TWI242818B - Process of mounting a passive component - Google Patents

Abstract

A process of mounting a passive component is disclosed. A hardenable ink is formed between at least two contact pads on a substrate. The hardenable ink has a height higher than the solder mask on the substrate. Next, the hardenable ink is cured to form a dam. Employing re-flow method of solder paste, a passive component is mounted to the contact pads. Flux used during the process is blocked by the dam so as not to flow cross and be remained between the contact pads.

Description

1242818 V. Description of the invention (1) ~-[Technical field to which the invention belongs] The present invention relates to a passive component bonding process, and particularly relates to a passive component bonding process to avoid improper residual flux. [Prior art] In the field of conventional semiconductor packaging, in addition to carrying two chips on a circuit substrate, if necessary, a passive component surface is bonded to the circuit substrate, such as an inductor, capacitor or Resistors, etc., are used to protect the chip or increase electrical performance. The related conventional package type S can be found in China's new patent certificate No. 244576 "chip package structure". '' However, the auxiliary agent J used in the process of bonding passive components is liable to remain under the passive components, which will not only damage the substrate, but also cause electrical disconnection / linkage in severe cases. Referring to FIG. 1, a substrate 10 suitable for a semiconductor package has an upper surface 丨 丨 On the upper surface U ^ of the substrate 10, a first pad 12 and a second pad 13 are formed and covered with Solder shield layer 1 2 =: sk). The first contact pads 12 and the second contact pads 13 are exposed in a covering layer 14 for bonding electrodes of a passive element 30. In general, 20 is first coated on the first pads 2 and the second pads 13 and then. The soldering method causes the solder paste 20 to join the two electrodes of the passive component 30 to the ^ pad 12 and the second pad 13. A flux is provided before reflow to help the solder paste 20 be soldered to the metal surfaces of the first and second pads 12 and 13. However, since there is a gap 31 between the passive component 30 and the space, and the flux is high in the high temperature state of reflow, the solder paste 20 and the flux will flow to the space. And remains on the bottom of the passive element 30 so that the flux does not

Page 6 Ϊ242818 V. Description of the invention (2) Easy to be removed. For example, after one of the current fluxes 13 diffuses, it is usually necessary to further seal the colloid to seal the post-soldering solder paste 20. When the colloid is sealed, the 31 rushes to the pad 12 and the [invention content] of the present invention. As shown in FIG. 2, after the passive component 30 is removed, a residual trace 21 is sent to the first pad 12 and the second connection phenomenon. In addition, an adhesive step is performed when the passive component 30 is bonded back to form a passive component 30 and a wafer (not shown) formed on the substrate 10. However, due to the return system, there is a considerable thermal expansion coefficient. The thermal expansion of the tin lean 20 during baking and curing will diffuse along the bottom of the passive element 30 with the flux remaining gap, so that the second and second connection The solder paste 20 on 13 bridges, causing an electrical short. The use of a hard-hardenable ink, so that the aging ink does not invent the brightener, and the substrate provided by the present invention, a first connection with the substrate in the mouth, is also disclosed, and the main purpose of the present invention is not A passive component bonding process is provided. The ink is formed between at least two pads, and then it can be matured into a dam, and its height is higher than a solder mask on the substrate. When the passive component is re-soldered, the retaining wall system is completed and can prevent the flux from flowing between the pads and remain between the passive component and the substrate. In addition, the purpose of the semiconductor package structure formed by the passive component bonding process is to provide a passive component bonding process. The solder mask layer has an opening that exposes a second pad of the substrate, the hardenable ink. The coating is applied on the open electrical layer, which is suitable for the fine-pitch micro-passive components which will leave flux. Another purpose is to provide a passive component

Page 7 1242818 V. Description of the invention (3) The surface of the passive component with the same color remaining traces is formed as a solder mask layer, and a brush is formed to form an ink-based system. Then, it is cooked into a load or similar to the solder mask layer. The color to facilitate the joining process includes: providing a substrate, a first pad, a second pad, and exposing the first pad and the second pad; and hardening ink on the upper surface of the substrate. Curing the hardenable ink between the first pad and the second pad to make the wall Uam); finally, reflowing the solder paste to the first pad and the second pad, It also provides an observation using the supporting wall, the flux according to the present invention, a solder mask layer on one of the substrates, after which, it can be printed, the hardenability is higher than the solder mask layer, and the hardenable ink-type welding is A flux for cleaning a metal surface, the flux is blocked by the retaining wall and cannot flow between the first pad and the second pad. [Embodiment] Referring to the attached drawings, the present invention will enumerate the following embodiment descriptions:-In the first specific embodiment of the present invention, as shown in Figs. 3A to "", a passive component bonding process is disclosed. First, referring to FIG. 3A, a soil plate 110 is provided. The substrate 1 10 is a circuit substrate, such as a multilayer printed circuit board or a multilayer ceramic circuit board. The substrate 11 has an upper surface m, and 2 It includes at least a dielectric layer 112, a circuit layer, a plated through hole (illustrated in the drawing), and the like. A first pad 114 and a solder mask are formed on the upper surface. Layer ii5 (soldermask), the mask layer 115 is exposed to the first pad 1 3 and the second pad 11 4, and 7 may be partially exposed or completely exposed. In this embodiment, The first contact pad 3 and the second contact 丨 丨 4 are used to join micro-pitch passive components, such as electrical 1242818 V. Description of the Invention (4), inductance, capacitance or resistance, etc. The solder mask layer 11 5 The system may have an opening til 16 (as shown in FIG. 4) to expose the first pad 113 and the second pad 114 at the same time. In addition, in this embodiment, the trace connecting the first pad 11 3 and the second pad 1 1 4 is covered and is not exposed behind the opening 116 of the solder mask layer 115, please refer to FIG. 3B, a hardenable ink 1 30 is patterned on the upper surface 1 11 of the substrate 1 10, and the hardenable ink 1 30 is located on the first pad 11 3 and the second pad 1 1 4 and higher than the solder mask layer 115. The ink 130 can be made of the same material as the solder mask layer 115 or other hardenable resin. The formation of the hardenable ink 1 3 0 can be A mask 120 is formed on the upper surface 111 of the substrate 111 in advance. The mask 120 can be a screen or a dry film, and the mask 120 can be Cover at least the first pad 1 1 3 and the first pad 11 4 and have an opening 1 2 1 to expose the substrate 1 1 〇 between the first pad 113 and the second pad 114 The upper surface ln. After that, I apply the hardenable ink i 30 to a predetermined position of the substrate by printing. In this embodiment, the hardenable ink i 30 is hardened. The ink 130 is coated in the opening 116, and the hardenable ink 130 is formed on the base electric layer 112. Next, referring to the redundant figure, before or after removing the mask 120 This ii (CUring) the hardenable ink 13〇 can be baked or matured to form a retaining wall 131 (dam). The chemical step is a necessary and important step, which is The supporting wall 1 3 1 formed by the hardenable weight can be solid and resistant to reflow temperature.

Page 9 1242818 ___ V. Description of the invention (5) It is located on the substrate 1-10. Please refer to FIGS. 3C and 4. The retaining wall 131 has a first wall surface 132 and a second wall surface 133, and the first wall surface 132 is oriented toward the first connection 11 3 'the second The wall surface 1 3 3 is facing the second connection 11 4 to facilitate blocking of the flux during the subsequent reflow step. Preferably, the retaining wall 1 3 1 has a melting point or glass transition temperature that is relatively higher than the reflow temperature, and does not flow and deform during the process of 0 {day.

Afterwards, please refer to FIGS. 3D and 3E, and solder a passive element 150 to the first pad 113 and the second pad 114 by reflow soldering. The passive element 150 has a first electrode 151 and a second electrode. The electrode 152 is bonded to the first pad 113 by a solder paste 1 40 after re-soldering, and the second electrode 152 is bonded to the second pad 114. Before performing the baking reflow, a flux, such as rosin, is provided to clean the metal surfaces of the first pad 113 and the second pad 114. The flux can be contained in the solder paste 1 40, or it can be applied by itself. Please refer to FIG. 3E again. During the refreshing process, the flux has high fluidity, but because it is hindered by the supporting wall 131, it is not allowed to connect the first connection ns and the second connection pad 11 4 The flux flows between them, so the flux does not collect at the bottom of the passive component. Preferably, the passive component bonding process of the present invention further includes a flux cleaning step. Since the flux is not hidden between the bottom of the passive component 150 and the upper surface ln of the substrate π, it is easy Cleared. Referring to FIG. 5, a destructive test can be used to remove the passive π member 150, which can be found that the generated flux traces 141 are relatively small and will not go to the substrate 1. At the first pad 113 and the Between the second pads 114

Page 10 1242818 V. Description of the invention (6) The Shanghai system is caused by the blocking effect of the retaining wall 131. Better color: Wide: The color is the same or similar to the color of the solder mask layer 115 ~ Identify the flux trace 141. Subsequently, the substrate 11 (3 series is suitable for semiconductor packaging, and M ISI ^ The upper surface 111 of the substrate 110 may be provided at least

m _ draw), and can perform another glue step, please refer to the 3F glue system is formed on the substrate 110 on the top surface 111, the seal; each seal can branch the sealed wafer, the passive component 1 50 and After re-soldering, the month is 1/0. Although the thermal expansion coefficient of the solder paste i 4 〇 after re-soldering is considerably larger than the thermal expansion coefficient of the sealing compound 160, but in the process of baking and curing the sealing compound 160, there will be no residual at the bottom of the passive component Excessive flux will not help the solder paste 14 to flow between the first pad 113 and the second pad 114 to achieve a good package quality containing passive components. According to a second specific embodiment of the present invention, FIG. 6 is a schematic cross-sectional view of a passive component soldered to a substrate. A substrate 2 has an upper surface 211 on which a first pad 2 12, a second pad 213, and a solder mask layer 214 are formed. The solder mask layer 214 exposes the first The pad 212 and the second pad 213. In this embodiment, the first pads 212 and the second pads 2 13 are solder mask-defining pads (SMD pads). After that, a retaining wall 220 formed by curing with a hardenable ink is formed on the upper surface 211 of the substrate 21 0, and the retaining wall 2 2 0 is located on the welding mask layer 2 1 4 and on the first connection. Between the pad 21 2 and the second pad 213. A solder paste 230 is formed on the first pad 21 2 and the second pad 2 13, and then the solder paste 230 is re-soldered to solder a passive Η

IMI Page 11 1242818

Page 12 V. Description of the invention (7) Element 240, the passive element 240 has a first electrode 241 and a second electrode 24 2 which are soldered to the first pad 2 1 2 and the second% pad, respectively. 2 1 3. In addition, the flux that can clean the metal surface provided during reflow is blocked by the retaining wall 220 and cannot flow between the first pad 212 and the second pad 213 to facilitate removal and not remain in the Between the passive element 24o and the board 210. The scope of protection of the present invention shall be deemed to be defined by the scope of the appended patent application. Any person who is familiar with the art and does not deviate from any changes within the scope of the scope and evaluation and target modification belongs to the present invention. Protection of the compilation.

Brief Description of the Drawings Brief Description of the Drawings Figure 1: A schematic cross-sectional view of a conventional passive component soldered to a substrate. Figure 2 is not intended to be familiar. After removing the passive component, the upper surface of the substrate is 3A to 3F. According to the first specific embodiment of the present invention, a schematic cross-sectional view of the welding process of a passive component on a substrate; Figure: Partial schematic diagram of the upper surface of the substrate before soldering according to a first embodiment of the present invention;

Figures 5 and 5: According to the first specific embodiment of the present invention, a partial schematic diagram of the upper surface of the substrate after welding and removal of the passive 7L component; and Figure 6 according to the second specific embodiment of the present invention, a passive A schematic cross-sectional view of a component freshly attached to a substrate. Brief description of the component symbols 1 〇 On the substrate 11 13 Second pad 14 Solder 20 Solder paste 21 Help 30 Passive components 31 Room 110 On the substrate 111 On 113 First pad 114 The 116 Opening 120 Cover 130 Ink 131 Block 133 Second wall surface Surface 12 First solder mask layer residual trace gap surface 112 Dielectric layer two pads 11 5 solder mask layer 121 opening wall 132 first wall surface

Page 13 1242818 1 4 1 Traces of flux residues 151 First electrode 152 Second electrode pattern Brief description 140 Solder paste 150 Passive component 1 6 0 Sealant 2 1 0 Substrate 2 1 3 Second pad 2 2 1 First Wall surface 2 4 0 Passive component 211 Upper surface 214 Solder mask layer 2 2 2 Second wall surface 241 First electrode 2 1 2 First pad 220 Retaining wall 230 Solder paste 242 Second electrode a

Page 14

Claims (1)

1242818 6. Scope of patent application [Patent for patent application 1. A passively providing a base pad, a second connection pad and the second form a second pad which can be located on the first maturation and can be re-soldered. 2. If the application of the welding mask layer is 塾 0, 一 5, 该 6, 66, Ί6, Ί6, 另 6, 该 6, Ί6, 该 6, 该 6, 该 6, 该 6, 该 6, 该 6, 该 6, 该 6, gt6, gt6, 该 6, and 66, and other 该], the components are joined together, including: a board, an upper surface of one of the substrates is formed There is a first contact layer and a solder mask layer. The solder mask layer exposes the first pad; the hardened ink is between the upper surface of the substrate and the second pad and is higher than the glow mask layer ^ The ink is hardened by the ink system so as to form a dam; and a passive component is soldered to the first pad and the passive component joining process described in item 1 of the first range, which has a The opening is used to display the bonding process of the first pad and the second connection as described in item 1 of the scope of the patent application, and the hair spray is applied on the solder mask layer. " " According to the passive component bonding process described in item 1 of the scope of the patent application, the retaining wall has a first wall surface and a second wall surface, respectively facing the cymbal pad and the second pad. According to the passive component bonding process described in item 1 of the patent application, the solder paste contains a flux component. ′. The passive component bonding process as described in item 5 of the scope of the patent application, which includes a flux cleaning step. As in the passive component bonding process described in item 1 of the patent application scope, the seed wall can resist reflow temperature without deformation or flow. Page 15 1242818 VI. Patent application scope 8. The passive component bonding process described in item 1 of the patent application scope, wherein, when the hardenable ink is formed, a mask is formed on the upper surface of the substrate, The mask covers at least the first pad and the second pad, and exposes a portion of the substrate between the first pad and the second pad. 9. The passive component joining process described in item 8 of the scope of the patent application, wherein the mask is a screen (s c r e e n). 10. The passive component bonding process according to item 8 of the scope of the patent application, wherein the mask is a dry film. 11. The passive component bonding process described in item 1 of the scope of the patent application, wherein the color of the retaining wall is the same or similar to the color of the solder mask layer. 1 2. The passive component bonding process described in item 1 of the scope of patent application, which further includes forming a colloid on the upper surface of the substrate, and the sealing system seals the passive component and the re-soldered tin. paste. 13. A semiconductor package structure comprising: a substrate having a first pad, a second pad, and a solder mask layer formed on an upper surface thereof, wherein the solder mask layer exposes at least one of the first pad At least one part of the second pad and the second pad; a dam formed by curing of the hardenable ink, which is formed on the upper surface of the substrate, and is located on the first pad and the first pad; Between two pads and higher than the solder mask layer; a passive component that is soldered to the first and second pads by means of reflow solder paste; and a wafer that is disposed on the substrate On the surface. 14. The semiconductor package structure described in item 13 of the scope of Shenyan's patent, which is 1242818 In order to reveal the semiconductor package structure described in the first pad and the second item, the substrate of the cover layer is exposed. Sixth, the solder mask layer has an opening in the scope of patent application. 15. The retaining wall is bonded to the dielectric layer by the welding as described in the patent application No. 14. 16. The semiconductor package structure according to item 13 of the scope of the patent application, wherein the retaining wall has a first wall surface and a second wall surface, respectively facing the first pad and the second pad. 17. The semiconductor package structure as described in item 3 of the scope of patent application 18, and the item 13 in the scope of patent application, wherein the color of the wall is the same as or similar to the color of the solder mask layer. 19. The semiconductor package structure described in item 13 of the scope of patent application 'further includes a colloid, which is formed on the substrate in Table Two, and the # / system seals the passive component and the wafer. : Page 17