JP2008159724A - Manufacturing method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of easily removing air bubbles between a chip and an adhesive film upon die-bonding of the chip. <P>SOLUTION: A preform head PFH employed for the thermal pressure bonding of the adhesive film is formed of a collet CLT and a collet holder CLH for retaining the collet CLT while the collet CLT is formed of a material having elasticity, and is constituted so that the collet holder CLH retains the collet CLT by bending and fitting the collet CLT into an opening KKB on the lower surface of the collet holder CLH and, in this case, the lower surface of the collet CLT is configured so as to have a spherical shape having a radius of curvature protruded downward. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor device manufacturing technique, and more particularly to a technique that is effective when applied to a step of die bonding a semiconductor chip.

  Japanese Laid-Open Patent Publication No. 2003-203964 (Patent Document 1) discloses a technique for mounting a semiconductor chip using suction means having a convex surface for supplementing an elastically deformable semiconductor chip. . By such mounting means, the semiconductor chip is held in a convex shape by the suction means, and at the time of mounting, the center first collides with the mounting surface, and the convex shape of the suction means is increased according to the increase in pressure applied to the suction means through the semiconductor chip. The surface is gradually flattened, and the semiconductor chip being held is flattened accordingly. At this time, the pressure applied to the suction means (semiconductor chip) increases from the center of the surface of the suction means (semiconductor chip) toward the outside, so that air between the semiconductor chip and the mounting surface can be continuously released. it can.

  In JP-A-2004-6599 (Patent Document 2) and JP-A-2002-368823 (Patent Document 3), in a collet for transporting a thermocompression film, an adsorption surface is formed as a convex surface, and fluorine is formed on the adsorption surface. By providing a surface treatment part such as resin coating or fluororesin film attachment, and providing suction holes on the side of the convex surface, it is easy to release when the thermocompression film is transferred, preventing sticking of the thermocompression film. Techniques to do this are disclosed.

Japanese Patent Laid-Open No. 2002-310939 (Patent Document 4) provides coaxial illumination and oblique illumination in a bubble inspection apparatus for imaging bubbles in an inspected object such as a transparent object or a semi-transparent object. Extracting features in the image data using the first image data acquired at the time and the second image data acquired at the time of the oblique illumination irradiation, the presence or absence and shape of bubbles and impurities A technique capable of inspecting is disclosed.
JP 2003-203964 A JP 2004-6599 A Japanese Patent Laid-Open No. 2002-368023 JP 2002-310939 A

  In recent years, for the purpose of high-density mounting of semiconductor devices, a package in which a plurality of semiconductor chips (hereinafter simply referred to as chips) are stacked and mounted on a wiring board has been put into practical use.

  In stacking and mounting a plurality of chips, the two chips are bonded together by, for example, thermocompression bonding of an adhesive film. At the time of this thermocompression bonding, it is required that no bubbles remain between the chip and the adhesive film.

  The present inventors have studied a technique for preventing bubbles from remaining between the chip and the adhesive film when the chip is die-bonded using the adhesive film. Among them, the present inventors have found the following problems.

  That is, when laminating a plurality of chips, an adhesive film is first placed on a chip that has been previously die-bonded using a collet for transporting the adhesive film, and then provisional pressure bonding and main pressure bonding are sequentially performed. If the removal of the bubbles is performed at the time of either the temporary pressure bonding or the main pressure bonding, a means for providing the die bonder with two heads whose functions are divided for the temporary pressure bonding and the main pressure bonding is considered. However, the provision of the two heads increases the size of the die bonder, and there is a problem that it becomes impossible to meet the demand for size reduction of the die bonder. In addition, there is a problem that the price of the die bonder itself is increased by providing two heads.

  If the pre-bonding and the main bonding are performed with one head, it is necessary to provide a single head with a plurality of functions including the function of removing bubbles, and the accuracy of removing bubbles is included compared to the case with two heads. There is a problem that it becomes difficult to ensure the accuracy of crimping.

  Further, the bubbles existing between the chip and the adhesive film are not always in the same position, the same size, or the same shape. Therefore, there is a problem that the pressure bonding conditions must be changed as appropriate according to the position, size and shape of the bubbles.

  In consideration of removing the bubbles during die bonding, the head provided in the die bonder has a special shape. For this reason, there is a problem that the head itself cannot be supplied in a short period of time and at a low price.

  The objective of this invention is providing the technique which can remove easily the bubble between a chip | tip and an adhesive film at the time of die bonding of a chip | tip.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

1. A method for manufacturing a semiconductor device according to the present invention includes:
(A) preparing a first semiconductor chip in which a semiconductor element and an integrated circuit electrically connected to the semiconductor element are formed on a main surface;
(B) preparing a thermocompression adhesive film;
(C) The adhesive film or the first semiconductor chip is held by a bonding jig including an elastic collet and a holder for holding the collet, and the adhesive film or the first semiconductor chip is pressure-bonded to a chip mounting region. The process of
Including
The holder has an opening facing the adhesive film or the first semiconductor chip during the step (c), and holds the collet by fitting the collet into the opening.
The collet protrudes from the opening of the holder and extends along the outer periphery of the suction surface having a first curvature facing the adhesive film or the first semiconductor chip during the step (c). Holding the adhesive film or the first semiconductor chip in a form along the suction surface by vacuum suction from the suction hole,
The first curvature is changed between a case where the adhesive film is held and a case where the first semiconductor chip is held.

2. A method for manufacturing a semiconductor device according to the present invention includes:
(A) preparing a first semiconductor chip in which a semiconductor element and an integrated circuit electrically connected to the semiconductor element are formed on a main surface;
(B) preparing a thermocompression adhesive film;
(C) a step of holding the adhesive film by a bonding jig including an elastic collet and a holder for holding the collet, and crimping the adhesive film to a chip mounting region;
(D) After the step (c), a planar image of the adhesive film is acquired by an image acquisition unit, and a predetermined amount of bubbles is present between the adhesive film and the chip mounting region from the planar image of the adhesive film. If you have confirmed the process,
(E) In the step (d), when the presence of a predetermined amount of bubbles between the adhesive film and the chip mounting area is not confirmed from the planar image, the first semiconductor is formed on the adhesive film. Crimping the chip,
Including
The holder has an opening facing the adhesive film or the first semiconductor chip during the step (c), and holds the collet by fitting the collet into the opening.
The collet protrudes from the opening of the holder and extends along the outer periphery of the suction surface having a first curvature facing the adhesive film or the first semiconductor chip during the step (c). Holding the adhesive film or the first semiconductor chip in a form along the suction surface by vacuum suction from the suction hole,
The first curvature is changed when holding the adhesive film and when holding the first semiconductor chip,
When the bonding failure occurs in the step (d), the lowering speed of the bonding jig after the adhesive film comes into contact with the chip mounting area is decreased, and the adhesive film is bonded to the chip mounting area. Decrease in the rising speed of the bonding jig until the collet and the adhesive film are separated later, and toward the chip mounting area of the bonding jig after the adhesive film contacts the chip mounting area At least one condition of the increase in the pushing amount is fed back to the step (c).

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  That is, bubbles between the chip and the adhesive film can be easily removed during die bonding of the chip.

  Before describing the present invention in detail, the meaning of terms in the present application will be described as follows.

  A wafer is a single crystal silicon substrate (generally a substantially planar circular shape), SOI (Silicon On Insulator) substrate, epitaxial substrate, sapphire substrate, glass substrate, other insulation, anti-insulation or semiconductor used in the manufacture of semiconductor elements or integrated circuits. A board | substrate etc. and those composite board | substrates are said. In addition, the term “semiconductor device” as used herein refers not only to a semiconductor device such as a silicon wafer or a sapphire substrate or an insulator substrate, but particularly to a TFT (Thin Film Transistor) and unless otherwise specified. It also includes those made on other insulating substrates such as glass such as STN (Super-Twisted-Nematic) liquid crystal.

  The device surface or element formation surface is a main surface of a wafer on which a device pattern corresponding to a plurality of chip regions is formed by lithography.

  A collet is used to transfer an adhesive film used to transfer chips one by one, and an adhesive film used for chip bonding, after the wafer is divided into individual chips by dicing or the like. This is a suction holding tool.

  In the following embodiments, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not irrelevant to each other. There are some or all of the modifications, details, supplementary explanations, and the like.

  Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and may be more or less than the specific number.

  Further, in the following embodiments, the constituent elements (including element steps and the like) are not necessarily indispensable unless otherwise specified and apparently essential in principle. Needless to say. In addition, when referring to the constituent elements in the embodiments, etc., “consisting of A” and “consisting of A” do not exclude other elements unless specifically stated that only the elements are included. Needless to say.

  Similarly, in the following embodiments, when referring to the shapes, positional relationships, etc. of the components, etc., the shapes are substantially the same unless otherwise specified, or otherwise apparent in principle. And the like are included. The same applies to the above numerical values and ranges.

  In addition, when referring to materials, etc., unless specified otherwise, or in principle or not in principle, the specified material is the main material, and includes secondary elements, additives It does not exclude additional elements. For example, unless otherwise specified, the silicon member includes not only pure silicon but also an additive impurity, a binary or ternary alloy (for example, SiGe) having silicon as a main element.

  In addition, components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted.

  In the drawings used in the present embodiment, even a plan view may be partially hatched to make the drawings easy to see.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
The first embodiment is applied to the manufacture of a semiconductor package in which chips are stacked and mounted on a wiring board, and the manufacturing method will be described in the order of steps with reference to FIGS.

  First, a semiconductor element and an integrated circuit that is electrically connected to the semiconductor element are formed on the main surface of a wafer 1W made of single crystal silicon as shown in FIG. 1, and then a plurality of chips partitioned by lattice-like scribe lines. An electrical test is performed on the integrated circuits formed in each of the formation regions 1CA, and the quality is determined. In the first embodiment, an electric batch erase type EEPROM (Electric Erasable Programmable Read Only Memory; hereinafter referred to as a flash memory) is exemplified as the integrated circuit formed on the main surface of the wafer 1W. When the semiconductor package is a memory product such as a flash memory, the memory capacity of one semiconductor package can be increased by stacking chips as described above.

  Next, as shown in FIG. 2, a back grind tape 3 for protecting the integrated circuit is attached to the integrated circuit forming surface (the lower surface in the drawing) of the wafer 1W. Then, in this state, the back surface (upper surface side in the figure) of the wafer 1W is ground with a grinder, and subsequently, the damaged layer on the back surface caused by this grinding is removed by a method such as wet etching, dry polishing, plasma etching or the like. Thus, the wafer 1W is thinned. The processing methods such as wet etching, dry polishing, and plasma etching are slower in processing speed in the wafer thickness direction than grinding speed by the grinder, but the damage to the wafer is compared with grinding by the grinder. In addition, the damage layer inside the wafer generated by grinding by the grinder can be removed, and there is an effect that the wafer 1W and the chip are hardly broken.

  Next, after the back grind tape 3 is removed, as shown in FIG. 3, the DAF (adhesive for mounting the chip on the wiring substrate on the back surface of the wafer 1W (the surface opposite to the integrated circuit formation surface) ( The dicing tape 4 is further affixed on the DAF, and the peripheral portion of the dicing tape 4 is fixed to the wafer ring 5 in this state. In many cases, a method of attaching the wafer 1W to a DAF (Die Attach Film) attached in advance to the dicing tape 4 is used. The dicing tape 4 was cut into a circular shape having a tackiness by applying an adhesive to the surface of a tape substrate made of polyolefin (PO), polyvinyl chloride (PVC), polyethylene terephthalate (PET), or the like. In many cases, UV curable adhesives are used.

  Next, as shown in FIG. 4, the wafer 1W is diced by using a dicing blade 6 to divide each of the plurality of chip formation regions 1CA into chips (first semiconductor chips) 1C. At this time, since it is necessary to leave the divided chips 1C on the circular dicing tape 4, the dicing tape 4 is cut by only several tens of μm in the thickness direction. When a UV curable adhesive tape is used as the dicing tape 4, the dicing tape 4 is irradiated with ultraviolet rays prior to the chip 1C peeling process described below to reduce the adhesive strength of the adhesive.

  Next, as shown in FIG. 5, the chip 1 </ b> C is peeled from the dicing tape 4 using an adsorption collet (not shown), and conveyed to the next process (pellet attaching process) while being adsorbed and held by the adsorption collet. The chip 1 </ b> C conveyed to the pelletizing process is mounted at a mounting position on the wiring substrate 11 by thermocompression bonding via the DAF 10 that has been attached to the back surface in advance. Subsequently, the chip 1 </ b> C is electrically connected to the electrode 13 of the wiring substrate 11 through the Au wire 12.

  Next, as shown in FIG. 6, the adhesive film 14 is thermocompression bonded to a region that does not overlap the Au wire 12 on the plane on the chip 1 </ b> C. Although details will be described later, in the first embodiment, since the chip 1C having the same plane size is laminated on the chip 1C via the adhesive film 14 so as to overlap with each other in a plane, the adhesive film 14 is a loop of the Au wire 12. Use a thickness that is higher than the area. In the first embodiment, as the adhesive film 14, an acrylic material, a silicon-based material, or the like is used as a base and an epoxy resin or the like is added to form a film, or a thermoplastic polyimide resin is used as a reinforcing layer. And the like can be exemplified.

  Next, as shown in FIG. 7, a chip 1 </ b> C similar to the chip 1 </ b> C already mounted on the wiring substrate 11 is die-bonded on the adhesive film 14, and the upper and lower two chips 1 </ b> C are heated via the adhesive film 14. Crimp. At this time, as described above, the upper chip 1C is die-bonded so as to overlap the lower chip 1C in a plane. Subsequently, the upper layer chip 1 </ b> C is electrically connected to the electrode 16 of the wiring substrate 11 through the Au wire 15.

  Thereafter, the wiring substrate 11 is conveyed to a molding process, and the stacked package 18 of the first embodiment is sealed by sealing the chip 1C, which is stacked and mounted in two layers, with a mold resin 17, as shown in FIG. Complete.

  Here, the process of thermocompression bonding the above-described adhesive film 14 will be described in more detail.

  FIG. 9 is an explanatory plan view of a bonder for performing thermocompression bonding of the adhesive film 14 and thermocompression bonding of the chip 1C in the first embodiment. The bonder shown in FIG. 9 includes a magazine loader MGL, a frame loader FLD, a frame lifter FLL, a wafer cassette lifter WCL, a wafer table WTL, an adhesive film supply unit SFK, a preform head PFH, camera heads CMH1, CMH2, a bonding head BDH, It has an unloader ULD and an operation panel SSP.

  The magazine loader MGL supplies a magazine (not shown) in which the wiring board 11 is accommodated to a predetermined position so that the wiring board 11 can be taken out and supplied to the transport rail HRL.

  The frame loader FLD and the frame lifter FLL supply the wiring board 11 supplied from the magazine as a work to the transport rail HRL.

  Wafer cassette lifter WCL supplies a wafer cassette (not shown) containing wafer 1W to a predetermined position.

  Wafer table WTL is a place where wafer 1W taken out from the wafer cassette is placed and held, and from here, individual chips 1C are picked up and supplied to the die bonding process.

  The adhesive film supply unit SFK supplies the above-described adhesive film 14 (see FIG. 6), and the preform head PFH picks up the adhesive film 14 from the adhesive film supply unit SFK.

  The camera head CMH1 acquires an image of the thermocompression bonding position of the adhesive film 14 on the wiring substrate 11, and can check whether the thermocompression bonding position of the adhesive film 14 is accurate based on the image. .

  The camera head CMH2 acquires an image of the die bonding position of the chip 1C on the wiring substrate 11, and can check whether the die bonding position of the chip 1C is accurate based on the image.

  The bonding head BDH performs die bonding (thermocompression bonding) on the wiring substrate 11 of the chip 1C.

  The unloader ULD accommodates a magazine that accommodates the wiring substrate 11 on which the adhesive film 14 and the chip 1C are thermocompression bonded.

  The operation panel SSP has an operator operating the magazine loader MGL, frame loader FLD, frame lifter FLL, wafer cassette lifter WCL, wafer table WTL, adhesive film supply unit SFK, preform head (bonding jig) PFH, camera head CMH1, It is used for controlling operations of the CMH2, the bonding head BDH, the unloader ULD, and the like.

  The preform head PFH is used for thermocompression bonding the above-described adhesive film 14 on the wiring board 11 (chip 1C mounted on the wiring board 11). Here, FIG. 10 shows the lower surface (adhesion surface of the adhesive film 14) of the preform head PFH, and FIG. 11 shows a cross section of the main part of the preform head PFH.

  As shown in FIGS. 10 and 11, the preform head PFH is formed of a collet CLT and a collet holder CLH that holds the collet CLT. The collet CLT is formed of an elastic material, and in the first embodiment, the elastic material can withstand heat without being melted even at a temperature (for example, about 270 ° C.) at the time of thermocompression bonding of the adhesive film 14. Rubber can be exemplified. An opening KKB is provided on the lower surface of the collet holder CLH, and the collet holder CLH holds the collet CLT by bending and fitting the collet CLT into the opening KKB. That is, the plane size of the opening KKB on the lower surface of the collet holder CLH is formed smaller than the plane size of the collet CLT. By such fitting, the lower surface of the collet CLT (the suction surface of the adhesive film 14) becomes a spherical shape having a convex curvature (first curvature) toward the wiring board 11. That is, since the lower surface of the spherical collet CLT having such a convex curvature (the adsorbing surface of the adhesive film 14) is not produced by special processing, the collet CLT itself is supplied in a short period of time and at a low price. It becomes possible. Further, the collet holder CLH is provided with a suction hole KIK1 that communicates with the opening KKB, and the collet CLT is provided with a suction hole (suction hole) KIK2 that penetrates the front and back surfaces. A gap SKM is formed between the collet holder CLH and the collet CLT by bending and fitting the collet CLT into the KKB. A vacuum is supplied to the lower surface (adhesion surface of the adhesive film 14) of the collet CLT through the suction holes KIK1, the gap SKM, and the suction hole KIK2, and the adhesive film 14 can be vacuum-adsorbed to the lower surface of the collet CLT.

  12 to 15 are cross-sectional views of main parts sequentially illustrating the movement of the preform head PFH during the process of thermocompression bonding the adhesive film 14.

  The preform head PFH held by vacuum-adsorbing the adhesive film 14 on the lower surface (adhesive surface of the adhesive film 14) of the collet CLT is lowered toward the chip 1C mounted on the wiring board 11 (see FIG. 12). When the adhesive film 14 comes into contact with the chip 1C mounted on the wiring substrate 11, the vacuum suction of the adhesive film 14 is released (see FIG. 13). As described above, the lower surface (adhesive surface of the adhesive film 14) of the collet CLT has a spherical shape with a convex curvature toward the lower side, and the collet CLT itself has elasticity. By lowering the head PFH, a load due to contact with the chip 1C is applied to the lower surface (adhesive surface of the adhesive film 14) of the collet CLT in order from the center toward the outer periphery on the plane, and the shape of the upper surface of the chip 1C is increased. Follow and flatten. At this time, the adhesive film 14 positioned between the collet CLT and the chip 1C also receives a load due to contact with the chip 1C in order from the center toward the outer periphery in the plane, and follows the shape of the upper surface of the chip 1C. It becomes flat. Thereby, even when bubbles (voids) exist between the adhesive film 14 and the chip 1C, the bubbles are pushed out from the center of the adhesive film 14 toward the outer periphery in a plane as the preform head PFH descends. Finally, it is deaerated from the outer periphery of the adhesive film 14 to the outside (see FIG. 14). Then, the entire surface of the lower surface of the collet CLT (adhesion surface of the adhesive film 14) becomes flat following the shape of the upper surface of the chip 1C, and the adhesive film 14 can be pressed by the entire surface of the lower surface of the collet CLT (adsorption surface of the adhesive film 14). Until then, the lowering of the preform head PFH is stopped, and the adhesive film 14 is subjected to thermocompression bonding. By performing thermocompression bonding of the adhesive film 14 by such a method, it is possible to prevent bubbles (voids) from remaining between the adhesive film 14 after thermocompression bonding and the chip 1C.

  By the way, if the suction hole KIK2 is opened at the center on the lower surface of the collet CLT, when a slight vacuum remains in the suction hole KIK2 when the adhesive film 14 and the chip 1C start to contact, Even if the lower surface of the collet CLT (adhesion surface of the adhesive film 14) is gradually flattened from the center following the shape of the upper surface of the chip 1C, air bubbles (voids) remain between the adhesive film 14 and the chip 1C. There is a risk of it. On the other hand, in the first embodiment, as described above, since the suction hole KIK2 is opened at a position relatively close to the outer periphery on the lower surface of the collet CLT, a slight vacuum state remains in the suction hole KIK2. However, by gradually flattening from the center of the lower surface of the collet CLT, the collet CLT can be reliably pushed toward the outer periphery even under the suction hole KIK2. That is, it is possible to reliably prevent bubbles (voids) from remaining between the adhesive film 14 after thermocompression bonding and the chip 1C.

  If air bubbles (voids) remain between the adhesive film 14 after thermocompression bonding and the chip 1 </ b> C, it is caused by heat generated when the Au wire 12 is connected or heat generated when the mold resin 17 is sealed. There is a concern that the bubbles expand and the adhesive film 14 (upper chip 1C) and lower chip 1C are peeled off. On the other hand, according to the first embodiment, it is possible to reliably prevent bubbles (voids) from remaining between the adhesive film 14 after thermocompression bonding and the chip 1C. It is possible to reliably prevent a problem that (the upper chip 1C) and the lower chip 1C are peeled off by heating.

  According to the first embodiment described above, the adhesive film 14 can be thermocompression bonded with only one preform head PFH. Thereby, it is not necessary to provide the bonder with two preform heads, a preform head for temporary pressure bonding of the adhesive film 14 and a preform head for final pressure bonding. As a result, the bonder provided with the preform head PFH of the first embodiment can be reduced in size. Further, since only one preform head PFH can be used, the bonder according to the first embodiment can be produced at a low price.

  Further, the structure of the preform head PFH of the first embodiment can also be applied to the bonding head BDH (see FIG. 9). Here, the chip 1C is easily damaged when a "bending" force is applied, but is highly resistant to the action of the "compressing" force, so the structure of the preform head PFH is bonded. When applied to the head BDH, it is necessary to flatten the lower surface of the collet CLT (adhesion surface of the adhesive film 14). As described above, since the collet CLT is formed of an elastic material, the lower surface of the collet CLT (adhesion surface of the adhesive film 14) is flattened by, for example, the opening KKB of the collet holder CLH into which the collet CLT is fitted. This can be realized by reducing at least one of the depth and the thickness of the collet CLT.

(Embodiment 2)
In the first embodiment, the adhesive film 14 is attached to the chip 1C using the preform head PFH including the collet CLT whose lower surface (adhesive surface of the adhesive film 14) has a spherical shape with a convex curvature downward. A technique for reliably preventing bubbles from remaining between the adhesive film 14 after thermocompression bonding and the chip 1C by thermocompression bonding has been described (see FIGS. 10 to 15).

  Here, even when the thermocompression bonding technique for the adhesive film 14 described in the first embodiment is used, the inventors of the present invention, if the lowering speed of the preform head PFH is too fast, It has been found that air bubbles (voids) remain between the chip 1C. This is because the collet CLT is formed of a material having elasticity, so that when there are air bubbles (voids) between the adhesive film 14 and the chip 1C, the air bubbles (voids) are degassed. This is because the collet CLT is deformed before and bubbles (voids) are trapped between the adhesive film 14 and the chip 1C while the preform head PFH is lowered.

  Further, after completion of the thermocompression bonding of the adhesive film 14, the preform head PFH is raised again, and the collet CLT is pulled away from the adhesive film 14. Since the lower surface of the collet CLT has a spherical shape with a convex curvature downward when not in contact with the chip 1C, the collet CLT has an adhesive film from the outer periphery of the plane as the preform head PFH rises. 14 is separated (see FIG. 16), and finally the plane center is separated and separated from the adhesive film 14 (see FIG. 17). Here, since the adhesive film 14 also has an adhesive force to the collet CLT, when the rising speed of the preform head PFH is too fast, the adhesive film 14 sticks to the collet CLT particularly near the center of the plane, and the chip 1C The present inventors have found that they may be peeled off.

  Therefore, in the second embodiment, air bubbles (voids) are formed between the adhesive film 14 and the chip 1C by appropriately changing the descending and rising speeds of the series of preform heads PFH during the thermocompression bonding process of the adhesive film 14. ) Is confined and the adhesive film 14 after thermocompression bonding is prevented from being peeled off from the chip 1C.

  Here, FIG. 18 shows the relationship between the time from the start of the process and the height (position) of the preform head PFH in the process of thermocompression bonding one adhesive film 14. In FIG. 18, the time when the lower surface of the collet CLT (adhesion surface of the adhesive film 14) becomes flat following the surface shape of the chip 1C is set to zero. The operation (up and down) speeds of the preform head PFH are changed in the section A, the section B, the section C, the section D, the section E, and the section F, respectively. Here, the section A is from the start of the operation of the preform head PFH until the predetermined interval from the chip 1C is reached at time T1. Section B is from time T1 to time T2 until the adhesive film 14 contacts the chip 1C. Section C is from time T2 when the adhesive film 14 starts contact with the chip 1C to time T3 when the lower surface of the collet CLT (adhesion surface of the adhesive film 14) follows the surface shape of the chip 1C and is pressed until the entire surface becomes flat. . The section D is a section in which the adhesive film 14 is thermocompression bonded until the preform head PFH stops operating at time T3 and the preform head PFH starts to rise at time T4. The section E is a section until the preform head PFH starts to rise at time T4 and the collet CLT and the adhesive film 14 are completely separated at time T5. The section F is a section from the time when the collet CLT and the adhesive film 14 are completely separated at time T5 to the time when the preform head PFH returns to the position at the start of operation at time T6.

  As shown in FIG. 18, in the sections A, B, and C where the preform head PFH descends, the descending speed of the preform head PFH in the section B is made slower than the descending speed of the preform head PFH in the section A. The lowering speed (second speed) of the preform head PFH in the section C is made slower than the lowering speed (first speed) of the preform head PFH in the section B. Further, in the sections E and F in which the preform head PFH rises, the rising speed (third speed) of the preform head PFH in the section E is changed to the rising speed (fourth speed) of the preform head PFH in the section F. Make it slower. By controlling the operation speed of the preform head PFH, air bubbles are confined between the adhesive film 14 and the chip 1C while preventing the time required for the thermocompression bonding process of the adhesive film 14 from being increased. And the adhesive film 14 after thermocompression bonding can be prevented from being peeled off from the chip 1C.

  According to the second embodiment as described above, the same effect as in the first embodiment can be obtained.

(Embodiment 3)
In the third embodiment, in the thermocompression bonding process of the adhesive film 14 using the bonder (see FIG. 9) described in the first and second embodiments, a planar image of the adhesive film 14 after the thermocompression bonding is obtained, If the adhesion state of the adhesive film 14 is determined by analyzing the planar image and a good adhesion state is not obtained, the operation speed of the preform head PFH described in the second embodiment with reference to FIG. In addition, the amount of descending is changed.

  As described with reference to FIG. 9 in the first embodiment as well, the camera head (image acquisition unit) CMH1 provided in the bonder acquires an image of the thermocompression bonding position of the adhesive film 14 on the wiring substrate 11. is there.

  In the adhesive film 14 in the image PIC acquired by the camera head CMH1, the presence of bubbles (voids) VD is confirmed in an area (second area) CA (shown with hatching) in the center of the plane. (Void) When the area of the VD is equal to or larger than a predetermined value (see FIG. 19), the operation speed of the preform head PFH is changed. As described in the second embodiment, if the lowering speed of the preform head PFH is too fast, bubbles (voids) VD remain between the adhesive film 14 and the chip 1C after the thermocompression bonding, This is because, when the raising speed of the reforming head PFH is too fast, the adhesive film 14 is stuck to the collet CLT particularly near the center of the plane and is peeled off from the chip 1C. In order to change the operation speed of the preform head PFH, first, the lowering speed of the preform head PFH in the section C described with reference to FIG. Since the operation speed of the preform head PFH is slower at the time of lowering than at the time of rising, the lowering of the lowering speed first suppresses the decrease in productivity of the semiconductor device of the third embodiment as much as possible. Can do. Next, even if the lowering speed of the preform head PFH is slowed, if bubbles VD of a predetermined area or more are confirmed in the image PIC, the cause of the formation of the bubbles VD is the preform head. Assuming that the rising speed of the PFH is present, a slowing of the rising speed of the preform head PFH is fed back to the process conditions. Thereby, it is possible to prevent the generation of bubbles in the area CA.

  In addition, in the adhesive film 14 in the image PIC acquired by the camera head CMH1, there is a bubble (void) VD in an area (first area) OA (shown with hatching) relatively near the outer periphery. If it is confirmed that the area of the bubble (void) VD is equal to or larger than a predetermined value (see FIG. 20), it is considered that the push-in amount of the preform head PFH, that is, the descending amount is insufficient. That is, since the lowering amount of the preform head PFH is insufficient, the lower surface of the collet CLT (the adsorbing surface of the adhesive film 14) does not follow the surface shape of the chip 1C particularly near the outer periphery, and the collet CLT applies the adhesive film 14 to the adhesive film 14. This is because the pressure is insufficient in the vicinity of the outer periphery of the adhesive film 14. Therefore, if the presence of bubbles VD in the region OA is confirmed, and the area of the bubbles VD is greater than or equal to a predetermined value, the lowering amount of the preform head PFH is increased. To give feedback. Thereby, it is possible to prevent the generation of bubbles in the area OA.

  In the third embodiment, the change in the operation speed and the descending amount of the preform head PFH as described above is automatically performed appropriately by a computer provided in the bonder in accordance with the generation state of bubbles (voids) VD. As a result, the operating speed and the amount of lowering of the preform head PFH can be changed without depending on the ability of the operator (operator), so that it is possible to suppress a decrease in the operating rate of the bonder. .

  According to the third embodiment as described above, the same effect as in the first and second embodiments can be obtained.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  In the above embodiment, the lower layer chip to be mounted on the wiring board is exemplified as being bonded to the wiring board by thermocompression bonding using DAF previously attached to the back surface of the chip. Then, the lower chip may be stuck on the DAF. In attaching the DAF to the wiring board, a preform head having the structure described in the above embodiment may be used. In the embodiment, the preform head is used to attach an adhesive film on the lower layer chip when the upper layer chip is mounted on the lower layer chip. In addition, as the DAF to be affixed to the wiring board, those obtained by adding an epoxy resin or the like based on an acrylic material or a silicon-based material to be processed into a film shape, those obtained by adding a thermoplastic polyimide resin as a reinforcing layer thereto, Examples thereof include those obtained by processing an Ag (silver) -containing bonding paste material into a film shape.

  The method for manufacturing a semiconductor device of the present invention can be widely applied to a manufacturing process of a semiconductor device including a step of mounting a chip via an adhesive film.

It is a perspective view of the semiconductor chip used for manufacture of the semiconductor device which is Embodiment 1 of this invention. It is a side view which shows the grinding process of a semiconductor wafer. It is a side view which shows the process of affixing a dicing tape on a semiconductor wafer. It is a side view which shows the dicing process of a semiconductor wafer. It is principal part sectional drawing in the manufacturing process of the semiconductor device which is Embodiment 1 of this invention. FIG. 2 is a fragmentary cross-sectional view of the semiconductor device during a manufacturing step following that of FIG. 1; FIG. 7 is an essential part cross sectional view of the semiconductor device during a manufacturing step following FIG. 6; FIG. 8 is a fragmentary cross-sectional view of the semiconductor device during a manufacturing step following that of FIG. 7; It is plane | planar explanatory drawing of the bonder used for manufacture of the semiconductor device which is Embodiment 1 of this invention. FIG. 10 is a bottom view of a preform head included in the bonder shown in FIG. 9. It is principal part sectional drawing of the preform head shown in FIG. It is principal part sectional drawing explaining the thermocompression bonding process of the adhesive film in the manufacturing process of the semiconductor device which is Embodiment 1 of this invention. It is principal part sectional drawing in the thermocompression bonding process of the adhesive film following FIG. It is principal part sectional drawing in the thermocompression bonding process of the adhesive film following FIG. It is principal part sectional drawing in the thermocompression bonding process of the adhesive film following FIG. It is principal part sectional drawing explaining the thermocompression bonding process of the adhesive film in the manufacturing process of the semiconductor device which is Embodiment 2 of this invention. It is principal part sectional drawing in the thermocompression bonding process of the adhesive film following FIG. It is explanatory drawing which showed the relationship between the time from the process start at the time of the thermocompression bonding process of the adhesive film in the manufacturing process of the semiconductor device which is Embodiment 2 of this invention, and the height (position) of a preform head. It is explanatory drawing of the plane image of the adhesive film acquired after the thermocompression bonding process of the adhesive film in the manufacturing process of the semiconductor device which is Embodiment 3 of this invention. It is explanatory drawing of the plane image of the adhesive film acquired after the thermocompression bonding process of the adhesive film in the manufacturing process of the semiconductor device which is Embodiment 3 of this invention.

Explanation of symbols

1C chip (first semiconductor chip)
1CA chip formation area 1W wafer 3 back grind tape 4 dicing tape 5 wafer ring 6 dicing blade 10 DAF
DESCRIPTION OF SYMBOLS 11 Wiring board 12 Au wire 13 Electrode 14 Adhesive film 15 Au wire 16 Electrode 17 Mold resin 18 Stacked package BDH Bonding head CA area | region (2nd area | region)
CLH Collet holder CLT Collet CMH1 Camera head (image acquisition means)
CMH2 Camera head FLD Frame loader FLL Frame lifter HRL Transport rail KIK1 Suction hole KIK2 Suction hole (Suction hole)
KKB opening MGL magazine loader OA area (first area)
PFH preform head (bonding jig)
PIC Image SFK Adhesive film supply section SKM Gap SSP Operation panel ULD Unloader VD Bubble
WCL Wafer cassette lifter WTL Wafer table

Claims (12)

(A) preparing a first semiconductor chip in which a semiconductor element and an integrated circuit electrically connected to the semiconductor element are formed on a main surface;
(B) preparing a thermocompression adhesive film;
(C) The adhesive film or the first semiconductor chip is held by a bonding jig including an elastic collet and a holder for holding the collet, and the adhesive film or the first semiconductor chip is pressure-bonded to a chip mounting region. The process of
Including
The holder has an opening facing the adhesive film or the first semiconductor chip during the step (c), and holds the collet by fitting the collet into the opening.
The collet protrudes from the opening of the holder and extends along the outer periphery of the suction surface having a first curvature facing the adhesive film or the first semiconductor chip during the step (c). Holding the adhesive film or the first semiconductor chip in a form along the suction surface by vacuum suction from the suction hole,
The method of manufacturing a semiconductor device, wherein the first curvature is changed between a case where the adhesive film is held and a case where the first semiconductor chip is held. In the manufacturing method of the semiconductor device according to claim 1,
The method of manufacturing a semiconductor device, wherein the suction surface of the collet is convex toward the adhesive film when the adhesive film is held, and is flat when the first semiconductor chip is held. The method of manufacturing a semiconductor device according to claim 2.
The adsorption surface of the collet is implemented by reducing at least one of the depth of the opening of the holder or the thickness of the collet in the depth direction of the opening of the holder. A method for manufacturing a semiconductor device, characterized in that: In the manufacturing method of the semiconductor device according to claim 1,
The suction surface of the collet starts to deform when the adhesive film or the first semiconductor chip comes into contact with the chip mounting region, and the chip mounting is completed when the adhesive film or the first semiconductor chip is completely crimped. A method of manufacturing a semiconductor device, wherein the semiconductor device is deformed into a shape along a surface shape of a region. In the manufacturing method of the semiconductor device according to claim 1,
The method of manufacturing a semiconductor device, wherein the collet is formed of a heat-resistant rubber that can withstand heat during pressure bonding of the adhesive film or the first semiconductor chip. In the manufacturing method of the semiconductor device according to claim 1,
The method for manufacturing a semiconductor device, wherein the chip mounting region is provided on a main surface of a second semiconductor chip die-bonded in advance before pressure bonding of the first semiconductor chip. In the manufacturing method of the semiconductor device according to claim 1,
In the step (c), the bonding jig descends toward the chip mounting area at a first speed until the adhesive film or the semiconductor chip comes into contact with the chip mounting area. While the semiconductor chip is in contact with the chip mounting area and is pushed in by a predetermined pushing amount, the semiconductor chip is lowered at a second speed slower than the first speed,
The second speed is a speed that does not leave air bubbles between the adhesive film or the semiconductor chip and the chip mounting area after the adhesive film or the semiconductor chip is pressure-bonded to the chip mounting area. A method for manufacturing a semiconductor device. In the manufacturing method of the semiconductor device according to claim 1,
In the step (c), after the adhesive film or the first semiconductor chip starts contact with the chip mounting area, the vacuum suction of the adhesive film or the first semiconductor chip by the collet is released,
After the step (c),
(D) Raising the bonding jig, separating the adhesive film or the first semiconductor chip and the collet, and raising the bonding jig;
Including
When the adhesive film is pressure-bonded to the chip mounting region in the step (c), the bonding jig is moved at a third speed until the adhesive film and the collet are separated from each other in the step (d). Rise, and after the adhesive film and the collet are separated, rise at a fourth speed faster than the third speed,
The third speed is a speed at which the adhesive film is not peeled off from the chip mounting region. (A) preparing a first semiconductor chip in which a semiconductor element and an integrated circuit electrically connected to the semiconductor element are formed on a main surface;
(B) preparing a thermocompression adhesive film;
(C) a step of holding the adhesive film by a bonding jig including an elastic collet and a holder for holding the collet, and crimping the adhesive film to a chip mounting region;
(D) After the step (c), a planar image of the adhesive film is acquired by an image acquisition unit, and a predetermined amount of bubbles is present between the adhesive film and the chip mounting region from the planar image of the adhesive film. If you have confirmed the process,
(E) In the step (d), when the presence of a predetermined amount of bubbles between the adhesive film and the chip mounting area is not confirmed from the planar image, the first semiconductor is formed on the adhesive film. Crimping the chip,
Including
The holder has an opening facing the adhesive film or the first semiconductor chip during the step (c), and holds the collet by fitting the collet into the opening.
The collet protrudes from the opening of the holder and extends along the outer periphery of the suction surface having a first curvature facing the adhesive film or the first semiconductor chip during the step (c). Holding the adhesive film or the first semiconductor chip in a form along the suction surface by vacuum suction from the suction hole,
The first curvature is changed when holding the adhesive film and when holding the first semiconductor chip,
When the bonding failure occurs in the step (d), the lowering speed of the bonding jig after the adhesive film comes into contact with the chip mounting area is decreased, and the adhesive film is bonded to the chip mounting area. Decrease in the rising speed of the bonding jig until the collet and the adhesive film are separated later, and toward the chip mounting area of the bonding jig after the adhesive film contacts the chip mounting area A method of manufacturing a semiconductor device, comprising feeding back at least one condition of an increase in the amount of pushing into the step (c). In the manufacturing method of the semiconductor device according to claim 9,
In the planar image of the adhesive film, when the presence of a predetermined amount of the bubbles is confirmed in the first region relatively close to the outer periphery of the adhesive film, the adhesive film comes into contact with the chip mounting region. A method for manufacturing a semiconductor device, comprising feeding back to the step (c) a condition for increasing the amount by which the bonding jig is pushed toward the chip mounting area. In the manufacturing method of the semiconductor device according to claim 9,
In the planar image of the adhesive film, when the presence of a predetermined amount of the bubbles is confirmed in the second region including the center of the adhesive film, the adhesive film is in contact with the chip mounting region. At least of the lowering of the lowering speed of the bonding jig and the lowering of the rising speed of the bonding jig until the collet and the adhesive film are separated after the adhesive film is pressure-bonded to the chip mounting region. One or more conditions are fed back to the step (c). A method for manufacturing a semiconductor device, comprising: In the manufacturing method of the semiconductor device according to claim 9,
The condition for reducing the lowering speed of the bonding jig after the adhesive film comes into contact with the chip mounting area is that the collet and the adhesive film are separated after the adhesive film is pressure-bonded to the chip mounting area. A method of manufacturing a semiconductor device, comprising: feeding back to the step (c) prior to a condition for reducing the ascending speed of the bonding jig.

Images