JP2009038349A - Manufacturing method of wafer-level flip chip package using acf/ncf solution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique using an anisotropic conductive adhesive (ACA) or a non-conductive adhesive (NCA) in a semi-cured initial state in order to improve non-solder flip chip techniques. <P>SOLUTION: A wafer-level flip chip package is manufactured by steps of: applying a mixture solution 115 containing an insulating polymer resin, a curing agent, and an organic solvent onto a wafer 100 having a non-solder bump formed thereon and then drying the wafer to initialize the mixture 115 applied on the wafer 100 into a semi-cured state (B-stage); dicing the dried wafer 100 into individual chips 200; aligning the diced semiconductor chips 200 with electrodes of a substrate 300 and then applying heat and pressure to perform flip chip connection. Since an adhesive is directly coated on the wafer in a solution state and is used, shadow effects being apt to occur on a wafer surface being not flat can be prevented, and the thickness of coating is easy to control. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

    The present invention directly coats a solution of anisotropic conductive adhesive (ACA) or non-conductive adhesive (NCA) directly on a wafer. It is related with the method which can manufacture a flip chip package by doing.

    Electronic packaging technology is a very wide-ranging and diverse system manufacturing technology that includes all stages from semiconductor devices to final products, and in particular, with the rapid development of electronic products, miniaturization and weight reduction of equipment, This is a very important technology to achieve high performance. Electronic packaging technology is a very important technology that determines the performance, size, price, reliability, etc. of the final electronic product. Especially in recent electronic products pursuing electrical high performance, ultra-small / high density, low power, multi-function, ultra-high-speed signal processing, and permanent reliability, ultra-small package parts are computers, information communications, mobile communications Flip Chip technology, which is an essential part of high-end household appliances, etc., and is one of the technologies for mounting a chip on a substrate, is currently used in smart cards, LCDs, PDPs, etc. The range of use has been expanded to display packaging, computers, mobile phones, communication systems, and so on.

Such flip chip technology can be roughly divided into two types: a solder flip chip using solder and a non-solder flip chip that does not use solder. The solder flip chip has complicated connection processes such as solder flux application, chip / substrate alignment, solder bump reflow, flux removal, underfill filling and curing, and has a problem of an increase in production unit price. Therefore, recently, in order to reduce such complicated processes, non-solder flip chip technology has been greatly developed.

      A typical technique of the non-solder flip chip is a flip chip technique using ACA. The flip chip technology using the existing ACA is a process in which an ACA material is applied or temporarily bonded to a substrate, the chip and the substrate are aligned, and finally heat and pressure are applied to complete a flip chip package. However, such a process has a long process time for forming a film and applying or temporarily bonding ACA material to each substrate.

      Therefore, recently, there has been an interest in wafer level package technology in which a polymer material having functions of flux and underfill is applied and processed in a wafer state. Recently, it is cheaper than general solder flip chips, and can be used with extremely fine electrode pitches. It has advantages such as lead free, environmentally friendly fluxless process, and low temperature process. Development of a flip-chip connection technology using a conductive adhesive is ongoing.

      Adhesives used in electronic packaging are divided into film and paste forms according to their usage, and are divided into conductive, anisotropic conductive, and nonconductive depending on whether conductive particles are included or not. It is done. Therefore, adhesives used for electronic packaging are anisotropic conductive film (ACF), anisotropic conductive paste (ACP), non-conductive It is divided into a film (NCF; Non-Conductive Film, hereinafter referred to as NCF) and a non-conductive paste (NCP; Non-Conductive Paste, hereinafter referred to as NCP).

      There are significant differences between film-form adhesives (ACF, NCF) and paste-form adhesives (ACP, NCP) depending on their form and composition. First, the ACF contains an organic solvent that improves the coating property in the composition so that it can be coated in a film form. After coating in the film form, the organic solvent is dried and then commercialized. Is done.

      Unlike ACP, ACP is applied directly on a substrate by a method such as dispensing to perform a flip chip process. Therefore, ACP does not contain an organic solvent in order to prevent generation of internal bubbles. In addition, it is filled with a paste in a syringe and commercialized.

      US Pat. No. 5,323,051 (Semiconductor wafer level package) is a technique for cutting a wafer into respective chips in a wafer state or after adhering another cap wafer with a glass adhesive. This is a patent different from that in which ACA is applied and this is used for connecting a package.

      Another US Pat. No. 5,918,113 (Process for producing a semiconductor device using anisotropic conductive adhesive) electrically attaches an ACA to a substrate and then electrically contacts the semiconductor chip with the substrate by heat and pressure. Although this is a method of connection, the present invention is a very different technical method in that ACA is pre-applied to a chip formed with non-solder bumps in a wafer state.

      As literature, S.M. H. Shi et al. (Development of the Wafer Level Compressive-Flow Underfill Process and Its Required Materials, 1999, ECTC, pp.961-966) shows that the solder bump function is formed on the wafer with the solder flux function. After applying the fill material, each chip is diced and then placed on the substrate using an existing SMT assembly device. As a result, after the existing solder reflow connection, the method of introducing the underfill material between the chip and the substrate is introduced as a simplified method.

      In Korean Patent No. 361640 (a method for manufacturing a wafer type flip chip package using an applied anisotropic conductive adhesive), in the case of ACF, a lamination process method of applying heat and pressure after coating on a release paper film In the case of ACP, the method of applying on the wafer by spraying, doctor blade or meniscus method is clearly shown. Therefore, when using the film form, it is necessary to perform a lamination process in which heat and pressure are applied and a release paper are removed by positioning the film on the upper part of the wafer, and the film form of ACA or NCA is applied to the surface of the wafer which is not flat. When adhering, a shadow effect is likely to appear, and when using a paste form, it is difficult to adjust the thickness of the coating.

The present invention uses an anisotropic conductive adhesive film or a non-conductive adhesive film coated on a wafer directly in a solution state, so that the anisotropic conductive adhesive film or the non-conductive adhesive film is used. Since the process of laminating the adhesive film on the wafer and removing the release paper is unnecessary, the process is simple and the process is simple, and the coating is performed in the solution state instead of the film. It effectively suppresses the shadow effect that tends to occur on non-flat wafer surfaces, and has the advantage of being easy to adjust the coating thickness, which is difficult with anisotropic conductive adhesive pastes or non-conductive adhesive pastes. Through simple drying that volatilizes the solvent, there is an advantage that a semi-cured initial state that does not lose the curing potential can be obtained.

    The object of the present invention is to use a simple process with high productivity to effectively suppress the shadow effect that tends to occur on a non-flat wafer surface, to easily adjust the coating thickness, and to perform simple drying. Through the semi-cured initial state anisotropic conductive adhesive (ACA) or non-conductive adhesive (NCA) or NCA ) Can be obtained, and a method for manufacturing a wafer type flip chip package using ACA or NCA is provided.

    The method for producing a wafer type flip chip package of the present invention comprises: (a) applying a mixture solution containing an insulating polymer resin, a curing agent and an organic solvent on a wafer on which non-solder bumps are formed, followed by drying. A stage in which the mixture applied on the wafer is semi-cured (B-stage); (b) dicing the dried wafer into individual chips; and (c) diced into the individual chips. And aligning the semiconductor chip with the electrodes of the substrate and then applying heat and pressure to make a flip chip connection.

    The core idea of the present invention is that the material constituting an anisotropic conductive film (ACF) or non-conductive film (NCF) is not a film form. In the solution state using an organic solvent, a wafer type flip chip package is manufactured by directly coating on a wafer on which non-solder bumps are formed.

    Since the manufacturing method of the present invention based on the core idea of the present invention coats a wafer in a solution state using an organic solvent instead of a film form, the lamination process and the process of removing the release paper are not necessary, Through the method of adjusting the rheological properties, it is possible to effectively suppress the shadow effect that is likely to occur on a non-flat wafer surface, and basically use a solution containing a composition similar to that constituting ACF or NCF. Therefore, the coating thickness can be easily adjusted, and a semi-cured initial state can be obtained through simple drying that volatilizes the organic solvent.

Since the compositional characteristics of ACF and NCF are the same except for the presence or absence of conductive particles, 5 to 20 parts by weight of conductive particles are added to 100 parts by weight of the insulating polymer resin in the mixture solution. Furthermore, an ACF solution can be manufactured by adding. As the conductive particles, conductive particles usually used for ACF or ACP can be used. Preferably, gold, silver, nickel, metal-coated polymer, conductive polymer, or insulating polymer is used. Preferably coated metal particles, or a mixture thereof, more preferably gold particles, silver particles, nickel particles, gold coated polymer, silver coated polymer, nickel coated polymer, More preferably gold particles coated with an insulating polymer, silver particles coated with an insulating polymer or nickel particles coated with an insulating polymer, or a mixture thereof, most preferably nickel particles, gold coated Polymer, nickel coated Polymer or nickel particles insulating polymer coated, or, most preferably a mixture thereof.

    Hereinafter, the manufacturing method of the present invention will be described in more detail with reference to FIG. FIG. 1 is shown for easy explanation, and the present invention is not limited to FIG.

    As shown in FIGS. 1A and 1B, a wafer 100 to which a mixture solution is applied is a wafer manufactured through a general semiconductor process, and a chip 110 that is usually used is one. Input / output terminals (I / O pads 112) for electrical signal communication with the outside are formed on each chip.

    At this time, the type of the chip is not particularly limited, and for example, a display driving circuit IC, an image sensor IC, a memory IC, a non-memory IC, an ultrahigh frequency or RF IC, a semiconductor IC mainly composed of silicon, Or it is a compound semiconductor IC.

    A non-solder bump 113 is formed on the input / output terminal. The non-solder bump is a metal stud bump or a metal plating bump formed by using a bonding wire bonder or a plating method, and a gold stud bump, It may be a copper stud bump, a gold plated bump, a copper plated bump, an electroless nickel / gold bump or an electroless nickel / copper / gold bump, and the upper portion of the wafer on which the non-solder bump is not formed is passivated with an insulating material 114. It is normal to be (passivation).

    As shown in FIG. 1 (c), the ACF or NCF mixture solution was formed into non-solder bumps of the wafer by spraying, doctor blade, meniscus, spin coating, screen printing, stencil printing, or comma roll coating. It is applied to the upper part of the surface. The wafer to which the mixture is applied is dried at 70 to 80 ° C. for 1 to 4 minutes to volatilize the organic solvent, and through the drying, the applied mixture 115 passes through an uncured state (A-stage) that is easy to flow. When it is heated, it has a physical property that can be operated while maintaining its form at room temperature, and when heated, it enters a semi-cured initial state (B-stage) that has fluidity. The meaning of the semi-curing initial state is a curing initial state that does not lose the potential for the curing reaction to occur only at a specific high temperature or higher, even in the semi-curing state from the time when the curing starts to the time when the curing ends. The dried mixture has curing properties that can be cured at 180-200 ° C. within 10-30 seconds.

    At this time, the thickness of the applied mixture is preferably 10 to 100 μm after the drying. This is because, within the above range, the physical adhesive force necessary for flip chip connection can be obtained, the shadow effect is minimized, and electrical insulation and electrical connection are smoothly performed on the chip. is there.

    The wafer to which the mixture is applied is mounted on a wafer dicing machine, and diced into individual chips 200 of symbol 200 shown in FIG. 1 (d) with reference to the scribe line of the wafer. The diced individual chip 200 can be used as one flip chip package because it is similar to the case where semi-cured ACF or NCF is bonded. After the individual chips are arranged with the electrodes 310 of the substrate 300, a flip chip bonder is used to apply heat and pressure to cure the mixture, so that the individual chips and the substrate are physically and electrically connected. A flip chip assembly can be obtained.

    As mentioned above, the core idea of the present invention is that ACF or NCF is manufactured in solution form, not in film form, and coated directly on the wafer, so that the mixture solution is a commonly used ACF. Alternatively, it can be prepared by mixing a substance constituting NCF and an organic solvent, and the mixture solution is 100 to 400 parts by weight of the curing agent and 50 to 200 parts by weight with respect to 100 parts by weight of the insulating polymer resin. In particular, a mixture of 120 to 375 parts by weight of a curing agent and 80 to 150 parts by weight of an organic solvent is more preferable with respect to parts by weight of the insulating polymer resin.

    The insulating polymer resin is a thermoplastic resin or a thermosetting resin, and the thermoplastic resin is an acrylic resin, a phenoxy resin or a rubber, or a mixture thereof, and the thermosetting resin is an epoxy resin. Or a polyimide resin, or a mixture thereof, and the organic solvent is preferably selected from toluene, methyl ethyl ketone, acetone, dimethylformamide, or cyclohexane, or a mixture thereof. Those selected from amine-based or mixtures thereof are preferred.

    The weight ratio of the organic solvent is such that the mixture solution containing a composition similar to that of the substance constituting ACF or NCF is coated on the surface of a wafer that is normally manufactured and dried to adhere an adhesive in the form of a film. The weight ratio of the organic solvent that determines the rheological properties of the mixture solution depends on the surface of the wafer, such as the thickness of the non-solder bumps and the number of non-solder bumps. It is preferable to adjust the degree of uniformity.

FIG. 1 (a) is a wafer, FIG. 1 (b) is a cross-sectional view taken along line AB of FIG. 1 (a), and FIG. 1 (c) is a mixture. FIG. 1D is a cross-sectional view taken along the line A-B of the wafer to which the solution is applied, and FIG. 1D is a view showing flip-chip connection of the diced individual chips.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Wafer 110 Chip on wafer 111 Semiconductor material 112 Input / output pad 113 Non-solder bump 114 Passivation layer 115 Mixed mixed solution 200 Discrete chip 300 Substrate 310 Electrical wiring on substrate

Claims (10)

(a) A mixture solution containing an insulating polymer resin, a curing agent, and an organic solvent is applied on a wafer on which non-solder bumps are formed, and then dried, so that the mixture applied on the wafer is in a semi-cured state ( (B-stage)
(b) dicing the dried wafer into individual chips;
(c) The semiconductor chip diced into the individual chips is aligned with the electrodes of the substrate, and then the chip is manufactured by applying heat and pressure to perform flip chip connection. Manufacturing method.
The flip chip package manufacturing method according to claim 1, wherein the mixture solution of step (a) further includes 5 to 20 parts by weight of conductive particles based on the weight of the insulating polymer resin. Method.
The method of claim 1, wherein the application in the step (a) is performed by spraying, doctor blade, meniscus, spin coating, screen printing, stencil printing, or comma roll coating.
Stage (a) is dried at 70 to 80 ° C. for 1 to 4 minutes to volatilize the organic solvent, and the applied mixture is subjected to a semi-cured state (B-stage) initial stage at which the curing potential is not lost. The method of manufacturing a flip chip package according to claim 1, wherein:
5. The method of claim 4, wherein the dried mixture has a curing time of 10 to 30 seconds at 180 to 200 ° C. 6.
The method of manufacturing a flip chip package according to claim 1, wherein the thickness of the mixture solution applied in step (a) is 10 to 100 m after the drying.
The mixture solution in the step (a) is a mixture of 100 to 400 parts by weight of a curing agent and 50 to 200 parts by weight of an organic solvent with respect to 100 parts by weight of the insulating polymer resin. A method of manufacturing a flip chip package according to claim 1.
The insulating polymer resin is a thermoplastic resin or a thermosetting resin, and the thermoplastic resin is an acrylic resin, a phenoxy resin or a rubber, or a mixture thereof, and the thermosetting resin is an epoxy resin. The method of manufacturing a flip chip package according to claim 7, wherein the flip chip package is a polyimide resin or a mixture thereof.
8. The method of manufacturing a flip chip package according to claim 7, wherein the organic solvent is toluene, methyl ethyl ketone, acetone, dimethylformamide or cyclohexane, or a mixture thereof.
    The conductive particles according to claim 2, wherein the conductive particles are gold, silver, nickel, a polymer coated with metal, a metal particle coated with a conductive polymer or an insulating polymer, or a mixture thereof. Manufacturing method of flip chip package.