JP3733950B2 - Assembling method of semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a semiconductor device in which a reinforcing member is bonded to the back surface of a bump forming surface of a semiconductor element with an adhesive.
[0002]
[Prior art]
A semiconductor device mounted on a substrate of an electronic device is manufactured through a packaging process in which a lead frame pin or a metal bump is connected to a semiconductor element on which a circuit pattern is formed in a wafer state and sealed with a resin or the like. Has been. Along with the recent miniaturization of electronic devices, the miniaturization of semiconductor devices is also progressing, and in particular, efforts to make semiconductor elements thinner are being actively carried out.
[0003]
Since a thinned semiconductor element is weak against external force and easily damaged during handling, a semiconductor device using a thinned semiconductor element is sealed with a resin layer for reinforcement. The structure is common. For this resin layer formation, a method in which a reinforcing resin member is individually bonded to an individual semiconductor element with an adhesive is used. As this adhesion method, a method of applying a liquid adhesive material, a method of using an adhesive material previously formed in a tape shape, or the like is used.
[0004]
[Problems to be solved by the invention]
However, when the above-described method is used for forming the resin layer, there have been the following problems. First, in the method of applying a liquid adhesive, misalignment due to movement of the mounted semiconductor element due to the fluidity of the adhesive is likely to occur, and it is difficult to ensure shape accuracy. In addition, in the method using an adhesive previously molded into a tape shape in order to prevent this positional deviation, there is a problem that the cost is increased due to the preparation of such an adhesive.
[0005]
Accordingly, an object of the present invention is to provide a method for assembling a semiconductor device capable of bonding a reinforcing member at a low cost without causing a shape defect in a thinned semiconductor element.
[0006]
[Means for Solving the Problems]
The method for assembling a semiconductor device according to claim 1 is a method for assembling a semiconductor device in which a structure having rigidity higher than that of the semiconductor element is bonded to the back surface of the semiconductor element having a plurality of terminals for external connection formed on the front surface by a resin. A first resin supply step of supplying a first resin having a high thixotropy to the semiconductor element bonding position of the plate-like member serving as the structure in a dotted manner; and a plate-like member after the first resin supply step. A second resin application step of applying a second resin having low thixotropy in a semiconductor element adhesion range; and mounting a plurality of semiconductor elements in an aligned state at the semiconductor element adhesion position, and the rear surface side of the semiconductor element is the first A semiconductor element mounting step for holding the position of the semiconductor element with respect to the plate-like member by contacting the resin, and a resin for curing the first resin and the second resin to adhere the semiconductor element to the plate-like member Hardener Including the door.
[0007]
According to the present invention, by supplying a high thixotropic first resin to a plate-like member as a structure in a dotted manner, and then supplying a constant thixotropic second resin, a semiconductor element is mounted, The position of the semiconductor element can be fixed by the first resin, and the reinforcing member can be bonded at a low cost without causing a shape defect in the thinned semiconductor element.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. 1A is a perspective view of a semiconductor device according to an embodiment of the present invention, FIG. 1B is a partial cross-sectional view of the semiconductor device according to an embodiment of the present invention, and FIGS. FIG. 4 is a perspective view of a plate member used in the semiconductor device according to the embodiment of the present invention, and FIG. 5 is a semiconductor according to the embodiment of the present invention. 6 is a perspective view of an electronic component mounting apparatus used for assembling the apparatus, FIG. 6 is a perspective view of a dicing apparatus used for assembling a semiconductor device according to an embodiment of the present invention, and FIG. 7 is an embodiment of the present invention. FIG. 8A is a sectional view of a mounting structure according to an embodiment of the present invention, and FIG. 8B is a sectional view of the embodiment of the present invention. FIG. 9A is a perspective view of a semiconductor device according to an embodiment of the present invention, and FIG. It is a plan view of a semiconductor device of an embodiment of the present invention.
[0009]
First, a semiconductor device will be described with reference to FIG. 1A and 1B, the semiconductor device 1 has a configuration in which a bumper 4 (structure) is bonded to the back surface of the semiconductor element 2 by a resin layer 5. Bumps 3 are formed on the electrodes 2a, which are a plurality of external connection terminals formed along.
[0010]
Here, the semiconductor element 2 is in a state after being thinned by a method such as mechanical polishing or etching. Generally, in a state where a semiconductor element is mounted on a substrate via bumps, the smaller the thickness dimension of the semiconductor element, the better the bonding reliability after mounting. This is because even if the stress is concentrated on the joint portion of the bump 3 due to the difference in thermal stress between the semiconductor element 2 and the substrate, the stress is distributed by the semiconductor element 2 itself being deformed (bent) in the thickness direction. Because it does. For this reason, in the present embodiment, the semiconductor element 2 is thinned as described above and set so that the thickness t1 is in the range of 10 to 150 μm, thereby enabling deformation (deflection) in the thickness direction. .
[0011]
In the thinning process, the surface opposite to the circuit formation surface of the semiconductor element 2 is roughly processed by mechanical polishing using a grindstone or the like, and finish processing is performed by dry etching or wet etching with a chemical solution. When mechanical polishing is performed, a damaged layer having a large number of microcracks on the back surface is formed. Although this damage layer is a factor that lowers the bending strength of the semiconductor element, the damage layer can be removed by finishing to increase the bending strength of the semiconductor element 2.
[0012]
The bumper 4 has a function of facilitating stable holding of the semiconductor device 1 during handling such as when the semiconductor device 1 is mounted and also protecting the semiconductor device 1 after being mounted on a substrate or the like from an external force. It is. Accordingly, the bumper 4 has a shape that satisfies the above-described function, such as a metal, ceramic, or resin, that is, a thickness t2 that has higher rigidity than the semiconductor element 2 and is larger than the outer shape of the semiconductor element 2. What was processed into is used.
[0013]
Here, the resin layer 5 for bonding the semiconductor element 2 to the bumper 4 is made of an adhesive resin made of a material having a low elastic coefficient and easily deformed, and the semiconductor element 2 is allowed to be deformed in the thickness direction. The element 2 is bonded to the bumper 4. Thereby, in a state where the semiconductor device 1 is mounted on the substrate, the semiconductor element 2 is deformed following the deformation state of the substrate. In the present embodiment, two types of resins having different thixotropic properties are used as the resin for forming the resin layer 5 as described later.
[0014]
As shown in FIG. 1, the resin layer 5 protrudes from the end portions of the four sides over the entire circumference of the semiconductor element 2, and the protruding resin part 5 a crawls along the side surface 2 b of the semiconductor element 2 and partially forms the side surface 2 b. It has a shape that covers it. The resin portion 5 a that covers the side surface 2 b forms a reinforcing portion that reinforces the edge of the semiconductor element 2.
[0015]
At the edge of the semiconductor element 2, minute cracks generated when the semiconductor wafer is diced and cut into individual semiconductor elements 2 are likely to remain as they are, and breakage may occur from the cracks. The resin portion 5a covering the side surface 2b reinforces the edge of the semiconductor element 2 including such a microcrack, and in a state where the semiconductor device 1 is mounted on the substrate 10 as described later, the substrate and the semiconductor element 2 The semiconductor element 2 has a function of preventing the semiconductor element 2 from being excessively deformed due to the stress generated by the difference in thermal deformation with respect to.
[0016]
Next, an assembling method of the semiconductor device 1 will be described with reference to FIGS. In FIG. 2A, the plate-like member 6 is an intermediate part before the bumper 4 constituting a part of the semiconductor device 1 is cut off. As shown in FIG. 3, a partition 6a protruding in a lattice shape is provided on the upper surface of the plate-like member 6, and a recess 6b surrounded by the partition 6a is a semiconductor element bonding position to which the semiconductor element 2 is bonded. It has become. As will be described later, the partition 6a is a dam that restricts the resin from spreading beyond the semiconductor bonding position when the resin for bonding the semiconductor element 2 is applied in the recess 6b.
[0017]
A groove portion 6 c is formed at a position corresponding to the partition portion 6 a on the lower surface of the plate-like member 6. The groove 6c is formed by cutting a lattice-like groove from the lower surface side of the plate-like member 6 having a thickness dimension t4, and thereby has a thin portion whose thickness dimension t3 from the upper surface is smaller than t4. This thin portion coincides with the cutting position when the plate-like member 6 is cut and separated into the bumper 4.
[0018]
Next, as shown in FIG. 2 (b), the first resin 5A is discharged by the dispenser 7A to the semiconductor element bonding position in each recess 6b of the plate-like member 6, and is formed in a protruding dot shape at a plurality of locations. It is supplied (first resin supply step). The first resin 5A has high thixotropy, has low fluidity, and does not spread even after being discharged by the dispenser 7A, and the protruding shape is maintained as it is.
[0019]
Next, as shown in FIG. 2C, the second resin 5B is discharged by the dispenser 7B and applied to the recess 6b at the semiconductor element bonding position in each recess 6b after the first resin supply step. (Second resin application step). Since the second resin 5B has low thixotropy and high fluidity, the second resin 5B wets and spreads around the already supplied first resin 5A and fills the inside of each recess 6b. In the application of the second resin 5B, since the partition portion 6a as a dam portion is provided around the recess 6b, the second resin 5B is prevented from spreading beyond the semiconductor bonding position. The
[0020]
Further, in the second resin application step, when the second resin 5B that has been spread by the semiconductor element 2 after application protrudes outward from the end of the semiconductor element 2, the side surface 2b of the semiconductor element 2 is removed as described above. An appropriate amount of the second resin 5 </ b> B that is not excessive or insufficient for covering is discharged from the dispenser 7.
[0021]
Thereafter, the plate-like member 6 to which the second resin 5B is applied is sent to the semiconductor element bonding step. In this semiconductor element bonding step, as shown in FIG. 3A, the semiconductor element 2 is mounted in an aligned state at the semiconductor element bonding position of the plate-like member 6 (semiconductor element mounting step). An electronic component mounting apparatus used in this semiconductor element mounting process will be described with reference to FIG. In FIG. 4, the component supply table 11 is provided with an adhesive sheet 12 on which the semiconductor elements 2 are attached in a lattice shape. Below the component supply table 11, a semiconductor element peeling mechanism 13 is disposed. When the semiconductor element peeling mechanism 13 is driven by the semiconductor element peeling mechanism driving unit 14, the ejector pin mechanism 13a causes the lower surface of the adhesive sheet 12 to be lower. Thus, when the semiconductor element 2 is picked up by the mounting head 16, the semiconductor element 2 is peeled off from the upper surface of the adhesive sheet 12.
[0022]
A substrate holding unit 15 is disposed on the side of the component supply table 11, and the plate-like member 6 after resin supply is held on the substrate holding unit 15. A mounting head 16 driven by a mounting head driving unit 19 is disposed above the component supply table 11 and the substrate holding unit 15. The mounting head 16 includes the suction nozzle 8, picks up the semiconductor element 2 from the adhesive sheet 12, and mounts it on the plate-like member 6 on the substrate holding unit 15.
[0023]
A camera 17 is disposed above the component supply table 11, and the camera 17 images the semiconductor element 2 adhered to the adhesive sheet 12. The position of the semiconductor element 2 on the adhesive sheet 12 is recognized by performing a recognition process on the image captured by the camera 17 by the semiconductor element recognition unit 20. The position recognition result is sent to the control unit 21 and also sent to the semiconductor element peeling mechanism driving unit 14. Thereby, when the semiconductor element 2 is picked up by the mounting head 16, the suction nozzle 8 and the ejector pin mechanism 13a are aligned with the semiconductor element 2 to be picked up.
[0024]
A camera 18 is disposed above the substrate holding unit 15, and the camera 18 images the plate-like member 6 held by the substrate holding unit 15. The mounting position recognition unit 22 recognizes the image captured by the camera 18 to detect the semiconductor element mounting position on the plate member 6. The position recognition result is sent to the control unit 21, and the control unit 21 controls the mounting head driving unit 19 based on the position recognition result, so that it is held by the suction nozzle 8 when the semiconductor element 2 is mounted by the mounting head 16. The semiconductor element 2 is aligned with the detected mounting position.
[0025]
When the semiconductor element 2 is mounted on the plate-like substrate 6 by this electronic component mounting apparatus, the surface side on which the bump 3 of the semiconductor element 2 is formed is sucked and held by the suction nozzle 8 as shown in FIG. First, the back surface of the semiconductor element 2 is brought into contact with the protrusions of the first resin 5A supplied in the form of dots. Then, the semiconductor element 2 is further lowered, and the second resin 5 </ b> B is expanded by the back surface of the semiconductor element 2.
[0026]
In this resin expansion operation, the second resin 5 that protrudes outside the edge of each semiconductor element 2 (see arrow A) is adjusted by adjusting the pressing height of the suction nozzle 8 according to the amount of the resin 5 applied. Then, the side surface 2b of the semiconductor element 2 is scooped up so as to cover the side surface 2b (see the resin 5a shown in FIG. 1B). At this time, if the end portion on the back surface side of the semiconductor element 2 where damage during dicing is likely to remain is completely covered and reinforced, the side surface 2b is completely covered or only partially covered. But either is fine.
[0027]
In the present embodiment, since the semiconductor elements 2 are mounted one by one while being pressed against the resin 5 by the mounting head 16, the mounting load (pressing force) can be reduced as compared with the case where the semiconductor elements 2 are collectively mounted (pasted). Therefore, a die bonding apparatus, a chip mounter, or the like can be used as the electronic component mounting apparatus. Further, since the semiconductor element 2 after being mounted is held in position with respect to the plate-like member 6 by the highly viscous first resin 5A, the positional deviation and height of the semiconductor element 2 due to the flow of the second resin 5B. The posture is not changed, and the state when the semiconductor element 2 is mounted can be maintained as it is.
[0028]
Thus, the plate-like member 6 on which the semiconductor element 2 is mounted is sent to the heating furnace. Then, by heating at a predetermined temperature, the first resin 5A and the second resin 5B are thermally cured as shown in FIG. 2D, and the resin layer that adheres the semiconductor element 2 to the plate member 6 Resin curing step in which 5 is formed). At this time, the second resin 5B that protrudes outside the edge of each semiconductor element 2 rises further to the side surface 2b of the semiconductor element 2 due to surface tension due to a temporary viscosity drop during the thermosetting process, and the side surface 2b It is cured with the shape covered. Thereby, after hardening of the 2nd resin 5B, the resin part 5a as a reinforcement part shown in FIG.1 (b) is formed.
[0029]
In the above embodiment, the first resin 5A and the second resin 5B are thermally cured by sending the plate-like member 6 to the heating furnace after the semiconductor element 2 is mounted. A device incorporating a means may be used, and heating may be performed while the semiconductor element 2 is mounted.
[0030]
When heating by the mounting head 16, the dedicated heating step shown in FIG. 2 (d) may be omitted, and in this way, the heating furnace can be omitted and the equipment can be simplified. There is. However, in this case, since the tact time of the mounting head 16 is limited by the thermosetting time, the overall productivity is lower than when the mounting process and the heating process are performed separately. Moreover, although the example which uses a thermosetting resin is shown in the said embodiment as a resin kind for forming the resin layer 5, it may replace with this and may use a thermoplastic resin raw material.
[0031]
The plate-like member 6 to which the semiconductor element 2 is bonded in this way is sent to a cutting step, and as shown in FIG. 2 (e), the plate-like member 6 to which the semiconductor element 2 is bonded is turned into a rotary cutting blade 24a. Is cut at a cutting position between adjacent semiconductor elements 2 (cutting step). As a result, the plate-like member 6 is cut and separated into bumpers 4 for each semiconductor element 2, and the assembly of the semiconductor device 1 is completed.
[0032]
This cutting process will be described with reference to FIGS. FIG. 5 shows a dicing apparatus used for this cutting. On the upper surface of the substrate fixing portion 23, the plate-like member 6 on which the semiconductor element 2 is mounted and the resin curing is completed is placed on the substrate fixing portion 23. A cutting head 24 having a rotary cutting blade 24a is disposed above the substrate fixing portion 23, and the cutting head 24 is moved in the X direction and the Y direction while rotating the rotary cutting blade 24a. The shaped member 6 is cut along a cutting position coinciding with the groove 6c.
[0033]
As shown in FIG. 6, suction holding portions 25 are provided on the upper surface of the substrate fixing portion 23 at positions corresponding to the semiconductor elements 2 on the plate-like member 6, and suction grooves are provided on the upper surface of the suction holding portion 25. 25a is formed. The suction groove 25 a communicates with a suction hole 23 a provided in the substrate fixing portion 23, and the suction hole 23 a is further connected to a vacuum suction source 26. By driving the vacuum suction source 26 in a state where the lower surface of the plate-like member 6 is in contact with the suction holding portion 25, the plate-like member 6 is sucked and held by the suction holding portion 25, thereby the position of the plate-like member 6. Is fixed.
[0034]
Then, the rotary cutting blade 24a is positioned on the partition portion 6a of the plate-like member 6 fixed in this manner, and the thin portion in the groove 6c is cut by lowering the rotary cutting blade 24a while rotating it. Is done. At this time, by using the rotary cutting blade 24a whose blade width is smaller than the interval between the adjacent semiconductor elements 2, the bumper 4 after the plate-like member 6 is separated into individual pieces protrudes from the end face of the semiconductor element 2. Cut in shape. Therefore, in the semiconductor device 1 separated into pieces, the outer shape of the bumper 4 is larger than the outer shape of the semiconductor element 2.
[0035]
In this cutting, since the groove 6c is formed in advance on the lower surface, the cutting allowance by the rotary cutting blade 24a is reduced. Thereby, the required lowering amount of the rotary cutting blade 24a in the cutting process can be made as small as possible, and it is possible to prevent an accident that the cutting edge comes into contact with the substrate fixing portion 23 when the cutting blade is lowered.
[0036]
Next, an electronic component mounting structure formed by mounting the above-described semiconductor device 1 on a substrate will be described with reference to FIG. As shown in FIG. 7A, the semiconductor device 1 is mounted on the substrate 10 by connecting the bumps 3 to the electrodes 10a formed on the upper surface of the substrate 10 by solder bonding. FIG. 7B shows a deformed state of the semiconductor element 2 located outside the bump 3. In the structure in which the thinned semiconductor element 2 is bonded to the substrate 10 via the bump 3 as shown in this embodiment, the bump is caused by the stress generated by the difference in thermal deformation between the semiconductor element 2 and the substrate 10. The range from 3 to the outside tends to be greatly bent toward the substrate 10 (see the semiconductor element 2 indicated by a broken line). Along with this deformation, a high level surface stress is generated on the lower surface of the semiconductor element 2 near the outside of the bump 3, which may cause the semiconductor element 2 to be damaged.
[0037]
On the other hand, as shown in the present embodiment, when the semiconductor device 1 reinforced by the resin 5a covering the side surface 2b of the semiconductor element 2 is mounted on the substrate 10, the outermost bump 3 is in the outer range. The downward deflection of the semiconductor element 2 is greatly reduced. That is, the resin portion 5 a acts to cover the side surface 2 b of the semiconductor element 2 and prevent excessive bending deformation of the semiconductor element 2. By this action, downward deformation of the semiconductor element 2 is prevented, and damage due to bending deformation of the semiconductor element 2 can be prevented.
[0038]
Note that, as in the semiconductor device 1A shown in FIG. 8, the range of the resin portion 5a that protrudes from the edge of the semiconductor element 2 is limited to the diagonal direction of the semiconductor element 2, and the side surface of the semiconductor element 2 is covered with the resin portion 5a. The part may be formed only at the corner of the semiconductor element 2. In this case, when the second resin 5B is applied by the dispenser 7B in FIG. 2 (b), the application of the dispenser 7 is performed so that the second resin 5B is applied only to the range shown in FIG. 8 (b). The trajectory is set in an X shape and the discharge amount from the dispenser 7 is controlled. By limiting the formation range of the reinforcing portion to the corner portion of the semiconductor element 2 in this manner, the corner portion that is most likely to be damaged in the mounted state after completion of the semiconductor device can be intensively reinforced.
[0039]
Moreover, in this Embodiment, although the 1st resin supply process and the 2nd resin supply process are performed with a dispenser, you may perform with another apparatus (for example, screen printing machine). In particular, if a screen printing machine is used, productivity can be improved as compared with a dispenser.
[0040]
【The invention's effect】
According to the present invention, by supplying a high thixotropic first resin to a plate-like member as a structure in a dotted manner, and then supplying a constant thixotropic second resin, a semiconductor element is mounted, The position of the semiconductor element can be fixed by the first resin, and the reinforcing member can be bonded at a low cost without causing a shape defect in the thinned semiconductor element.
[Brief description of the drawings]
1A is a perspective view of a semiconductor device according to an embodiment of the present invention; FIG. 1B is a partial cross-sectional view of a semiconductor device according to an embodiment of the present invention; FIG. FIG. 3 is a process explanatory diagram of a semiconductor device assembly method according to an embodiment of the present invention. FIG. 4 is a diagram of a plate-like member used in a semiconductor device according to an embodiment of the present invention. FIG. 5 is a perspective view of an electronic component mounting apparatus used for assembling a semiconductor device according to an embodiment of the present invention. FIG. 6 is a dicing used for assembling a semiconductor device according to an embodiment of the present invention. FIG. 7 is a partial cross-sectional view of a dicing apparatus used for assembling a semiconductor device according to an embodiment of the present invention. FIG. 8A is a cross-sectional view of a mounting structure according to an embodiment of the present invention. (B) Partial cross-sectional view of a mounting structure according to an embodiment of the present invention. Plan view of a semiconductor device of an embodiment of a perspective view of a semiconductor device of the facilities in the form (b) The present invention Description of Reference Numerals]
DESCRIPTION OF SYMBOLS 1,1A Semiconductor device 2 Semiconductor element 2a Electrode 3 Bump 4 Bumper 5 Resin layer 5A 1st resin 5B 2nd resin 6 Plate-like member 6a Partition part 6b Recessed part 7A, 7B Dispenser

Claims (1)

A method of assembling a semiconductor device in which a structure having a rigidity higher than that of a semiconductor element is bonded to a back surface of a semiconductor element having a plurality of external connection terminals formed on the front surface by a resin, wherein the plate-like member serving as the structure is A first resin supply step for supplying a first resin having a high thixotropy at a semiconductor element adhesion position in a dot shape, and a second resin having a low thixotropy for a semiconductor element adhesion range of a plate-like member after the first resin supply step. A second resin application step of applying the resin, and mounting a plurality of semiconductor elements in an aligned state at the semiconductor element adhesion position, and bringing the back surface side of the semiconductor elements into contact with the first resin to form a plate A semiconductor device comprising: a semiconductor element mounting step for holding a position with respect to a member; and a resin curing step for curing the first resin and the second resin to adhere the semiconductor element to a plate member. of Stand way.

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