JP5451053B2 - Flip chip mounting method and flip chip mounting apparatus - Google Patents

Description

  The present invention relates to a flip chip mounting method.

  In recent years, a semiconductor device in which a bare semiconductor chip is directly mounted on a wiring board (bare chip mounting) has been required due to the demand for downsizing and thinning of electronic devices. In particular, there is a demand for a semiconductor device in which the circuit surface of the semiconductor chip is mounted so as to face the wiring board (flip chip mounting).

  2. Description of the Related Art Conventionally, a flip-chip type semiconductor device is configured by mounting a semiconductor chip 51 having internal connection terminals such as metal bump electrodes on a wiring board 50 by flip-chip connection as shown in FIG. 52 is an anisotropic conductive adhesive.

In this semiconductor device, when an external force acts on the semiconductor chip 51, the anisotropic conductive adhesive 52 is damaged, and a poor electrical connection between the wiring substrate 50 and the semiconductor chip 51 occurs.
Therefore, in Patent Document 1, as shown in FIG. 23, asperity 53 is formed on a portion (fillet) of the anisotropic conductive adhesive 52 that protrudes from the outer periphery of the semiconductor chip 51, whereby the anisotropic conductive adhesive 52 is machined. The occurrence of poor electrical connection between the wiring substrate 50 and the semiconductor chip 51 is reduced by improving the mechanical strength.
JP 2000-277666 A

  In the flip-chip mounting method of Patent Document 1, since the unevenness 53 is formed in the fillet by controlling the process of heating the anisotropic conductive adhesive 52, the uneven shape is gradual and the shape varies.

In addition, in a high temperature and high humidity environment, moisture is likely to enter the electrical connection portion between the wiring substrate 50 and the semiconductor chip 51 and has low reliability.
An object of the present invention is to provide a flip chip mounting method capable of forming irregularities having a stable shape in the fillet portion and obtaining a semiconductor device having higher mechanical reliability and electrical connection than before. With the goal.

  In the flip chip mounting method of the present invention, a thermosetting underfill resin is interposed between a semiconductor chip and a wiring board to flip chip mount the semiconductor chip on the wiring board, and the semiconductor chip is placed on the wiring board. When bonding the covering container, when the semiconductor chip positioned and disposed with a thermosetting underfill resin (insulating resin) sandwiched between the wiring substrate and the semiconductor chip is pressurized and heated with a crimping tool An uneven portion is formed on the surface of the underfill resin that protrudes around the semiconductor chip, and the inner surface of the container covering the semiconductor chip and the uneven portion on the surface of the underfill resin are joined.

  In addition, by pressing the crimping tool through the film around the semiconductor chip and the semiconductor chip, the uneven shape formed on the surface of the film is transferred to the surface of the underfill resin protruding around the semiconductor chip. Then, the uneven portion is formed.

  Further, by pressing the crimping tool around the semiconductor chip and the semiconductor chip through a film, an uneven shape formed on the surface of the crimping tool is formed on the surface of the underfill resin that protrudes around the semiconductor chip. The concavo-convex portion is formed by transfer.

  Further, when the semiconductor chip positioned and disposed with a thermosetting underfill resin sandwiched between the wiring board and the semiconductor chip is pressed and heated with a crimping tool, the underflow protruding around the semiconductor chip Form a concavo-convex portion on the surface of the fill resin, set a mold on the wiring board and the semiconductor chip flip-chip mounted on the wiring board to form a cavity, fill the cavity with resin, and cure And forming the container.

  The flip chip mounting apparatus of the present invention flip-chip mounts a semiconductor chip on a wiring board by interposing a thermosetting underfill resin between the semiconductor chip and the wiring board, and the semiconductor chip is placed on the wiring board. A flip chip mounting apparatus for joining a container to be covered, wherein the semiconductor chip is supported at an upper position of the semiconductor chip positioned and disposed with a thermosetting underfill resin interposed between the wiring board and the semiconductor chip. A film having a concavo-convex shape formed on the surface thereof, a crimping tool that presses the semiconductor chip and the underfill resin protruding to the periphery to the wiring substrate side through the film, and the wiring substrate. And a mold for forming a cavity over the semiconductor chip flip-chip mounted on the wiring board. Characterized in that was.

  The flip chip mounting apparatus of the present invention flip-chip mounts a semiconductor chip on a wiring board by interposing a thermosetting underfill resin between the semiconductor chip and the wiring board, and the semiconductor chip is placed on the wiring board. A flip chip mounting apparatus for bonding a container to be covered, the film being supported at an upper position of the semiconductor chip positioned and disposed with a thermosetting underfill resin interposed between the wiring substrate and the semiconductor chip; Pressing the underfill resin protruding to the periphery of the semiconductor chip with heating to the wiring substrate side through the film and a crimping tool having a concavo-convex shape formed on the surface of the semiconductor chip; and A circuit board and a semiconductor chip flip-chip mounted on the wiring board are formed on the wiring board to form a cavity. Characterized by providing a mold.

  According to this configuration, not only the uneven portion is formed on the surface of the underfill resin that protrudes around the semiconductor chip, but also the container that covers the semiconductor chip is attached, and the uneven portion on the inner surface of the container and the surface of the underfill resin Therefore, a semiconductor device with high electrical and mechanical connection reliability can be provided.

  Moreover, since the uneven | corrugated shape currently formed in the surface of the said film or the said crimping | compression-bonding tool is transcribe | transferred to the said underfill resin, and the said uneven | corrugated | grooved part is formed, the uneven | corrugated | grooved part formed in the said underfill resin is stable.

(Embodiment 1)
1 to 15 show Embodiment 1 of the present invention.
1 to 13 show a flip chip mounting process, and FIG. 13 shows the completed semiconductor device.

First, the pre-process shown in FIGS. 1 (a) and 1 (b) will be described.
As shown in FIG. 1A, bumps 3 are provided on the electrode pads 2 of the semiconductor chip 1. The thickness of the semiconductor chip 1 was 0.15 to 0.2 mm. The bump 3 is mainly formed from at least one of gold, copper, palladium, nickel, tin, aluminum, solder and the like. The bump 3 may be formed with a stud bump or a tear bump by a known wire bonding method, and a trace element may be added to and contained in the wire for forming the bump 3. In this case, the bump height was about 50 μm and the base diameter was 55 μm. The bump 3 may be formed by a known plating method or printing method.

  The wiring substrate 4 having a thickness of 0.2 to 0.4 mm is a glass epoxy substrate (which may be an aramid substrate, a silicon substrate, or a silicon interposer), and a terminal electrode 5 made of copper (may be nickel + Au plated) is provided on the upper surface. Is formed. On the wiring substrate 4 and the terminal electrode 5, an insulating resin 6 is attached as an underfill resin that is cut to a size slightly larger than that of the semiconductor chip 1 as necessary. Here, an epoxy resin cured at 180 ° C. was used as the insulating resin 6.

  The semiconductor chip 1 is attracted by the mounting tool 7 as shown in FIG. 1B, and the bumps 3 of the semiconductor chip 1 correspond to the respective terminal electrodes 5 corresponding to the respective phases at the desired positions of the terminal electrodes 5 on the wiring board 4. It is mounted so as to overlap. At this time, the bump 3 is in a state of being pierced into the insulating resin 6. Some of the bumps 3 penetrate the insulating resin 6 and are deformed by hitting the terminal electrodes 5. The positioning load is about 10 g per bump. The mounting tool 7 may be heated by a built-in heater, but the resin should not be cured 100%. The mounting tool 7 is detached after mounting the semiconductor chip 1.

The insulating resin 6 may be heated in advance at a temperature of about 50 to 80 ° C. so that the insulating resin 6 can be adhered and pasted onto the wiring board 4. A tool (not shown) may be heated. The pasting load is 5 to 10 kgf / cm ² . The insulating resin 6 having a thickness of 50 μm was used. If the insulating resin 6 has two layers with a protective separator (not shown), it is peeled off. The insulating resin 6 may be, for example, an epoxy resin, a phenol resin, a polyimide, or an insulating thermoplastic resin such as polyphenylene sulfide (PPS), polycarbonate, modified polyphenylene oxide (PPO), or these insulating materials. A mixture of a thermosetting resin and an insulating thermoplastic resin can be used. The amount of inorganic filler used was 50 wt%. The amount of filler is determined from the stress generated by thermal expansion and warpage between the semiconductor chip 1 and the wiring substrate 4. Moreover, it determines with the reliability by moisture-resistant adhesiveness by a moisture absorption reflow test, a humidity bias test, etc. The insulating resin 6 preferably has reflow heat resistance (265 ° C. for 10 seconds).

  Next, in the subsequent process, the film 13 is pressed onto the semiconductor chip 1 mounted in FIG. 1B using the crimping tool 8 shown in FIGS. 2 to 7 to form a fillet of the insulating resin 6. Is called. The crimping tool 8 includes a pressing portion 9 and a frame body 10 attached to the lower surface of the pressing portion 9 by screws 11 so as to be exchangeable. The material of the frame 10 may be a thermosetting epoxy resin, a phenol resin, polyimide, silicone, Teflon, or a rubber-based resin. These are a mixture of an insulating thermosetting resin and an insulating thermoplastic resin. What you did is fine.

  In FIG. 2A, a film 13 stretched between the support jigs 12 a and 12 b is provided between the crimping tool 8 and the stage 15, and the figure is placed on the stage 15 below the film 13. The semiconductor chip 1 in the mounted state 1 (b) is set. The size of the film 13 is larger than the semiconductor chip 1 both vertically and horizontally. The film 13 is preferably a film having heat resistance (NCF curing temperature). The material of the film 13 is preferably a heat-resistant thermoplastic film such as polyimide, polyphenylene sulfide, fluororesin, silicone rubber, or a two-layer structure thereof. Here, the film 13 has a thickness of about 20 to 30 μm. An uneven shape 13 a is formed on the lower surface of the film 13. The enlarged view is shown in FIG. Specifically, a wave-like pattern of about 3 mm is formed with a 1 mm pitch of 0.5 mm width and 0.5 mm thickness while being heated and pressed with a wave-like concave roller during manufacture of the film 13.

  In FIG. 3, the support jigs 12 a and 12 b are lowered and brought into contact with the stage 15 to loosen the holding of the film 13 by the support jigs 12 a and 12 b, and the film 13 is disposed almost on the semiconductor chip 1. In addition, the insulating resin 6 is disposed almost at the top of the semiconductor chip 1 that sticks out of the periphery of the semiconductor chip 1.

  In FIG. 4, the crimping tool 8 is further lowered toward the stage 15 to cover the frame body 10 on the semiconductor chip 1, and the upper surface of the semiconductor chip 1 and the fillet portion of the insulating resin 6 are interposed via the film 13. Press while heating.

The film 13 may be guided and disposed on the insulating resin 6 by suction or the like from the wiring board 4 or the stage 15 side.
Next, as shown in FIG. 5, the crimping tool 8 further presses the semiconductor chip 1 against the wiring substrate 4 while heating the film 13 through the film 13, and the insulating resin 6 protruding from the semiconductor chip 1 through the film 13. The frame body 10 is pressed and heated and pressurized.

  Next, as shown in FIG. 6, the crimping tool 8 continues to apply pressure while gradually deforming the bumps 3 of the semiconductor chip 1, and at the same time, the frame 10 also protrudes from the semiconductor chip 1 through the film 13. Continue to pressurize the insulating resin 6.

By applying a load with the crimping tool 8, all of the bumps 3 break through the insulating resin 6 and are deformed while being in contact with the terminal electrodes 5 of the wiring board 4.
Next, as shown in FIG. 7, the height of the bump 3 of the semiconductor chip 1 is set to a desired value with the crimping tool 8, and the insulating resin 6 is cured. As a result, the uneven shape 13 a of the film 13 is transferred to the insulating resin 6 protruding from the end of the semiconductor chip 1, and the uneven shape 16 a is formed in the insulating resin 6.

  The bump deformation load at this time is about 50 g per bump. The load is controlled according to the size of the bump 3. In this case, the bump height is set to 25 μmt. Further, if necessary, the stage 15 may be heated or cooled to control the internal pressure applied to the insulating resin 6 and suppress the generation of voids.

Finally, as shown in FIG. 7, the crimping tool 8 and the supporting jigs 12a and 12b were released to obtain a flip chip mounting body. On top of this, the container 40 is formed by the steps of FIGS.
In FIG. 8, the flip chip mounting body of FIG. 7 is placed at a desired position of the substrate fixing stage 27, and the transfer mold 26 is covered from above the flip chip mounting body.

Next, as shown in FIG. 9, the mold resin 30 is heated and injected from the gate 28 portion of the transfer mold 26 while being pushed by the pressure cylinder 29.
Next, as shown in FIG. 10, the cavity 26 </ b> A is completely filled with the mold resin 30 including the semiconductor chip 1 of the flip chip mounting body and the fillet uneven portion 16.

Next, as shown in FIG. 11, the pressure cylinder 29 is opened, and the transfer mold 26 is released and removed.
Next, as shown in FIG. 12, the molded flip chip mounting body is fixed with a dicing tape 32, set in a dicing apparatus, and cut into a desired size with a blade 41.

The molded flip chip mounting body may be laser dicing. In that case, the mounting body is fixed to the substrate suction fixing jig.
In this way, the molded semiconductor device 33 shown in FIG. 13 is completed.

  According to the flip chip mounting method of the first embodiment, the uneven shape 13a of the film 13 can be transferred to the insulating resin 6 to form a uniform uneven shape 16a having no variation as shown in FIG. Furthermore, when the inner surface of the molded container 40 enters and is joined to the concavo-convex shape 16a of the insulating resin 6, the contact area between the two is large, and the adhesive strength with the container 40 is enhanced by an anchor (throwing) effect. be able to.

  Further, since the insulating resin 6 is pressure-molded and cured by the pressure bonding tool 8 through the film 13, generation of voids can be suppressed. By joining the container 40, it is highly reliable that moisture does not easily enter the electrical connection portion between the wiring substrate 4 and the semiconductor chip 1 in a high-temperature and high-humidity environment.

  In addition, since moisture absorption into the insulating resin 6 is small, moisture is hardly heated and expanded during reflow, and the interface between the container 40 and the insulating resin 6 is hardly peeled off. The tensile stress acting between the bump 3 and the terminal electrode 5 can be reduced, and the reliability of electrical connection is improved.

  The crimping tool 8 according to the first embodiment transmits heat to the semiconductor chip 1 through the film 13 and further sets the insulating resin 6 to 210 ° C. so that the curing temperature of the insulating resin 6 becomes 180 ° C. did.

In addition, although the constant heat type is used this time, a ceramic high-speed heating type may be used.
(Embodiment 2)
16 and 17 show the second embodiment.

  In the first embodiment, the surface of the film 13 on the side of the semiconductor chip 1 having the corrugated pattern 13a shown in FIG. 14 is used. In the second embodiment, the film 13 on the side of the semiconductor chip 1 is used. The only difference is that a surface having a corrugated pattern 13b having a wavy pattern shown in FIG. 16 is used. Specifically, the mesh pattern irregularities are formed while heating and pressing with a roller when the film 13 is manufactured. FIG. 17 shows the concavo-convex portion 16 b formed in the fillet portion of the insulating resin 6. The rest is the same as in the first embodiment.

(Embodiment 3)
FIG. 18 shows a third embodiment.
In the first and second embodiments, the film 13 having the concavo-convex shape 13a or 13b is used, and this is transferred to form the concavo-convex portion 16a or 16b in the fillet portion of the insulating resin 6. In the third embodiment, the uneven portion 10 a is formed on the surface of the frame body 10 of the crimping tool 8, and the uneven portion is formed by transferring the uneven portion 10 a to the fillet portion of the insulating resin 6 on the surface of the frame body 10. Only the point is different. The finished shape is the same as in FIG. In the case of this Embodiment 3, the uneven | corrugated shape 13a is not formed in the surface at the side of the semiconductor chip 1 of the film 13, The film with which both surfaces are flat is used.

  This embodiment using the crimping tool 8 with the concavo-convex portion 10a is compared to the case where the concavo-convex shape is transferred to the film 13 as in the first embodiment or the second embodiment. It is easy to change the transfer shape by exchanging the film, and it can be realized at a lower cost than the film processing cost.

(Embodiment 4)
FIG. 19 shows the crimping tool 8 used in the fourth embodiment.
In the third embodiment, the corrugated pattern irregularities are formed on the surface of the frame 10, but in FIG. 19, the only difference is that the mesh pattern irregularities 10b are formed. Yes. The finished shape is the same as in FIG. The uneven part 16b formed in the fillet part of the insulating resin 6 is the same as FIG. On the surface of the film 13 on the side of the semiconductor chip 1, a film having no uneven shape 13 a and flat on both sides is used.

(Embodiment 5)
FIG. 20 shows the crimping tool 8 used in the fifth embodiment.
In FIG. 20, uneven portions 10 c having a staircase pattern are formed on the surface of the frame 10 at intervals of a staircase width of 0.5 mm on one side and a staircase step height of 0.5 mm. The rest is the same as in the fourth embodiment. On the surface of the film 13 on the side of the semiconductor chip 1, a film having no uneven shape 13 a and flat on both sides is used.

(Embodiment 6)
FIG. 21 shows the crimping tool 8 used in the sixth embodiment.
The sixth embodiment is different from the fifth embodiment only in that the direction of the stepped pattern on the surface of the frame 10 is the circumferential direction. Specifically, the uneven portion 10d of the staircase pattern is formed at intervals such that the upper staircase is 0.5 mm wide on one side and the height of the staircase step is 0.5 mm thick. Yes.

  In addition, since the uneven | corrugated | grooved part of the crimping | compression-bonding tool 8 elastically deforms the insulating resin 6 which protruded from the periphery of the semiconductor chip 1 at the time of pressurization, the uneven | corrugated space | interval of a pressurization direction may be 0.5 mm or more. Moreover, the slide moat recess may be wide and shallow toward the lower part. The rest is the same as in the fifth embodiment.

(Embodiment 7)
The concave and convex portions formed on the fillet portion of the insulating resin 6 in FIG. 20 are formed by grooves extending in parallel with the wiring board 4 being stacked at regular intervals in the vertical direction, and the lower groove and the upper groove are connected. However, one or a plurality of spiral protrusions extending from the lower end opening of the frame 10 toward the back of the frame 10 are formed on the surface of the frame 10, and this is used as a fillet portion of the insulating resin 6. It can also be constructed by transcription.

Specifically, the spiral groove has a depth (length) of 0.5 mm, and a spiral pattern is formed at intervals of 0.5 mm.
In addition, since the uneven | corrugated | grooved part of the crimping | compression-bonding tool 8 elastically deforms the insulating resin 6 which protruded from the periphery of the semiconductor chip 1 at the time of pressurization, the spiral groove space | interval of a pressurization direction may be 0.5 mm or more. The rest is the same as in the fifth embodiment.

  In each of the above embodiments, the insulating resin 6 is used. However, an anisotropic conductive film (ACF) may be used instead of the insulating resin 6, and conductive particles contained in the anisotropic conductive film. By using a nickel powder plated with gold as (not shown), the connection resistance value between the terminal electrode 5 and the bump 3 can be lowered, and good connection reliability can be obtained. Furthermore, the conductive particles may be particles obtained by applying nickel or gold plating to resin balls. Furthermore, the conductive particles can be obtained in an alloy state from the contact state connection between the terminal electrode 5 and the bump 3 by using fine particles such as solder, and further improve the connection reliability. be able to.

  As described above, according to the flip chip mounting method of the present invention, a highly reliable semiconductor device with a short lead time and high productivity can be manufactured.

  INDUSTRIAL APPLICABILITY The present invention can contribute to high performance of a small and thin semiconductor device in which a semiconductor chip is flip-chip mounted on a wiring board.

Sectional drawing of the flip chip mounting process of Embodiment 1 of this invention Sectional view of flip chip mounting process of the embodiment Sectional view of flip chip mounting process of the embodiment Sectional view of flip chip mounting process of the embodiment Sectional view of flip chip mounting process of the embodiment Sectional view of flip chip mounting process of the embodiment Sectional view of flip chip mounting process of the embodiment Sectional view of flip chip mounting process of the embodiment Sectional view of flip chip mounting process of the embodiment Sectional view of flip chip mounting process of the embodiment Sectional view of flip chip mounting process of the embodiment Sectional view of flip chip mounting process of the embodiment Sectional view of the completed semiconductor device of the embodiment Plan view of the film of the same embodiment Front view of flip chip mounting before covering the container of the same embodiment The top view of the film of Embodiment 2 of this invention Front view of flip chip mounting before covering the container of the same embodiment Sectional drawing of the flip-chip mounting apparatus of Embodiment 3 of this invention Sectional drawing of the crimping | compression-bonding tool 8 used with the flip-chip mounting apparatus of Embodiment 4 of this invention. Sectional drawing of the crimping | compression-bonding tool 8 used with the flip chip mounting apparatus of Embodiment 5 of this invention Sectional drawing of the crimping | compression-bonding tool 8 used with the flip chip mounting apparatus of Embodiment 6 of this invention Cross-sectional view of conventional flip chip mounting body Cross-sectional view of another conventional flip chip mounting body

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor chip 2 Electrode pad 3 Bump 4 Wiring board 5 Terminal electrode 6 Insulating resin 7 Mounting tool 8 Crimping tool 9 Press part 10 Frame body 10a, 10b, 10c, 10d, 16a, 16b Concavity and convexity part 12a, 12b Support jig 13 Films 13a, 13b Uneven shape 15 Stage 16 Fillet uneven portion 26 Transfer mold die 26A Cavity 28 Gate 29 Pressure cylinder 30 Mold resin 32 Dicing tape 33 Semiconductor device 40 Container 41 Blade

Claims (6)

When the thermosetting underfill resin is interposed between the semiconductor chip and the wiring board to flip-chip mount the semiconductor chip on the wiring board, and when the container covering the semiconductor chip is joined to the wiring board,
An underfill resin that protrudes around the semiconductor chip when the semiconductor chip positioned and disposed with a thermosetting underfill resin sandwiched between the wiring board and the semiconductor chip is pressed and heated with a crimping tool. Forming irregularities on the surface,
A flip chip mounting method in which an inner surface of the container covering the semiconductor chip and the uneven portion on the surface of an underfill resin are joined. Pressing the crimping tool through the film around the semiconductor chip and the semiconductor chip, the uneven shape formed on the surface of the film is transferred to the surface of the underfill resin protruding around the semiconductor chip. The flip chip mounting method according to claim 1, wherein the uneven portion is formed. The pressing tool is pressed around the semiconductor chip and the semiconductor chip through a film, and the uneven shape formed on the surface of the pressing tool is transferred to the surface of the underfill resin that protrudes around the semiconductor chip. The flip chip mounting method according to claim 1, wherein the uneven portion is formed. When the semiconductor chip positioned and disposed with a thermosetting underfill resin sandwiched between the wiring board and the semiconductor chip is pressed and heated with a crimping tool, the underfill resin surface that protrudes around the semiconductor chip is applied. Forming irregularities,
A cavity is formed by setting a molding die on the wiring chip and the semiconductor chip flip-chip mounted on the wiring board,
A flip chip mounting method in which the cavity is filled with a resin and cured to mold the container. Flip chip mounting apparatus for flip chip mounting a semiconductor chip on a wiring substrate by interposing a thermosetting underfill resin between the semiconductor chip and the wiring substrate, and bonding a container covering the semiconductor chip on the wiring substrate Because
A film having a concavo-convex shape formed on a surface on the side of the semiconductor chip supported at an upper position of the semiconductor chip positioned and disposed with a thermosetting underfill resin interposed between the wiring board and the semiconductor chip; ,
A crimping tool that presses the semiconductor chip and the underfill resin protruding to the periphery while heating the underfill resin to the wiring board side through the film;
A flip chip mounting apparatus provided with the wiring board and a mold for forming a cavity on the semiconductor chip flip chip mounted on the wiring board. Flip chip mounting apparatus for flip chip mounting a semiconductor chip on a wiring substrate by interposing a thermosetting underfill resin between the semiconductor chip and the wiring substrate, and bonding a container covering the semiconductor chip on the wiring substrate Because
A film supported at an upper position of the semiconductor chip positioned and disposed with a thermosetting underfill resin interposed between the wiring board and the semiconductor chip;
A pressure-bonding tool in which an uneven shape is formed on the surface of the semiconductor chip while pressing the semiconductor chip and the underfill resin protruding to the periphery while heating the wiring substrate side through the film;
A flip chip mounting apparatus provided with the wiring board and a mold for forming a cavity on the semiconductor chip flip chip mounted on the wiring board.

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