JP2011230423A - Resin sealing device and resin sealing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid resin sealing failure and shorten the time for resin sealing even when the resin sealing thickness having a small amount of resin is thin.SOLUTION: In a resin sealing device 100, a semiconductor chip 104 mounted on a substrate 102 is disposed on a cavity of a mold 114 together with a resin 106, pressure reduction and heating of the mold 114 are performed, and compression pressure is applied to the semiconductor chip 104 to seal the resin. A driving speed V5 from the lowest speed switching position Y5 to an acceleration position Y6 is made to the lowest in a mold clamping of the mold 114, a driving speed V3 from the first touch position Y3 to a low-speed switching position Y4, a driving speed V4 from a low-speed switching position Y4 to the lowest switching position Y5, and a driving speed V6 from the acceleration position Y6 to a pressure keeping position Y7 are made to be faster than a driving speed V5 from the lowest speed switching position Y5 to the acceleration position Y6.

Description

  The present invention relates to a technical field of a resin sealing device and a resin sealing method.

  In Patent Document 1, an object to be molded (semiconductor chip and accompanying bonding wire, etc.) mounted on a substrate is placed in a mold cavity together with a thermosetting resin, and the mold is decompressed and heated to perform the process. There has been proposed a resin sealing device that applies a compression pressure to a product to be molded and performs resin sealing. In addition, this resin sealing apparatus has a metal mold | die provided with the 1st metal mold | die and the 2nd metal mold | die which can approach / separate relatively with respect to this 1st metal mold | die.

  Here, the thermosetting resin has a flat plate shape (solid). For this reason, the resin is once softened from the solid by heating to become a low-viscosity liquid, and is cured again to return to the solid. That is, the resin sealing device is controlled so that the movement of the mold in mold clamping is completed within a time (referred to as gel time) until the resin changes from solid to liquid and returns to solid again.

JP 2005-186439 A

  However, in the resin sealing device as shown in Patent Document 1, for example, when the bonding wire of the molded product is thin, if the resin sealing is performed with the conventional control for a small amount of resin, the following problems occur. The inventor has found that this occurs. That is, if the resin sealing is performed with a thin resin sealing thickness, the deformation amount of the bonding wire is increased and a resin sealing failure may occur.

  Therefore, in order to reduce the pressure of the resin applied to the bonding wire, the inventor reduces the driving speed (approach speed) of the second mold with respect to the first mold at the time of resin sealing so that the distance to each other becomes short. The process was slowed down, and the mold was clamped and resin sealing was attempted. At that time, the movement of the mold was completed within the gel time. However, even if such control is performed, a resin sealing defect has occurred. At the same time, there has been a problem that the time for resin sealing becomes longer.

  Therefore, the present invention has been made to solve the above-described problems, and can prevent a resin sealing failure even when the resin sealing thickness is small and the resin sealing thickness is thin, and can further shorten the time for resin sealing. It is an object to provide a compression molding apparatus and a compression molding method.

  The present invention has a mold including a first mold and a second mold that can be moved closer to and away from the first mold by a driving source, and is mounted on a substrate. In a resin sealing device that places a molded product together with a thermosetting resin in the mold cavity, depressurizes and heats the mold, applies compression pressure to the molded product, and seals the resin, The sum of the thickness of the substrate and the resin sealing thickness of the molded article corresponds to the distance between the surface of the first mold and the surface of the second mold constituting the cavity. The index position by the drive source of the second mold with respect to the one mold is set as a reference position, and the resin and the molded product are respectively disposed in the first mold and the second mold and heated. In the state, the second mold with respect to the first mold is in a state where the resin and the molded article are not in contact and immediately before contact. The reference position is a first position, which is closer to the first mold than the first position, but far from the reference position and immediately before the compression pressure rises. The index position of the second mold is set as a second position, the position relative to the first mold is closer to the reference position, and the first mold is immediately after the compression pressure rises. The index position of the second mold is the third position, the first position is closer to the first mold than the reference position, and the compression pressure is the maximum compression pressure applied to the workpiece. The index position of the second mold with respect to the mold is a fourth position, and the drive source of the second mold with respect to the first mold from the second position to the third position The drive speed by the slowest in the mold clamping of the mold and the first position The driving speed from the second position to the second position and the driving speed from the third position to the fourth position higher than the driving speed from the second position to the third position. By providing the means, the above-mentioned problems are solved.

  The present invention incorporates new insights into the interpretation of changes in viscosity of thermosetting resins, and changes the driving speed of the second mold relative to the first mold during resin sealing in stages. is there. The new insight will be described below with reference to FIG.

  FIG. 3B schematically shows how the viscosity Vs of the resin changes with respect to time t when a thermosetting resin (also simply referred to as resin) is heated for a certain time. The graph representing the viscosity of the resin that the inventor originally estimated is represented by Gv. In this case, even if the driving speed of the second mold relative to the first mold is decreased as the distance between the first mold and the mold decreases, the resin maintains a low viscosity over a wide range BR of the gel time Tg. It seems possible to avoid defects. However, from the inventor's new insight, the graph representing the viscosity of the resin is assumed to be Gv1. That is, even within the gel time Tg, the low-viscosity region of the resin is narrow, and the state of the lowest viscosity of the resin comes at an early timing in the first half of the gel time. The resin gradually increases in viscosity from the time tv when the resin reaches its minimum viscosity, and curing proceeds. For this reason, it is considered that simply reducing the driving speed increases the load on the bonding wire due to the increase in the viscosity of the resin, resulting in a resin sealing failure. In particular, a slight increase in the viscosity of the resin greatly affects the thinning of the bonding wire.

  Therefore, according to the present invention, the movement of the mold in the mold clamping is completed at the earliest possible time within the gel time Tg, that is, the thermosetting resin has the lowest possible viscosity even when the driving speed is slowed down. Yes.

  Specifically, the present invention specifies the fourth position from the reference position and the first position for the position of the second mold (the index position by the drive source) with respect to the first mold, respectively. The driving speed from the second position immediately before the compression pressure rises to the third position immediately after the compression pressure rises is the slowest in mold clamping. At the same time, the driving speed from the first position immediately before contact between the resin and the molded product to the second position and the driving speed from the third position to the fourth position where the compression pressure becomes the maximum compression pressure are set. The driving speed from the second position to the third position is higher.

  That is, according to the present invention, only when the compression pressure rises, the drive speed is the slowest in mold clamping. And since the driving speed is increased immediately after the compression pressure rises, contrary to the conventional idea, it is possible to complete the movement of the mold in the mold clamping while the viscosity of the resin is low. For this reason, due to these synergistic effects, the influence of the thermosetting resin on the molded product (for example, a bonding wire) is minimized. That is, a resin sealing failure can be avoided even when the resin sealing thickness is small with a small amount of resin. At the same time, the time for resin sealing can be shortened.

  In addition, the specific parameter regarding the “index position” by the drive source for specifying the position of the second mold with respect to the first mold is not particularly limited. However, if the index position by the drive source is obtained from a position (number of rotations) determined by a rotary encoder attached to the rotary drive source, for example, the drive source is a low cost. A reproducible index position can be obtained.

  The driving speed from the third position to the fourth position is faster than the driving speed from the second position to the third position, but is not particularly limited numerically. . However, for example, the driving speed from the third position to the fourth position may be three times or more the driving speed from the second position to the third position. In this case, it is possible to speed up the completion of the movement of the mold in the mold clamping as compared with the conventional case, and it is possible to avoid the resin sealing failure and to greatly shorten the time for the resin sealing. Alternatively, the driving speed from the second position to the third position is converted into the approach speed when no load is applied to the first mold. The driving speed from the third position to the fourth position may be 1 mm / sec or more in terms of the no-load approach speed.

  Note that when the compression pressure at the third position is between 1 MPa and 2 MPa, even if there is a practical error in the amount of resin, from the second position to the third position. The resin can be distributed almost throughout the cavity during the slowest driving speed. For this reason, resin sealing failure can be avoided most stably while shortening the resin sealing time.

  The distance between the surface of the first mold and the surface of the second mold obtained from the index position by the drive source at the first position is the thickness of the substrate and the thickness of the resin sealing. More preferably, the sum is 4 times or more. This numerical value does not necessarily require strictness.

  Furthermore, the control means sets the index position between the first position and the second position as a fifth position, and sets the driving speed from the fifth position to the second position as the fifth position. When the driving speed from the third position to the fourth position is slower than the driving speed, a part of the molded product (for example, a part of the bonding wire) is in contact with the resin at the second position. If it is in a state, it is possible to slow down the drive speed to reach it. That is, it is possible to further reduce the influence of the thermosetting resin on the molded article, and to further reduce the occurrence of resin sealing defects.

  The distance between the surface of the first mold and the surface of the second mold that is obtained from the index position by the drive source at the fifth position is the thickness of the substrate and the thickness of the resin sealing. It is preferable that the sum is 1.8 times or more. This numerical value does not necessarily require strictness.

  The time from when the mold is heated to a predetermined temperature and the resin is loaded in the cavity until the second mold moves to the third position is the gel time of the resin at the temperature. When the resin is between 20% and 40%, even if the resin is in a solid state, the compression pressure can be raised by softening and melting the resin to ensure a low viscosity. . At the same time, the completion of the movement of the mold can be surely shortened in the mold clamping as compared with the prior art, so that it becomes possible to avoid the resin sealing failure and to shorten the time for resin sealing.

  Note that the present invention uses a mold including a first mold and a second mold that is relatively close to and away from the first mold by a driving source, on a substrate. In the resin sealing method in which the mounted product to be molded is placed in the mold cavity together with the thermosetting resin, and the mold is decompressed and heated to apply a compression pressure to the product to be sealed, In each case, the sum of the thickness of the substrate and the resin sealing thickness of the molded article corresponds to the distance between the surface of the first mold and the surface of the second mold constituting the cavity. The index position by the drive source of the second mold with respect to the first mold is set as a reference position, and the resin and the product to be molded are respectively disposed in the first mold and the second mold and heated. In this state, the second mold with respect to the first mold is in a state where the resin and the molded article are not in contact and immediately before contact. The index position is a first position, which is closer to the first mold than the first position, but far from the reference position and immediately before the compression pressure rises. The index position of the second mold with respect to the first mold is a second position, the first mold is closer to the reference position and immediately after the compression pressure rises. The index position of the second mold is a third position, the first position is closer to the first mold than the reference position, and the compression pressure is the maximum compression pressure applied to the product. The driving position of the second mold relative to the first mold from the second position to the third position is set as the fourth position, the index position of the second mold relative to the first mold. A step of performing the drive speed by the source at the slowest in the mold clamping of the mold, and The driving speed from the first position to the second position and the driving speed from the third position to the fourth position are expressed by the driving speed from the second position to the third position. It can also be regarded as a resin sealing method characterized by including a process performed at a high speed.

  According to the present invention, defective resin sealing can be avoided even when the resin sealing thickness is small and the amount of resin is small, and the time for resin sealing can be further shortened.

The schematic diagram which shows an example of the resin sealing apparatus concerning embodiment of this invention The figure which shows the flowchart which shows the partial operation | movement of a resin sealing device similarly Similarly, an operation diagram (FIG. 3A) showing a partial operation of the resin sealing device and a diagram schematically showing a change in viscosity of the resin (FIG. 3B). Schematic diagram showing a part of the operation diagram of FIG. 3 in detail Schematic diagram showing the relationship between a part of the operation diagram of FIG. 4 and the compression pressure 4 is a schematic diagram showing a positional relationship between a representative upper mold and a lower mold in the operation diagram of FIG.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  Initially, the schematic structure of the resin sealing apparatus concerning embodiment of this invention is demonstrated using FIG. The “substrate 102” is shown as a representative example of a substrate that supports a semiconductor chip such as a PCB substrate or a lead frame. The “semiconductor chip 104” is included in the molded product. In the present embodiment, the molded product includes a bonding wire for connecting the substrate 102 and the semiconductor chip 104 and the like. In addition, “resin 106” indicates a thermosetting resin, and in the present embodiment, it is a flat plate shape (solid) formed in advance. The thickness of the “resin 106” is substantially the same as a resin sealing thickness h1 described later.

  As shown in FIG. 1, the resin sealing device 100 includes an upper mold 120 (first mold) and a lower mold 130 (first mold) that can be moved closer to and away from the upper mold 120 by a drive source (not shown). 2 dies). The resin sealing device 100 places the semiconductor chip 104 mounted on the substrate 102 together with the resin 106 in the cavity of the mold 114, depressurizes and heats the mold 114 and applies a compression pressure to the semiconductor chip 104 to seal the resin. Stop. A drive source (not shown) is a motor (rotation drive source) described later.

  Hereinafter, the components will be specifically described.

  As shown in FIG. 1, the mold 114 includes an upper mold 120 and a lower mold 130. The upper mold 120 includes an upper compression mold 122 and an upper frame 124. The upper compression mold 122 is attached and fixed to the fixed platen 110 of the mold 114. The upper compression mold 122 is provided with a decompression mechanism 116 so that the closed space generated when the mold 114 is clamped can be decompressed. The upper compression mold 122 is provided with a suction mechanism 118 so that the substrate 102 can be sucked and held on the surface of the upper compression mold 122. The upper frame 124 has a frame shape surrounding the outer periphery of the upper compression mold 122 and is attached to the upper compression mold 122 via a spring 126. For this reason, the upper frame 124 is movable relative to the upper compression mold 122. A sealing member (such as an O-ring) 124 </ b> A is provided on the surface facing the lower mold 130 of the upper frame 124. A sealing member (not shown) is also provided on the sliding surface between the upper compression mold 122 and the upper frame 124.

  The lower mold 130 includes a lower compression mold 132 and a lower frame 134. The lower compression mold 132 is attached to the movable platen 112 of the mold 114. For this reason, the lower mold | type 130 can be approached / separated relatively with respect to the upper mold | type 120 in the up-down direction of FIG. The lower frame 134 has a frame shape that surrounds the outer periphery of the lower compression mold 132, and is attached to the lower compression mold 132 via a spring 136. For this reason, the lower frame 134 is movable relative to the lower compression mold 132. When the upper mold 120 and the lower mold 130 approach each other, the lower frame 134 can sandwich (clamp) the substrate 102 together with the upper compression mold 122. At the same time, the lower frame 134 can be brought into contact with the upper frame 124 via the lower frame film 108. The lower mold 130 is provided with a lower frame drive mechanism 138 for controlling the vertical movement of the lower frame 134 relative to the lower compression mold 132. For this reason, the position of the lower frame 134 can be appropriately controlled by the lower frame driving mechanism 138 in the resin sealing process.

  Further, the lower mold 130 is provided with a film suction mechanism (not shown) so that the lower frame film 108 laid on the surface of the lower mold 130 can be sucked and held. The lower frame film 108 is stretchable and has good releasability from the lower mold 130 and the molded product after resin sealing even when heated.

  A motor (rotation drive source) (not shown) is connected to the movable platen 112 to which the lower mold 130 is attached. The motor is provided with a rotary encoder (not shown) for detecting the rotation amount. For this reason, the lower mold 130 can be moved toward and away from the upper mold 120 by a motor, and a rotary encoder attached to the motor identifies “(depending on the drive source) for specifying the position of the lower mold 130 relative to the upper mold 120. ) "Index position". The “index position” based on this rotary encoder is the lower mold until the lower mold 130 contacts the upper mold 120 via the substrate 102, the resin 106 and the lower frame film 108 (until a reference position Yst described later). There is a correlation with the actual distance (or driving speed) with respect to the upper mold 120. Then, after the lower mold 130 comes into contact with the upper mold 120 through the substrate 102, the resin 106, and the lower frame film 108, there is a correlation with the compression pressure (or the increasing speed of the compression pressure). Moreover, since this reproducibility is high, it is optimal in the present embodiment that the position determined by the rotary encoder attached to the motor is the “index position”. In addition, the specific value of the driving speed between each index position shown in the following description is converted into the speed when no load is applied to the upper mold 120 of the lower mold 130. The compression pressure is detected by a mechanism that detects a pressure (not shown).

  Reference numeral 128 denotes a movable projecting member provided on the upper mold 120. By projecting the protruding member 128 into the recess 134A on the lower frame 134 in accordance with the movement of the lower frame 134 relative to the lower compression mold 132, the amount of expansion and contraction of the lower frame film 108 is minimized. Although not shown in FIG. 1, a plurality of heaters are embedded in the upper mold 120 and the lower mold 130. The mold 114 is heated to a predetermined temperature (for example, 175 degrees) for resin sealing by the heater.

  A series of operations of the resin sealing device 100 is performed from an operation screen (not shown). Based on the operation from the operation screen, the operation of the mold 114 and the like is controlled by a processing device (control means) (not shown).

  Next, operation | movement of the resin sealing apparatus 100 is demonstrated using FIGS. 3 and 4, the vertical axis Y indicates the index position (hereinafter simply referred to as index position or lower mold 130) of the lower compression mold 132 (or movable platen 112) determined by a rotary encoder attached to the motor. (Referred to as index position). That is, as the index position Y is larger, the lower mold 130 is driven closer to the upper mold 120. The graph Gj in FIGS. 3 and 4 is based on the conventional control, and the graph Gh is according to the present embodiment. 6C, the sum of the thickness h of the substrate 102 and the resin sealing thickness h1 of the semiconductor chip 104 is the surface of the upper compression mold 122 of the upper mold 120 and the lower mold 130, which form a cavity. This corresponds to the distance from the surface of the lower compression mold 132. At this time, the index position Y of the lower mold 130 with respect to the upper mold 120 is set as a reference position Yst.

  First, in the mold open state in which the upper mold 120 and the lower mold 130 are separated from each other, the substrate 102 is attracted and fixed to the upper compression mold 122 by a transport mechanism (not shown). Then, a resin mounting hand (not shown) moves into the mold 114 (time t0 in FIG. 3). Further, the lower frame film 108 is disposed on the lower mold 130 and is adsorbed. At this time, the positions of the upper surface of the lower frame 134 and the upper surface of the lower compression mold 132 are made the same by the lower frame driving mechanism 138. Note that the mold 114 is heated to a certain temperature (for example, 175 degrees) during compression sealing.

  Next, the movable platen 112 is raised to change the index position Y of the lower mold 130 from Y0 to Y1. Then, the resin 106 is mounted on the lower frame film 108 (time t1 in FIG. 3). Then, the movable platen 112 is lowered to return the index position Y of the lower mold 130 to the position Y0 (step S2 in FIG. 2 and time t2 in FIG. 3). Then, the resin mounting hand is retracted from the area of the mold 114 to the outside (step S4 in FIG. 2).

  Next, the movable platen 112 is moved upward to bring the lower mold 130 closer to the upper mold 120. Then, when the index position Y of the lower mold 130 reaches the position Y2 (decompression position) (step S6 in FIG. 2, time t3 in FIG. 3), the movable platen 112 stops rising and depressurizes the mold 114. Start operation (start decompression time). At this time, the resin 106 on the lower mold 130 and the substrate 102 adsorbed on the upper mold 120 are not in contact with each other.

  Next, the movable platen 112 is moved upward to raise the index position Y of the lower mold 130 again from the pressure reduction position Y2 at a driving speed V2 (for example, 44 mm / s or less) by the motor (time t4 in FIGS. 3 and 4). . Then, the resin 106, the bonding wire, and the semiconductor chip 104 are not in contact with each other at the index position Y of the lower mold 130 with the resin 106, the bonding wire, and the substrate 102 placed on the upper mold 120 and the lower mold 130, respectively. Then, the position (first touch position) Y3 immediately before the contact is set (step S8 in FIG. 2, time t5 in FIGS. 3 and 4, state in FIG. 6A). Then, the drive speed V2 is decreased from the first touch position Y3 to the drive speed V3 (for example, about 2 mm / s). Then, the lower frame drive mechanism 138 starts to raise the lower frame 134. Before the first touch position Y3, the protruding member 128 protrudes and pushes the lower frame film 108 into the recess 134A as shown in FIG. Then, the upper frame 124 comes into contact with the lower frame 134 via the lower frame film 108, and the lower frame film 108 is fixed. That is, by this contact state, the closed space (the state of FIG. 6A) between the upper mold 120 and the lower mold 130 before the first touch position Y3 is in a sealed state, and decompression is performed. Then, the decompression ends at the stage where the lower frame 134 finishes rising (end of the decompression time and start of the compression time).

  The first touch position Y3 is specified as the first position referred to as the index position Y of the lower mold 130 with respect to the upper mold 120. In the present embodiment, the distance from the surface of the upper compression mold 122 to the surface of the lower compression mold 132 obtained from the index position Y by the motor at the first touch position Y3 is the thickness h of the substrate 102 and the resin sealing thickness h1. It is desirable to make it the sum with the value of 4 times or more. Strictly speaking, the distance is the sum of the thickness h of the substrate 102 and the value of three times or more of the resin sealing thickness h1 and the thickness of the resin 106, and the resin sealing thickness h1 and the thickness of the resin 106 are: Because it is almost the same. This is because a bonding wire that electrically connects the semiconductor chip 104 to the substrate 102 protrudes to a lower mold side than the semiconductor chip 104 at a certain height, for example. In such a case, a non-contact state between the bonding wire and the resin 106 can be ensured. The resin sealing thickness h1 is a value obtained by removing the thickness h of the substrate 102 from the thickness of the molded product including the substrate 102 after resin sealing, as shown in FIG. In the present embodiment, the maximum amount of displacement of the lower frame 134 with respect to the lower compression mold 132 is 4.5 mm. For this reason, the maximum distance from the surface of the upper compression mold 122 defined by the first touch position Y3 to the surface of the lower compression mold 132 is (4.5 mm + thickness h of the substrate 102).

  Next, the movable platen 112 is moved upward, and the lower die 130 is moved closer to the upper die 120 from the first touch position Y3 at the driving speed V3. Then, the index position Y of the lower mold 130 is set to a position Y4 (low speed switching position) (step S10 in FIG. 2, time t6 in FIG. 4, state in FIG. 6B). The driving speed V3 is changed to a low driving speed V4 (for example, about 0.5 mm / s) at the low speed switching position Y4. At the low speed switching position Y4, as shown in FIG. 6B, the lower frame 134 finishes rising, and the substrate 102 is sandwiched between the lower frame 134 and the upper compression mold 122. For this reason, the board | substrate 102 is fixed firmly. The low speed switching position Y4 is specified as the fifth position, which is the position of the lower mold 130 with respect to the upper mold 120. In this embodiment, the distance from the surface of the upper compression mold 122 to the surface of the lower compression mold 132 obtained from the index position Y by the motor at the low speed switching position Y4 is the thickness h of the substrate 102 and the resin sealing thickness h1. It is desirable that the sum is 1.8 times or more. Strictly speaking, the distance is the sum of the thickness h of the substrate 102 and the value of 0.8 times or more of the resin sealing thickness h1 and the thickness of the resin 106, and the resin sealing thickness h1 and the thickness of the resin 106. Is substantially the same. Alternatively, the distance from the surface of the upper compression mold 122 to the surface of the lower compression mold 132 may be the sum of the thickness h of the substrate 102, the resin sealing thickness h1, and the thickness h0 of the semiconductor chip 104. Note that the driving speed may be changed at a position between the first touch position Y3 and the low speed switching position Y4 as necessary.

  Next, the movable platen 112 is moved upward, and the lower die 130 is moved closer to the upper die 120 from the low speed switching position Y4 at the driving speed V4. The index position Y of the lower mold 130 is closer to the upper mold 120 than the first touch position Y3 (first position) and the low speed switching position Y4 (fifth position), but farther than the reference position Yst. A position Y5 (minimum speed switching position) immediately before the compression pressure rises (step S12 in FIG. 2, time t7 in FIGS. 3 and 4). The drive speed V4 is changed to the lowest drive speed V5 (for example, about 0.05 mm / sec and at most 0.2 mm / sec) at the lowest speed switching position Y5. The lowest speed switching position Y5 is specified as the second position referred to as the position of the lower mold 130 with respect to the upper mold 120. In the present embodiment, the distance from the surface of the upper compression mold 122 to the surface of the lower compression mold 132 obtained from the index position Y by the motor at the lowest speed switching position Y5 is the thickness h of the substrate 102 and the resin sealing thickness h1. And a value between 0.1 mm and 0.3 mm is desirable.

  Next, the movable platen 112 is moved upward, and the lower die 130 is moved closer to the upper die 120 from the lowest speed switching position Y5 at the driving speed V5. Then, the index position Y of the lower mold 130 is set to a position Y6 (acceleration position) that is closer to the upper mold 120 than the reference position Yst and immediately after the compression pressure rises (step S14 in FIG. 2 and FIG. 4). Time t8). At the acceleration position Y6, the driving speed is changed from the driving speed V5 to the accelerated driving speed V6 (for example, 1 mm / sec or more). The acceleration position Y6 is specified as the third position, which is the position of the lower mold 130 with respect to the upper mold 120. In this embodiment, the distance from the surface of the upper compression mold 122 to the surface of the lower compression mold 132 obtained from the index position Y by the motor at the acceleration position Y6 is the thickness h of the substrate 102 and the resin sealing thickness h1 ( It is desirable that the sum is a value between −0.05 mm and −0.15 mm. At the acceleration position Y6 (third position), a compression pressure of 1 MPa to 2 MPa is generated as shown in FIG. In the present embodiment, the time from when the resin 106 is mounted on the lower mold 130 constituting the cavity until the lower mold 130 moves to the acceleration position Y6 (third position) (time from time t1 to time t8). ) Between 20% (Tg1) and 40% (Tg2) of the gel time Tg as shown in FIG. 3 (B). That is, according to the present embodiment, the movement of the mold 114 can be completed in the low-viscosity area AR of the resin 106 even in the graph Gv1 based on the inventor's new insight. In the process of moving the movable platen 112 upward and causing the lower die 130 to approach the upper die 120 from the lowest speed switching position Y5 at the driving speed V5, the state shown in FIG. 6C occurs.

  Next, the movable platen 112 is moved upward, and the lower die 130 is moved closer to the upper die 120 from the acceleration position Y6 at the driving speed V6. Then, the index position Y of the lower mold 130 is set to a position Y7 (pressure holding position) at which the compression pressure is the maximum compression pressure applied to the semiconductor chip 104, closer to the upper mold 120 than the reference position Yst (in FIG. 2). Step S16, time t9 in FIGS. 3 and 4). The driving speed is made zero from the driving speed V6 at the pressure holding position Y7 (end of compression time and start of cure time). The pressure holding position Y7 is specified as the fourth position referred to as the index position Y of the lower mold 130 with respect to the upper mold 120. The maximum compression pressure is the holding pressure. The holding pressure is determined so as not to cause “sink (molding abnormality due to curing shrinkage of resin)” in the molded product during curing (curing), and is set between 8 MPa and 12 MPa in the present embodiment.

  Next, after the curing time has elapsed, the movable platen 112 is moved away from the fixed platen 110. Then, the upper mold 120 and the lower mold 130 are opened, and the resin-sealed substrate 102 (simply referred to as a molded product) is taken out by a conveying device (not shown).

  As described above, the present embodiment incorporates new insight into the interpretation of the viscosity change of the resin 106, and changes the driving speed of the lower mold 130 relative to the upper mold 120 during resin sealing in a stepwise manner. The new insight will be described below with reference to FIG.

  FIG. 3B schematically shows how the viscosity Vs of the resin 106 changes with respect to time t when the thermosetting resin 106 is heated for a certain time. A graph representing the viscosity of the resin 106 that was originally estimated by the inventor is represented by Gv. In this case, even if the driving speed of the lower mold with respect to the upper mold is decreased as the distance between the upper mold and the lower mold decreases, the resin 106 maintains a low viscosity over a wide range BR of the gel time Tg, thereby avoiding poor resin sealing. Seems to be possible. However, from the inventor's new insight, the graph representing the viscosity of the resin 106 is assumed to be Gv1. That is, even within the gel time Tg, the low-viscosity region of the resin 106 is narrow, and the lowest viscosity state of the resin 106 comes at an early timing in the first half of the gel time. The resin 106 gradually increases in viscosity from the time point tv when the resin 106 reaches its minimum viscosity, and curing proceeds. For this reason, it is considered that simply reducing the driving speed increases the load on the bonding wire due to the increase in the viscosity of the resin 106 and causes a resin sealing failure. In particular, a slight increase in the viscosity of the resin 106 greatly affects the thinning of the bonding wire.

  For this reason, in the present embodiment, the movement of the mold 114 in mold clamping is completed at the earliest possible time within the gel time Tg, that is, with the resin 106 having the lowest possible viscosity even when the driving speed is decreased.

  Specifically, in the present embodiment, the drive speed V5 from the lowest speed switching position Y5 (second position) to the acceleration position Y6 (third position) is the slowest in the mold clamping of the mold 114. At the same time, the driving speed V3 from the first touch position Y3 (first position) to the low speed switching position Y4 (fifth position), and the low speed switching position Y4 (fifth position) to the lowest speed switching position Y5 (second position). ), The driving speed V6 from the acceleration position Y6 (third position) to the pressure holding position Y7 (fourth position), and the acceleration speed Y6 from the lowest speed switching position Y5 (second position). It is faster than the driving speed V5 to (third position).

  That is, in this embodiment, only when the compression pressure rises, the drive speed V5 is slowed down most when the mold 114 is clamped. In particular, immediately after the compression pressure rises, the driving speed V6 is increased contrary to the conventional idea, so that the movement of the mold 114 in the mold clamping can be completed while the viscosity of the resin 106 is low. It becomes. For this reason, due to these synergistic effects, the influence of the resin 106 on the bonding wires of the semiconductor chip 104 is minimized. That is, even when the resin sealing thickness h1 with a small amount of the resin 106 is thin, a resin sealing failure can be avoided. At the same time, the time for resin sealing can be shortened. Actually, under the conditions of this embodiment, even if the bonding wire diameter is 20 μm or 18 μm and the resin thickness on the semiconductor chip is 0.3 mm, resin sealing failure can be avoided.

  The drive source of the lower mold 130 to which the movable platen 112 is attached is a motor, and the index position Y by the drive source is a position determined by a rotary encoder attached to the motor. For this reason, a reproducible index position can be obtained at low cost. In more detail, the actual position of the lower mold 130 is the same or only slightly changed with the volume change due to the phase change of the resin 106, and most of the rotation amount of the motor increases the compression pressure. Even at the acceleration position Y6 (third position) and the pressure holding position Y7 (fourth position), the output of the rotary encoder, that is, the index position has continuity, high accuracy and high With reproducibility, the position information and the compression pressure information of the lower mold 130 can be obtained. This will be described below with reference to FIG.

  FIG. 5 shows the relationship between the compression pressure and the index position Y of the lower mold 130 relative to the upper mold 120. The vertical axis P represents the compression pressure, and the vertical axis DY represents the index position-based distance between the upper mold 120 and the lower mold 130. As shown in FIG. 5, the compression pressure does not occur up to the lowest speed switching position Y5 (second position), but increases rapidly after the acceleration position Y6 (third position). That is, after the acceleration position Y6 (third position), most of the output of the motor for moving the movable platen 112 is used to generate the compression pressure, and the position detection by the rotary encoder is far from the actual position. The Rukoto. However, since the output of the rotary encoder is continuous and highly accurate, the position of the lower mold 130 by the movable platen 112 can be reproduced with high accuracy. However, it is not necessarily limited to a rotary encoder. For example, the movable platen may be moved by a toggle link, and the index position Y may be obtained based on the number of rotations of a ball screw that drives the toggle link.

  Further, the driving speed V5 from the lowest speed switching position Y5 (second position) to the acceleration position Y6 (third position) is converted into the approach speed when no load is applied to the upper mold 120 of the lower mold 130, and is the maximum. The driving speed V6 from the acceleration position Y6 (third position) to the pressure holding position Y7 (fourth position) is 0.2 mm / sec, and the upper mold 120 approaches the upper mold 120 when there is no load. It is set to 1 mm / sec or more in terms of speed. In addition, the driving speed V6 from the acceleration position Y6 (third position) to the pressure holding position Y7 (fourth position) is changed from the lowest speed switching position Y5 (second position) to the acceleration position Y6 (third position). ) To 3 times the driving speed V5. For this reason, it is possible to speed up the completion of the movement of the mold in the mold clamping compared to the conventional method, avoiding defective resin sealing, and greatly shortening the time for resin sealing compared to the conventional method.

  Further, since the compression pressure at the acceleration position Y6 (third position) is between 1 MPa and 2 MPa, even if there is a practical error (about ± 100 mg) in the amount of the resin 106, the lowest speed switching position The resin 106 can be distributed almost throughout the cavity during V5 with the slowest driving speed from Y5 (second position) to the acceleration device Y6 (third position). For this reason, the resin sealing failure can be avoided most stably while shortening the resin sealing time. However, it is not necessarily limited to this.

  Further, the surface of the upper mold 120 (upper compression mold 122) and the surface of the lower mold 130 (lower compression mold 132) obtained from the index position Y by the motor at the first touch position Y3 (first position). The distance is the sum of the thickness h of the substrate 102 and a value that is four times or more the resin sealing thickness h1, but is not necessarily strictly required. Moreover, it is not necessarily limited to this.

  Further, the processing device (control means) changes the position between the first touch position Y3 (first position) and the lowest speed switching position Y5 (second position) to the low speed switching position Y4 (fifth position). The driving speed V4 from the low speed switching position Y4 (fifth position) to the lowest speed switching position Y5 (second position) is changed from the acceleration position Y6 (third position) to the pressure holding position Y7 (fourth position). It is slower than the driving speed V6. For this reason, if, for example, a part of the bonding wire in the semiconductor chip 104 is in contact with the resin 106 at the lowest speed switching position Y5 (second position), the driving speed to reach that position can be reduced. Become. That is, it is possible to further reduce the influence of the thermosetting resin 106 on the semiconductor chip 104, the bonding wire, etc., and to further reduce the occurrence of resin sealing defects. However, it is not necessarily limited to this.

  The distance between the surface of the upper mold 120 and the surface of the lower mold 130 obtained from the index position Y by the motor at the low speed switching position Y4 (fifth position) is 1 of the thickness h of the substrate 102 and the resin sealing thickness h1. Although it is set as the sum with the value of 8 times or more, it is not necessarily limited to this. Moreover, this numerical value does not necessarily require strictness.

  In addition, the time (from time t1 to time) from when the mold 114 is heated to a predetermined temperature (175 degrees) and the lower mold 130 moves to the acceleration position Y6 (third position) after the resin 106 is mounted in the cavity. As shown in FIG. 3B, the period until t8 is between 20% and 40% of the gel time of the resin 106 at a predetermined temperature. For this reason, it is possible to raise the compression pressure by softening and melting the resin 106 from a solid state so that the viscosity of the resin 106 is reliably lowered. At the same time, it is possible to reliably shorten the completion of the movement of the mold 114 in the mold clamping as compared with the prior art, so that it is possible to further avoid the resin sealing failure and to shorten the time for resin sealing.

  In the present embodiment, the compression time, which actually took 20 seconds in the conventional control, was reduced to 10 seconds or less, and the bonding wire deformation amount of 3% or more was improved to about 1-2%.

  That is, according to this embodiment, even when the resin sealing thickness h1 with a small amount of the resin 106 is thin, a resin sealing failure can be avoided, and the time for resin sealing can be further shortened.

  Although the present invention has been described with reference to the present embodiment, the present invention is not limited to the present embodiment. That is, it goes without saying that improvements and design changes can be made without departing from the scope of the present invention.

  For example, in the present embodiment, a bonding wire is present, but the present invention is not limited to this, and may be a case of flip chip bonding of a semiconductor chip having no bonding wire. Moreover, the case where resin sealing thickness is comparatively thick may be sufficient. In any case, the present invention appropriately avoids resin sealing failure and further shortens the time for resin sealing.

  Further, in the present embodiment, the resin 106 is formed into a flat plate shape molded in advance, but the present invention is not limited to this. For example, a powdery or granular resin may be used.

  The resin sealing device of the present invention has a remarkable effect particularly when the semiconductor chip has a bonding wire or the like and the resin sealing thickness is small with a small amount of resin. Can be spread.

DESCRIPTION OF SYMBOLS 100 ... Resin sealing apparatus 102 ... Board | substrate 104 ... Semiconductor chip 106 ... Resin 108 ... Lower frame film 110 ... Fixed platen 112 ... Movable platen 114 ... Mold 116 ... Decompression mechanism 118 ... Adsorption mechanism 120 ... Upper mold 122 ... Upper compression mold Mold 124 ... Upper frame 126, 136 ... Spring 128 ... Projection member 130 ... Lower mold 132 ... Lower compression mold 134 ... Lower frame 138 ... Lower frame drive mechanism

Claims (10)

A mold having a first mold and a second mold that can be moved closer to and away from the first mold by a drive source;
A resin seal for sealing a resin by placing a molded product mounted on a substrate in a cavity of the mold together with a thermosetting resin and applying pressure to the molded product by reducing and heating the mold. In the stopping device,
In each case, the sum of the thickness of the substrate and the resin sealing thickness of the molded article corresponds to the distance between the surface of the first mold and the surface of the second mold constituting the cavity. The index position by the drive source of the second mold with respect to the first mold is set as a reference position,
The resin and the molded product are arranged in the first mold and the second mold, respectively, and the resin and the molded product are in non-contact and immediately before contact with the first mold and the second mold. The index position of the second mold with respect to the mold is the first position,
The index of the second mold with respect to the first mold, which is closer to the first mold than the first position but just before the compression pressure rises farther than the reference position. The position is the second position,
The index position of the second mold with respect to the first mold, which is immediately after the compression pressure rises closer to the first mold than the reference position, is a third position,
The index position of the second mold with respect to the first mold, which is closer to the first mold than the reference position and at which the compression pressure is the maximum compression pressure applied to the molded article, is 4 position,
The drive speed of the second mold from the second position to the third position by the drive source of the second mold with respect to the first mold is the slowest in the mold clamping and the first mold Making the drive speed from position to the second position and the drive speed from the third position to the fourth position faster than the drive speed from the second position to the third position A resin sealing device comprising a control means. In claim 1,
The resin sealing device, wherein the drive source is a rotation drive source, and an index position by the drive source is a position determined by a rotary encoder attached to the rotation drive source. In claim 1 or 2,
The drive speed from the third position to the fourth position is at least three times the drive speed from the second position to the third position. . In any one of Claims 1 thru | or 3,
The driving speed from the second position to the third position is 0.2 mm / sec at maximum in terms of the speed at which the second mold approaches the first mold when there is no load. ,and,
The resin sealing device, wherein the drive speed from the third position to the fourth position is 1 mm / sec or more in terms of the approach speed when there is no load. In any one of Claims 1 thru | or 4,
The resin sealing device, wherein the compression pressure at the third position is between 1 MPa and 2 MPa. In any one of Claims 1 thru | or 5,
The distance between the surface of the first mold and the surface of the second mold obtained from the index position by the drive source at the first position is 4 times or more the thickness of the substrate and the resin sealing thickness. A resin sealing device characterized by being a sum of the values. In any of claims 1 to 6, further
The control means sets the index position between the first position and the second position as a fifth position,
The resin sealing device, wherein the driving speed from the fifth position to the second position is slower than the driving speed from the third position to the fourth position. In claim 7,
The distance between the surface of the first mold and the surface of the second mold obtained from the index position by the drive source at the fifth position is the thickness of the substrate and the thickness of the resin sealing. A resin sealing device characterized by being a sum of eight times or more. In any one of Claims 1 thru | or 8.
The mold is heated to a predetermined temperature;
The time from when the resin is mounted in the cavity until the second mold moves to the third position is between 20% and 40% of the gel time of the resin at the temperature. A resin sealing device. Using a mold comprising a first mold and a second mold that is relatively close to and away from the first mold by a drive source,
Resin sealing that places a molded product mounted on a substrate in a cavity of the mold together with a thermosetting resin, applies pressure to the molded product by pressure reduction and heating of the mold, and seals the resin In the method
In each case, the sum of the thickness of the substrate and the resin sealing thickness of the molded article corresponds to the distance between the surface of the first mold and the surface of the second mold constituting the cavity. The index position by the drive source of the second mold with respect to the first mold is set as a reference position,
The resin and the molded product are arranged in the first mold and the second mold, respectively, and the resin and the molded product are in non-contact and immediately before contact with the first mold and the second mold. The index position of the second mold with respect to the mold is the first position,
The index of the second mold with respect to the first mold, which is closer to the first mold than the first position but just before the compression pressure rises farther than the reference position. The position is the second position,
The index position of the second mold with respect to the first mold, which is immediately after the compression pressure rises closer to the first mold than the reference position, is a third position,
The index position of the second mold with respect to the first mold, which is closer to the first mold than the reference position and at which the compression pressure is the maximum compression pressure applied to the molded article, is 4 position,
Performing the drive speed by the drive source of the second mold with respect to the first mold from the second position to the third position at the slowest in the mold clamping;
The driving speed from the first position to the second position and the driving speed from the third position to the fourth position are changed from the second position to the third position. A process performed at a speed higher than the speed,
A resin sealing method comprising:

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