JP2006086542A - Electronic component with bump electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component with bump electrode, which has an insulating film for surface protection in sufficient film thickness and a bump part in sufficient height and in which occurrence of an open fault is appropriately reduced in a manufacture process. <P>SOLUTION: The electronic component X1 is provided with a substrate 11, an electrode pad 12 arranged on the substrate 11, the insulating film 13 which has an opening part 13a corresponding to the electrode pad 12 and is laminated and formed on the substrate 11, a conductive connection part 14 disposed on the electrode pad 12 in the opening part 13a and the bump part 15 having a spherical part which is directly brought into contact with the conductive connection part 14 and is projected from the opening part 13a. A diameter of the spherical part of the bump part 15 is larger than that of the opening part of the insulating film 13. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique of electronic components with bump electrodes. More specifically, the present invention relates to a technology of electronic components such as a semiconductor chip having a bump electrode such as a ball grid array (BGA) and a printed wiring board.

  In recent years, regarding the mounting of electronic components on a printed wiring board or a ceramic substrate, there is an increasing demand for higher density, and the bare chip mounting method has attracted attention as a method that satisfies such a requirement. In the bare chip mounting method, instead of the conventional face-up mounting in which electrical connection between the semiconductor chip and the substrate wiring is achieved through wire bonding, it is achieved by interposing bumps between the electrode pads of the semiconductor chip and the wiring substrate. Face-down mounting, that is, flip chip bonding tends to be employed. In face-down mounting, bump electrodes are previously formed on the mounting surfaces of the semiconductor chip and the wiring board before mounting in order to interpose bumps between the semiconductor chip and the electrode pads of the wiring board. A technique related to such an electronic component with a bump electrode is described in Patent Document 1 below, for example.

Japanese Patent Laid-Open No. 4-112537

  FIG. 12 shows an example of a conventional method for manufacturing a semiconductor chip with bump electrodes. In the conventional method, first, a predetermined metal mask 44 is prepared for the semiconductor chip 40 as shown in FIG. On the surface of the base material 41 in the semiconductor chip 40, a wiring pattern including electrode pads 42 (not shown except for the electrode pads 42) is formed. On the base material 41, an insulating film 43 is further laminated from above the wiring pattern in order to protect the wiring pattern. The insulating film 43 has an opening 43 a at a position corresponding to each of the electrode pads 42. The metal mask 44 has an opening 44a formed in advance at a position corresponding to the electrode pad 42 and the opening 43a.

  Next, as shown in FIG. 12B, the opening 44 a and the electrode pad 42 are aligned, and the metal mask 44 is placed on the semiconductor chip 40. Next, as shown in FIG. 12C, a solder paste 45 containing a predetermined solder powder is supplied to the opening 44a of the metal mask 44 and the opening 43a of the insulating film 43 by a printing method. Next, as shown in FIG. 12D, the metal mask 44 is removed from the semiconductor chip 40 leaving the solder paste 45. Next, as shown in FIG. 12 (e), a bump portion 46 is formed on the electrode pad 42 through a heat treatment for once melting the solder powder in the solder paste 45.

  The semiconductor chip 40 on which the bump electrodes are formed in this way is flip-chip bonded to the wiring board 50 as shown in FIG. Specifically, the electrode pad 42 of the semiconductor chip 40 and the electrode pad 52 of the wiring substrate 50 are electrically and mechanically connected via the bump portion 46. In such flip chip bonding, generally, an adhesive or underfill agent 60 is filled between the semiconductor chip 40 and the wiring substrate 50 as shown in FIG. The underfill agent 60 protects the bump portions 46 connecting the electrode pads and protects the mounting surfaces of the semiconductor chip 40 and the wiring substrate 50. Such an underfill agent 60 ensures connection reliability over a long period in the flip chip bonding.

  However, in the conventional method for manufacturing an electronic component with a bump electrode described above with reference to FIG. 12, a so-called open (non-contact) defect often occurs in the bump electrode structure. The open defect means that when the heat treatment described above with reference to FIG. 12E is performed, the bump forming material is spheroidized mainly on the insulating film 43, and, for example, as shown in FIG. This is a defect in which a gap is formed between the insulating film 43 and the insulating film 43. In this case, the diameter of the spherical part of the bump part 46 to be formed, that is, the design dimension of the spherical part of the bump part 46 This may occur when the diameter of the opening 43a is larger than the diameter of the opening 43a. When an open failure occurs, the electrical connection between the electrode pad 42 and the bump portion 46 is not properly achieved. The open failure shown in FIG. 14A is likely to occur when all the bump forming materials are spheroidized on the insulating film 43 and the solder paste is used as the bump forming material as described above. The open defect shown in FIG. 14 (b) takes a form in which a part of the bump forming material is left on the electrode pad 42 and other bump forming materials are spheroidized on the insulating film 43, and molten solder or solder plating is used as the bump forming material. It tends to occur when used.

  The electrode pad 42 formed on the base material 41 in the semiconductor chip 40 has the same predetermined thickness as other wiring parts as a part of the wiring pattern formed on the surface of the base material 41. The insulating film 43 that covers and protects the wiring is required to have a certain film thickness according to the thickness of the wiring. The electrode pad 42 is positioned deeper in the opening 43a of the insulating film 43 as the film thickness of the insulating film 43 is increased to more reliably protect the wiring. As the electrode pad 42 is located deeper in the opening 43a, an open defect as shown in FIG. 14 is more likely to occur. On the other hand, the thinner the insulating film 43 is in order to suppress open defects, the easier it is for an insulation defect to occur due to pinholes generated in the insulating film 43. That is, the coverage of the insulating film 43 with respect to the wiring is lowered. Further, if the diameter of the opening 43a of the insulating film 43 is increased, it may not be possible to cope with a fine pitch.

  On the other hand, the bump portion 46 is desired to be higher within the constraints of the electrode pitch. In order to sufficiently fill the underfill agent 60 for maintaining the reliability of the connecting portion as shown in FIG. 13B, it is necessary to widen the gap between the semiconductor chip 40 and the wiring substrate 50. Because. The surface curvature of the higher bump portion 46, that is, the bump portion 46 having a larger volume, tends to be smaller, and therefore, the higher the bump portion 46, the smaller the degree of entry into the opening 43a. As the degree of entry of the bump part 46 into the opening 43a is smaller, an open defect as shown in FIG. 14 is more likely to occur.

  As described above, in the electronic component with bump electrodes, it is necessary to make the insulating film thicker than a certain value and make the bump part higher than a certain value at a certain electrode pitch. Therefore, in the conventional bump electrode structure, an open defect as shown in FIG. 14 often occurs in recent electronic components where the electrode pitch is becoming finer.

  The present invention has been conceived under such circumstances, and has an insulating film for surface protection having a sufficient thickness and a bump portion having a sufficient height, and has an open defect in the manufacturing process. An object of the present invention is to provide an electronic component with a bump electrode in which generation is appropriately reduced, and a manufacturing method thereof.

  According to a first aspect of the present invention, an electronic component with a bump electrode is provided. The electronic component includes a base material, an electrode pad provided on the base material, an insulating film having an opening corresponding to the electrode pad and formed on the base material, and an electrode in the opening. A conductive connecting portion provided on the pad; and a bump portion having a spherical portion that directly contacts the conductive connecting portion and protrudes from the opening. In this electronic component, the diameter (for example, diameter) of the spherical portion of the bump portion is larger than the diameter (for example, diameter) of the opening of the insulating film.

  The electronic component with a bump electrode having such a configuration appropriately includes a surface protective insulating film having a sufficient thickness and a bump portion having a sufficient height, and the occurrence of open defects is appropriately reduced in the manufacturing process. In the electronic component according to the first aspect, the conductive connecting portion is interposed between the electrode pad and the bump portion. The conductive connecting portion is provided on the electrode pad and is in direct contact with the bump portion in the opening of the insulating film. Therefore, in this electronic component, by providing a conductive connecting portion having an appropriate thickness or height, an open defect between the bump portion having a spherical portion larger than the diameter of the insulating film opening and the electrode pad is prevented. It is possible to provide an insulating film having a sufficient film thickness to protect the wiring pattern on the surface of the substrate in the electronic component while suppressing the occurrence, and depending on the depth of the electrode pad position in the opening. In addition, the bump portion having a sufficient height can be provided.

  The above-mentioned Patent Document 1 discloses a technique aimed at reducing open defects, but this technique employs an electroplating method when forming bump portions. Therefore, according to the technique, it is necessary to form a current-carrying layer for electroplating on the insulating film for surface protection and to remove the etching thereof, and to manufacture electronic components with bump electrodes with a high yield. Have difficulty. On the other hand, in the present invention, the bump portion is formed in direct contact with the conductive connecting portion. That is, the bump portion is not formed by electroplating. Moreover, in the technique disclosed in Patent Document 1, the electrode pad and the bump portion on the surface of the substrate are electrically connected by an electroless plating layer. In order to form a good electroplating bump portion, it is necessary to form the electroless plating layer until it is flush with the insulating film, and it takes a long time to form such an electroless plating layer. . Therefore, with the technique disclosed in the publication, it is difficult to manufacture electronic components with bump electrodes with a high yield.

  In a preferred embodiment, the conductive connecting portion has a lead-in protrusion that contacts the bump portion. Even if the height of the uppermost surface of the conductive connecting portion is not made uniform, and the height of only a part of the uppermost surface is secured, the above-described effect by the conductive connecting portion can be obtained.

  Preferably, the height H of the conductive connecting portion from the base material, the theoretical penetration depth h with respect to the opening of the true sphere having the same volume as the bump portion, and the film thickness L of the insulating film satisfy H + h ≧ L. Have a relationship. According to such a configuration, it is possible to appropriately reduce open defects.

  Preferably, the conductive connecting portion has a laminated structure including a plurality of layers. Preferably, the conductive contact portion or the layer in contact with the bump portion in the conductive contact portion is made of Au or Sn. Preferably, the conductive contact portion or the layer in contact with the bump portion in the conductive contact portion is made of a material that can be melted at a temperature equal to or lower than the melting temperature of the bump portion. With these configurations, various modes are possible for the conductive connecting portion, and the conductive connecting portion can be a preferable configuration for achieving good electrical connection.

  Preferably, the bump portion is made of a metal material selected from the group consisting of tin, indium, lead, bismuth, silver, copper, zinc, and antimony. A bump having a desired composition is preferably formed from such a metal material.

  According to a second aspect of the present invention, a method for manufacturing an electronic component with bump electrodes is provided. This manufacturing method includes a step of forming a conductive communication portion in an opening on the electrode pad in a base material provided with an electrode pad and an insulating film having an opening corresponding to the electrode pad; Forming a bump portion on the conductive connecting portion so as to directly contact the conductive connecting portion and protrude from the opening.

  According to the second aspect of the present invention, the electronic component according to the first aspect can be manufactured. Therefore, according to the method according to the second aspect, an electronic component with a bump electrode having a sufficiently thick surface protective insulating film and a sufficiently high bump portion is manufactured while reducing open defects in the manufacturing process. can do.

  Preferably, the step of forming the conductive communication portion is performed by an electroless plating method and / or an electroplating method. Preferably, in the step of forming the conductive communication portion, a plurality of plating materials are sequentially deposited. Preferably, the step of forming the conductive connection portion includes a step of forming a lead-in protrusion that protrudes toward the bump portion formation position. With such a configuration, a good conductive communication portion can be formed.

  In a preferred embodiment, the step of forming the bump portion includes a step of laminating a resin film on the insulating film, a step of forming an opening so that the conductive connection portion is exposed to the resin film, It includes a step of supplying a solder paste to the opening of the resin film, a step of forming a bump portion from the solder paste through heat treatment, and a step of peeling the resin film from the insulating film. Instead, the step of forming the bump portion includes a step of laminating a resin film on the insulating film, a step of forming an opening so that the conductive connecting portion is exposed to the resin film, and a resin. A step of supplying molten solder to the opening of the film, a step of cooling the molten solder to form a bump portion, and a step of peeling the resin film from the insulating film may be included. Instead, the step of forming the bump portion includes the step of laminating and forming a resin film on the insulating film, the step of forming an opening so that the conductive contact portion is exposed to the resin film, and plating. The method may include a step of depositing a solder material in the opening portion of the resin film, a step of forming a bump portion from the solder material through heat treatment, and a step of peeling the resin film from the insulating film. Instead of this, the step of forming the bump portion may include a step of placing a solder ball for each opening of the insulating film and a step of forming the bump portion from the solder ball through heat treatment. When a resin film is used for forming the bump portion, the resin film is preferably a photosensitive resin film.

  In the second aspect of the present invention, preferably, the height H of the conductive connecting portion from the base material, the theoretical penetration depth h with respect to the opening of the true sphere having the same volume as the bump portion, and the film of the insulating film The conductive connecting portion and the bump portion are formed so that the thickness L satisfies the relationship of H + h ≧ L.

  FIG. 1 is a partial cross-sectional view of an electronic component X1 with bump electrodes according to the first embodiment of the present invention. The electronic component X1 corresponds to a semiconductor chip, a printed wiring board, or the like, and includes a base material 11, an electrode pad 12, an insulating film 13, a conductive connecting portion 14, and a bump portion 15. On the surface of the base material 11, a wiring including the electrode pad 12 is formed in a pattern. The insulating film 13 is provided on the base material 11 in order to cover and protect the wiring, and has an opening 13 a at a location corresponding to the electrode pad 12. The conductive communication portion 14 is provided on the electrode pad 12 in the opening 13a. The bump portion 15 is provided in direct contact with the upper surface of the conductive connecting portion 14 and protrudes to the outside from the opening portion 13a. Moreover, the diameter of the spherical part shown in FIG. 1 of the bump part 15 is larger than the diameter of the opening part 13a.

  When the height of the conductive connecting portion 14 from the base material 11 is H [μm], the theoretical penetration depth of the bump portion 15 is h [μm], and the film thickness of the insulating film 13 is L [μm], this implementation In the form, the height H, the theoretical penetration depth h, and the film thickness L satisfy the relationship of the following formula (1). Here, regarding the bump portion 15, the theoretical approach depth h is a true sphere having the same volume as the bump portion 15, and the true sphere is placed so as to close the opening 13 a assumed to be a cavity. In this case, it means the maximum length that a true sphere can theoretically enter the opening 13a.

  Assuming that the diameter of the opening 13a of the insulating film 13 is D [μm] and a true sphere having the same volume as the bump part 15 that is spheroidized so as to close the opening 13a is assumed, the diameter of the true sphere is R Assuming that [μm], the theoretical penetration depth h [μm] is expressed by the following formula (2). In Expression (2), the first term on the right side is the radius of the true spherical bump portion, and the second term on the right side is the distance from the center of the true spherical bump portion to the opening 13a and is derived by the three square theorem. It is.

  Further, when the depth from the upper surface of the insulating film 13 to the uppermost surface of the conductive connecting portion 14 is t [μm], t is expressed by the following formula (3).

  In order not to cause an electrical open defect between the electrode pad 12 and the bump portion 15, the conductive connecting portion 14 connected to the electrode pad 12 and the bump portion 15 need to be in physical contact. When h and t satisfy the following formula (4), the conductive connecting portion 14 and the bump portion 15 tend to come into reliable contact.

  Therefore, the following formula (5) is derived by substituting the formulas (2) and (3) into the formula (4) for the condition that the open defect is sufficiently suppressed.

  When the thickness L of the insulating film 13 is 30 [μm] and the diameter R of the true spherical bump portion is 120 [μm], the height H of the conductive connecting portion 14 is taken on the vertical axis, and the diameter D of the opening portion 13a. Is taken on the horizontal axis, the relationship diagram shown in FIG. 2 is obtained. In FIG. 2, the ◯ plot means that the formula (5) is satisfied, and the x plot means that the formula (5) is not satisfied. Based on these plots, it is possible to obtain a boundary line graph B that divides a condition area that can significantly suppress open defects and a condition area that does not.

  In the conventional bump electrode structure in a semiconductor chip having a BGA or the like, H = 0 because there is no conductive connecting portion. Assuming that the height of the electrode pad from the substrate is also zero, if H = 0 is substituted into the equation (5) for deformation, and both sides are connected only by an equal sign, the following equation (6) is obtained. Further, when the formula (6) is modified, the following formula (7) is obtained.

  In equation (6) for the bump electrode structure provided in a conventional semiconductor chip or the like, if R on the right side, that is, the bump portion size is constant, the value on the right side decreases as the opening diameter D decreases as the electrode pitch decreases. Thus, the value of the film thickness L converges to zero. This means that in the conventional bump electrode structure, as the opening diameter D becomes smaller, the problem that the coverage of the insulating film with respect to the wiring on the substrate surface tends to be directly induced.

  On the other hand, in the formula (7) for the bump electrode structure provided in the conventional semiconductor chip or the like, if the right side L, that is, the thickness of the insulating film is constant, the right side becomes smaller as the opening diameter D becomes smaller as the electrode pitch becomes narrower. And the value of the bump portion diameter R converges to the value of the film thickness L. The convergence of the bump portion diameter R value to the film thickness L value corresponds to the bump protrusion height from the insulating film surface converging to zero. This is because, in the conventional bump electrode structure, the smaller the opening diameter D, the lower the height of the bump portion and the more difficult it is to fill the underfill agent. Means.

  On the other hand, in the present invention, the height H of the conductive communication portion 14 from the base material 11 has an action of relaxing the conventional tendency described above with reference to the formulas (6) and (7). Such advantages of the present invention are the same even when the height of the electrode pad is taken into consideration.

  3-5 represents the manufacturing method of the electronic component X1. In the manufacture of the electronic component X1, first, as shown in FIG. 3A, the insulating film 13 is laminated to cover the electrode pad 12 on the base material 11 having the electrode pad 12 provided on the surface. To do. At this time, with respect to the film thickness L shown in FIG. 1, the insulating film 13 is formed so as to satisfy the above formula (1) in the electronic component X1 finally obtained. In forming the insulating film 13, a liquid resin composition for forming an insulating film is applied to the substrate 11 by spin coating or a printing method using a screen mask, and dried. Alternatively, in the formation of the insulating film 13, a film-shaped resin composition may be placed on the substrate 11 using a laminator or the like, and then heat-pressed at 50 to 140 ° C. As a resin composition for forming an insulating film, a resin material containing epoxy acrylate, polyimide, or the like can be used.

  Next, as shown in FIG. 3B, openings 13 a are formed in the insulating film 13 at locations corresponding to the electrode pads 12. For the formation of the opening 13a, a UV-YAG laser, a carbon dioxide laser, an excimer laser, or the like can be used. When the insulating film 13 having photosensitivity is formed, photolithography can be employed to form the opening 13a.

  Next, as shown in FIG. 3C, the conductive connecting portion 14 is formed on the electrode pad 12 in the opening 13a. At this time, the conductive contact portion 14 is formed so as to satisfy the above formula (1) in the electronic component X1 finally obtained with respect to the height H shown in FIG.

  The conductive connecting portion 14 can be formed by an electroplating method or an electroless plating method. When the electroless plating method is adopted in the formation of the conductive connecting portion 14, for example, first, in the state shown in FIG. 3B, a predetermined catalyst is attached to at least the surface of the electrode pad 12 in the opening 13a. Let Next, the conductive communication portion 14 is deposited and grown on the electrode pad 12 by the electroless plating method using the catalyst as a nucleus. When the electroplating method is employed in forming the conductive contact portion 14, for example, first, in the state shown in FIG. 3B, the insulating film 13 and the electrode pad 12 are covered by sputtering such as Ti or Ni. Thus, an energization layer is formed. In forming the conductive layer, instead of sputtering, a method of performing electroless plating on the entire surface so as to cover the insulating film 13 and the electrode pad 12 may be employed. Next, a plating resist is patterned on the conductive layer. The plating resist pattern has an opening corresponding to the opening 13a. Next, the conductive connecting portion 14 is deposited and grown in the opening 13a by electroplating. Next, the plating resist pattern is removed by etching, and the conductive layer on the insulating film 13 is removed by etching.

  As a material for forming the conductive connecting portion 14, a single metal such as Al, Au, In, Sn, Cu, Ag, Pd, Sn, Pb, Ag, Cu, In, Bi, Zn, Sb, Al, An alloy made of a plurality of single metals selected from Au or the like can be used. For example, the conductive connecting portion 14 can be formed of a low melting point metal such as In or Sn—Bi alloy. When the conductive contact portion 14 is formed of a low melting point metal, there may be a case where electrical connection with the bump portion 15 can be achieved at a relatively low temperature in a process described later. In that case, in the electronic component X1 finally obtained, it is possible to suppress problems caused by heating, for example, warpage of the base material 11.

  Alternatively, a multi-layered conductive connecting portion 14 as shown in FIG. 4 may be formed by sequentially laminating metals having different compositions. For example, in the step shown in FIG. 3C, Cu having a low resistance is deposited thickly on the electrode pad 12 to form the lower layer 14 ′, and then Sn having a lower melting point and lower hardness than Cu is formed in the lower layer 14 ′. The upper layer 14 ″ may be formed by being thinly deposited on the surface of the substrate. In the conductive connecting portion 14 having such a laminated structure, it is Sn plating that is the upper layer 14 ″ that directly contacts the bump portion 15 in the process described later. When a metal material having a relatively low melting point or a low hardness is used for a portion that comes into contact with the bump portion 15 while mainly using a metal material having a low electric resistance, the resistance between the conductive connecting portion 14 and the bump portion 15 is low. It is possible to satisfactorily achieve the electrical connection.

  After forming the conductive connecting portion 14, as shown in FIG. 3 (d), a resin film 30 is laminated. In the formation of the resin film 30, the film-shaped resin composition is placed on the laminated surface side, and then pressure-bonded while being heated at 50 to 140 ° C. Alternatively, the liquid resin composition may be applied to the laminated surface by spin coating or a printing method using a screen mask, and dried.

  As a resin composition for forming the resin film 30, photosensitive acrylate resin or non-photosensitive resin can be used. When the photosensitive acrylate resin is used, photolithography can be employed when forming the opening 30a described later. The resin composition for forming the resin film 30 may be liquid or film. Preferably, the resin composition for forming the resin film 30 is a dry film having photosensitivity. By using the photosensitive dry film, the formation of the resin film 30 is simplified. The resin film 30 is formed of a resin composition having a basic composition different from that of the insulating film 13. This is for suppressing damage to the insulating film 13 in the later-described process of peeling the resin film 30 using an alkali stripping solution. Further, from the viewpoint of forming high bumps on the electrode pads 12 provided at a fine pitch, the thickness of the resin film 30 is preferably 30 to 150 μm.

  After the formation of the resin film 30, as shown in FIG. 3E, openings 30 a are formed in the resin film 30 at locations corresponding to the respective conductive communication portions 14. For the formation of the opening 30a, a UV-YAG laser, a carbon dioxide laser, an excimer laser, or the like can be used. When the resin film 30 having photosensitivity is formed, photolithography can be employed to form the opening 30a. From the viewpoint of suppressing damage to the conductive connecting portion 14, it is preferable to employ photolithography. When employing photolithography, the conductive contact portions 14 are exposed by subjecting the resin film 30 to exposure processing through a predetermined photomask (not shown) and subsequent development processing. An opening 30a is formed in the substrate.

  Next, as shown in FIG. 5A, the opening 30a is filled with a solder paste 31. The solder paste 31 is filled by a printing method using a squeegee (not shown). As the squeegee, a urethane rubber squeegee is used to avoid or reduce damage to the resin film 30. In order to reliably fill the opening 30a with a predetermined amount of the solder paste 31, it is desirable to perform squeezing with a squeegee twice or more.

  The solder paste 31 is composed of solder powder and a flux vehicle. The solder powder is obtained by pulverizing a single metal selected from Sn, Pb, Ag, Cu, In, Bi, Zn, Sb, or an alloy made of a plurality of single metals selected from these. The content of the solder powder in the solder paste 31 is set to an amount satisfying the above formula (1). Specifically, when it is assumed that a bump part that is transiently melted in the heat treatment described later is a true sphere, the theoretical approach depth h of the true sphere is higher in the electronic component X1 finally obtained. The content of the solder powder in the solder paste 31 is determined so as to satisfy the above formula (1).

  The flux vehicle includes rosin, activator, thixotropic agent, and solvent. Examples of rosin include rosin acid, rosin acid ester, rosin anhydride, fatty acid, abietic acid, pimaric acid, isopimaric acid, neoabietic acid, dihydroabietic acid, dehydroabietic acid, and the like. As the activator, for example, one or more organic acids and / or organic amines selected from sebacic acid, succinic acid, adipic acid, glutaric acid, triethanolamine, monoethanolamine, tributylamine, ethylenediamine and the like are used. can do. As the thixotropic agent, hydrogenated castor oil, hydroxystearic acid, and the like can be used. As the solvent, 2-methyl-2,4-pentanediol, diethylene glycol monobutyl ether, or the like can be used.

  After the filling of the solder paste 31, as shown in FIG. 5B, a bump portion 15 is formed through a heat treatment. Specifically, first, the solder paste 31 filled in the opening 30a is melted by heating. As a result, the flux vehicle contained in the solder paste 31 volatilizes and disappears, and the solder powder melts and gathers. The pump part 15 is formed by subsequent cooling.

  Next, as shown in FIG. 5C, the resin film 30 is removed by applying an alkali stripping solution. The alkaline stripping solution includes a strong alkaline stripping solution such as a sodium hydroxide aqueous solution, an organic alkaline stripping solution such as a monoethanolamine aqueous solution and a tetramethylammonium hydroxide aqueous solution, and those obtained by adding a predetermined additive to these. Can be used. As an additive, what shows the effect | action which prevents the peeling remainder by destroying the resin film 30 to be peeled into a strip is preferable. At this time, in order to appropriately avoid damage to the insulating film 13, it is desirable to use an alkaline stripping solution having a pH of 11.5 or less. In order to appropriately perform such alkali removal, in this embodiment, a combination of the insulating film 13 and the resin film 30 having a significant difference in resistance to the alkali stripping solution is employed.

  In the above-described series of steps, the electronic component X1 includes the height H of the conductive connecting portion 14 from the base material 11, the theoretical penetration depth h of the bump portion 15, and the film thickness L of the insulating film 13 as described above. It is manufactured to satisfy the formula (1). Therefore, the electronic component X1 includes the electrode pad 12 while including the insulating film 13 having a sufficient film thickness and the bump part 15 having a sufficiently high spherical portion having a larger diameter than the diameter of the insulating film opening 13a. There is no open defect with the bump portion 15.

  The electronic component X1 with bump electrodes manufactured in this way is flip-chip bonded to the wiring board 32 as shown in FIG. 5D when the electronic component X1 is a semiconductor chip, for example. Specifically, first, the electronic component X1 is mounted on the wiring board 32 by aligning the bumps 15 and the electrode pads 33 of the wiring board 32 so as to face each other. Next, by performing reflow heating, the bump portion 15 and the electrode pad 33 are mechanically joined and electrically connected. The maximum heating temperature in the heat treatment is, for example, 10 to 50 ° C. higher than the melting point of the solder. Thereafter, as shown in FIG. 5E, an underfill agent 34 is filled between the electronic component X1 and the wiring board 32 and cured.

  FIG. 6 shows another process subsequent to FIG. 3 in manufacturing the electronic component X1. As a solder supply material for forming the bump portion 15 of the electronic component X1, solder balls 35 can be used as shown in FIG. 6 instead of the solder paste 31 shown in FIG.

  Specifically, first, as shown in FIG. 6A, the solder ball 35 is placed in the opening 30 a of the resin film 30. The solder ball 35 is formed by spheroidizing a single metal selected from Sn, Pb, Ag, Cu, In, Bi, Zn, Sb or the like, or an alloy made of a plurality of single metals selected from these. Next, as shown in FIG. 6B, a bump portion 15 is formed through a heat treatment. Specifically, the solder ball 35 is mechanically and electrically connected to the electrode pad 12 by being melted once by heating. Next, as shown in FIG. 6C, the resin film 30 is removed by applying an alkali stripping solution in the same manner as described above with reference to FIG. 5C. Also by the above method, the bump part 15 can be formed and the electronic component X1 can be manufactured.

  FIG. 7 shows another process subsequent to FIG. 3 in manufacturing the electronic component X1. As a solder supply material for forming the bump portion 15 of the electronic component X1, instead of the solder paste 31 and the solder ball 35, a molten solder 36 can be used as shown in FIG.

  Specifically, first, as shown in FIG. 7A, molten solder 36 is filled into the opening 30a of the resin film 30 under heating. The melting solder 36 is obtained by heating and melting a single metal selected from Sn, Pb, Ag, Cu, In, Bi, Zn, Sb, or an alloy made of a plurality of single metals selected from these. The supply of the molten solder 36 can be achieved by immersing the electronic component in the state shown in FIG. 3E in a molten solder bath or by a printing method. Next, as shown in FIG. 7B, a bump portion 15 is formed on the electrode pad 12 by cooling. Next, as shown in FIG. 7C, the resin film 30 is removed by applying an alkali stripping solution as described above with reference to FIG. 5C. The bump portion 15 of the electronic component X1 can also be formed by the above method. Further, the bump portion 15 may be formed by an electroless plating method using the opening 30a of the resin film 30 instead of the above method.

  FIG. 8 is a partial cross-sectional view of an electronic component X2 with bump electrodes according to the second embodiment of the present invention. The electronic component X2 corresponds to a semiconductor chip, a printed wiring board, or the like, and includes a base material 21, an electrode pad 22, an insulating film 23, a conductive contact portion 24, and a bump portion 25. On the surface of the base material 21, wiring including the electrode pads 22 is formed in a pattern. The insulating film 23 is provided on the base material 21 to cover and protect the wiring, and has an opening 23 a at a position corresponding to the electrode pad 22. The conductive connecting portion 24 is provided on the electrode pad 22 in the opening 23a, and includes a base portion 24a and a lead-in protrusion 24b. The bump portion 25 is provided in direct contact with the upper surface of the base portion 24a and the lead-in protrusion 24b in the conductive connecting portion 24, and protrudes to the outside from the opening portion 23a. Moreover, the diameter of the spherical part shown in FIG. 8 of the bump part 25 is larger than the diameter of the opening part 23a.

  The conductive communication portion 24 of the electronic component X2 has a lead-in protrusion 24b that contacts the bump portion 25. Due to the action of the pull-in protrusion 24b, the occurrence of open defects in the bump electrode structure is appropriately suppressed in the manufacturing process of the electronic component X2. Specifically, as with the electronic component X1, the height H of the conductive connecting portion 24 from the base material 21, the theoretical penetration depth h of the bump portion 25, and the film thickness L of the insulating film 23 are listed above. (1) is satisfied.

  9 to 11 show a method for manufacturing the electronic component X2. In the manufacture of the electronic component X2, first, the electronic component in the state of FIG. 9A is obtained through the same steps as those described above with reference to FIGS. 3A and 3B regarding the manufacture of the electronic component X1. Prepare. Specifically, in the state shown in FIG. 9A, the electrode pad 22 is provided on the surface of the base material 21. Further, an insulating film 23 having an opening 23 a is laminated on the base material 21 at a location corresponding to the electrode pad 22. The insulating film 23 is formed so as to satisfy the above formula (1) in the electronic component X2 finally obtained with respect to the film thickness L shown in FIG.

  For the electronic component in such a state, as shown in FIG. 9B, the base portion 24a of the conductive connecting portion 24 is formed on the electrode pad 22 in the opening portion 23a. The base portion 24a can be formed by an electroless plating method or an electroplating method in the same manner as described above with reference to FIG. 3C regarding the formation of the conductive connection portion 14 of the electronic component X1.

  After the base portion 24a is formed, a resin film 37 is laminated as shown in FIG. In the formation of the resin film 37, the film-shaped resin composition is placed on the laminated surface side, and then pressure-bonded while being heated at 50 to 240 ° C. Alternatively, the liquid resin composition may be applied to the laminated surface by spin coating and dried. In the formation of the resin film 37, the same resin composition as that of the resin film 30 in the first embodiment can be used.

  After the formation of the resin film 37, as shown in FIG. 9D, openings 37a for forming the lead-in protrusions 24b are formed in the resin film 37 at locations corresponding to the respective base portions 24a. To do. For the formation of the opening 37a, a UV-YAG laser, a carbon dioxide laser, an excimer laser, or the like can be used. When the resin film 37 having photosensitivity is formed, photolithography can be employed for forming the opening 37a. When photolithography is employed, the base film 24a is exposed by subjecting the resin film 37 to exposure processing through a predetermined photomask (not shown) and subsequent development processing. Opening 37a is formed.

  Next, as shown to Fig.10 (a), the drawing protrusion 24b is formed on the base 24a in the opening part 37a. The lead-in protrusion 24b can be formed by an electroless plating method or an electroplating method as described above with reference to FIG. 3C regarding the formation of the conductive communication portion 14 of the electronic component X1. In the formation of the conductive connection portion 24, the base portion 24a and the pull-in projection portion 24b are formed so as to satisfy the above-described formula (1) in the electronic component X2 finally obtained with respect to the height H shown in FIG. . Next, as shown in FIG. 10B, the resin film 37 is removed by applying an alkali stripping solution in the same manner as described above with reference to FIG.

  Next, as shown in FIG. 10C, a resin film 38 is laminated. In the formation of the resin film 38, the film-shaped resin composition is placed on the laminated surface side, and then pressure-bonded while being heated at 50 to 140 ° C. Alternatively, the liquid resin composition may be applied to the laminated surface by spin coating and dried. In forming the resin film 38, the same resin composition as that of the resin film 30 in the first embodiment can be used.

  Next, as illustrated in FIG. 10D, openings 38 a are formed in the resin film 38 at locations corresponding to the respective conductive communication portions 24. For the formation of the opening 38a, a UV-YAG laser, a carbon dioxide laser, an excimer laser, or the like can be used. When the resin film 38 having photosensitivity is formed, photolithography can be employed for forming the opening 38a. When photolithography is employed, the conductive contact portions 24 are exposed by subjecting the resin film 38 to exposure processing through a predetermined photomask (not shown) and subsequent development processing. An opening 38a is formed in the substrate.

  Next, as shown in FIG. 11A, the solder paste 31 is filled in the opening 38a. The solder paste 31 is filled by a printing method using a squeegee (not shown). The constituent material of the solder paste 31, the material of the squeegee, and the squeegee in this step are the same as those described above with reference to FIG. 5A in the first embodiment.

  Next, as shown in FIG. 11B, a bump portion 25 is formed through heat treatment. Specifically, first, the solder paste 31 filled in the opening 38a is melted by heating. As a result, the flux vehicle contained in the solder paste 31 volatilizes and disappears, and the solder powder melts and gathers. The pump portion 25 is formed by subsequent cooling.

  Next, as shown in FIG. 11C, the resin film 38 is removed by applying an alkali stripping solution. At this time, in order to appropriately avoid damage to the insulating film 23, it is desirable to use an alkali stripping solution having a pH of 11.5 or less. In order to appropriately perform such alkali removal, in this embodiment, a combination of the insulating film 23 and the resin film 38 having a significant difference in resistance to the alkali stripping solution is employed.

  In the above-described series of steps, the electronic component X2 includes the height H of the conductive connecting portion 24 from the base material 21, the theoretical penetration depth h of the bump portion 25, and the film thickness L of the insulating film 23 as described above. It is manufactured to satisfy the formula (1). Therefore, the electronic component X2 includes the electrode pad 22 while including the insulating film 23 having a sufficient thickness and the bump portion 25 having a sufficient height having a spherical portion larger than the diameter of the insulating film opening 23a. There is no open defect with the bump portion 25. Further, the electronic component with bump electrode X2 manufactured in this way can be flip-chip bonded to the wiring board in the same manner as the electronic component X1 when the electronic component X2 is a semiconductor chip, for example.

  The first and second embodiments of the present invention have been described above with reference to partial cross-sectional views. The electronic parts with bump electrodes X1 and X2 of the present invention can be manufactured from a large substrate such as a wafer in an industrial production line.

Epoxy acrylate resin as an insulating film having photosensitivity by screen printing so as to cover the electrode pads on the surface of the wiring board (electrode diameter 110 μm, electrode pitch 220 μm, number of electrodes 3000) having Cu electrode pads A film was formed. The film thickness was 30 μm. Next, the insulating film was subjected to an exposure process and a subsequent development process to form a plurality of openings having a diameter of 90 μm so that each electrode pad was exposed. In the development processing, a 1.0% sodium carbonate (Na ₂ CO ₃ ) aqueous solution was used as a developer. Next, a 15 μm thick Ni plating layer was formed on the electrode pad in the opening by electroless plating. Next, an Au plating layer having a thickness of 0.1 μm was formed on the Ni plating layer by electroless plating. As a result, a conductive connecting portion made of a Ni plating layer and an Au plating layer was formed on the electrode pad.

Next, an acrylate resin film having photosensitivity was laminated on the insulating film so as to cover the opening of the insulating film. The film thickness was 50 μm. Next, the resin film was subjected to an exposure process and a subsequent development process to form a plurality of openings having a diameter of 200 μm so that each conductive connecting part was exposed. In the development process, a 1.0% Na ₂ CO ₃ aqueous solution was used as a developer. Next, solder paste was filled into the opening by squeezing the urethane rubber squeegee twice. The solder paste of this example consists of 10 parts by weight of resin consisting of rosin, activator, solvent, thixotropic agent, and 90 parts by weight of solder powder (Sn-3.5% Ag solder) having a particle size of 25 μm or less. The volume ratio of the solder powder is about 54 vol%. Next, the bump part was formed from the solder paste in each opening part through the heat processing of the maximum temperature of 240 degreeC. Next, the acrylate resin film was removed using a 5% monoethanolamine aqueous solution as an alkali stripping solution. As a result of the above steps, it was possible to obtain a wiring substrate having bump electrodes with bump portions having a height of 100 μm from the insulating film and a height variation of 3 μm. Here, the variation in height means that there is a variation of ± 3 μm with respect to the average height.

  Epoxy acrylate resin as an insulating film having photosensitivity by screen printing so as to cover the electrode pad on the surface of a semiconductor chip having a Cu electrode pad (electrode diameter 90 μm, electrode pitch 220 μm, number of electrodes 3000) A film was formed. The film thickness was 10 μm. Next, the insulating film was subjected to an exposure process and a subsequent development process to form a plurality of openings having a diameter of 70 μm so that each electrode pad was exposed. In the development process, a 1% tetramethylammonium hydroxide (TMAH) aqueous solution was used as a developer. Next, a Ni plating layer having a thickness of 3 μm was formed on the electrode pad in the opening by an electroless plating method. Next, an Au plating layer having a thickness of 0.1 μm was formed on the Ni plating layer by electroless plating. As a result, a conductive connecting portion made of a Ni plating layer and an Au plating layer was formed on the electrode pad.

Next, an acrylate resin film having photosensitivity was laminated on the insulating film so as to cover the opening of the insulating film. The film thickness was 150 μm. Next, the resin film was subjected to an exposure process and a subsequent development process to form a plurality of openings having a diameter of 200 μm so that each conductive connecting part was exposed. In the development process, a 1.0% Na ₂ CO ₃ aqueous solution was used as a developer. Next, a solder paste containing solder powder (Sn-3.5% Ag solder) having a particle size of 25 μm or less was filled into the opening by squeezing the urethane rubber squeegee twice. Next, the bump part was formed from the solder paste in each opening part through the heat processing of the maximum temperature of 240 degreeC. Next, the acrylate resin film was removed using a 5% monoethanolamine aqueous solution as an alkali stripping solution. As a result of the above steps, it was possible to obtain a semiconductor chip having bump electrodes with bump portions having a height of 160 μm from the insulating film and a height variation of 5 μm.

  Prepare the same wiring substrate as in Example 1 through the same steps as in Example 1 until an opening having a diameter of 200 μm is formed in the photosensitive acrylate resin film, and at the opening of the resin film in the wiring substrate. Flux was applied to the exposed electrode pad. Next, a solder ball (Sn-3.5% Ag solder) having a diameter of 130 μm was placed on each electrode pad to which the flux was applied. Next, a bump portion was formed from the solder ball in each opening by performing a heat treatment at a maximum temperature of 240 ° C. Next, the acrylate resin film was removed using a 5% monoethanolamine aqueous solution as an alkali stripping solution. As a result of the above steps, it was possible to obtain a wiring substrate having bump electrodes with bump portions having a height of 110 μm from the insulating film and a height variation of 2 μm.

  Prepare the same semiconductor chip as in Example 2 through the same process as in Example 2 until an opening with a diameter of 200 μm is formed in the photosensitive acrylate resin film. Flux was applied to the exposed electrode pad. Next, a solder ball (Sn-3.5% Ag solder) having a diameter of 160 μm was placed on each electrode pad to which the flux was applied. Next, a bump portion was formed from the solder ball in each opening by performing a heat treatment at a maximum temperature of 240 ° C. Next, the photosensitive acrylate resin film was removed using a 5% monoethanolamine aqueous solution as an alkali stripping solution. As a result of the above steps, it was possible to obtain a semiconductor chip having bump electrodes with bump portions having a height of 150 μm from the insulating film and a height variation of 4 μm.

  In the formation of the conductive contact portion by the electroless plating method, instead of the 15 μm thick Ni plating layer and the 0.1 μm thick Au plating layer thereon, the 15 μm thick Cu plating layer and the 0 thickness thereon A process from the formation of the insulating film to the formation of the bump portion was performed in the same manner as in Example 1 except that a 1 μm Sn plating layer was formed. As a result, it was possible to obtain a wiring board having bump electrodes with bump portions having a height of 102 μm from the insulating film and a height variation of 4 μm.

  In the formation of the conductive contact portion by the electroless plating method, instead of the 15 μm thick Ni plating layer and the 0.1 μm thick Au plating layer thereon, the 15 μm thick Cu plating layer and the 0 thickness thereon A process from the formation of the insulating film to the formation of the bump portion was performed in the same manner as in Example 3 except that a 1 μm thick Sn plating layer was formed. As a result, it was possible to obtain a wiring substrate having bump electrodes with bump portions having a height of 112 μm from the insulating film and a height variation of 2 μm.

  Epoxy acrylate resin as an insulating film having photosensitivity by screen printing so as to cover the electrode pad on the surface of a semiconductor chip having an Al electrode pad (electrode diameter 90 μm, electrode pitch 220 μm, number of electrodes 3000) A film was formed. The film thickness was 10 μm. Next, the insulating film was subjected to an exposure process and a subsequent development process to form a plurality of openings having a diameter of 70 μm so that each electrode pad was exposed. In the development processing, a 1% TMAH aqueous solution was used as a developer. Next, a Ni plating layer having a thickness of 3 μm was formed on the electrode pad in the opening by an electroless plating method. Next, an Au plating layer having a thickness of 0.1 μm was formed on the Ni plating layer by electroless plating. As a result, a conductive connecting portion made of a Ni plating layer and an Au plating layer was formed on the electrode pad.

Next, an acrylate resin film having photosensitivity was laminated on the insulating film so as to cover the opening of the insulating film. The film thickness was 150 μm. Next, the resin film was subjected to an exposure process and a subsequent development process to form a plurality of openings having a diameter of 200 μm so that each conductive connecting part was exposed. In the development process, a 1.0% Na ₂ CO ₃ aqueous solution was used as a developer. Next, flux was applied to the electrode pad exposed at the opening of the resin film. Next, a solder ball (Sn-3.5% Ag solder) having a diameter of 180 μm was placed on each electrode pad to which the flux was applied. Next, a bump portion was formed from the solder ball in each opening by performing a heat treatment at a maximum temperature of 240 ° C. Next, the acrylate resin film was removed using a 5% monoethanolamine aqueous solution as an alkali stripping solution. As a result of the above steps, it was possible to obtain a semiconductor chip having bump electrodes with bump portions having a height of 172 μm from the insulating film and a height variation of 4 μm.

  In the formation of the bump portion, instead of the solder ball having a diameter of 180 μm (Sn-3.5% Ag solder), a solder ball having a diameter of 160 μm (Sn-3.5% Ag solder) is placed on the electrode pad in the opening of the resin film. The steps from the formation of the insulating film to the formation of the bump portion were performed in the same manner as in Example 7 except that the substrate was placed. As a result, it was possible to obtain a semiconductor chip having bump electrodes with bump portions having a height of 151 μm from the insulating film and a height variation of 2 μm.

Comparative Example 1

Epoxy acrylate resin as an insulating film having photosensitivity by screen printing so as to cover the electrode pads on the surface of the wiring board (electrode diameter 110 μm, electrode pitch 220 μm, number of electrodes 3000) having Cu electrode pads A film was formed. The film thickness was 30 μm. Next, the insulating film was subjected to an exposure process and a subsequent development process to form a plurality of openings having a diameter of 90 μm so that each electrode pad was exposed. Next, an acrylate resin film having photosensitivity was laminated on the insulating film so as to cover the opening of the insulating film. The film thickness was 50 μm. Next, the resin film was subjected to an exposure process and a subsequent development process to form a plurality of openings having a diameter of 200 μm so that each conductive connecting part was exposed. In the development process, a 1.0% Na ₂ CO ₃ aqueous solution was used as a developer. Next, a solder paste containing solder powder (Sn-3.5% Ag solder) having a particle size of 25 μm or less was filled into the opening by squeezing the urethane rubber squeegee twice. Next, the bump part was formed from the solder paste in each opening part through the heat processing of the maximum temperature of 240 degreeC. Next, the acrylate resin film was removed using a 5% monoethanolamine aqueous solution as an alkali stripping solution. As a result of the above steps, a plurality of spheroidized bump portions were formed without filling the openings of the resin film, resulting in open defects at a plurality of locations, and a good wiring substrate with bump electrodes could not be obtained. .

Comparative Example 2

Epoxy acrylate resin as an insulating film having photosensitivity by screen printing so as to cover the electrode pad on the surface of a semiconductor chip having a Cu electrode pad (electrode diameter 90 μm, electrode pitch 220 μm, number of electrodes 3000) A film was formed. The film thickness was 10 μm. Next, the insulating film was subjected to an exposure process and a subsequent development process to form a plurality of openings having a diameter of 70 μm so that each electrode pad was exposed. Next, an acrylate resin film having photosensitivity was laminated on the insulating film so as to cover the opening of the insulating film. The film thickness was 50 μm. Next, the resin film was subjected to an exposure process and a subsequent development process to form a plurality of openings having a diameter of 200 μm so that each conductive connecting part was exposed. In the development process, a 1.0% Na ₂ CO ₃ aqueous solution was used as a developer. Next, a solder paste containing solder powder (Sn-3.5% Ag solder) having a particle size of 25 μm or less was filled into the opening by squeezing the urethane rubber squeegee twice. Next, the bump part was formed from the solder paste in each opening part through the heat processing of the maximum temperature of 240 degreeC. Next, the acrylate resin film was removed using a 5% monoethanolamine aqueous solution as an alkali stripping solution. As a result of the above steps, a plurality of spheroidized bump portions were formed without filling the openings of the resin film, resulting in open defects at a plurality of locations, and a good semiconductor chip with bump electrodes could not be obtained. .

It is a fragmentary sectional view of the electronic component with a bump electrode concerning a 1st embodiment of the present invention. It is a related figure of each condition regarding the electronic component shown in FIG. 2 represents a part of the steps in the method for manufacturing the electronic component with bump electrodes shown in FIG. The conductive connection part which has a multilayer structure is represented. The process following FIG. 3 is represented. It represents another process following FIG. It represents another process following FIG. It is a fragmentary sectional view of the electronic component with a bump electrode concerning a 2nd embodiment of the present invention. FIG. 9 shows some steps in the method of manufacturing the electronic component with bump electrodes shown in FIG. 8. The process following FIG. 9 is represented. The process following FIG. 10 is represented. The process of a part of conventional manufacturing method of the electronic component with a bump electrode is represented. This represents a conventional electronic component mounting process. This represents an open failure that has occurred in conventional electronic components with bump electrodes.

Explanation of symbols

X1, X2 Electronic parts 11, 21 Base material 12, 22 Electrode pad 13, 23 Insulating film 13a, 23a Opening part 14, 24 Conducting connection part 24a Base part 24b Recessing projection part 15, 25 Bump part 30, 37, 38 Resin film 30a, 37a, 38a Opening 31 Solder paste 35 Solder ball 36 Molten solder

Claims (3)

A substrate;
An electrode pad provided on the substrate;
An insulating film laminated on the substrate having an opening corresponding to the electrode pad;
In the opening, a conductive communication portion provided on the electrode pad;
A bump portion having a spherical portion that directly contacts the conductive connecting portion and protrudes from the opening, and
An electronic component with a bump electrode, wherein a diameter of the spherical portion of the bump portion is larger than a diameter of the opening portion of the insulating film.   The electronic component with a bump electrode according to claim 1, wherein the conductive connecting portion has a lead-in protrusion that contacts the bump portion.   The height H of the conductive connecting part from the base material, the theoretical penetration depth h with respect to the opening part of the true sphere having the same volume as the bump part, and the film thickness L of the insulating film are H + h ≧ The electronic component with a bump electrode according to claim 1 or 2, having a relationship of L.

Images