TWI585876B - Method for planting solder balls on encapsulated mother board of semiconductor assemblies - Google Patents

Description

Ball placement method of packaged semiconductor module mother chip

The present invention relates to the field of semiconductor chip packaging, and more particularly to a ball bonding method for a packaged semiconductor module mother substrate, which is suitable for fabricating a ball grid array package structure (BGA package).

One common type of semiconductor chip package is a Ball Grid Array package, which is provided with a plurality of equidistantly arranged solder balls on the bottom surface of the package structure. In general, the solder ball mounting process is performed after the molding process and before the singulation process, that is, the solder balls are bonded to the strip-shaped packaged semiconductor module master to avoid the molding process. Damage to the solder balls and a large number of solder balls can be mounted on the master in batches. The mold encapsulation system formed on the semiconductor module mother board is used to protect and seal the semiconductor wafer mounted on the semiconductor chip master. The specific structure of one of the strip-shaped packaged semiconductor module mother sheets is a molded substrate strip, and the packaged semiconductor module mother sheet can form a plurality of separated and soldered semiconductors after the singulation process. Wafer package construction. Usually, in the pre-balling process, the solder ball is first separated into a single type, temporarily positioned on the semiconductor module master under the adhesion of the flux, and then soldered to the solder ball. The semiconductor module master has been packaged. However, within the semiconductor module master, for example There is a difference in thermal expansion coefficient between the components such as the wafer, the substrate strip and the molding compound, and the thermal curing treatment of the molding colloid causes the semiconductor module to generate a slight warp deformation, which leads to the ball placement process. The solder ball is not installed correctly.

During the temporary positioning of the solder balls of the conventional ball-planting process, the packaged semiconductor module master is first fixed to a vacuum chuck by adsorption. The composition of the conventional vacuum chuck is a rigid all-metal material, and the adsorption surface of the vacuum chuck is integrally formed with a plurality of rigid metal bumps, and the packaged semiconductor module is leveled by metal bumps of equal height during adsorption. sheet. Under the above-mentioned leveling force, the molding compound has residual stress and the wafer in the molding compound is prone to crack defects. In particular, when the shape of the semiconductor module mother substrate is developed from a strip shape to a panel shape, residual stress and wafer cracking problems become more serious.

In order to solve the above problems, the main object of the present invention is to provide a ball bonding method for a packaged semiconductor module mother substrate, which improves the risk of wafer cracking in a packaged semiconductor module mother chip without changing or increasing the packaging process operation conditions. Reduce the stress remaining on the packaged master during the process.

The object of the present invention and solving the technical problems thereof are achieved by the following technical solutions. The ball placement method of a packaged semiconductor module mother substrate disclosed in the present invention comprises the following steps. In a providing step, a vacuum chuck is provided, the vacuum chuck comprising a support substrate and an elastic buffer layer formed on the support substrate, the support substrate having a plurality of adsorption holes, the elastic buffer layer having a plurality of The adsorption groove pattern, the adsorption groove patterns are not connected to each other, and an adsorption groove pattern The pattern is connected to an adsorption hole, and the adsorption groove pattern radiates a plurality of branch channels in a uniform fixed manner around the corresponding adsorption holes, so that the adsorption groove patterns are arranged in a "X X ..." shape distribution. In an adsorption step, a packaged semiconductor module mother substrate is adsorbed on the vacuum chuck, and the packaged semiconductor module master has a plurality of ball pads. In a stamping step, a plurality of fluxes are applied to the ball pads, wherein the packaged semiconductor module master is held in a state of being adsorbed to the vacuum chuck. In a placing step, a plurality of solder balls are placed on the ball pads, and the solder balls are temporarily fixed by the flux, wherein the packaged semiconductor module master is held in the vacuum chuck State.

The object of the present invention and solving the technical problems thereof can be further achieved by the following technical measures.

In the foregoing ball placement method, the ball placement method of the packaged semiconductor module mother substrate may further comprise an adsorption force releasing step after the step of placing the solder balls, releasing the adsorption force of the vacuum chuck to take out the The semiconductor module master package is packaged; and a solder reflow step is performed to reflow the solder balls to fix the solder balls to the ball pads.

In the aforementioned ball placement method, the composition of the elastic buffer layer may comprise rubber.

In the foregoing ball placement method, the width of the branch channels may be no more than the diameter of the holes of the corresponding adsorption holes.

In the foregoing ball placement method, adjacent branch channels of the adjacent adsorption groove patterns may be perpendicular to each other.

By the above technical means, the present invention can achieve an average adsorption of the packaged semiconductor module master. Moreover, in the manner of correcting rather than rigidly flattening the warpage of the packaged semiconductor module master, the die crack in the packaged semiconductor module mother substrate can be improved and the residue can be slowed down without changing the parameters in the process program. Stress. The invention further has the effect of greatly reducing the material processing process and reducing the cost of the mold.

Step 1‧‧‧ Provide a vacuum cup

Step 2‧‧‧Adsorption of a packaged semiconductor module master on a vacuum chuck

Step 3‧‧ ‧ Printing a plurality of fluxes on the packaged semiconductor module master

Step 4‧‧‧ Place a plurality of solder balls on the packaged semiconductor module master

Step 5‧‧‧Release the suction force of the vacuum chuck

Step 6‧‧‧Reflow solder balls

100‧‧‧vacuum suction cup

110‧‧‧ Support base plate

111‧‧‧Adsorption holes

120‧‧‧Flexible buffer layer

130‧‧‧Adsorption groove pattern

131‧‧‧ branch channel

132‧‧‧Slot extension

210‧‧‧Packed semiconductor module master

211‧‧‧ ball mat

220‧‧‧ Flux

221‧‧‧welding layer

222‧‧‧welding tray

223‧‧‧weld printing head

230‧‧‧ solder balls

231‧‧‧ Template

232‧‧‧Ball adsorption head

1 is a block flow diagram of a ball placement method of a packaged semiconductor module master according to an embodiment of the present invention.

2 is a perspective view showing a vacuum chuck provided in the ball placement method according to an embodiment of the present invention.

Figure 3 is an exploded perspective view of the vacuum chuck in accordance with an embodiment of the present invention.

Figure 4 is a schematic view showing the adsorption surface of the vacuum chuck according to an embodiment of the present invention.

Figure 5 is a cross-sectional view of the vacuum chuck taken along line 5-5 of Figure 2, in accordance with an embodiment of the present invention.

Figure 6 is a schematic view showing the components of the method of adsorbing a packaged semiconductor module in the method of ball implantation according to an embodiment of the present invention.

Figure 7 is a schematic view of the components in the step of printing the flux in the ball placement method in accordance with an embodiment of the present invention.

Figure 8 is a schematic view showing the components in the step of placing a solder ball in the ball placement method according to an embodiment of the present invention.

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings in which FIG. The components and combinations related to this case, the components shown in the figure are not drawn in proportion to the actual number, shape and size of the actual implementation. Some size ratios are proportional to other related sizes or have been exaggerated or simplified to provide clearer description of. The actual number, shape and size ratio of the implementation is an optional design, and the detailed component layout may be more complicated.

In accordance with an embodiment of the present invention, a method of ball placement of a packaged semiconductor module master is illustrated in the block diagram of FIG. The ball placement method includes the steps of "providing a vacuum chuck", "adsorbing a packaged semiconductor module master on a vacuum chuck", and "staining a plurality of fluxes on the packaged semiconductor module master". Step 3, Step 4 of "Place a plurality of solder balls on the packaged semiconductor module master", Step 5 of "Release the suction force of the vacuum chuck", and Step 6 of the "Reflow solder ball", Step 1 to Step 4 is a combination of the main steps for achieving the efficacy of the present invention, and steps 5 and 6 are for more specific selection steps of the present invention.

Perform step 1 of "Providing a Vacuum Suction Cup". Figure 2 is a schematic perspective view showing one of the vacuum chucks provided in the ball placement method. Figure 3 is a schematic exploded view of the vacuum chuck. Figure 4 is a schematic view of the adsorption surface of the vacuum chuck. Figure 5 is a schematic cross-sectional view of the vacuum chuck taken along line 5-5 of Figure 2; Referring to FIGS. 2 to 5, a vacuum chuck 100 is provided. The vacuum chuck 100 includes a support substrate 110 and an elastic buffer layer 120 formed on the support substrate 110. The support base plate 110 is specifically made of a rigid metal material. The composition of the elastic buffer layer 120 The system may specifically comprise a rubber. The elastic buffer layer 120 may have a hardness ranging from 75 to 85 degrees (shore A). The thickness of the elastic buffer layer 120 can range from 2 to 4 millimeters (mm).

Moreover, the support base 110 has a plurality of adsorption holes 111. The elastic buffer layer 120 has a plurality of adsorption groove patterns 130. The adsorption groove patterns 130 are not connected to each other. A adsorption groove pattern 130 is connected to an adsorption hole 111, and the adsorption groove pattern 130 corresponds to the adsorption groove pattern 130. A plurality of branch channels 131 are radiated from the adsorption holes 111 at a center in a uniform fixed point manner, so that the adsorption groove patterns 130 are arranged in a "XX ..." shape. The so-called "uniform pointing mode" is such that the shape of the adsorption groove pattern 130 can provide a relatively uniform vacuum suction force, and each branch channel 131 has a slot extending end 132 that is not directly connected to other channels. The distance between each slot extending end 132 to the corresponding adsorption hole 111 or the center point of the corresponding adsorption groove pattern 130 is equal, and the branch channels 131 have the same width, and the width range may be between 3~ 5 mm (mm). In addition, the shape of the adsorption groove patterns 130 is specifically an oblique cross shape, that is, not parallel to the long side and the wide side of the vacuum chuck 100, and the branch channels 131 are arranged in pairs in pairs to define radiation. On a straight line. The angles between the adjacent two adjacent branch channels 131 in the same adsorption groove pattern 130 to the corresponding adsorption holes 111 or the center points of the corresponding adsorption groove patterns 130 are equal. When one adsorption groove pattern 130 has four branch channels 131, The angle between the two adjacent branch channels 131 is 90 degrees. When the adsorption groove pattern has six branch channels, the angle between the adjacent branch channels is 60 degrees. Referring to FIGS. 2 to 4, the adjacent branch channels 131 adjacent to the adjacent adsorption groove patterns 130 are preferably Perpendicular to each other. Referring to Figures 3 and 4, the width of the branch channels 131 may be no larger than the diameter of the holes of the correspondingly-connected adsorption holes 111. Therefore, the adsorbed objects will not be excessive in the branch channels 131. The depressions provide an appropriate and uniform vacuum extraction force to the adsorbate. The term "uniform extraction vacuum force" as used herein is due to the fact that when the branch channel 131 is subjected to a relatively strong vacuum extraction force in the vicinity of the corresponding adsorption hole 111, the width of the relevant interval of the branch channels 131 is naturally reduced. The branch channels 131 are subjected to a relatively weak vacuum extraction force in a section away from the corresponding adsorption holes 111, and the widths of the relevant sections of the branch channels 131 are not reduced, thereby achieving a uniform effect of the adsorption force. Specifically, the percentage of the width of the branch channels 131 relative to the corresponding width of the vacuum chuck 100 ranges from 10 to 16.67%, and the slots of the branch channels 131 cover the overall area relative to the vacuum. The suction area of the suction cup 100 is between 6.11 and 12.57%.

Perform step 2 of "Adsorbing a packaged semiconductor module master on a vacuum chuck". FIG. 6 is a schematic view showing the components in the step of adsorbing the packaged semiconductor module master in the ball placement method. Referring to FIG. 6, a packaged semiconductor module mother substrate 210 is adsorbed on the vacuum chuck 100. The packaged semiconductor module mother substrate 210 has a plurality of ball pads 211. In one embodiment, the packaged semiconductor module mother substrate 210 can be a molded substrate strip; in a variant embodiment, the packaged semiconductor module mother substrate 210 can be a panel-shaped molded package. The mother sheet may or may not have a substrate structure, and a molded mother sheet having no substrate structure is, for example, a fan-out type panel-level package mother sheet. One side of the vacuum chuck 100 is provided with a flux tray 222, and a soldering layer 221 is provided on the surface thereof. A soldering paste head 223 having a multi-needle structure is disposed on the upper side of the soldering tray 222; a template 231 is disposed on the other side of the vacuum chuck 100 for providing a plurality of individually separated solder balls 230. A ball adsorption head 232 is disposed above the template 231 for adsorbing the solder balls 230.

In the step 2 of the adsorption step, the adsorption holes 111 of the support substrate 110 are diffused and adsorbed in a manner that the individual adsorption center points are the main axes and uniformly diffused outward, and the vacuum chuck 100 can slow down the phenomenon that the vacuum pressure is weakened. The more uniform pressure values desorb the entire packaged semiconductor module master 210. In addition, the definition of the adsorption groove pattern 130, particularly the oblique cross, conforms to the uniform fixed point adsorption mode, and the adsorption force is distributed to the corners and sides of the packaged semiconductor module mother substrate 210 to facilitate the expansion of the adsorption force when vacuum is drawn. Coverage.

Perform step 3 of "Staining a plurality of fluxes on the packaged semiconductor module master". Figure 7 is a schematic view of the components in the step of printing the flux in the ball placement method. Referring to FIG. 7, a plurality of fluxes 220 are applied to the ball pads 211, wherein the packaged semiconductor module mother substrate 210 is held in a state of being adsorbed to the vacuum chucks 100. In this step, the soldering paste head 223 is adhered to the soldering layer 221 on the soldering tray 222 with its needle end, and the soldering agent 220 is adhered to the needle end, and is printed. On the ball pads 211 of the packaged semiconductor module mother substrate 210.

Perform step 4 of “Placing a plurality of solder balls on the packaged semiconductor module master”. Figure 8 is a schematic view showing the components in the step of placing the solder balls in the ball placement method. Referring to FIG. 8 , a plurality of solder balls 230 are placed on the ball pads 211 , and the solder balls 220 are temporarily fixed by the fluxes 220 , wherein the solder balls 230 are temporarily fixed. The packaged semiconductor module mother substrate 210 is maintained in a state of being adsorbed to the vacuum chuck 100. In this step, the ball adsorption head 232 is first adsorbed on the solder balls 230 of the template 231, and then the ball adsorption head 232 is moved and the solder balls 230 are aligned with the ball pads 211.

More specifically, the step 5 of performing the "release force of the vacuum chuck" is performed, after the step 4 of placing the solder balls, releasing the adsorption force of the vacuum chuck 100 to take out the packaged semiconductor module mother 210, and The vacuum chuck 100 is separated. The packaged semiconductor module master 210 is then loaded into a reflow oven.

More specifically, step 6 of "reflow solder balls" is performed to reflow the solder balls 230 so that the solder balls 230 are fixed to the ball pads 211.

Therefore, the vacuum chuck provided by the present invention is used for correcting the warpage of the packaged semiconductor module mother piece, and replaces the mode in which the conventional vacuum chuck is forcibly leveling the warpage of the packaged semiconductor module mother piece by a steel vacuum chuck. The stress damage of the packaged semiconductor module mother piece is low and has a relatively uniform adsorption force.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, and thus equivalent changes made in the claims of the present invention are still within the scope of the present invention.

100‧‧‧vacuum suction cup

110‧‧‧ Support base plate

111‧‧‧Adsorption holes

120‧‧‧Flexible buffer layer

130‧‧‧Adsorption groove pattern

131‧‧‧ branch channel

132‧‧‧Slot extension

Claims (9)

A method for ball-planting a semiconductor chip package includes: providing a vacuum chuck, the vacuum chuck comprising a support substrate and an elastic buffer layer formed on the support substrate, the support substrate having a plurality of adsorption holes The elastic buffer layer has a plurality of adsorption groove patterns, and the adsorption groove patterns are not connected to each other, and an adsorption groove pattern is connected to an adsorption hole, and the adsorption groove pattern is centered on the corresponding adsorption hole. The uniform spotting method radiates a plurality of branch channels, so that the adsorption groove patterns are arranged in a "XX ..." shape distribution; and a packaged semiconductor module mother chip is adsorbed on the vacuum chuck, the packaged semiconductor module mother The film system has a plurality of ball pads; a plurality of fluxes are coated on the ball pads, wherein the packaged semiconductor module master is held in a state of being adsorbed to the vacuum chuck; and a plurality of solder balls are placed on the balls On the pad, the solder balls are temporarily fixed by the flux, wherein the packaged semiconductor module master is held in a state of being adsorbed to the vacuum chuck. The method of placing a ball of a packaged semiconductor module as described in claim 1, after the step of placing the solder balls, further comprising: releasing an adsorption force of the vacuum chuck to take out the packaged semiconductor mold a group of mother sheets; and reflowing the solder balls to fix the solder balls to the ball pads. The method of ball-planting a packaged semiconductor module mother substrate according to claim 1, wherein the elastic buffer layer comprises a rubber. The method of ball-planting a packaged semiconductor module according to claim 1, wherein the width of the branch channels is not greater than a diameter of the holes of the correspondingly-connected adsorption holes. The method of ball-planting a packaged semiconductor module mother substrate according to claim 1, 2, 3 or 4, wherein the adjacent branch channels of the adjacent adsorption groove patterns are perpendicular to each other. A vacuum chuck for use in a method for implanting a semiconductor chip of a packaged semiconductor module, the vacuum chuck comprising a support substrate and an elastic buffer layer formed on the support substrate, the support substrate having a plurality of adsorption holes, The elastic buffer layer has a plurality of adsorption groove patterns, and the adsorption groove patterns are not connected to each other, and an adsorption groove pattern is connected to an adsorption hole, and the adsorption groove pattern is uniformly fixed with the corresponding adsorption hole as a center. The method radiates a plurality of branch channels such that the adsorption groove patterns are arranged in a "XX ..." shape distribution. A vacuum chuck for use in a method of implanting a packaged semiconductor chip master according to claim 6, wherein the elastic buffer layer comprises rubber. The vacuum chuck used in the method of ball-planting a packaged semiconductor module according to claim 6, wherein the width of the branch channels is not greater than the diameter of the holes of the correspondingly-connected adsorption holes. A vacuum chuck for use in a method of ball-planting a packaged semiconductor module according to claim 6, wherein the adjacent ones of the plurality of adjacent groove channels are adjacent to each other. Perpendicular to each other.