JP2007165830A - Mounting structure of electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost mounting structure of electronic component with a small size where the spreading of underfill on an insulating coat is suppressed by a film removing portion. <P>SOLUTION: In the mounting structure of the electronic components, spreading of the underfill 8, prepared on the insulating coat 3, is controlled by the coat exception portion 6, and the spreading of the underfill 8 beyond it does not exist. Since the suppression effects of the spreading of the underfill 8 is not relevant to the thickness, the depth and the width of the film removing portion 6, the film removing portion 6 can be made thin, shallow and narrow, and low cost, and thus miniaturization and thinning of an insulating substrate 1 can be facilitated. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

The present invention relates to an electronic component mounting structure suitable for use in various electrical devices, electronic circuit units, and the like.

  FIG. 16 is an explanatory view showing a mounting structure of a conventional electronic component. Next, the configuration of the mounting structure of the conventional electronic component will be described with reference to FIG. Then, the electronic component 54 is attached to the wiring pattern 52 provided on the insulating substrate 51 by the bumps 53.

An insulating film 55 is provided on the insulating substrate 51 and the wiring pattern 52 except for the area of the electronic component 54, and the insulating film 55 is provided with a film removing portion 55 a at a location including the area of the electronic component 54. An underfill 56 made of resin is provided between the insulating substrate 51 and the electronic component 54 of the film removing portion 55a, and the underfill 56 is prevented from flowing out by the edge of the film removing portion 55a. It has a configuration (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-214586

  However, in the conventional electronic component mounting structure, the underfill 56 is prevented from flowing out by the edge of the film removal portion 55a, so that the insulating film 55 needs to be thick to prevent the underfill 56 from spreading. In this case, the formation of the thick insulating film 55 is cumbersome and expensive, and if the insulating film 55 is made thin in order to prevent the underfill 56 from spreading, the film removal portion 55a is widened. In this case, there is a problem that the insulating substrate 51 becomes large.

  The present invention has been made in view of such a state of the art, and the object thereof is to achieve a compact and inexpensive electronic component mounting structure in which the underfill on the insulating film is suppressed from being spread by the film removing portion. Is to provide.

  To achieve the above object, the present invention provides an insulating substrate provided with a plurality of terminals, an insulating film provided on the insulating substrate while avoiding the terminals, and an electrode provided on the lower surface of the main body. And an underfill made of a resin provided between the insulating film and the electronic component and between the insulating substrate and the electronic component, and the insulating film is disposed in the vicinity of the main body. It has the film removal part provided, The underfill provided on the insulating film was suppressed by the film removal part.

  In the present invention configured as described above, the spread of the underfill provided on the insulating film is suppressed by the film removal unit, and no further underfill spread is eliminated. Since the thickness, depth, and width of the portion are not concerned, the film removal portion can be made thin, shallow, narrow, inexpensive, and the insulating substrate can be easily reduced in size and thickness.

  Further, the present invention is characterized in that, in the above-mentioned invention, the film removal portion is provided so as to surround the main body portion, and the underfill stops at the edge of the film removal portion. In the present invention configured as described above, it is possible to more reliably prevent the underfill from spreading due to the film removal portion surrounding the main body portion.

  According to the present invention, in the above invention, the electronic component is formed of a semiconductor chip. The present invention configured as described above is suitable for a semiconductor chip that requires mounting reinforcement by underfill.

  Moreover, the present invention is characterized in that, in the above-mentioned invention, the angle between the side surface of the insulating film located at the film removing portion and the surface of the insulating substrate is formed in the range of 80 degrees to 90 degrees. The present invention configured as described above can satisfactorily stop the underfill at the surface edge portion of the insulating film, and can increase the contact angle formed by the insulating film and the underfill.

  Moreover, the present invention is characterized in that, in the above invention, when the underfill is in a liquid state, the contact angle formed by the insulating film and the underfill is 90 degrees to 135 degrees. In the present invention configured as described above, when the contact angle of the liquid underfill is less than 90 degrees, the fluidity of the underfill 8 becomes high and the underfill 8 flows out widely. If the contact angle exceeds 135 degrees, the fluidity of the underfill decreases and the flow of the underfill 8 deteriorates. Therefore, when the contact angle is in the range of 90 to 135 degrees, the fluidity of the underfill is low. It can be in a range that is neither low nor high, and the insulating film and the underfill are not easily wetted.

  Further, the present invention is characterized in that, in the above invention, the insulating coating and the underfill are formed of an epoxy resin. According to the present invention configured as described above, a fluid having a contact angle in the range of 90 degrees to 135 degrees in a state where the fluidity of the underfill is neither low nor high is easily obtained.

  In the present invention, the spread of the underfill provided on the insulating film is suppressed by the film removal portion, and there is no further spread of the underfill, and the effect of suppressing the spread of the underfill is the thickness of the film removal portion, Since the depth and width are not concerned, the film removal portion can be made thin, shallow and narrow, inexpensive, and the insulating substrate can be easily reduced in size and thickness.

  An embodiment of the invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a main part according to the electronic component mounting structure of the present invention, and FIG. 2 is a plan view of an insulating substrate according to the electronic component mounting structure of the present invention. 3 is an enlarged view of a portion A in FIG. 1, FIG. 4 is a front view showing the electronic component mounting method of the present invention, FIG. 5 is a plan view showing the electronic component mounting method of the present invention, and FIG. FIG. 7 shows a second flow state of the liquid underfill according to the electronic component mounting method of the present invention. FIG. 8 is an explanatory diagram showing a third flow state of the liquid underfill according to the electronic component mounting method of the present invention, and FIG. 9 is a liquid underfill according to the electronic component mounting method of the present invention. It is explanatory drawing which shows the 4th flow state.

  FIG. 10 relates to the electronic component mounting structure of the present invention, and is an explanatory view showing a first step relating to the method of forming the film removal portion in the insulating film, and FIG. 11 relates to the electronic component mounting structure of the present invention, insulating. FIG. 12 is an explanatory view showing a second step according to the method for forming the film removal portion in the film, FIG. 12 is a cross-sectional view of the main part according to another embodiment of the electronic component mounting structure of the present invention, and FIG. FIG. 14 is an enlarged view, FIG. 14 relates to another embodiment of the electronic component mounting structure of the present invention, and is an explanatory view showing a first step relating to a method of forming a film removal portion in an insulating film, and FIG. It is explanatory drawing which concerns on other embodiment of a mounting structure and shows the 2nd process which concerns on the formation method of the film removal part in an insulating film.

  Next, the configuration of the electronic component mounting structure according to the present invention will be described with reference to FIGS. 1 to 3. On the insulating substrate 1 made of a laminated substrate or the like, a plurality of terminals 2 that are part of a wiring pattern are provided. The terminals 2 are arranged in two rows in a square shape (b-shaped) along the square line.

  An insulating film 3 such as a solder resist made of an epoxy resin is provided on the insulating substrate 1 while avoiding the terminals 2, and the insulating film 3 is provided along the arrangement of the terminals 2. The first film removing unit 4 has a rectangular shape (b-shaped), and the first film removing unit 4 has a first shape located on a first line parallel to each other. It has the deletion part 4a and the 2nd deletion part 4b which is connected to this 1st deletion part 4a, and is located in a square-shaped 2nd mutually parallel line.

  Furthermore, the insulating film 3 has an island-shaped film portion 3a provided at a position surrounded by the first film removal portion 4, and the first deletion portion 4a and the first deletion portion 4a from the end of the first deletion portion 4a. The second film removal section 5 extending in a straight line and the second film removal section 5 extending outward at right angles from the vicinity of the center of the first deletion section 4a are connected to the second film removal section 5. An annular third film removal unit 6 is provided.

  The insulating film 3 has a thickness of about 25 μm, which is thicker than the thickness of the terminal 2 (10 μm), and the widths of the first and second film removing portions 4 and 5 are 10 μm or more. Has been.

  A rectangular parallelepiped electronic component 7 made of a semiconductor chip or the like has a main body portion 7a and a plurality of electrodes 7b provided on the lower surface of the main body portion 7a and arranged in a square shape (in a square shape). The electrode 7b is attached to the terminal 2 by soldering or ball grid array.

  At this time, the film part 3a is located at the center of the main body part 7a, the second film removal part 5 protrudes outward from the peripheral edge of the main body part 7a, and the third film removal part 6 is formed of the main body part 7a. It is arranged so as to surround the vicinity, and the space between the lower surface of the insulating substrate 1 and the main body portion 7a is about 50 to 80 μm, and the first, second and third film removing portions 4, 5, 6, the angle K1 between the side surface of the insulating film 3 and the surface of the insulating substrate 1 is 90 degrees as shown in FIG.

  The underfill 8 made of epoxy resin is provided between the insulating film 3 and the lower surface of the main body portion 7a, between the insulating substrate 1 and the lower surface of the main body portion 7a, and at the peripheral edge portion of the main body portion 7a. The underfill 8 that protrudes and protrudes from the peripheral edge of the main body portion 7a is suppressed from spreading at the edge by the third film removal portion 6 for suppressing spread. As shown in FIG. 3, the liquid underfill 8 at the edge of the third film removal portion 6 has a contact angle formed by the insulating film 3 and the underfill 8 in the range of 90 to 135 degrees. Yes.

  When the contact angle of the liquid underfill 8 is less than 90 degrees, the fluidity of the underfill 8 becomes high and the underfill 8 flows out widely, and the contact angle of the liquid underfill 8 increases to 135 degrees. If it exceeds, the fluidity of the underfill 8 becomes low, the flow of the underfill 8 becomes poor, and when the contact angle is in the range of 90 to 135 degrees, the insulating film 3 and the underfill 8 are difficult to wet. It becomes.

  Next, the electronic component mounting method of the present invention will be described with reference to FIGS. 4 to 9. First, as shown in FIGS. 4 and 5, the dispenser 9 for injecting the liquid underfill 8 is an electronic component. 7 is arranged at a position orthogonal to another first deletion portion 4a opposite to the first deletion portion 4a provided with the second film removal portion 5 in the vicinity of the center.

  In this state, when the liquid underfill 8 is injected by the dispenser 9, as shown in FIG. 6, since the gap between the insulating film 3 and the main body portion 7a is small, the underfill 8 flows in by capillary action therebetween. Next, the underfill 8 overflowing between the insulating film 3 and the main body portion 7 a flows into the first deletion portion 4 a close to the dispenser 9 by capillary action.

  The underfill 8 overflowing from the first deletion portion 4a flows between the coating portion 3a having a small gap and the main body portion 7a, and is located at the edge of the second coating removal portion 5. Since the amount thereof is small, it stops at the edge of the second film removing portion 5 due to the viscosity of the underfill 8 and does not flow into the second film removing portion 5.

  Further, when the liquid underfill 8 is injected, as shown in FIG. 7, the second deleted portion 4b having a gradually larger gap is introduced while the inflow of the underfill 8 precedes between the insulating film 3 having a small gap and the main body portion 7a. Is filled with the underfill 8, and a part of the first deletion portion 4a and the second deletion portion 4 which are far from the dispenser 9 is left, and during this time, air is 2 is discharged from the film removal section 5.

  Furthermore, when the liquid underfill 8 is injected, as shown in FIG. 8, a part of the first deletion portion 4a and the second film removal portion 5 which are located far from the dispenser 9 are left, Subsequently, when the liquid underfill 8 is injected, the air present in a part of the first deletion portion 4a located far from the dispenser 9 is discharged from the second film removal portion 5 as shown in FIG. It becomes a state.

  In the state of FIG. 9, the underfill 8 overflowing from the lower surface of the main body portion 7a fills the periphery of the main body portion 7a and partly flows out to the third film removal portion 6 side. The film removal unit 6 becomes a weir for the underfill 8, has a contact angle as shown in FIG. 3, and further outflow of the underfill 8 is prevented, and the mounting of the electronic component is completed.

  Next, an example of a method for forming the film removal portion in the insulating film of the present invention will be described with reference to FIGS. 10 and 11. First, as shown in FIG. 10, on the insulating substrate 1 on which the terminals 2 are formed, In a state where the terminal 2 is covered, a photosensitive insulating film 3 is prepared by printing or the like.

  Next, as a first step shown in FIG. 10, a mask 11 having a light transmitting portion 11a is prepared at the positions of the first, second, and third film removing portions 4, 5, and 6, and this mask 11 is insulated. After being placed on the film 3, the insulating film 3 is exposed by parallel light rays from the light source 12.

  Next, as a second step shown in FIG. 11, when the insulating film 3 is developed in a state where the mask 11 is removed, as shown in FIG. 11 and FIG. Thus, the first, second, and third film removing portions 4, 5, and 6 are formed, and the side surfaces of the insulating film 3 in the first, second, and third film removing portions 4, 5, and 6 are insulated. The angle K1 with the surface of the substrate 1 is formed at 90 degrees, and the formation of the film removal portion is completed.

  FIGS. 12 and 13 show other embodiments of the electronic component mounting structure of the present invention. The other embodiments will be described. First, second, and third film removing portions 4, 5, and 6 are described. The angle K2 between the side surface of the insulating film 3 and the surface of the insulating substrate 1 is formed at about 80 degrees, and the other configurations are the same as those in the above embodiment and are the same as the same parts. A number is assigned and description thereof is omitted here.

  When the angle K2 is formed at about 80 degrees, the insulating substrate 1 of the underfill 8 from the surface end portion of the insulating coating 3 particularly at the position of the third coating removal portion 6 shown in FIG. Can be suppressed as much as possible to the surface (third coating removal portion 6), and the underfill 8 can be satisfactorily stopped at the surface edge of the insulating coating 3, and the insulating coating 3 and the underfill 8 The contact angle made can be increased.

  In addition, since the electronic component mounting method according to another embodiment of the present invention is performed in the same manner as in the above-described example, the description thereof is omitted here.

  Next, an example of a method for forming a film removal portion in an insulating film according to another embodiment of the present invention will be described with reference to FIGS. 14 and 15. First, as shown in FIG. On the substrate 1, there is prepared a photosensitive insulating film 3 formed by printing or the like with the terminal 2 covered, and the first, second and third film removing portions 4, 5, 6. A mask 11 having a light transmission part 11a at a position is prepared.

  Next, as a first step shown in FIG. 14, the mask 11 is placed on the insulating film 3, and the light transmission holes 13 b partitioned in a lattice pattern by the partition walls 13 a between the mask 11 and the light source 12. The light-scattering member 13 having the above is disposed, and the insulating coating 3 is exposed from the light transmission hole 13 b by the movement of the light source 12.

  Then, the light passing through the light transmission hole 13b becomes vertical light and inclined light with respect to the mask 11, and the vertical light and the inclined light pass through the light transmitting portion 11a to expose the insulating coating 3.

  Next, as a second step shown in FIG. 15, when the insulating film 3 is developed in a state where the mask 11 is removed, as shown in FIG. 15 and FIG. Thus, the first, second, and third film removing portions 4, 5, and 6 are formed, and the side surfaces of the insulating film 3 in the first, second, and third film removing portions 4, 5, and 6 are insulated. The angle K2 between the substrate 1 and the surface of the substrate 1 is formed at about 80 degrees (acute angle), and the formation of the film removal portion is completed.

  In this embodiment, the degree of the acute angle K2 can be changed by changing the size or length of the opening of the light transmission hole 13b of the light scattering member 13.

It is principal part sectional drawing which concerns on the mounting structure of the electronic component of this invention. It is a top view of the insulated substrate which concerns on the mounting structure of the electronic component of this invention. It is an enlarged view of the A part of FIG. It is a front view which shows the mounting method of the electronic component of this invention. It is a top view which shows the mounting method of the electronic component of this invention. It is explanatory drawing which shows the 1st flow state of a liquid underfill regarding the mounting method of the electronic component of this invention. It is explanatory drawing which shows the 2nd flow state of a liquid underfill regarding the mounting method of the electronic component of this invention. It is explanatory drawing which shows the 3rd flow state of a liquid underfill regarding the mounting method of the electronic component of this invention. It is explanatory drawing which shows the 4th flow state of a liquid underfill regarding the mounting method of the electronic component of this invention. It is explanatory drawing which shows the 1st process which concerns on the mounting structure of the electronic component of this invention, and forms the film removal part in an insulating film. It is explanatory drawing which shows the 2nd process which concerns on the mounting structure of the electronic component of this invention, and forms the film removal part in an insulating film. It is principal part sectional drawing which concerns on other embodiment of the mounting structure of the electronic component of this invention. It is an enlarged view of B part of FIG. It is explanatory drawing which concerns on other embodiment of the mounting structure of the electronic component of this invention, and shows the 1st process which concerns on the formation method of the film removal part in an insulating film. It is explanatory drawing which concerns on other embodiment of the mounting structure of the electronic component of this invention, and shows the 2nd process which concerns on the formation method of the film removal part in an insulating film. It is explanatory drawing which shows the mounting structure of the conventional electronic component, and its mounting method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Terminal 3 Insulating film 3a Film part 4 1st film removal part 4a 1st deletion part 4b 2nd deletion part 5 2nd film removal part 6 3rd film removal part 7 Electronic component 7a Main body part 7b Electrode 8 Underfill 9 Dispenser K1, K2 Angle 11 Mask 11a Light transmission part 12 Light source 13 Light scattering member 13a Partition wall 13b Light transmission hole

Claims (6)

An insulating substrate provided with a plurality of terminals, an insulating film provided on the insulating substrate in a state avoiding the terminals, an electronic component in which an electrode provided on the lower surface of the main body is connected to the terminals, An underfill made of a resin provided between the insulating film and the electronic component and between the insulating substrate and the electronic component, the insulating film being a film provided in the vicinity of the main body portion A mounting structure for an electronic component, comprising: a removal portion, wherein the underfill provided on the insulating film is suppressed from spreading by the film removal portion. 2. The electronic component mounting structure according to claim 1, wherein the film removal portion is provided so as to surround the main body portion, and the underfill stops at an edge of the film removal portion. 3. The electronic component mounting structure according to claim 1, wherein the electronic component is formed of a semiconductor chip. The angle between the side surface of the insulating film located at the film removing portion and the surface of the insulating substrate is formed in the range of 80 degrees to 90 degrees. Mounting structure for electronic components as described in 1. 5. The electronic component according to claim 1, wherein when the underfill is in a liquid state, a contact angle formed by the insulating film and the underfill is set to 90 degrees to 135 degrees. Implementation structure. 6. The electronic component mounting structure according to claim 5, wherein the insulating film and the underfill are formed of an epoxy-based resin.

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