured. Therefore, even when an external force is applied to the conductive protrusion 9 in a state where the conductive protrusion 9 is fixed, peeling at the interface between the substrate 1 and the land 4 can be effectively suppressed. Here, since the land 4b has a larger area than the land 4a, the land 4b is made of a metal glaze material, and the effect of increasing the fixing strength by covering the entire surface with the fixing member is larger.

  Moreover, it can replace with the said metal glaze and can also use a conductive adhesive. This is because, for example, a conductive adhesive mainly composed of an epoxy resin or an acrylic resin can be firmly fixed to the surface of the ceramic substrate 1 made of alumina or the like as well as the metal glaze material.

  In the electronic component of the present invention and a preferable electronic component based on the electronic component, it is more preferable that the conductive protrusion 9 includes a ball 10 and the land 4 has means for holding the ball 10. When the area of the land 4 is increased, there is a concern about a deviation in the fixing position of the ball 10 disposed thereon. When the shape of the land 4 is not a circle such as a quadrangle as in the present invention, it is caused by the surface tension of the molten solder when solder is used for the fixing member between the land 4 and the ball 10 as compared to the case of a circle. In some cases, it is difficult to expect the effect of correcting the position of the ball 10. A specific example of the ball 10 holding means is a means in which a protruding member 14 capable of holding the ball is disposed in advance on the surface of the substrate 1 under the conductive film such as a metal glaze material constituting the land 4. . According to such means, the protruding member 14 exists so as to raise the conductive film, and has an effect of holding the ball 10 on the conductive film even after the conductive film is formed. The protrusions 14 are arranged on the surface of the substrate 1 by, for example, screen printing of a paste such as glass or resin (FIG. 6).

  Further, in the case where the electronic component of the present invention and the preferred electronic component based thereon are resistors, the electrode in which the resistor 3 is formed on the substrate 1 and the electrode 2 is directly formed on the resistor 3 More preferably, the two portions constitute the land 4. This is because the land 4 can be formed also in the electrode 2 region where the resistor 3 and the electrode 2 overlap, and a larger land 4 area can be secured. In the conventional configuration in which the electrode 2 is formed on the substrate 1 and the resistor 3 is formed directly on the electrode 2, the land 2 is formed in the electrode 2 region where the resistor 3 and the electrode 2 overlap. 4 cannot be formed or is very difficult.

  According to the present invention, it is possible to obtain an electronic component using a conductive protrusion having a structure capable of withstanding an external force after mounting as a terminal.

(Manufacture of network resistor as an example of the first and second electronic components of the present invention)
A large insulating substrate 1 made of alumina ceramic is prepared. Dividing grooves are provided vertically and horizontally on both surfaces of the large insulating substrate 1, and the insulating substrate 1 of the smallest unit after the division constitutes a unit network resistor. The process of forming a large number of resistance elements on the surface of the large insulating substrate 1 having the grooves will be described below with reference to FIG. In the drawing, the minimum unit insulating substrate 1 (corresponding to FIG. 1A) is shown.

  First, a metal glaze-based Ag—Pd conductive paste is screen-printed on the insulating substrate 1 shown in FIG. 2A and then fired, and a part thereof becomes the terminal connection land 4 of the resistance element. An electrode film 2a and a common electrode film 2b are obtained (FIG. 2A). As shown in the figure, the shape of the two individual electrode films 2a from the left and right ends of the substrate 1 where the lands 4b are formed later is a straight line connecting the centers of the lands 4 (not shown) that form the pair. It is assumed that there may be a region where the electrode film 2 and the resistor film 3 are overlapped and connected, avoiding the above. Further, the individual electrode film 2a dimension along the long side direction of the substrate 1 is made larger than the individual electrode film 2a dimension along the short side direction.

  Next, the common electrode film 2b and the individual electrode film 2a are made into a pair of electrode films 2, and a metal glaze resistor paste mainly composed of ruthenium oxide and glass frit is screen-printed so as to be in contact with both, and then fired. Thus, the resistor film 3 is obtained (FIG. 2B). Thus, a resistance element is obtained. Next, a glass paste is screen-printed so as to cover the resistor film 3, and then fired to obtain a glass film 5 (FIG. 2 (c)). As shown in the figure, the resistor film 3 formed between the individual electrode film 2a in which the land 4b is formed later and the common electrode film 2b at the other end of the land 4b are formed on the land 4 in the pair. It is formed so as to avoid a region where the electrode film 2 and the resistor film 3 are overlapped and connected on a straight line connecting the centers.

  Next, in order to set the resistance value of the resistance element to a desired value, a step of adjusting the resistance value by forming a trimming groove 6 in the resistor film 3 by laser irradiation is performed (FIG. 2D). At this time, the glass film 5 acts to suppress damage of the entire resistor film 3 as much as possible.

  Next, in order to protect the entire resistance element with the overcoat film 7, an epoxy resin paste is screen-printed, and then the paste is heat-cured (FIG. 2E). When the overcoat film 7 is disposed, the land 4 portion which is a necessary portion in the individual electrode film 2a and the common electrode film 2b is exposed. The land 4 shape was rounded at the four corners of the rectangle. In the land 4 portion, the individual electrode film 2a and the land 4b on the common electrode film 2b located at two positions from the left and right ends of the insulating substrate 1 are about 1.4 times the land 4a. When the conductive protrusion 9 is fixed only on the land 4b, the network resistor can stand up in a state where the conductive protrusion 9 and the flat ground are in contact with each other.

  Next, commercially available solder solder 8 made of a Sn-Ag-Cu alloy is disposed on these lands 4 by screen printing using a metal mask having an opening substantially corresponding to each land 4 area value (FIG. 2). (F)). At this time, the cream solder 8 was spread over the entire area of each land 4, and the cream solder 8 as the fixing member in an amount proportional to the land 4 area was supplied to each land 4.

  Then, with a commercially available solder ball mounting device, a commercially available pure copper ball 10 (surface coated with Sn plating) as a conductive ball is mounted on the cream solder 8 portion.

  Thereafter, at a temperature at which the cream solder 8 is melted and solidified, it is subjected to a so-called reflow process in which the insulating substrate 1 is held together with the resistance element and the pure copper ball 10 for a predetermined time, and the land 4 and the pure copper ball 10 are fixed and connected. . At this time, a part of the pure copper ball 10 is melted and re-solidified together with the cream solder 8, thereby forming the “conductive protrusion 9” mainly composed of pure copper. The pure copper ball 10 moved to the center of each land 4 when the cream solder 8 was melted. This is due to the surface tension of the molten cream solder 8.

  Through the above process, the network resistor of the present invention can be obtained. Thereafter, when the stress is applied along the dividing grooves provided in the insulating substrate 1, the individual network resistors of the present invention can be obtained.

  The obtained land portion of the present example and the conventional network resistor were observed. FIG. 3A and FIG. 7A show a fixed state between the land 4 and the ball 10 in this example. FIG. 3B and FIG. 7B show a fixed state of the ball 10 with the conventional circular land 4 (a land area that is π / 4 times the land 4 area of this example). FIGS. 3A and 3B show a state in which the cream solder is attached to substantially the entire area of the ball 10 (the solder has good wettability). FIGS. 7A and 7B show a state in which the cream solder is attached only to the vicinity of the land 4 of the conductive ball 10. In the manufactured network resistor, both the one shown in FIGS. 3A and 3B and the one shown in FIGS. 7A and 7B were observed.

  3A, 3B, 7A, and 7B, it can be seen that the amount of the solidified cream solder 11 fixed to the land 4 of this example is larger than that of the conventional circular land 4. And it turns out that the conductive ball 10 arrange | positioned at the land 4 of this example is supported by many fixing members. Therefore, the conductive protrusions 9 in which the solidified cream solder 11 shown in FIGS. 3 (a) and 3 (b) is deposited over almost the entire area of the ball 10 are conductive protrusions fixed to the conventional circular land 4 in the same state. Compared to 9, it was about 1.2 times the maximum thickness.

  3 (a), (b) and FIGS. 7 (a), (b) are substantially common in that the bonding strength of the ball 10 in the land 4 of this example is a conductive ball in the conventional circular land 4. This is an improvement of about 40% in comparison with the 10 sticking strength. In the fixing strength measurement method, the conductive ball 10 is fixed to the land 4 by the same method as described above, and stress is applied from the fixed state to the side of the conductive ball 10 along the surface of the substrate 1 until the ball 10 is peeled off. In this case, the stress was measured. 3 (a), (b) and FIGS. 7 (a) and 7 (b) have substantially the same fixing strength, the major factor determining the fixing strength is not the thickness of the conductive protrusion 9, It can be inferred that this is the fixed area between the conductive ball 10 and the land 4.

  Furthermore, the network resistor of the present invention was surface-mounted on a circuit board 12 (mounting board) which is an epoxy resin molded body mixed with glass fiber. When mounting, the same solder paste 8 as the cream solder 8 is screen-printed on the land 13 of the circuit board, and each conductive protrusion 9 of the network resistor of the present invention is mounted at the position of the land 13 of the circuit board. And it used for the reflow process similar to the above. Then, the mounting state shown in FIG. 4B or 7D was obtained. Thereafter, when a test for applying a repeated thermal shock to the mounted body in a mounted state (according to JIS C5201-1, the number of repeated thermal shocks was 2000) was performed, both ends in the long side direction (ceramics) The above-mentioned “external force” due to a positional shift of the substrate 1 (position close to both outer ends on the short side) was generated. Such an external force is caused by the circuit board 12 slightly expanding and contracting as shown in FIG. However, the appearance of the conductive ball 10 fixed to the land 4 did not change. Here, it can be seen that the deformation is large because the two conductive protrusions 9 at positions close to the outer end of the substrate 1 in FIGS. 5B and 5C are subjected to a larger external force than the other conductive protrusions 9. .

  On the other hand, in the network resistor not according to the present invention in which all the lands 4 are the above-described conventional circular lands 4, the mounting state is as shown in FIG. 4 (a) or FIG. 7 (c). Position where the amount of solidified cream solder 11 deposited in the surroundings is small, and a slight deformation is seen in the state of appearance of the pure copper ball 10 to the land 4a, and the land 4b in FIG. The conductive protrusion 9 was peeled off from the land 4a corresponding to. This is presumably that a large stress was applied to the fixing portion between the land 4a and the conductive protrusion 9 as it approached the outer edge in the long side direction of the substrate 1.

  In the manufacture of the network resistor of the present invention, a fired product of a metal glaze material is used as the material of the land 4, but it goes without saying that other materials can be used. For example, a copper foil material or a conductive adhesive that is arranged on the surface of the circuit board 12 and patterned.

  In the manufacture of the network resistor of the present invention, pure copper balls 10 are used, but solder balls can be used. In place of the solder balls, conductive balls such as resin core balls can be used.

  Further, it goes without saying that the manufacturing process of the network resistor of the present invention shown in FIG. 2 can be similarly applied to the network resistor of the present invention having the arrangement of FIG. Here, the advantage of the network resistor by the arrangement of FIG. 1B is prevention of heat concentration as described above. On the other hand, the first advantage of the electronic component by the arrangement of FIG. 1A is that the external dimensions of the resistor can be made slightly smaller than in the case of FIG. The second advantage is that the shape of the individual electrode film 2a on which the land 4a is formed can be simplified as compared with the case of FIG. Accordingly, when the electrode film 2a is formed by a thick film such as screen printing, the shape variation can be particularly reduced, which is preferable. This is particularly advantageous as the network resistor is reduced in size. On the other hand, the advantage of the arrangement shown in FIG. 1B is that all the lands 4 can be used as the lands 4b as shown in the figure, and the fixing strength between the lands 4 and the conductive protrusions 10 can be improved. .

  Moreover, although the said groove | channel for a division | segmentation is formed in both surfaces of the board | substrate 1, it cannot be overemphasized that one side may be sufficient. Particularly when grooves are formed by laser scribing, it is generally difficult to align the groove positions on both sides, and it is rather preferable to form grooves only on one side.

  In the present embodiment, lands 4b having a large area are arranged at both ends in the long side direction of the substrate 1, and the remaining lands 4a have a relatively small area. However, in the present invention, all the lands can be the lands 4a having a relatively small area or the lands 4b having a large area. It goes without saying that even with such a configuration, the problem to be solved by the present invention can be solved as long as the area of the land 4 can be increased as compared with the prior art.

  INDUSTRIAL APPLICABILITY The present invention can be used in an electronic component related industry having a circuit element such as a plurality of resistance elements on the substrate surface and an external terminal of the circuit element made of a conductive protrusion.

It is a figure which shows the positional relationship of the electrode film of a network resistor of this invention, a resistor film, and the land. The lands 4a and 4b illustrate the outlines of regions that become lands after subsequent processes. It is a figure which shows the process in which the network resistor of this invention is manufactured. In the network resistor of this invention, (a) is a longitudinal cross-sectional schematic diagram of a normal land, (b) is a figure which shows the vertical cross-sectional schematic diagram of a land with a large area. When the network resistor of the present invention is mounted on a circuit board, (a) is a schematic vertical sectional view of ordinary lands and conductive protrusions, and (b) is a schematic vertical sectional view of large lands and conductive protrusions. FIG. (A) is a schematic diagram which shows the side surface state of the board | substrate long side before implementing a thermal shock provision test with respect to the network resistor which concerns on this invention. (B) is a schematic diagram showing a side surface state on the long side of the substrate during cooling in the thermal shock application test. (C) is a schematic diagram which shows the side surface state of the substrate long side at the time of the heating of a thermal shock provision test. It is a figure which shows the state which raises a part of land which concerns on this invention, and hold | maintains a conductive ball. In the network resistor according to the present invention, (a) is a schematic vertical sectional view of a normal land, (b) is a schematic vertical sectional view of a land having a large area, and (c) is a circuit board of the network resistor according to the present invention. FIG. 4D is a vertical cross-sectional schematic diagram of a normal land and conductive protrusion when mounted on a circuit board, and FIG. 4D is a vertical cross-section of a land and conductive protrusion having a large area when the network resistor according to the present invention is mounted on a circuit board. It is a figure which shows a schematic diagram.

Explanation of symbols

1. Substrate 2. Electrode, electrode film 2a. Individual electrode film 2b. 2. Common electrode film 3. Resistor, resistor film Land 4a. Small land 4b. 4. Land with large area Glass film6. 6. Trimming groove Overcoat film 8. Cream solder9. Conductive protrusion 10. Ball 11. 11. Solidified cream solder Circuit board 13. Circuit board land 14. Protruding member

Claims (9)

In an electronic component having a plurality of circuit elements formed on a rectangular substrate surface and having external terminals of the circuit elements made of conductive protrusions,
While leaving a part of the electrodes constituting the circuit element as a land, the circuit element is covered with an overcoat film,
The land long side dimension of the land is larger than the substrate short side dimension,
The electronic component according to claim 1, wherein the conductive protrusion is fixed to the land by an amount of fixing member substantially proportional to the land area value.   2. The electronic component according to claim 1, wherein the unit circuit element has two external terminals, and lands constituting the external terminals are arranged along the short side direction of the substrate.   The circuit element is a resistance element having an electrode film and a resistor film extending from a pair of lands, and an area where the electrode film extending from the land and the resistor film overlap and are connected is a pair. The electronic component according to claim 1, wherein the electronic component is present avoiding a straight line connecting the centers of the lands.   4. The electronic component according to claim 1, wherein the conductive protrusion does not substantially contain lead.   5. The electronic component according to claim 4, wherein the conductive protrusion is mainly made of copper.   6. The electron according to claim 1, wherein all of the resistors constituting the network resistor have substantially the same shape, and the distance between the adjacent resistors is substantially the same. parts.   The circuit element and the conductive protrusion are arranged on the same substrate surface, or the circuit element and the conductive protrusion are arranged on both surfaces of the substrate, respectively. The electronic component described.   The electronic component according to claim 1, wherein the conductive protrusion includes a ball, and the land includes means for holding the ball.   9. The electronic component according to claim 1, wherein the electronic part is a resistor, and the electrode portion in which the resistor is formed on the substrate and the electrode is directly formed on the resistor constitutes a land. Electronic component according to crab.

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