JP2010199190A - Bonding method and device manufacturing method - Google Patents

Abstract

It is possible to perform bonding at low cost in a short time without uneven load while keeping the pressure applied to each bonding member constant while a plurality of bonding members are closely adjacent to each other on a substrate.
A curable substance having an elastic modulus A is placed on the surface of a plurality of joining members. The curable substance 7 is deformed or elastically deformed by the pressing jig 5, and the surface opposite to the surface in contact with each curable material 7 (surface on the joining member 2 side) is made flat. After the curable material 7 is cured to an elastic modulus B (B> A) by UV or heat, the surface opposite to the surface in contact with each curable material 7 is pressurized and heated by the pressure jig 5. Then, the substrate 1 is pushed in the direction of the substrate 1 to bond the bonding portion 3 of the substrate 1 and the bonding member 2 together.
[Selection] Figure 6

Description

  The present invention relates to a bonding method for bonding a plurality of bonding members respectively bonded to a plurality of electrodes provided on a substrate while applying pressure by a pressurizing unit, and a device manufacturing method using the bonding method.

  Conventionally, when a bonding method that requires a pressing force is adopted, a plurality of substrates and a plurality of bonding members are divided in advance and arranged in a tray, or expanded after dicing from a wafer state The process of picking up the product from the bottom of the dicing sheet, and the process of recognizing the attitude and position of each board based on the camera image, or grasping the attitude of each board by laser or pressing Go through.

  The surfaces to be joined are held in a state of facing each other, and when high accuracy is required, the posture is further controlled using image recognition or the like in the facing posture, and joining is performed with a desired alignment accuracy. After joining, the product is transported to a tray or the like for storing the joined product, or is returned to the substrate supply process to repeat the operation.

  At the time of joining, solder, plating bumps, stud bumps, etc. are used to join electrically / mechanically. The bonding methods include pressure welding, ultrasonic bonding, solder bonding, and diffusion bonding.

  The pressure welding method is a method of joining by increasing the contact area on the joint surface while melting the metal or alloy at the joint while heating at the time of joining, or by causing plastic deformation or elastic deformation.

  By the way, in recent years, since higher precision is required due to the evolution of devices, an alignment correction function using a recognition camera that can detect the deviation between the substrate and the joining member with high precision is required. Further, a means for accurately operating the alignment correction value, for example, a correction operation unit having two or more axes in the X direction and the Y direction is necessary. However, in the case of a pressure welding method that requires high pressure, the pressurizing mechanism requires a highly rigid mechanism. For this reason, the correction operation unit capable of fine operation cannot withstand the applied pressure.

  In addition, since the airflow around the camera fluctuates due to heat by heating, recognition accuracy may not be obtained when high-precision alignment is required.

  Therefore, a method of manufacturing by separating the bonding process into a process of arranging with high accuracy and a process of heating and pressing to complete the bonding is actually employed.

  However, the process of heating and pressing is a process that takes more time than the process of arranging with high accuracy, and the balance of time required for the process of heating and pressing is lost. Specifically, the step of arranging with high accuracy is about 1.4 s to 6 s, whereas the step of heating and pressing is about 20 s to 60 s, which is more than three times the capacity of the step of arranging with high accuracy. Will be needed.

  Therefore, the need for a bonding method capable of simultaneously processing a plurality of pressure heating processes has been increasing.

  In some devices, a wafer-on-chip (hereinafter referred to as “WonC”) on which a chip-like product is mounted on a wafer can be an optimal mass-production method at present.

  The reason is that by using a bonding member as a wafer, simplification of handling and reduction of contamination can be expected. Specifically, when the joining member is thin with a thickness of 50 μm or less, it becomes difficult to handle by dicing into pieces, so it is better to complete the joining on the wafer in advance and increase the rigidity of the joining member before handling. It is easy, and the tact, which is the time required for production in each process, is also improved.

  In addition, when a device that dislikes providing a fine pattern or contamination on the joining member is formed, it is very difficult to handle the joining member without touching it during handling for joining. In addition, it is conceivable that contamination is generated from the impact at the time of suction or delivery from the edge portion formed into chips. For this reason, the yield of goods can be improved by bonding a board | substrate and protecting the device surface, and then separating and handling.

  For these reasons, there is a need for the development of a method that can be joined together in WonC.

Numerous inventions have been made in a method of mounting a plurality of elements, such as a method in which an indenter is fixed to a diaphragm as described in Patent Document 1, and a method as described in Patent Document 2 below. There are some which have a spring component in each support part. Further, as described in Patent Document 3, there is also known a method in which a sheet-like elastic body is sandwiched and heated under pressure.
JP-A-6-302945 Japanese Patent Laid-Open No. 2005-219065 Japanese Patent No. 4001341

  However, in the conventional technique, in the method described in Patent Document 1, when several tens of thousands of joining members are pressurized and heated all at once, the number of indenters increases and the cost increases. In addition, in order to freely move the diaphragm, it is necessary to increase the width between the joining members, and it is necessary to take a distance between adjacent devices in the wafer-like substrate, which increases the cost of the substrate. is there.

  In the method described in Patent Document 2, since the support portion includes a spring component, it is effective when the substrate on the chip and the bonding member are bonded, but in the case where the substrate is a wafer-like collective substrate like WonC. Cannot expect the desired effect.

  In the method described in Patent Document 3, the amount of deformation of the elastic body becomes nonuniform on the joining member, the applied pressure changes in the joining member, and the applied pressure applied to the joined portion is not uniform. In addition, similarly to Patent Document 1, a narrowly adjacent joining member is affected by the amount of deformation caused by the adjacent joining member, and there is a problem that the applied pressure is not uniform.

  FIG. 7 is a diagram showing an initial state of bonding in the conventional method described in Patent Document 3, wherein 1 is a substrate, 2 is a bonding member as various components, 3 is a bonding portion such as an electrode on the substrate 1, and 5 is The pressure jig 6 is an elastic body, and the bonding member 2 is pressed against the bonding portion 3 on the substrate 1 by the pressure jig 5 through the elastic body 6, and the bonding member 3 and the bonding portion 2 are Join.

  In this conventional method, at the time of joining, since the posture of the joining member 2 varies as shown in the figure, the elastic body 6 is partially abutted, and the elastic body 6 is deformed at the abutting portion, whereby the elastic body 6 is deformed. However, the contact area with the joining member 2 is increased, and the pressurization and joining by the pressurizing jig 5 are stabilized.

  However, as shown in FIG. 8 showing the state at the end of joining, as the deformation of the elastic body 6 progresses, the reaction force in the deformed portion increases, and there is a point where the deformation does not proceed further. If the deformation does not proceed, only a part of the joining member 2 is pressurized, and a uniform load cannot be applied to the joining member 2. Moreover, the deformation | transformation of the adjacent joining member 2 affects the contact to the elastic body 6 of the adjacent joining member 2, and a contact area will decrease.

  In this way, when a plurality of joining members 2 are joined while the contact area is undetermined, the applied pressure depends on the contact area, so that the variation in the contact area remains as it is for each joining member 2. This results in variations in the applied pressure, resulting in the joining member 2 having insufficient joining force. For example, the elastic body 6 is deformed and pressure is applied to the joining portion 3 in the A portion in FIG. 8, but the elastic body 6 is separated from the joining member 2 in the joining portion 3 in the B portion. Sufficient pressure is not applied.

  The present invention solves the above-described conventional problems, and in a state where a plurality of joining members are closely adjacent to each other on a substrate, joining is performed at a low cost in a short time without uneven load while keeping the pressing force of each joining member constant. An object is to provide a bonding method and a device manufacturing method that can be performed.

  In order to achieve the above object, according to the present invention, a plurality of bonding members respectively bonded to the plurality of bonding portions are pressed against a substrate having a plurality of bonding portions on a surface by a single pressure member. In the bonding step, an elastic member having an elastic modulus A is provided on the surface of the bonding member opposite to the surface facing the substrate, and after the elastic member comes into contact with the pressure member, the elastic member has an elastic modulus. The elastic member is cured to an elastic modulus B larger than A, and after the curing, the joining member is pressurized by the pressure member via the elastic member, and the joining member is joined to the joining portion.

  For this reason, when pressurizing a joining member via an elastic member by a pressurizing member and joining it to a joint portion, after the elastic member comes into contact with the pressurizing member, the elastic member is cured, whereby each pressurizing member Since it is possible to pressurize the joining member with a desired pressure without uneven load, it is possible to suppress insufficient joining and strength reduction due to uneven load.

  According to the present invention, when each joining member is pressurized by one pressure member via the elastic member and joined to the plurality of joints, after the elastic member contacts the pressure member, the elastic modulus of the elastic member By increasing the length of the elastic member, unnecessary deformation in the elastic member can be eliminated, so that the pressure bonding by the pressure member performed through the elastic member is surely performed, and the shortage of bonding and the decrease in strength are suppressed. The desired bonding strength can be obtained. And since the said pressurization joining is performed by one pressurization member, it becomes possible to perform a pressurization joining process in a short time cheaply.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, members corresponding to those described in FIGS. 7 and 8 are denoted by the same reference numerals.

  1-3 is explanatory drawing which shows the principal part of the member used for embodiment of the joining method which concerns on this invention.

  FIG. 1 is a plan view of a substrate used in this embodiment, and shows an example in which a bonding portion 2 is formed on a substrate 1. The substrate 1 is a wafer-like collective substrate, and a pattern formed by a thin film and a structure made by wet etching, dry etching, sputtering, vapor deposition, or the like are provided outside the joint portion 3.

  Examples of the joint 3 include adhesives that are cured by heat, UV light, and the like, protrusions by soldering, metal plating, and the like. In this example, protrusions such as electrodes by gold plating are used. The joint 3 may be formed by an adhesive, or in the case of solder, using a printing method.

  FIG. 2 is a view showing a state where the bonding member 2 is mounted with high precision alignment on the substrate 1 of FIG.

  A slight load is applied to the bonding portion 3 of the substrate 1 during the alignment, and it is deformed to cause a tack force (adhesive force) or a partial bonding, and the posture of the bonding member 2 is maintained unless an external force is applied. Is done. Moreover, the joining member 2 is in a disjointed posture due to the variation in the height of the joining portion 3 regardless of the joining member 2 in which the posture of each joining member 2 is adjacent.

  FIG. 3 is a diagram illustrating an example of a bonding surface of the bonding member 2.

  The bonding pattern 4 formed on the bonding member 2 is a pattern for contact bonding with the bonding portion 3, and is formed of a material that can be easily bonded if it is an adhesive, and is also electrically conductive such as solder or metal. If necessary, the wiring pattern is used.

  The joining pattern 4 and the joining portion 3 may be formed of the same material. Further, in the present embodiment, the bonding portion 3 is formed on the substrate 1 that can be supplied in a batch, but there is no problem if it is formed on the bonding member 2 side. In this embodiment, since the sealed package is fried as an example, it is arranged in a rectangular shape and in an annular shape so that contamination cannot flow into the bonding pattern 4 after bonding.

  Although not shown, the bonding surface of the bonding member 2 is provided with a pattern formed of a thin film in addition to the bonding pattern 4 and a structure made by wet etching, dry etching, sputtering, vapor deposition, or the like.

  The features of the pressure bonding process in this embodiment will be described with reference to FIGS.

  FIG. 4 shows a state in which the curable substance 7, which is an elastic member used in the bonding method according to the present embodiment, is placed on the upper portion of the bonding member 2 (the surface opposite to the surface facing the substrate 1). The placement method of the curable substance 7 varies depending on the material of the curable substance 7, but if the adhesive has a high viscosity, a dispensing method or a printing method is appropriate. It is desirable to supply. Since the coating method can be applied in a minute amount and an accurate amount, it is considered that it is the most suitable method at present for disposing the curable substance 7.

  The height dimension of the curable material 7 must be larger than the maximum value of the inclination of the joint 2. The reason is to avoid contacting the joining member 2 before the curable substance 7 contacts the pressing jig 5.

  This is because when the bonding member 2 is contacted prior to the curable substance 7, a pressure is partially applied to the bonding member 2, and a partial load is applied to the bonding member 2. Further, it is desirable that the curable substance 7 is formed at a center position that is point-symmetric with respect to the bonding pattern of the bonding member 2. The purpose of using the curable substance 7 is to apply an equal weight to the joining member 2, because the proportion of partial weight increases when the symmetry is lost.

  Further, the curable substance 7 should not come into contact with another curable substance 7 on the joining member 2 that is narrowly adjacent. This is because when they come into contact with each other, they are affected by the reaction force, and a partial load is applied.

  When the force necessary for elastic deformation of the curable material 7 after curing is sufficiently smaller than the applied pressure necessary for deformation of the joint 3, the curable material 7 may be cured before contacting the pressure jig 5. Good. In this case, it is necessary to align the contact area due to the deformation of the crest portion of the curable substance 7. The curing method of the curable substance 7 varies depending on the material of the curable substance 7, but is generally a method of curing with heat or UV light.

  In this embodiment, after the curable substance 7 contacts the pressurizing jig 5, a method of curing the curable substance 7 with heat is adopted. Further, in the case of using a curable substance 7 that is cured by UV light instead of heat curing, the curable substance 7 is irradiated with UV light by forming the pressure jig 5 with a transparent material. Harden.

  FIG. 5 shows a state in which the curable substance 7 is cured after contacting the pressure jig 5. When the pressurization jig 5 is lowered to the position shown in FIG. 5, the pressurization jig 5 is lowered while monitoring the reaction force applied to the pressurization jig 5, and all the curable substances 7 are in contact with each other. The member 2 is stopped as long as it does not deform, and the curable material 7 is cured.

  After the curable material 7 is cured, a pressing force necessary for bonding is applied to increase the bonding force of the bonded portion.

  In this way, the joining can be completed without changing the posture of the joining member 2 as shown in FIG.

The steps of the joining process in this embodiment are summarized as follows (1) to (4).
(1) The curable substance 7 having an elastic modulus (hardness) A is placed on the surfaces of the plurality of joining members 2.
(2) The curable material 7 is deformed or elastically deformed by the pressurizing jig 5, and the surface opposite to the surface in contact with each curable material 7 (the surface on the bonding member 2 side) is made flat.
(3) The curable substance 7 is cured to an elastic modulus B by UV or heat. At this time, B> A.
(4) The pressure jig 5 pressurizes and heats the surface opposite to the surface in contact with each curable substance 7 and pushes it in the direction of the substrate 1 to bond the bonding portion 3 and the bonding member 2 of the substrate 1. .

  As the curable substance 7, a substance that can be softened again after curing (for example, a resin that hardens at a low temperature and softens at a high temperature) is provided at a contact position between the pressing jig 5 and the joining member 2. ) To (4).

  The bonding method according to the present embodiment is a bonding process when packaging a MEMS (Micro Electro Mechanical Systems) device configured by bonding a mechanical element component or an electronic circuit component to a bonding portion of a substrate as a bonding member. It is effective to implement.

  A MEMS device is a device in which mechanical component parts, sensors, actuators, and electronic circuits are integrated on a single silicon substrate, glass substrate, organic material, etc., for example, a micro switch, an acceleration sensor, an angular velocity sensor, a flow sensor. There are small microphones.

  In the present invention, desired bonding can be satisfactorily performed at a low cost in a short time. For example, in the field of device and semiconductor element mounting, MEMS mounting and packaging, room temperature bonding, etc., bonding is performed via protrusions formed by plating. In particular, if the chip-like lid-like member is applied to the wafer-like substrate by applying a predetermined load to the wafer-like substrate, mass production becomes possible.

The top view of the board | substrate used for embodiment of the joining method which concerns on this invention The figure which shows the state which the joining member was aligned and mounted on the board | substrate highly accurately in this embodiment The figure which shows an example of the joining surface of the joining member in this embodiment The figure which shows a state when providing the sclerosing | hardenable substance in the joining member in this embodiment. The figure which shows a state when hardening a curable substance in this embodiment. The figure which shows the state at the time of completion | finish of joining in this embodiment Diagram showing the initial state of bonding in the conventional method The figure which shows the state at the time of the end of joining in the conventional method

DESCRIPTION OF SYMBOLS 1 Substrate 2 Joining member 3 Joining part 4 Joining pattern 5 Pressure jig 7 Curable substance

Claims (2)

A bonding method in which a plurality of bonding members bonded to the plurality of bonding portions are bonded to a substrate provided with a plurality of bonding portions on a surface while being pressed by a single pressure member,
An elastic member having an elastic modulus A is provided on the surface of the bonding member opposite to the surface facing the substrate, and after the elastic member comes into contact with the pressure member, the elastic member has an elastic modulus larger than the elastic modulus A. A bonding method comprising: curing to B, pressurizing the bonding member via the elastic member by the pressure member after curing, and bonding the bonding member to the bonding portion.   A packaging method for a MEMS (Micro Electro Mechanical Systems) device comprising a mechanical element component or an electronic circuit component as a bonding member, and bonding the bonding member to a bonding portion of a substrate. A device manufacturing method comprising:

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