JP5928379B2 - Manufacturing method of semiconductor device - Google Patents

Description

  The present invention relates to a method for manufacturing a semiconductor device in which a part of a constituent member sealed inside a resin is exposed from the resin.

  Conventionally, a semiconductor device in which a semiconductor chip is mounted on a lead frame and a part of the lead frame is exposed from resin has been proposed (for example, see Patent Document 1).

  In such a semiconductor device, a semiconductor chip is mounted on a lead frame, the lead frame and the semiconductor chip are sealed with resin, and then the resin is irradiated with a laser so that a part of the lead frame is exposed and removed. It is manufactured by.

JP2011-258680A

  In recent years, it has been desired to shorten the lead time by shortening the time for removing the resin.

  For this reason, in the case of exposing a part of the constituent member sealed inside the resin in Japanese Patent Application No. 2011-263800, the present applicant has a wavelength in which the resin has a higher absorption rate than the constituent member. It is proposed to irradiate. According to this, even if the removal efficiency of the resin is improved by increasing the energy of the laser, the constituent member hardly absorbs the laser (because the laser transmits), so that the resin is not damaged without damaging the constituent member. It can be removed efficiently. That is, the time for removing the resin can be shortened without damaging the constituent members.

  However, even in such a manufacturing method, if the energy of the laser is increased too much, the component member hardly absorbs the laser beam but absorbs it somewhat, and the component member may be damaged.

  In the above description, the case where a part of the lead frame (component) is exposed from the resin has been described. However, for example, the case where the laser is irradiated to expose a part of the semiconductor chip (component) from the resin is also described. A similar problem occurs.

  An object of the present invention is to provide a method of manufacturing a semiconductor device that can shorten the time for removing the resin without damaging the constituent members.

  In order to achieve the above-mentioned object, in the invention according to claim 1, the step of sealing the constituent member (10) having the one surface (11) with the resin (20) and irradiating the resin with the laser (L) And a removing step of removing the resin so that a part of the constituent member is exposed. In the method of manufacturing a semiconductor device, in the resin removing step, the resin has a wavelength that has a higher absorption rate than the constituent member. In the region formed by the laser that has been condensed by the condenser lens (60) and passed through the condenser lens, the region having energy that damages the constituent members is smaller than the energy of the first region (L1) and the first region. When the region having energy is the second region (L2), the resin is removed by irradiating only the resin to the first region.

  According to this, the first region having a large energy that damages the constituent member is formed by condensing the laser with the condensing lens, and the first region is removed by irradiating the resin. For this reason, the time for removing the resin can be shortened.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

1 is a plan view of a semiconductor device according to a first embodiment of the present invention. It is a schematic sectional drawing in alignment with the II-II line | wire in FIG. It is a top view which shows the manufacturing process of the semiconductor device in 1st Embodiment of this invention. It is sectional drawing which shows the manufacturing process of the semiconductor device in 1st Embodiment of this invention. It is a schematic diagram which shows the relationship between the 1st area | region after a laser passes a condensing lens, and a 2nd area | region. It is a schematic diagram at the time of removing resin. It is a schematic diagram at the time of removing resin in 2nd Embodiment of this invention. It is a schematic diagram at the time of removing the resin in the third embodiment of the present invention. It is a schematic diagram at the time of removing resin in 4th Embodiment of this invention. It is a schematic diagram at the time of removing the resin in the fifth embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
A first embodiment of the present invention will be described. As shown in FIGS. 1 and 2, the semiconductor device of this embodiment is configured by sealing a part of a semiconductor chip 10 with a resin 20. In the present embodiment, the semiconductor chip 10 corresponds to a constituent member of the present invention.

  The semiconductor chip 10 is configured by using a rectangular plate-like silicon substrate having four side surfaces 13 to 16 that connect the front surface 11 and the back surface 12 and the end portions (end sides) of the front surface 11 and the back surface 12. In the present embodiment, the side surface on the one end 10a side in the longitudinal direction is the side surface 13, the side surface facing the side surface is the side surface 14, and the side surfaces extending from the one end 10a to the other end 10b are the side surfaces 15 and 16. In the present embodiment, the surface 11 corresponds to one aspect of the present invention.

  And the sensing part 17 which outputs the sensor signal according to physical quantity is formed in the surface 11 by the side of the other end 10b. In this embodiment, a recess 18 is formed on the back surface 12 of the semiconductor chip 10 by anisotropic etching or the like, and the sensing portion 17 is formed using a thin diaphragm 19 constituted by the recess 18. That is, the semiconductor chip 10 of the present embodiment is a pressure sensor used for the diaphragm 19 to perform pressure detection, a thermal flow sensor in which a thermal flow element is formed on the diaphragm 19, or the like.

Further, the semiconductor chip 10, although not shown, diffusion line and constructed by diffusing impurities, SiN, or the like protective film composed of an inorganic material such as SiO ₂ or the like is appropriately formed.

  The back surface 12 of the semiconductor chip 10 is fixed to the substrate 30 via an adhesive 40 such as an epoxy resin so that the other end 10b side where the sensing unit 17 is formed protrudes. The substrate 30 includes a lead frame in which a metal such as Cu or 42 alloy is etched or pressed, and a wiring substrate such as a printed substrate, a ceramic substrate, or a flexible substrate.

  The semiconductor chip 10 and the substrate 30 are electrically connected via a bonding wire (not shown). Although not particularly shown, a part of the substrate 30 is configured as a terminal portion.

  The semiconductor chip 10 and the substrate 30 are sealed with a resin 20 so that the other end 10b on the side where the sensing portion 17 is formed is exposed and the terminal portion is exposed. The resin 20 is a mold resin such as an epoxy resin, and is formed by a transfer molding method using a mold or the like and then removed as appropriate.

  The above is the configuration of the semiconductor device in this embodiment. Next, a method for manufacturing the semiconductor device will be described with reference to FIGS.

  First, as shown in FIG. 3A and FIG. 4A, the semiconductor chip 10 is fixed to the substrate 30 via the adhesive 40 so that the other end 10b side of the semiconductor chip 10 protrudes. Then, a resin 20 that covers the semiconductor chip 10 and the substrate 30 is formed by a transfer molding method or the like. The terminal portion of the substrate 30 may be exposed from the resin 20 during this step, or may be exposed from the resin 20 by a method similar to the method of exposing the semiconductor chip 10 described later from the resin 20. May be.

  Next, as shown in FIG. 3B and FIG. 4B, the laser L is irradiated from the normal direction to the surface 11 of the semiconductor chip 10 and shown in FIG. 3C and FIG. 4C. As described above, the semiconductor device is manufactured by removing the resin 20 that seals the other end 10b of the semiconductor chip 10 on which the sensing unit 17 is formed. In addition, when the terminal part of the board | substrate 30 is sealed by the resin 20, the terminal part is also exposed by irradiating the laser L. Below, the process of removing the resin 20 that seals the other end 10b side of the semiconductor chip 10 will be specifically described.

  As shown in FIG. 4B, a laser light source 50 that oscillates a laser L is used. As the laser light source 50, a laser L having a wavelength at which the absorption rate of the resin 20 is larger than that of the semiconductor chip 10 is used. Prepare something to oscillate. For example, the laser light source 50 oscillates a laser L having a wavelength exceeding 1 μm, such as CO2 (wavelength: about 10 μm), ErYAG (wavelength: about 3 μm), HoYAG (wavelength: about 1.5 μm), or a fiber laser. Prepare.

  On the other hand, as the semiconductor chip 10, a semiconductor chip 10 made of a material having an absorption rate of the laser L smaller than that of the resin 20 is used in accordance with the laser L. As described above, the semiconductor chip 10 of the present embodiment is configured by forming a diffusion wiring, a protective film, or the like on a silicon substrate. However, a material having a laser L absorption rate smaller than that of the resin 20 is used. Configured.

  Then, a condensing lens 60 having a curved surface is disposed between the laser light source 50 and the resin 20, and the laser L oscillated from the laser light source 50 is passed through the condensing lens 60 to the resin 20. Irradiate.

  Specifically, the laser L that has passed through the condenser lens 60 is focused near the focal point. The central portion of the region near the focal point is a region where the semiconductor chip 10 is processed because the semiconductor chip 10 hardly absorbs the laser L but the energy is too large. In other words, the central portion of the region near the focal point is a region where the semiconductor chip 10 is damaged. That is, as shown in FIG. 5, the laser L that has passed through the condenser lens 60 forms a first region L1 having energy that damages the semiconductor chip 10 in the central portion of the region near the focal point. A second region L2 having energy that does not damage the semiconductor chip 10 is formed around the first region L1.

  In FIG. 5, the direction parallel to the laser L passing through the center of the condenser lens 60 (the direction parallel to the optical axis) is the Z direction, and the distance from the focal point to the condenser lens 60 side is negative. The distance on the resin 20 side from the focal point is positive.

  For this reason, as shown in FIG. 6, the laser L is irradiated so that the first region L1 is irradiated only to the resin 20, and the resin 20 is sublimated and removed. In other words, the resin 20 is removed by irradiating the laser L so that the first region L1 does not overlap the semiconductor chip 10.

  Then, as shown in FIG. 3B, the resin L that seals the other end 10 b side of the semiconductor chip 10 is removed by scanning the laser L so that it protrudes beyond the outline of the surface 11 of the semiconductor chip 10. To do.

  Although not particularly illustrated, the condenser lens 60 can be displaced by a control device or the like, and the interval between the condenser lens 60 and the resin 20 can be appropriately changed. That is, when the laser L is also applied to the semiconductor chip 10, the position of the condenser lens 60 is changed as appropriate, so that only the second region L2 is applied to the semiconductor chip 10.

  In FIG. 6, the laser L is irradiated with the outer focus, but the laser L may be irradiated with the inner focus. That is, the energy distribution in the direction perpendicular to the laser L passing through the center of the condenser lens 60 (the direction perpendicular to the optical axis) has a larger maximum energy on the outer focus side when the distance from the focal point is equal. However, there is no particular problem even if the resin 20 is irradiated with the laser L by the inner focus.

  As described above, in this embodiment, the laser L is condensed by the condenser lens 60, and the resin 20 is irradiated with the first region L1 having a large energy that damages the semiconductor chip 10 to the resin 20. It has been removed. For this reason, the time for removing the resin 20 can be shortened. When the semiconductor chip 10 is irradiated with the laser L, the semiconductor chip 10 is not damaged because the semiconductor chip 10 is irradiated only with the second region L2.

(Second Embodiment)
A second embodiment of the present invention will be described. In this embodiment, the direction in which the laser L is irradiated is changed with respect to the first embodiment, and the other aspects are the same as those in the first embodiment, and thus the description thereof is omitted here.

  As shown in FIG. 7, in this embodiment, when removing the resin 20 by irradiating the laser L, the laser L is irradiated from a direction inclined with respect to the normal direction to the surface 11 of the semiconductor chip 10. In other words, the laser L passing through the center of the condenser lens 60 is irradiated from a direction inclined by a predetermined angle with respect to the normal direction to the surface 11 of the semiconductor chip 10. That is, the laser L is irradiated so that the optical axis is not parallel to the normal direction to the surface 11 of the semiconductor chip 10.

  According to this, the same effect as that of the first embodiment can be obtained while efficiently removing the resin 20 located at the end of the semiconductor chip 10 on the back surface 12 side.

  That is, when the laser L is condensed by the condenser lens 60, the first region L1 is formed almost symmetrically with respect to the optical axis (see FIG. 5B). When the distance from the focal point is the same, the maximum energy is larger on the outer focus side.

  For this reason, when the resin L is irradiated with the laser L with the outer focus, when the laser L is irradiated from the normal direction with respect to the front surface 11 of the semiconductor chip 10, the optical axis is made to coincide with the end on the back surface 12 side of the semiconductor chip 10. Is difficult. On the other hand, by irradiating the laser L from the direction inclined with respect to the normal direction to the surface 11 of the semiconductor chip 10, the optical axis in the vicinity of the first region L1 can be made coincident with the end portion. Therefore, the resin 20 located at the end of the semiconductor chip 10 on the back surface 12 side can also be efficiently removed. In addition, the edge part by the side of the back surface 12 of the semiconductor chip 10 is a connection part of the back surface 12 and the side surfaces 14-16.

(Third embodiment)
A third embodiment of the present invention will be described. In this embodiment, the direction in which the laser L is irradiated is changed with respect to the first embodiment, and the other aspects are the same as those in the first embodiment, and thus the description thereof is omitted here.

  As shown in FIG. 8, in this embodiment, the resin 20 is removed by irradiating the laser L from the direction normal to the side surface 14. Thus, the direction in which the laser L is irradiated is not particularly limited. By irradiating the laser L so that the first region L1 does not overlap the semiconductor chip 10, the same effects as those in the first embodiment can be obtained. Can be obtained.

  Although not particularly illustrated here, for example, the laser L may be irradiated from the normal direction to the side surfaces 15 and 16 and the back surface 12 of the semiconductor chip 10.

(Fourth embodiment)
A fourth embodiment of the present invention will be described. In this embodiment, the shape of the condensing lens 60 is changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment, and thus the description thereof is omitted here.

  As shown in FIG. 9, in this embodiment, a condenser lens 60 having a curved surface on the resin 20 side is disposed between the laser light source 50 and the resin 20.

  According to this, compared with the case where the condensing lens 60 which has a curved surface is arrange | positioned at the laser light source 50 side, the diameter of a focus becomes large, but 1st area | region L1 becomes small. For this reason, the resin 20 can be efficiently removed locally.

  Here, an example using the condensing lens 60 having a curved surface on the resin 20 side has been described. However, even when the condensing lens 60 having a curved surface on the laser light source 50 side is used, the curvature of the curved surface and the like are appropriately set. By increasing the spherical aberration, the effect of this embodiment can be obtained.

(Fifth embodiment)
A fifth embodiment of the present invention will be described. In the present embodiment, two laser light sources 50 are used with respect to the first embodiment, and the other aspects are the same as those in the first embodiment, and thus the description thereof is omitted here.

  As shown in FIG. 10, in this embodiment, two laser light sources 50 are prepared, and the laser L oscillated from each laser light source 50 passes through different condensing lenses 60 to irradiate the resin 20. . According to this, the effect similar to the said 1st Embodiment can be acquired, shortening the time which removes the resin 20 further.

(Other embodiments)
The present invention is not limited to the embodiment described above, and can be appropriately changed within the scope described in the claims.

  For example, in each of the embodiments described above, the semiconductor chip 10 may not be a silicon substrate but may be a SiC substrate, for example. As described above, even when the SiC substrate is used, the first region L1 and the second region L2 may be appropriately defined, and the laser L may be irradiated so that the first region L1 does not overlap the semiconductor chip 10.

  Further, the portion exposed from the resin 20 of the semiconductor chip 10 may not be the sensing unit 17, and may be a heat generating unit in which a power element or the like is formed, for example.

  The substrate 30 may be mounted with electronic elements other than the semiconductor chip 10, circuit chips, and the like. In such a case, the semiconductor chip 10 and these other electronic elements and circuit chips may be further connected inside the resin 20 by wire bonding or the like.

  Furthermore, although each said embodiment demonstrated as a method of exposing a part of semiconductor chip 10 sealed by the resin 20, what is sealed by the resin 20 is not limited to the semiconductor chip 10. FIG. That is, for example, the present invention can be applied when a part of the lead frame sealed with the resin 20 is exposed.

  And in each said embodiment, when changing the space | interval of the condensing lens 60 and resin 20, you may change space | interval by displacing resin 20. FIG. Further, by adjusting the position of the condenser lens 60 in advance so that the first region L1 does not overlap the semiconductor chip 10 when the laser L is scanned, the condenser lens 60 and the resin when the laser L is scanned are adjusted. The interval with 20 may be kept constant.

10 Semiconductor chip (component)
20 Resin L Laser L1 First region L2 Second region

Claims (6)

Sealing the component (10) having one surface (11) with a resin (20);
In the method of manufacturing a semiconductor device, performing a removing step of removing the resin so that a part of the constituent member is exposed by irradiating the resin with a laser (L).
In the resin removing step, the laser having a wavelength at which the resin has a larger absorption rate than the constituent member is condensed by the condenser lens (60), and the laser passing through the condenser lens is formed. When the region having energy that damages the component member is the first region (L1) and the region having energy smaller than the energy of the first region is the second region (L2), the first region is A method of manufacturing a semiconductor device, wherein the resin is removed by irradiating only the resin.   2. The method of manufacturing a semiconductor device according to claim 1, wherein, in the resin removing step, the laser is irradiated so that only the second region is irradiated on the component member.   2. The resin removing step, wherein the laser that passes through the center of the condenser lens irradiates the laser from a direction inclined by a predetermined angle with respect to a normal direction to one surface of the component member. Or the manufacturing method of the semiconductor device of 2.   3. The semiconductor device according to claim 1, wherein, in the resin removing step, the laser is irradiated from a direction perpendicular to the normal direction with respect to a normal direction to one surface of the constituent member. Production method.   5. The method of manufacturing a semiconductor device according to claim 1, wherein the condenser lens has a curved surface on the side opposite to the resin side. 6. 5. The method of manufacturing a semiconductor device according to claim 1, wherein a lens having a curved surface on the resin side is used as the condenser lens.

Images