JP4428658B2 - Resin composition for mounting electronic components and method for mounting electronic components - Google Patents

Description

  The present invention relates to an electronic component mounting used for mounting an electronic component on a substrate having an opening therethrough so that a functional surface of the electronic component such as a solid-state imaging device faces the opening by a flip chip method. The present invention relates to a resin composition for use, and an electronic component mounting method using the same.

  Conventionally, as a method for mounting an electronic component such as a semiconductor element on a substrate, a chip-on-board method is often used. In this method, the electronic component is fixed on the substrate using an adhesive, and the electrode of the electronic component and the conductor layer of the substrate are connected by wire bonding.

  In recent years, there has been an increasing demand for high-density mounting of electronic components. In order to satisfy this requirement, recently, as described in Patent Documents 1 to 3, for example, a method of mounting an electronic component on a substrate by a flip chip method is also used. In this mounting method, for example, when a solid-state imaging device is used as an electronic component, a plurality of electrodes are provided around the functional surface on one surface on which the functional surface that is a light receiving surface is arranged. On the other hand, the substrate is provided with an opening through which the functional surface of the electronic component is exposed. The substrate is provided with a plurality of conductor layers exposed on one surface and connected to the electrodes of the electronic component. The electronic component is disposed such that its functional surface faces the opening of the substrate, and the electrode of the electronic component and the conductor layer of the substrate are electrically connected. Further, the electrical connection portion between the electrode and the conductor layer is sealed.

  In a method of mounting an electronic component by a flip-chip method, an electrode and a conductor layer are electrically and mechanically connected directly by metal bonding or via a conductive material such as solder, and then the electrode and the conductor layer are connected. There is a method of filling a sealing resin around the connecting portion. Hereinafter, this method is referred to as a first mounting method. In addition, in the method of mounting an electronic component by the flip chip method, a sealing resin is previously disposed around the portion of the conductor layer where the electrode is connected, and the electrode and the conductor layer are brought into contact with each other. There is a method of fixing the positional relationship between the electrode and the conductor layer by electrically connecting and curing the sealing resin. Hereinafter, this method is referred to as a second mounting method.

  Patent Document 1 describes a mounting method in which an electrode of an image pickup device and an electrode of a substrate are connected by a conductive adhesive layer such as a solder bump. The sealing of the connecting part is not described. In the mounting method described in Patent Document 1, after the connection between the electrode of the image pickup element and the electrode of the substrate, a sealing resin is filled around the connection portion, thereby providing the first mounting method.

  Patent Document 2 describes a mounting method in which a bump of a solid-state imaging device chip and a wiring pattern of a casing are connected using an anisotropic conductive resin. This mounting method is considered to correspond to the second mounting method.

  Patent Document 3 describes a method of mounting a substrate on which an imaging element and a bump are formed on a printed wiring board having an opening by the second mounting method described above. Patent Document 3 describes a technique in which a dam-shaped protrusion is provided on the periphery of the opening in order to prevent the sealing resin from flowing into the opening of the printed wiring board.

  Note that Patent Document 4 describes a thermosetting resin that has appropriate thixotropy and is suitable for connecting two wiring boards to each other.

JP 2002-51268 A JP 2003-189195 A JP 2003-209332 A JP 2004-363167 A

  In the first mounting method described above, when the electrode and the conductor layer are connected, the electrode and the conductor layer become high temperature, and as a result, an electronic component having poor heat resistance tends to become high temperature. Therefore, the first mounting method has a problem that the electrical function of the electronic component may be impaired by heat. Further, in the first mounting method, since it is necessary to fill the sealing resin in a narrow space, it is necessary to use a low-viscosity sealing resin. Therefore, the first mounting method has a problem in that the sealing resin flows onto the functional surface of the electronic component, and the optical function may be impaired when the electronic component is a solid-state imaging device. .

  In the second mounting method, when the sealing resin is cured, it is heated. However, the temperature of the sealing resin at that time is lower than the temperatures of the electrode and the conductor layer when the electrode and the conductor layer are connected in the first mounting method. Therefore, the second mounting method has an advantage that the electrical function of the electronic component is not impaired by heat. Further, the second mounting method has an advantage that the cost can be reduced because the process is simple. Further, the second mounting method has an advantage that the range of design of the sealing resin is widened because it is not necessary to lower the viscosity of the sealing resin unlike the first mounting method.

  However, also in the second mounting method, it is necessary to prevent the sealing resin from flowing onto the functional surface of the electronic component. Conventionally, this problem has not been solved by controlling the properties of the sealing resin, and the sealing resin can be formed into a film or sealed in the opening as described in Patent Document 3. This problem has been avoided by adopting a structure that prevents the inflow of water.

  Further, when the electronic component is mounted on the substrate by the second mounting method, in the sealing resin after curing, there are no voids and the fillet has a good shape without distortion, Sufficient performance in terms of sealing is required.

  However, conventionally, sufficient studies have not been made on the specific characteristics of a sealing resin suitable for mounting an electronic component on a substrate by the second mounting method.

  Therefore, conventionally, when an electronic component is mounted on a substrate by the second mounting method, for example, a highly reliable resin has been used for other purposes. However, in this case, the range of mounting conditions for obtaining sufficient performance as described above in the cured sealing resin is very narrow, and the failure occurrence rate of the cured sealing resin is high. There was a problem of becoming.

  The thermosetting resin described in Patent Document 4 has characteristics suitable for connecting two wiring boards to each other. However, this characteristic cannot be said to be suitable when an electronic component is mounted on a substrate by the second method.

  The above-described problems are not limited to the case where the solid-state imaging device is mounted by the flip chip method on the substrate having the opening that penetrates, but by the flip chip method on the substrate that has the opening that penetrates. This applies to the case where the electronic component is mounted so that the functional surface faces the opening. Examples of electronic components other than the solid-state imaging device include a light emitting device, a light receiving device, and various sensors.

  The present invention has been made in view of such problems, and an object of the present invention is to provide an electronic component such that a functional surface of the electronic component faces the opening by a flip-chip method with respect to a substrate having an opening that penetrates. A resin composition for mounting electronic components used for mounting, for mounting electronic components that does not interfere with the functions of the electronic components and can exhibit sufficient performance in terms of mounting and sealing It is in providing the resin composition and the mounting method of an electronic component using the same.

The resin composition for mounting an electronic component of the present invention is used for mounting an electronic component on a substrate having an opening that penetrates the substrate so that the functional surface of the electronic component faces the opening by a flip chip method. Is. This resin composition contains an epoxy resin and a latent curing catalyst. Further, this resin composition has a viscosity minimum value η ₀ of 1.0 × 10 ² Pa · s or more in a viscosity-temperature curve obtained by measurement with a rheometer at a temperature rising rate of 5 ° C./min. 0.0 × 10 ⁴ Pa · s or less, the temperature at which the viscosity becomes the minimum value η ₀ is in the range of 50 to 80 ° C., and the maximum in the temperature range of at least 10 ° C. in the range of 50 to 80 ° C. When the viscosity and the minimum viscosity are η _a and η _b , respectively, the value of (log ₁₀ η _a -log ₁₀ η _b ) / 10 is 0 or more and 0.05 or less, and the viscosity is 1.0 × 10 ⁵ Pa The temperature at which s is in the range of 100 to 130 ° C., and the viscosity at 30 ° C. is η ₃₀ , the value of η ₃₀ / η ₀ is 1 or more and 10 or less.

  The resin composition for mounting an electronic component of the present invention has a viscosity measured by an E-type viscometer at a temperature of 25 ° C., and a value obtained by dividing the viscosity at a rotation speed of 1 rpm by the viscosity at a rotation speed of 10 rpm is in the range of 3 to 10. It may have a value property.

  The electronic component mounting method of the present invention is a method of mounting an electronic component on a substrate having an opening therethrough so that the functional surface of the electronic component faces the opening by a flip chip method. The electronic component has an electrode arranged around the functional surface on one surface where the functional surface is arranged, and the substrate has a conductor layer exposed on one surface and connected to the electrode. .

The electronic component mounting method of the present invention includes:
On one surface of the substrate, the step of disposing the resin composition for mounting an electronic component of the present invention on a portion of the conductor layer connected to the electrode;
Placing the electronic component on the substrate such that the functional surface faces the opening and the electrode faces the conductor layer;
With the resin composition interposed between the substrate and the electronic component, the electrode and the conductor layer are brought into contact with each other, and at least one of the electrode and the conductor layer is heated to a temperature in the range of 200 to 240 ° C. While pressing the electrode and the conductor layer so that they are in close contact with each other for a time in the range of 5 to 30 seconds, the electrode and the conductor layer are connected and the resin composition is cured to form the electrode. And a heating / pressurizing step for sealing the periphery of the connection portion between the conductive layer and the conductor layer.

  According to the resin composition for mounting an electronic component of the present invention, when mounting an electronic component on a substrate having an opening that penetrates the flip-chip method so that the functional surface of the electronic component faces the opening, There is an effect that the function of the electronic component is not hindered and sufficient performance in terms of mounting and sealing can be exhibited.

  In addition, according to the electronic component mounting method of the present invention, the resin composition does not interfere with the function of the electronic component, and can exhibit sufficient performance in terms of mounting and sealing. Play.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, an electronic component mounting method according to an embodiment of the present invention will be described with reference to FIGS. This embodiment is an example in which a solid-state imaging device is used as an electronic component. 1 to 3 are explanatory views for explaining each step in the electronic component mounting method according to the present embodiment. FIG. 4 is a plan view of a solid-state imaging device including a substrate and an electronic component (solid-state imaging device).

  The electronic component mounting method according to the present embodiment is a method of mounting the solid-state imaging device 20 as an electronic component on the substrate 10. First, the board | substrate 10 and the solid-state image sensor 20 which are used in this Embodiment are demonstrated. The substrate 10 has one surface 10a and an opposite surface 10b. The substrate 10 also has an opening 11 that passes therethrough. The substrate 10 further has a plurality of conductor layers 12 exposed on one surface 10a.

  The solid-state imaging device 20 has one surface 20a and a surface 20b on the opposite side. In addition, the solid-state imaging device 20 has a functional surface (light receiving surface) 21 disposed on one surface 20a. The solid-state imaging device 20 further includes a plurality of electrodes 22 arranged around the functional surface 21 on the surface 20a. The electrode 22 is, for example, a bump. The opening 11 of the substrate 10 described above is for exposing the functional surface 21 of the solid-state imaging device 20. Further, the conductor layer 12 of the substrate 10 is connected to the electrode 22 of the solid-state imaging device 20.

  In the mounting method according to the present embodiment, first, as shown in FIG. 1, the substrate 10 has one surface 11 a facing upward and the opposite surface 11 b in contact with the upper surface of the support base 30. It is placed on the support base 30. The support base 30 has a built-in heater capable of adjusting the temperature. When the solid-state imaging device 20 is mounted on the substrate 10, the support base 30 and the substrate 10 thereon are heated so as to have a temperature in the range of 50 to 80 ° C., for example.

  Next, on one surface 10a of the substrate 10, on the portion of the conductor layer 12 that is connected to the electrode 22 of the solid-state imaging device 20, an electronic component mounting resin composition according to the present embodiment (hereinafter, The resin composition is simply referred to as a resin composition). Next, the solid-state imaging device 20 is sucked and held by the heating / pressurizing tool 40. The heating / pressurizing tool 40 incorporates a temperature-adjustable heater. Furthermore, the heating / pressurizing tool 40 can move in the vertical and horizontal directions, and can apply a load to the held solid-state imaging device 20.

  Next, as shown in FIG. 2, the heating / pressurizing tool 40 is lowered so that the functional surface 21 faces the opening 11 of the substrate 10 and the electrode 22 faces the conductor layer 12 of the substrate 10. In addition, the solid-state imaging device 20 is disposed on the substrate 10.

  Next, in a state where the resin composition 13 is interposed between the substrate 10 and the solid-state imaging device 20, the electrode 22 and the conductor layer 12 are brought into contact with each other, and at least one of the electrode 22 and the conductor layer 12 is 200 to 240. The electrode 22 and the conductor layer are heated by pressurizing the electrode 22 and the conductor layer 12 so that they are in close contact with each other for a time within a range of 5 to 30 seconds while being heated to a temperature in the range of ° C. 12 and the resin composition 13 is cured to seal the periphery of the connection portion between the electrode 22 and the conductor layer 12. This step corresponds to the heating / pressurizing step in the present invention. The heating of at least one of the electrode 22 and the conductor layer 12 is performed, for example, by heating the solid-state imaging device 20 with the heating / pressurizing tool 40.

  Through the above series of steps, as shown in FIG. 3, the solid-state imaging device 20 is mounted on the substrate 10 by a flip chip method, and a solid-state imaging device including the substrate 10 and the solid-state imaging device 20 is manufactured. In this solid-state imaging device, the functional surface 21 of the solid-state imaging device 20 is disposed so as to face the opening 11 of the substrate 10 and is exposed from the opening 11.

  According to the mounting method according to the present embodiment, the resin composition 13 is prevented from flowing onto the functional surface 21 of the solid-state imaging device 20 by using the resin composition 13 having characteristics that will be described in detail later. Can do. Moreover, according to this Embodiment, in the resin composition 13 after hardening, while being able to prevent generation | occurrence | production of a void, a well-shaped fillet can be formed. Therefore, according to the present embodiment, the resin composition 13 does not interfere with the function of the solid-state imaging device 10 and can exhibit sufficient performance in terms of mounting and sealing.

  Next, the resin composition 13 according to the present embodiment will be described in detail. This resin composition 13 contains an epoxy resin and a latent curing catalyst. In addition, the resin composition 13 satisfies the following three requirements in the viscosity-temperature curve of the resin composition 13 obtained by measurement with a rheometer at a heating rate of 5 ° C./min.

The first requirement is that the minimum value η _{0 of the} viscosity is 1.0 × 10 ² Pa · s or more and 1.0 × 10 ⁴ Pa · s or less, and the temperature at which the viscosity becomes the minimum value η ₀ is 50-80. When the maximum viscosity and the minimum viscosity in the temperature range of at least 10 ° C. in the range of 50 to 80 ° C. are η _a and η _b , respectively (log ₁₀ η _a -log ₁₀ η _b ) / 10 value is 0 or more and 0.05 or less.

The second requirement is that the temperature at which the viscosity becomes 1.0 × 10 ⁵ Pa · s is in the range of 100 to 130 ° C.

The third requirement is that the value of η ₃₀ / η ₀ is 1 or more and 10 or less when the viscosity at 30 ° C. is η ₃₀ .

  Although there is no restriction | limiting in particular as an epoxy resin used for the resin composition 13, The thing which is liquid at normal temperature (25 degreeC) is preferable. The epoxy resin that is liquid at normal temperature here is not particularly limited as long as it satisfies the requirement that it is liquid at normal temperature. Examples of the epoxy resin used in the resin composition 13 include bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol AD type epoxy resin, bisphenol F type epoxy resin, carboxylic acid glycidyl ester type epoxy resin, phenol There are novolac type epoxy resins, urethane-modified bisphenol A type epoxy resins and the like. The epoxy resin used for the resin composition 13 may be one of the resins exemplified above or a mixture of two or more. When the epoxy resin used for the resin composition 13 is a mixture of two or more kinds of resins, it is preferably in a liquid state at room temperature in a mixed state. In addition, the liquid state includes a state having some viscosity. In addition, epoxy resins that are liquid at room temperature include those that are semi-solid epoxy resins that exhibit a softening point above room temperature, melt at high temperatures, exhibit poor crystallinity at room temperature, and have fluidity . The epoxy resin preferably has a hydrolyzable chlorine content of 600 ppm or less.

  In addition, the latent curing catalyst used for the resin composition 13 is a resin composition that exhibits stability when the resin composition 13 is stored and when the resin composition 13 is at a low temperature during the mounting process of the solid-state imaging device 20. Thus, the workability in the mounting process of the solid-state imaging device 20 is improved. The latent curing catalyst here has a property of rapidly functioning as an epoxy resin curing catalyst when a specific temperature or higher is reached. There are several types of latent curing catalysts that can be used for the resin composition 13 such as a microcapsule type and an amine adduct type. Among these, it is particularly preferable to use a microcapsule type latent curing catalyst from the viewpoint of mountability and stability. The resin composition 13 may be used in combination with a plurality of types of latent curing catalysts.

Next, the 1st requirement of the resin composition 13 is demonstrated. The first requirement includes the following three requirements (1-1), (1-2), and (1-3).
(1-1) The minimum value η _{0 of the} viscosity is 1.0 × 10 ² Pa · s or more and 1.0 × 10 ⁴ Pa · s or less.
(1-2) The temperature at which the viscosity reaches the minimum value η ₀ is in the range of 50 to 80 ° C.
(1-3) When the maximum viscosity and the minimum viscosity in the temperature range of at least 10 ° C. in the range of 50 to 80 ° C. are η _a and η _b respectively, (log ₁₀ η _a -log ₁₀ η _b ) / The value of 10 is 0 or more and 0.05 or less.

The requirement (1-1) represents that the resin composition 13 has appropriate fluidity when the solid-state imaging device 20 is mounted. The minimum value η _{0 of the} viscosity is more preferably 1.0 × 10 ² Pa · s or more and 1.0 × 10 ³ Pa · s or less.

  The requirement (1-2) is that the resin composition 13 has very high stability when stored at room temperature (25 ° C.), and the temperature is in the range of 50 to 80 ° C. when the solid-state imaging device 20 is mounted. This indicates that the fluidity is increased when heated to a high temperature.

The requirement (1-3) is that when the resin composition 13 is heated when the solid-state imaging device 20 is mounted, the temperature rising rate of the resin composition 13 is within a range of 50 to 80 ° C., for example, When the temperature is 5 ° C./min, the viscosity is almost constant for at least 2 minutes. This indicates that there is a time for bubbles generated in the resin composition 13 during mounting to move through the resin composition 13 and be discharged to the outside. The value of (log ₁₀ η _a -log ₁₀ η _b ) / 10 is more preferably 0 or more and 0.02 or less. Moreover, it is more preferable that the temperature at which the viscosity becomes the minimum value η ₀ is included in the temperature range of 10 ° C. in the requirement (1-3).

  When the resin composition 13 satisfies the first requirement including the requirements (1-1), (1-2), and (1-3), the resin composition 13 has a stability during storage and a solid-state imaging device. 20 satisfies the moderate fluidity at the time of mounting 20 and the ease of air bubble removal at the time of mounting the solid-state imaging device 20.

The 2nd requirement expresses that resin composition 13 stops showing fluidity at the temperature within the range of 100-130 ° C. This means that the mounting of the solid-state imaging device 20 on the substrate 10 is almost completed at a temperature in the range of 100 to 130 ° C. The temperature at which the viscosity is 1.0 × 10 ⁵ Pa · s is more preferably in the range of 100 to 110 ° C. so that conditions more suitable for mounting of the solid-state imaging device 20 can be set. A viscosity of 1.0 × 10 ⁵ Pa · s does not mean that the curing reaction of the resin composition 13 has been completed.

The value of η ₃₀ / η ₀ in the third requirement relates to the flow characteristics of the resin composition 13, and the smaller this value is, the more the resin composition 13 flows into the functional surface 21 of the solid-state imaging device 20. It becomes easy. Therefore, the value of η ₃₀ / η ₀ is preferably 1 or more and 10 or less, more preferably 1 or more and 5 or less, as in the third requirement.

The resin composition 13 further has a viscosity increase starting point within the range of 80 to 90 ° C. in the viscosity-temperature curve of the resin composition 13 obtained by measurement with a rheometer at a temperature rising rate of 5 ° C./min. Preferably there is. Here, the starting point of the viscosity increase is a temperature equal to or higher than the temperature at which the viscosity becomes the minimum value η _0, and the maximum viscosity and the minimum viscosity in a temperature range of at least 10 ° C. are η _c and η _d , respectively. The temperature at which the value of (log ₁₀ η _c -log ₁₀ η _d ) / 10 first shows a continuous viscosity increase slope exceeding 0.05. If the starting point of the viscosity increase is lower than 80 ° C., a step of completing the curing of the resin composition 13 is required after a series of steps in the mounting method of the solid-state imaging device 20 according to the present embodiment.

  The parameters in the above first to third requirements depend on the skeleton structure of the epoxy resin and the type of the latent curing catalyst. Therefore, the design of the resin composition 13 suitable for the mounting method of the solid-state imaging device 20 according to the present embodiment is to appropriately select the epoxy resin and the latent curing catalyst so as to satisfy the first to third requirements. Is done by.

In addition, the resin composition 13 has a viscosity measured by an E-type viscometer at a temperature of 25 ° C., a value obtained by dividing the viscosity at a rotation speed of 1 rpm by the viscosity at a rotation speed of 10 rpm (hereinafter referred to as a thixo ratio). It preferably has a property of a value in the range of -10. When the thixo ratio of the resin composition 13 is less than 3, the resin composition 13 easily flows from the connection portion between the electrode 22 and the conductor layer 12 to the functional surface 21 of the solid-state imaging device 20 due to a capillary phenomenon. Moreover, when the thixo ratio of the resin composition 13 exceeds 10, it becomes difficult to apply | coat the resin composition 13 stably. Although depending on the size of the solid-state imaging device 20 and the type of the substrate 10, the thixo ratio of the resin composition 13 is more preferably a value within the range of 3 to 8, and a value within the range of 3 to 6. Most preferred.

  Further, in the resin composition 13, in addition to the epoxy resin and the latent curing catalyst, other resin components, a small amount of a surfactant, a colorant, a modifier, a curing agent, as long as the mounting property and reliability are not impaired. Additives such as accelerators and other fillers can be blended. In this case, the blending amount of components other than the epoxy resin and the latent curing catalyst is preferably limited to 15% by weight or less.

[Example]
Hereinafter, the Example in this Embodiment and the comparative example for comparing with this Example are demonstrated. First, the raw material of the resin composition in an Example and a comparative example is demonstrated. The epoxy resin A is a bisphenol A type epoxy resin (liquid, epoxy equivalent 150 g / eq). Epoxy resin B is a bisphenol F type epoxy resin (liquid, epoxy equivalent 150 g / eq). The latent curing catalyst A is NovaCure HX-3722 (trade name) (effective catalyst component 35%) manufactured by Asahi Kasei Chemicals Corporation. The latent curing catalyst B is Novacure HX-3088 (trade name) (effective catalyst component 35%) manufactured by Asahi Kasei Chemicals Corporation. Additive A is Aerosil RY-200 (trade name) manufactured by Nippon Aerosil Co., Ltd.

  The measurement of the resin composition with a rheometer was performed using a rheometer RS150L (trade name) manufactured by Haake, Germany. Moreover, the conditions in this measurement were set as follows. The control mode was a strain control mode. The amount of strain was 0.10%. The frequency was 1.000 Hz. The measurement temperature range was 30.0 to 200.0 ° C. The heating rate was 5 ° C./min.

  The resin composition was applied using a dispenser manufactured by Iwashita Engineering Co., Ltd. Moreover, the mounting of the solid-state image sensor 20 with respect to the board | substrate 10 was performed using Matsushita Electric Industrial Co., Ltd. flip chip bonder FCB-11M (brand name).

  Next, evaluation items and determination criteria for the solid-state imaging devices manufactured according to the examples and the comparative examples will be described. There are five evaluation items: [curability of resin composition], [flow of resin composition], [fillet], [temperature cycle test], and [humidity resistance test].

[Curability of resin composition]
This evaluation item uses the above-mentioned flip chip bonder FCB-11M (trade name) manufactured by Matsushita Electric Industrial Co., Ltd. to heat the solid-state image sensor 20 at 220 ° C. It is related with the aspect of hardening of the resin composition when mounted. This evaluation item was evaluated according to the following criteria.
A: Curing was completed within 60 seconds.
A: Temporary curing was possible within 60 seconds, but a step for completing the curing after mounting was necessary.
(Triangle | delta): Although temporary hardening was able to be performed within several minutes, the process of completing hardening after mounting was required.
X: Temporary curing could not be performed within several minutes.

[Pouring of resin composition]
This evaluation item relates to the degree of the resin composition flowing into the functional surface 21 of the solid-state imaging device 20. About this evaluation item, it evaluated visually by the following criteria.
(Double-circle): There was no inflow to the functional surface direction.
○: There was a flow in the vicinity of the functional surface.
Δ: Inflow until just before the function.
X: There was a flow into the functional aspect.

[Fillet]
This evaluation item relates to the shape of the fillet of the cured resin composition. About this evaluation item, it evaluated visually by the following criteria.
A: Fillet shape was good.
○: The shape of the fillet was distorted.
(Triangle | delta): The shape of the fillet was distorted and the void was generated in the fillet.
X: The fillet was incomplete.

[Temperature cycle test]
This evaluation item relates to a result of a temperature cycle test performed on the solid-state imaging device in a temperature range of −40 ° C. to 85 ° C. This evaluation item was evaluated according to the following criteria.
A: Connection failure occurrence time exceeded 1000 cycles.
○: Connection failure occurred between 501 and 1000 cycles.
Δ: Connection failure occurred between 250 and 500 cycles.
X: Connection failure occurrence time was less than 250 cycles.

[Moisture resistance test]
This evaluation item relates to a result of a moisture resistance test performed on the solid-state imaging device under conditions of a temperature of 85 ° C. and a humidity of 85%. This evaluation item was evaluated according to the following criteria.
○: Connection failure occurred for over 1000 hours.
Δ: Connection failure occurred between 500 and 1000 hours.
X: Connection failure occurrence time was less than 500 hours.

  Next, the resin composition in an Example and the 1st and 2nd comparative example is demonstrated. The resin compositions in the examples were prepared by mixing 50 parts by weight of latent curing catalyst A and 9 parts by weight of additive A with respect to an epoxy resin composed of 50 parts by weight of epoxy resin A and 50 parts by weight of epoxy resin B. Manufactured. The resin composition in the first comparative example is composed of 50 parts by weight of latent curing catalyst A and 4 parts by weight of additive A with respect to an epoxy resin composed of 50 parts by weight of epoxy resin A and 50 parts by weight of epoxy resin B. Partially mixed to produce. The resin composition in the second comparative example is 50 parts by weight of the latent curing catalyst B and 9 parts by weight of the additive A with respect to the epoxy resin composed of 50 parts by weight of the epoxy resin A and 50 parts by weight of the epoxy resin B. Partially mixed to produce.

  In any of the examples and the first and second comparative examples, the solid-state imaging device 20 was mounted on the substrate 10 by the mounting method under the following conditions to manufacture a solid-state imaging device. As the substrate 10, a flexible wiring substrate constituted by forming a conductor layer 12 of a 12 μm thick copper foil on a 25 μm thick polyimide film was used. In this mounting method, first, the substrate 10 has one surface 11a on which the conductor layer 12 is disposed on the support base 30 of the flip chip bonder FCB-11M (trade name) manufactured by Matsushita Electric Industrial Co., Ltd. It was placed so that it faced up. Next, on the one surface 10a of the substrate 10 at room temperature, a resin composition is dispensed on the portion of the conductor layer 12 connected to the electrode 22 of the solid-state imaging device 20, and dispenser manufactured by Iwashita Engineering Co., Ltd. It arrange | positioned by apply | coating using. Next, the solid-state imaging device 20 was disposed on the substrate 10 such that the functional surface 21 faces the opening 11 of the substrate 10 and the electrode 22 faces the conductor layer 12 of the substrate 10. Next, in a state where the resin composition is interposed between the substrate 10 and the solid-state imaging device 20, the electrode 22 and the conductor layer 12 are brought into contact with each other, and the electrode 22 and the conductor layer 12 are in close contact with each other. Pressurized as follows. The pressure at this time was 40 g per electrode 22. The pressing time was 30 seconds. At this time, the electrode 22, the conductor layer 12, and the resin composition were heated by heating the solid-state imaging device 20 at a constant temperature of 240 ° C. In this way, the electrode 22 and the conductor layer 12 were connected, and the resin composition 13 was cured.

  The compositions of the resin compositions in the examples and the first and second comparative examples and the evaluation results for each of the aforementioned evaluation items are shown in the following table.

  Moreover, the viscosity-temperature curve of the resin composition in an Example is shown in FIG. 5, the viscosity-temperature curve of the resin composition in a 1st comparative example is shown in FIG. 6, and the viscosity of the resin composition in a 2nd comparative example A temperature curve is shown in FIG.

  As shown in FIG. 5, the resin compositions in the examples satisfy all the first to third requirements. And the evaluation result of each evaluation item in an Example was all favorable.

  As shown in FIG. 6, the resin composition in the first comparative example does not satisfy the first requirement. And the evaluation result of each evaluation item in a 1st comparative example was inferior to the evaluation result in an Example in items other than sclerosis | hardenability of a resin composition. In particular, in the first comparative example, the evaluation results of the flow of the resin composition, the temperature cycle test, and the moisture resistance test were poor. In addition, voids were generated in the cured resin composition in the first comparative example.

  As shown in FIG. 7, the resin composition in the second comparative example does not satisfy the second requirement. And in the evaluation result of each evaluation item in the second comparative example, the curability of the resin composition was inferior. Therefore, in the second comparative example, the resin composition was not temporarily cured under the above-described mounting conditions in which the pressurization time was 30 seconds, and the process of completing the curing after mounting could not be performed.

  As described above, according to the present embodiment, it is possible to prevent the resin composition 13 from flowing onto the functional surface 21 of the solid-state imaging device 20, and in the cured resin composition 13, there are voids. Can be prevented, and a well-shaped fillet can be formed. Therefore, according to the present embodiment, the resin composition 13 does not interfere with the function of the solid-state imaging device 10 and can exhibit sufficient performance in terms of mounting and sealing.

  Further, according to the present embodiment, the solid-state imaging device 20 can be mounted on the substrate 10 in a simple process and in a short time.

  In addition, this invention is not limited to the said embodiment, A various change is possible. For example, in the heating / pressurizing step, at least one of the electrode and the conductor layer may be set to a temperature in the range of 200 to 240 ° C. Therefore, in the heating / pressurizing step, the substrate 10 may be heated instead of heating the solid-state imaging device 20.

  In addition, the present invention is not limited to the case where the solid-state imaging device is mounted by a flip chip method on a substrate having a penetrating opening. The present invention can be applied to all cases where the functional surface is mounted so as to face the opening. Examples of electronic components other than the solid-state imaging device include a light emitting device, a light receiving device, and various sensors.

It is explanatory drawing for demonstrating one process in the mounting method of the electronic component which concerns on one embodiment of this invention. It is explanatory drawing for demonstrating the process following the process shown in FIG. FIG. 3 is an explanatory diagram for explaining a process following the process illustrated in FIG. 2. 1 is a plan view of a solid-state imaging device including a substrate and a solid-state imaging element according to an embodiment of the present invention. It is a characteristic view which shows the viscosity-temperature curve of the resin composition in an Example. It is a characteristic view which shows the viscosity-temperature curve of the resin composition in a 1st comparative example. It is a characteristic view which shows the viscosity-temperature curve of the resin composition in a 2nd comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 11 ... Opening part, 12 ... Conductor layer, 13 ... Resin composition, 20 ... Solid-state image sensor, 21 ... Functional surface, 22 ... Electrode.

Claims (3)

A resin composition for mounting an electronic component used to mount an electronic component such that a functional surface of the electronic component faces the opening by a flip-chip method with respect to a substrate having an opening that passes therethrough,
Contains an epoxy resin and a latent curing catalyst,
In the viscosity-temperature curve obtained by measurement with a rheometer at a heating rate of 5 ° C./min,
The minimum value η _{0 of the} viscosity is 1.0 × 10 ² Pa · s or more and 1.0 × 10 ⁴ Pa · s or less,
The temperature at which the viscosity is the minimum value η ₀ is in the range of 50-80 ° C.,
When the maximum viscosity and the minimum viscosity in the temperature range of at least 10 ° C. in the range of 50 to 80 ° C. are η _a and η _b , respectively, the value of (log ₁₀ η _a −log ₁₀ η _b ) / 10 is 0. Or more and 0.05 or less,
The temperature at which the viscosity becomes 1.0 × 10 ⁵ Pa · s is in the range of 100 to 130 ° C.,
A resin composition for mounting an electronic component, wherein a value of η ₃₀ / η ₀ is 1 or more and 10 or less when the viscosity at 30 ° C. is η ₃₀ .   The electronic component mounting resin composition has a value obtained by dividing the viscosity at a rotation speed of 1 rpm by the viscosity at a rotation speed of 10 rpm with respect to the viscosity measured by an E-type viscometer at a temperature of 25 ° C. The resin composition for mounting an electronic component according to claim 1, wherein the resin composition has the following properties. A method of mounting an electronic component on a substrate having an opening penetrating by a flip chip method so that a functional surface of the electronic component faces the opening,
The electronic component has an electrode disposed around the functional surface on one surface where the functional surface is disposed, and the substrate is exposed on one surface and is a conductor layer connected to the electrode. And the method comprises:
The step of disposing the resin composition according to claim 1 or 2 on a part of the conductor layer connected to the electrode on one surface of the substrate;
Disposing the electronic component on the substrate so that the functional surface faces the opening and the electrode faces the conductor layer;
In a state where the resin composition is interposed between the substrate and the electronic component, the electrode and the conductor layer are brought into contact with each other, and at least one of the electrode and the conductor layer is brought to a temperature within a range of 200 to 240 ° C. The electrode and the conductor layer are connected to each other by pressurizing the electrode and the conductor layer so that they are in close contact with each other for a time within a range of 5 to 30 seconds while being heated. A method for mounting an electronic component, comprising: a heating / pressurizing step for curing the composition and sealing a periphery of a connection portion between the electrode and the conductor layer.

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